# Waste treatment system at Gold Refinery



## 4metals (May 28, 2022)

This thread has been broken off from the Gold loss thread at Gold Refinery specifically to address the waste treatment system they have.




4metals said:


> I assume you are treating your waste with a process known as classic destruct. This involves adding caustic liquid to the acid waste until the metals. in solution are converted over to. metal hydroxides


Our classic filtration system has 4 stations with the method of adding caustic soda according to the image.
The first station has a motor mixing with the blade. In the first station we add AL.

The second station has pipe with air injection.

The third station has a motor mixer with a dosing pump to add caustic soda.

The fourth station is for final maintenance and control only.

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## 4metals (May 28, 2022)

Finally, the liquid goes by a diaphragm pump to press the filter.

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## 4metals (May 28, 2022)

4metals said:


> Our classic filtration system has 4 stations with the method of adding caustic soda according to the image.
> The first station has a motor mixing with the blade. In the first station we add AL.


It is excellent that you have a cementation tank built into your system but I question why you are choosing to use aluminum to drop your values? There are many threads on the forum about electromotive series and what metals effectively displace others in solution but for your first tank, I would be cementing with copper. If you cement with aluminum you will drop all of the copper, zinc, nickel, and any remaining gold or platinum group metals. If you cement with copper you will be dropping only Gold and Platinum group metals (and technically mercury but I doubt it's even present). This process will yield only values and some excess copper and all of the base metals will pass on to tank 2. This would also be a good place for the canister filter because any small fines pumped out of tank 1 with the liquids you want to keep. 
Tank 2 should have the pH raised slightly with soda ash and you can add scrap iron to recover all of the copper in your solutions. 
Tank 3 is where you add liquid caustic to a pH of 10. This will drop all of the metals as hydroxides. These hydroxides are collected in your filter press and the liquid from the press goes to tank 4 where you will likely need to lower the pH to discharge to sewer. 
The tank where you add caustic can actually also drop all of the metals remaining in your waste including copper if you choose to skip the iron step. If you did skip the iron step, the best use of the tank space would be to fill the first tank with waste acid and add the copper with mixing. Continue to mix until you start to fill tank 2 with the same waste to be cemented with copper. When you are getting close to filling tank 2 shut the mixer in tank 1 so it can settle overnight and test to be sure the metals have dropped. I the morning tank 1 can be pumped into tank 3 for hydroxide precipitation. By using the first 2 tanks for copper cementation you can maximize the time exposed to copper and get the best recovery. 

This is a very old thread about dealing with waste but it uses the same concepts you will use so it may be a good read. 

Dealing with Waste


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## Gold.refinery (May 29, 2022)

4metals said:


> but I question why you are choosing to use aluminum to drop your values?


Add aluminum suggested by the manufacturer.
Of course, I have to remind you that when we filter the gold in the settling tank, we transfer the mother solution to the secondary tank (this tank *is not* from waste treatment stations) and we add aluminum there. 
Copper sludge was then deposited on the bottom of the tank (as shown). Then we filtered the solution to the first waste treatment station. Most of this sludge is copper, but it also has some gold.(Approximately 5-15/1000)

Are we allowed to add this sludge to Tumblr for the next operation?
In one of the previous operations, we added that sludge to the Tumbler for the next operation. The result of the unearned gold improved in the end (6.6 / 2900 g). Not sure if this is true or not?


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## Gold.refinery (May 29, 2022)

I read your description of stations 1 to 4 several times. I did not understand some of them clearly.

Suppose we filter the solution after taking gold and we have 50 liters of solution.



4metals said:


> I would be cementing with copper.


Suppose we filter the solution after taking gold and we have 50 liters of solution.
How much copper should we add first?
(Cu powder :This copper can be obtained from previous operations with iron, right?)



4metals said:


> If you cement with copper you will be dropping only Gold and Platinum group metals


how to filter precious metals if they have precipitated?(will be very little)



4metals said:


> Tank 2 should have the pH raised slightly with soda ash and you can add scrap iron to recover all of the copper in your solutions.


Why should we raise the pH with soda ash?


4metals said:


> This would also be a good place for the canister filter because any small fines pumped out of tank 1 with the liquids you want to keep.


I do not understand what you mean by *conister*.



4metals said:


> Tank 3 is where you add liquid caustic to a pH of 10. This will drop all of the metals as hydroxides. These hydroxides are collected in your filter press and the liquid from the press goes to tank 4


By adding caustic soda we increased the pH to 8. 10 is better?
Can it be transferred to the filter press immediately after reaching pH 10 or do we have to wait a day?



4metals said:


> If you did skip the iron step, the best use of the tank space would be to fill the first tank with waste acid and add the copper with mixing.


Do you mean that if we do not want to take copper from the solution with iron, use the first and second tanks for cementing with copper for one solution. Both tanks for cementing copper with solution ??


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## nickvc (May 29, 2022)

Using copper to cement your solution will reduce the amount of sludge including values that have to be refined which saves money and time, in fact you could quickly dissolve this material separately and recover any values easily making accounting easier , by doing this we can then head backwards in the process to find where any other loses are occurring.


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## Gold.refinery (May 29, 2022)

nickvc said:


> in fact you could quickly dissolve this material separately and recover any values easily making accounting easier


You mean, after we add copper, we can calculate the total amount of gold and balance the accounting. Did I get it right?


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## nickvc (May 29, 2022)

Gold.refinery said:


> You mean, after we add copper, we can calculate the total amount of gold and balance the accounting. Did I get it right?


Yes if you use copper you will have a small amount of material to work with which could be refined or melted to confirm how much gold is there… the other point I made is if you can confirm the lose there any other loses should be before this .


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## 4metals (May 30, 2022)

Gold Refinery, I think you want to make money refining, correct? You will never do that if you go off looking for every gram of gold that doesn't come out of your process lots. As I said before, with all of your equipment issues patched up, you should be able to achieve 99.75% accountability on all lots. Then the gold that is retained in the silver chlorides is not chased for every lot, it is processed when the quantity warrants or the production schedule allows. Same is true for the dilute quantities of gold you have cemented in your waste treatment. 

The tumbler plant is not designed for low grade, low yield metallics like the cemented sludges you get from the aluminum cementing. If you use copper, it will be much more concentrated and almost exclusively precious metals in your tank. But not enough to recover from every batch. 



Gold.refinery said:


> By adding caustic soda we increased the pH to 8. 10 is better?
> Can it be transferred to the filter press immediately after reaching pH 10 or do we have to wait a day?


Depending on what metals are in your waste you select the proper pH to drop your hydroxides. pH 8 is a good starting point. If the liquid emerges from the press anything but clear, raise the pH in a bucket of water from the press slowly 0.5 pH units at a time and see if more hydroxides drop. There is a graph showing pH vs metals dropped which I will find and post here (if and when I find it). It only allows metals to redissolve if you wait too long to press it, especially if you used urea so I would press it quickly.


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## silver1 (May 30, 2022)

I seen him mention hydrogels in another post. Is he using hydrogels, caustic, both?


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## 4metals (May 30, 2022)

From this you can see that copper will be out by pH 8 but zinc and nickel around 10. also note that zinc starts to go back into solution if you go up above 10 so don't over add either.


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## orvi (May 31, 2022)

Gold.refinery said:


> Add aluminum suggested by the manufacturer.
> Of course, I have to remind you that when we filter the gold in the settling tank, we transfer the mother solution to the secondary tank (this tank *is not* from waste treatment stations) and we add aluminum there.
> Copper sludge was then deposited on the bottom of the tank (as shown). Then we filtered the solution to the first waste treatment station. Most of this sludge is copper, but it also has some gold.(Approximately 5-15/1000)
> 
> ...


As it was said, aluminium is rather unselective precipitant, if you are trying to scavenge last bits of values out of waste solutions. It will even precipitate cadmium out.

We usually use copper bars hanged into the solution, but copper powder will also work, if stirred properly and constantly. Powdered metals gave you advantage of very quick cementations, if stirred good - due to great surface area.

I sometimes encounter the need to concentrate dilute values (AuAg) - say 0,3-0,5g from 3 liters of solution. In these cases, I add like 10 grams of copper powder to the stirred solution and let it mix for like one hour. Then I filter the solution and redissolve the powder in AR.
You can also use the same principle, but stirring is necessary.

Eventually, if you add aluminium, all the nickel, copper and also the gold will precipitate. What happen next is that good portion of the less reactive metals like nickel or iron will cement out even more copper - simultaneously passing to the solution as ferric or nickel ions. Sounds good, you say, I create copper in the solution, that´s what I wanted - *but you will precipitate awful lot of metal sludge which needs to be processed AGAIN.*
Your intention is to GET RID OF THE BASE METALS, that is why you refine the gold. Not to just stick aluminium to the precipitation tank to get them back and repeating the process one more time, with values even more diluted.


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## Gold.refinery (May 31, 2022)

4metals said:


> Same is true for the dilute quantities of gold you have cemented in your waste treatment.


After the end of each operation, if we reach 99.75 incoming gold, we can hope that some gold is in the mother solution and also some gold is trapped in the silver chloride. 

It is probably wise to recover silver chloride every two weeks, but it is not possible to keep the mother solution for more than 4 or 5 days.



4metals said:


> But not enough to recover from every batch.


So what to do with these conditions?

We are currently using urea temporarily, so after seeing the metal hydroxide in, it should be transferred to the filter press immediately.right?

Finally, There we have green sludge (as shown).
What should we do to recover the precious metals of these this Hydroxides ? 
(Shall we give it to the recycling workshops we go to every month with Smelting method?)


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## Gold.refinery (May 31, 2022)

orvi said:


> I sometimes encounter the need to concentrate dilute values (AuAg) - say 0,3-0,5g from 3 liters of solution. In these cases, I add like 10 grams of copper powder to the stirred solution and let it mix for like one hour. Then I filter the solution and redissolve the powder in AR.


So we have to dissolve about 200 grams of copper powder for 50 liters of solution and we have to stir well for an hour. 
But our tanks does not have a *mixer*, unfortunately, but it has a filter at the bottom. 

The first waste water tank has a mixer but not has filter.

What should we do with these conditions?


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## FrugalRefiner (May 31, 2022)

Take a look at When In Doubt, Cement It Out. At the end of the post, you'll see a cementation rig used by one of 4metals' customers.

Dave


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## orvi (May 31, 2022)

You need to agitate somehow the solution around the copper. This will speed up the process rapidly. If you have no chance of getting mixer, forgot the powdered copper and use copper sheet or bar. And use air bubbler to circulate the solution around it as suggested in thread When in doubt, cement it out as Dave suggested.


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## Gold.refinery (May 31, 2022)

orvi said:


> You need to agitate somehow the solution around the copper. This will speed up the process rapidly. If you have no chance of getting mixer, forgot the powdered copper and use copper sheet or bar. And use air bubbler to circulate the solution around it as suggested in thread When in doubt, cement it out as Dave suggested.


Thank you very much for your support, it is very helpful


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## silver1 (May 31, 2022)

Gold.refinery said:


> It is probably wise to recover silver chloride every two weeks, but it is not possible to keep the mother solution for more than 4 or 5 days.


Why? Also how much materials are we talking about do you run in a weeks avg. Are you running 25 kilos a day. week. month? What volume are to trying to run avg? 

Keep the chlorides wet and don't let them dry out. Especially keep them away from that ammonium you have been using.


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## Gold.refinery (May 31, 2022)

Gold.refinery said:


> Finally, There we have green sludge (as shown).
> What should we do to recover the precious metals of these this Hydroxides ?
> (Shall we give it to the recycling workshops we go to every month with Smelting method?)


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## silver1 (May 31, 2022)

I don't know about laws where you live, but if you can't sell it then you are going to have to have to pay to have it carted off. If you can find a way to dispose of it for free i would go with that. Waste is a negative in this business. I used to go the route you are now. I then found a licensed waste disposal company that would take mine for free for the metal content. Win Win far as i'm concerned. That's also the reason i ask you about why you couldn't let processed solution build up more than the 3-4 days as you said. Here i'm only allow to store so much waste until i pass a threshold and then i'm in violation territory. One trick my state EPA allows is to classify my waste as IN PROCESS, not storage. My cementation tank where i hold my waste solution is not classified as IN STORAGE, because it has air bubbling through it and copper hanging in it circulating while the process continues. It has an evaporator and when it's time to empty you suck it out like an old septic tank. The waste tank is a continual process for me, NOT a batch process. Two things never get shut down in my shop. The fans and the waste tank.

ALL you values should be removed by this point. I've never specifically processed hydroxides for value after going through my system.


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## Gold.refinery (May 31, 2022)

I took a few pieces of blue hydroxide, crushed them and mixed them. 
I tested with XRF, in some places it averaged 17/1000 to 28/1000 gold, and it also had about 4/1000 platinum.

I know the standard for testing powders varies, but some color changes were visible on the XRF lens, which also varied in Numerical values.

These values may have passed to the last station due to the presence of ammonia in the solution.???


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## silver1 (May 31, 2022)

Gold.refinery said:


> I took a few pieces of blue hydroxide, crushed them and mixed them.
> I tested with XRF, in some places it averaged 17/1000 to 28/1000 gold, and it also had about 4/1000 platinum.
> 
> I know the standard for testing powders varies, but some color changes were visible on the XRF lens, which also varied in Numerical values.
> ...


Could be a whole lot of reasons. No answer for that right now as your still trying to work out the kinks in your process and system. Once 4metals and these guys gets you hooked up this problem will solve itself. It's like death from a thousand cuts when your chasing the answer to a problem. It's a combination of problems and not just a specific one. Maybe someone can help you with the hydroxide issue you are facing now though.


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## Gold.refinery (May 31, 2022)

silver1 said:


> It's like death from a thousand cuts when your chasing the answer to a problem.


Exactly …


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## 4metals (May 31, 2022)

What is the volume of the tank you will be cementing the waste solutions in? And do you expect to refine 1 lot of 20-25kg per day? This will help work out your wastes retention time in the tank. The speed may not be an issue. And you need to get it out of your head that you are going to recover a few grams of gold from your cemented waste on a lot by lot basis. After the cemented waste sits in the tank agitated and exposed to copper metal the values will drop. You will empty the tank to the next treatment step and preferably pump through a canister filter to catch any values before the waste tank. You empty the tank, leaving what has settled on the bottom and refill the tank with fresh spent solution for cementation. The tank is emptied and cleaned out on a schedule that likely approaches once a month. You cannot afford the labor or the chemistry to chase after small amounts from each lot.


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## Gold.refinery (May 31, 2022)

4metals said:


> What is the volume of the tank you will be cementing the waste solutions in?


4 cubic Tank= 4*500 liter

2 cylindrical Tank = 2*300 liter 
(Except for the gold settling tank)



4metals said:


> And do you expect to refine 1 lot of 20-25kg per day?


Maybe 15 kg daily


4metals said:


> And you need to get it out of your head that you are going to recover a few grams of gold from your cemented waste on a lot by lot basis


Why? 
Can not workshop that recycle by non-chemical methods recover low values(Smelting)?



4metals said:


> After the cemented waste sits in the tank agitated and exposed to copper metal the values will drop. You will empty the tank to the next treatment step and preferably pump through a canister filter to catch any values before the waste tank. You empty the tank, leaving what has settled on the bottom and refill the tank with fresh spent solution for cementation. The tank is emptied and cleaned out on a schedule that likely approaches once a month. You cannot afford the labor or the chemistry to chase after small amounts from each lot.


Can you explain a little more and more clearly. I'm confused


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## Yggdrasil (May 31, 2022)

4 cubic Tank= 4*500 liter

2 cylindrical Tank = 2*300 liter
(Except for the gold settling tank)


Maybe 15 kg daily


> 4metals said:
> 
> And you need to get it out of your head that you are going to recover a few grams of gold from your cemented waste on a lot by lot basis


Why? 
Can not workshop that recycle by non-chemical methods recover low values(Smelting)?
*Because it is not practical to cement then settle and so clean out the tank after each lot.
It is labor intensive and takes time. 
Better cement and let settle, filter out what is there and the tank is ready for a new batch.*



> 4metals said:
> After the cemented waste sits in the tank agitated and exposed to copper metal the values will drop. You will empty the tank to the next treatment step and preferably pump through a canister filter to catch any values before the waste tank. You empty the tank, leaving what has settled on the bottom and refill the tank with fresh spent solution for cementation. The tank is emptied and cleaned out on a schedule that likely approaches once a month. You cannot afford the labor or the chemistry to chase after small amounts from each lot.


Can you explain a little more and more clearly. I'm confused
*Here 4metals explain why you should not do it lot by lot.*


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## Shark (May 31, 2022)

Chasing .25% has the potential to cost more than the values recovered. “Spending dollars to chase dimes” is a saying we use fairly often to describe those situations.


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## Yggdrasil (May 31, 2022)

If you read the "Cementing it out" thread you will se a description on a device one of our members made, to increase the agitation around the copper.
It basically is a piece of plastic tube within which the copper are placed/hung.
Inside this, a piece of plastic hose to the bottom, bubbles air, this will create a strong turbulent flow around the copper and also circulate the whole tank.
For a large tank it may be better with more than one, or even have a smaller temporary tank on top of the main tank and a small pump circulating the liquid through copper scrap and then back into the main tank. There are many ways to do it.


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## Gold.refinery (May 31, 2022)

Before the hydroxide tank, we have 4 tanks. 

Two 300 liter tanks without mixer, one tank with mixer and blade, one tank with air injection for stirring. How to use these tanks to maximize copper cementation to obtain residual values?


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## Yggdrasil (May 31, 2022)

Gold.refinery said:


> Before the hydroxide tank, we have 4 tanks.
> 
> Two 300 liter tanks without mixer, one tank with mixer and blade, one tank with air injection for stirring. How to use these tanks to maximize copper cementation to obtain residual values?


Do you read the links and threads we give you?


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## Yggdrasil (May 31, 2022)

Do you have a layout drawing/Sketch?


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## 4metals (May 31, 2022)

Gold.refinery said:


> 4 cubic Tank= 4*500 liter
> 
> 2 cylindrical Tank = 2*300 liter
> (Except for the gold settling tank)


You didn't mention the cylindrical tanks or the gold settling tank. Where in the line of tanks do these fit in. Is one of the cylindrical tanks where you precipitate the gold? What is the other one for? and which one is the gold settling tank. (if you filter it properly you have no need for a tank where it settles out) You cannot keep adding tanks and expect us to know what you are doing. You sent us photo's of 4 cubic tanks prominently numbered 1,2,3,4. now 2 or 3 more spring up?



Yggdrasil said:


> Can you explain a little more and more clearly. I'm confused
> *Here 4metals explain why you should not do it lot by lot.*


If you do it lot by lot we will see you post your equipment up for sale because you cannot make any money. Someone who knows how to do this will use your equipment (purchased at auction rather inexpensively) and produce good saleable gold and handle the wastes and values collected from the process hang-ups (that 0.25%) If you get your filters working properly and pump the solutions to the proper tanks for processing you will not need to do it lot by lot. And if you feel you must do it lot by lot, you are in the wrong business. Most of your gold will be in the chlorides anyway. 

Assuming the first of the 4 tanks (the square ones) are 500 liters and you process 15kg a day. You will use about 65 liters of acid. Generally you will use about the same quantity of water rinsing everything down and cooling it. So daily you will generate 130 liters of waste. That gives you 500/130= 3.84 days before the tank is full. Earlier I suggested when the first tank is full start adding to the second (500 liter) tank. When tank 2 is half full check tank 1 with stannous for values. All the while tank 1 is mixing to keep the solution in motion and keep new solution contacting copper metal. If you detect any values on stannous, add fine powdered (atomized copper) do not add a lot and keep it mixing because if it settles to the bottom it is not as effective. The next morning the PM's should be out of solution and the solution can be pumped, after it settles, to waste treatment. Pump it through a canister filter to trap any values that are still suspended. The solution you are now pumping out will not hold payable quantities of precious metal and are, as the name implies, waste acid. This is what you drop with caustic to form hydroxides. If you use the 2 tanks alternatively, you will be able to hold solution for 3 or 4 days to allow the copper slabs to work and if needed some fine atomized copper metal can finish the job.


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## Yggdrasil (May 31, 2022)

Just to visualize the cementing contraption, I made this sketch so it may be easier to understand.
At lest this is close to how I do it.
It has been made transparent to emphasize function.


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## Gold.refinery (Jun 1, 2022)

4metals said:


> You didn't mention the cylindrical tanks or the gold settling tank. Where in the line of tanks do these fit in. Is one of the cylindrical tanks where you precipitate the gold? What is the other one for? and which one is the gold settling tank. (if you filter it properly you have no need for a tank where it settles out) You cannot keep adding tanks and expect us to know what you are doing. You sent us photo's of 4 cubic tanks prominently numbered 1,2,3,4. now 2 or 3 more spring up?


You can see all the cylindrical tanks with filters and waste water stations in the two photos below.

Now you recommend the best route. 
You will probably skip some tanks. 
We can skip. Or use them for more time to Contact with copper.


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## orvi (Jun 1, 2022)

Shark said:


> Chasing .25% has the potential to cost more than the values recovered. “Spending dollars to chase dimes” is a saying we use fairly often to describe those situations.


28/1000 is 2.8 % if I calculated it correctly. If true, that is very concerning number. At least as I see it - obtaining solid hydroxide cake with more than 2% gold. Maybe the readout of the XRF isn´t correct.


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## Yggdrasil (Jun 1, 2022)

I asked for a layout or if not possible for a sketch so we can make a plan for the flow.
Since the OP have not reacted I made one from the pictures.
But it is highly inaccurate since I don't know the shape/size of the room and so on.
So please give some input to this.


Edit: Swapped Sketch to one with text.


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## orvi (Jun 1, 2022)

Gold.refinery said:


> We can skip. Or use them for more time to Contact with copper.


Speed of cementation is proportional to* active surface area* of copper plate/bar. If the solution only sit in the tank, only mixing force is diffusion, and that is very very slow for you purposes. You need to move the solution. Either by mixing or with air bubbler. Not just a small stream of bubbles, you need it to bubble quite a lot - of course, not that violent it spits the solution everywhere  

If any gold is present in soluble form as Au3+, it will fall off on the surface of the copper as brown precipitate. More contact time surely help to assure you, that all values were precipitated. But on the other hand, in acidic solution, and in presence of air, copper is dissolved even in HCL. So it is a balance act of necessity and certainty  If you want to speed the cementation, use multiple pieces of copper sheet metal or casted flat bars to increase surface area. *Don´t forget to brush the surface of the copper after cementation* - some gold can be still attached to the surface of the copper, but gentle brushing will take it off. The quickest way how to dross off the gold powder from copper is to use ultrasonic cleaner. But considering the size of copper bars, it will probably be impractical.

As 4metals told you, stannous test will tell you if there is a soluble gold in solution. 
If you want to be completely sure, you can take small portion of the solution (say 200 mL) and use aluminium or zinc to completely cement all of the metals to the sludge. Filter the sludge and measure with XRF. But I think that with stannous and trained eye, you will be fine.


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## Gold.refinery (Jun 1, 2022)

Yggdrasil said:


> I asked for a layout or if not possible for a sketch so we can make a plan for the flow.
> Since the OP have not reacted I made one from the pictures.


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## Yggdrasil (Jun 1, 2022)

Thanks, it is much easier to see the flow when you know how things are placed.


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## 4metals (Jun 1, 2022)

I'm a bit busy today but if you provide one more photo of the inside of the tank so we can see the drainage of the gold precipitation tank it will be helpful. From the image you just posted it appears the entire tank will not drain into the filter. 

This evening I will list every step and where it is done and issues you may face.


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## 4metals (Jun 1, 2022)

Shark said:


> Chasing .25% has the potential to cost more than the values recovered. “Spending dollars to chase dimes” is a saying we use fairly often to describe those situations.


28/1000 is 2.8 % if I calculated it correctly. If true, that is very concerning number. At least as I see it - obtaining solid hydroxide cake with more than 2% gold. Maybe the readout of the XRF isn´t correct.
_________________________

The 28/1000 figure was given by Gold Refinery while looking for gold in hydroxides, and yes it is high but with an XRF on a soggy powder sample confidence in the result is low.

The .25% Shark was talking about is the general lot accountability. When a lot is processed if the actual gold recovered is within 99.75% of the expected gold by assay, the rest is deemed recoverable from the silver chlorides or the waste. Occasionally a lot will be short in excess of the .25% and it warrants chasing it. I remember one lot from back in the fire assay days where a large portion was green gold so the silver was high. At the end of the day when the accountant came out of his box and announced the “loss” we simply screened the chlorides and found it. Case closed. We never mixed the chlorides into the bulk chlorides until we knew it was within accountability limits. Same for spent solutions. Gold Refinery has enough tanks to hold solutions and chlorides separate until the results of the lot are announced. Usually daily if not the next morning.


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## Gold.refinery (Jun 1, 2022)

4metals said:


> The 28/1000 figure was given by Gold Refinery while looking for gold in hydroxides, and yes it is high but with an XRF on a soggy powder sample confidence in the result is low.


I tested a completely dry sample. I also combined a few sample.


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## Shark (Jun 1, 2022)

I may have misunderstood it. I was looking back to the post where he said:


Gold.refinery said:


> After the end of each operation, if we reach 99.75 incoming gold, we can hope that some gold is in the mother solution and also some gold is trapped in the silver chloride.
> 
> It is probably wise to recover silver chloride every two weeks, but it is not possible to keep the mother solution for more than 4 or 5 days.
> 
> ...


2 or 3% at the volume he is working with would be another story.


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## Palladium (Jun 1, 2022)

Shark said:


> I may have misunderstood it. I was looking back to the post where he said:
> 
> 2 or 3% at the volume he is working with would be another story.



That much on a large lot and i'm pumping the brakes! Especially on some karat gold.


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## Palladium (Jun 1, 2022)

I'm interested to know the rest of the sample reading from the hydroxides.


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## 4metals (Jun 1, 2022)

Gold.refinery said:


> I tested a completely dry sample. I also combined a few sample.


If you dried the hydroxides, what was the weight of dried hydroxides. Also, by hydroxides do you mean the sludges of metal hydroxides generated when you add caustic and pass it through the filter press?


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## 4metals (Jun 1, 2022)

You have more process tanks than you need actually, never a bad thing. It would be interesting to hear what the manufacturer suggests you do with those tanks.


Gold.refinery said:


> Now you recommend the best route.
> You will probably skip some tanks.
> We can skip. Or use them for more time to Contact with copper.


I have labeled your drawing and posted it here and I will explain how I would proceed.



The smaller room with the filter press is what I consider your waste treatment room. If you do everything correctly, the liquids and solids generated in the waste treatment room should not have payable values other than copper if you can find a buyer. 

The room with the tumbler plant is the acid room. This is where the gold alloys are dissolved and recovered, the silver chlorides are separated and retained, and any cemented values are accumulated. 

Start by placing the scrap to be refined in the tumbler. It should be in shot form and preferably melted as a single lot so it all is consistently mixed and homogeneous. You know the weight, you know the assay, so you can calculate the expected yield. If at all possible keep the Silver assay under 9% or you will begin to experience more gold retained in your insoluble chlorides. 

Add the Hydrochloric Acid according to the spreadsheet and then add 1/3 of the calculated Nitric Acid. As the reaction diminishes, add the second third of nitric, followed by the balance of the nitric as the reaction allows. The peroxide is an option, it will work well without it.

When the reaction is quieted down (ideally overnight) add ice or cold water to cool the acid and limit the silver chloride solubility. Filter the cold acid through your filter (if you only have the narrow paper, use 2 sheets at 90º to each other so the edges of the sheet do not expose the fabric filter support). Use a strainer as I described earlier to collect any insolubles where they are easy to rinse clean and quantify. filter all of the acid through the funnel and discharge into the gold precipitation tank.


rinse the tumbler well to get all of the remaining acid liquid film into the filter. Rinse the filter until a drop of stannous chloride placed on a sample of the paper shows no gold remains. (There will always be some indication of gold but keep it to a minimum and know the papers are saved and eventually processed for values.). Remove the filter papers and rinse the chlorides into a bucket of water for accumulation and processing later. Now rinse under the filter plate so all of the gold retaining acid has passed into the gold precipitation tank. 

Add urea to the tank without the mixer running. If you add too much urea and have a mixer running it may foam over so go easy with the urea. Again urea isn't my first choice but without heat and with cold acid there is no option for you. Slowly add urea prills, you will see it fizz and foam up so go easy, when it settles add some more until the emission of gas subsides. At the end, you will see little reaction and the prills of urea, added just a few at a time will float to the surface before dissolving and that is indication the addition is complete. Stir the liquid to make sure it will not foam up. 

You now have a solution that has been "de-NOxed" and is ready for precipitation. You will be using sodium metabisulfite to drop the gold. Start the stirring mixer and sprinkle the metabisulfite on the surface, it will darken as gold drops and may blow a little red until any remaining free nitric is consumed. Continue to add metabisulfite to the well mixing solution slowly allowing it to react before adding more. From time to time dip in a glass rod and test to be sure there is still gold in solution until you are experienced enough to notice the color shift from bright green to a dull green. When all of the gold is dropped and tested to confirm, shut the mixer and stir the mud to allow any pregnant acid under the mud to react. Agitate and test again. Now it is time to filter the acid into the funnel. 

If you notice on the gold precipitation tank, there are 2 valves visible. 


the larger shut off is made to drain the majority of the liquid from the tank into the filter. I prefer to drain the liquid first as it contains no gold and should run quickly through the filter. No sense in filling the filter with gold sponge and pulling all of the base metal laden acid through it. The second smaller valve should drain all the way to the bottom but it doesn't look like it does. Is there a bottom drain to completely drain all of the solids into the filter through? I hope there is or that is something you will be mentioning to the manufacturer as well. You need to allow all of the precipitated solids into the filter (which is why a large diameter bottom hole is hopefully available) then you can wash the gold in the filter as the rinse is pulled through the filter. 

Allow the filter to suck the well rinsed gold sponge dry. Solution that was not rinsed clear of the sponge and is allowed to dry on the sponge is a large contributor to impurity. 

The liquid from this process, which now shows no indication of gold on your stannous chloride, is pumped into the center tank. This tank should be set up to hang slabs of copper metal which are aerated to keep the solution moving. Look at the link FrugalRefiner sent you about cementing with air to agitate. The air needs to bathe the bar to dislodge any displaced values and expose more clean copper. This tank is used to hold solution for cementation for as long as you can hold it before needing the space for more acid. If you test it and it does not indicate any values, it can be pumped to the waste treatment room. If it still indicates values it can be pumped to the next cylindrical tank where you can add atomized copper powder sparingly and with a mixer (preferably a blade). When this tank is full and testing negative it can also be pumped to the waste treatment room. Any discharge line from either of the copper cementation tanks should be passed through a cylindrical canister filter to catch any fines. 

The liquid leaving these tanks should be through the side wall outlet of the tanks and always leaving liquid and settled solids on the bottom. They are collected periodically for processing and that is the only time you will need a filter under the tank to collect all of the values for processing. And processing 20 kg a day the frequency of running the solids cemented will likely be quarterly. Time and experience will determine that. 

By filtering properly you should have trapped all of the silver chlorides and collected them on the filter. You should have any larger chunks of undissolved karat sitting on the pre filter screen to easily collect and quantify. you should have all of your filtered and precipitated and rinsed gold on the filter and de-watered enough to melt it, and the solution should be sitting in a tank with copper slabs. Nothing leaving this room if you followed these procedures will be precious metals. 

Next post, waste treatment room.


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## 4metals (Jun 1, 2022)

Waste treatment.

As I said earlier there should be no payable precious metals in your waste stream at this point.

You have 4 tanks here but only really need 1. 




Tank 1 has a blade so it could be used for copper cementation with the powder but I do not believe the drains will drain these tanks completely so for cemented liquids that can contain values I think you are better off with the round tanks. Let's hope they have a large bottom drain. Getting cemented values out of this tank may be difficult. 

Really, the only tank you need here is the tank you add the waste acid into and raise the pH with caustic to form the hydroxides. Everything else is extra. Drums of liquid caustic do get heavy and freeze up at 14.4 ºC. For that reason lots of users prefer to purchase sodium hydroxide as a flake and mix it with water in their facility where it won't freeze up as easily. It is not a pleasant job mixing caustic flake and paddling it in a drum to dissolve it but tank #1 with a mechanical mixer can make easy work of it for you. So if it were me, I'd be mixing my own liquid caustic in tank #1. 

Once it is mixed, you can feed it directly into the pH dosing pump to add to the third tank which has the mixer and is where the pH is raised. 

The second tank has a bubbler to keep it mixing and it can serve as a holding tank to hold waste before you process it in tank #3. 

Tank #4 doesn't have many details about mixing or draining so I am not sure what you want to use it for. 

Once the waste is raised to the desired pH, it can be pumped through the filter press. I prefer to cycle from the hydroxide tank #3 through the press and back to tank #3 until the discharge runs clear, then divert some valves to pump it out, either to sewer (not likely) or to a holding tank (#4?) where the solution can be tested to see if it meets discharge standards or to lower the pH a bit so it isn't so corrosive before discharge. That is likely what tank #4 is there for. 

The filter press will fill up and slow considerably until it stops flowing because it is full of hydroxide cakes. Usually compressed air is connected to an inlet on the press to dry the cakes with airflow so they drop easier. Releasing the pressure will drop the cakes from the filter press you will be left with something like this;



These hydroxides contain a high % of Copper but (at least in the US) it may be hard to find someone to buy them without them being dried and screened.


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## EMRE (Jun 1, 2022)

Gold.refinery said:


> You can see all the cylindrical tanks with filters and waste water stations in the two photos below.
> 
> Now you recommend the best route.
> You will probably skip some tanks.
> We can skip. Or use them for more time to Contact with copper.


is this equipment made in Turkey? Usually Turkish refineries prefer to drop gold with AL rather than Cu. Just curious..


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## Gold.refinery (Jun 2, 2022)

4metals said:


> If you dried the hydroxides, what was the weight of dried hydroxides


1920 gr


4metals said:


> by hydroxides do you mean the sludges of metal hydroxides generated when you add caustic and pass it through the filter press?


Yes


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## 4metals (Jun 2, 2022)

Refiners who treat their waste acids as you do often incinerate, crush and sift the hydroxides and ship them to copper smelters. A 55 gallon drum of prepared hydroxides weighs around 500 pounds and refiners who do not cement their wastes (foolish but yes there are a few) typically will get about 2 ounces of Gold out of a drum. That works out to 0.00027% gold. A bit different than 2.8%

The only way I can see that happening is if you did not add sufficient precipitant to a lot and, did not test with stannous, and did not drop all of the metals with aluminum. That material was treated with caustic and the gold you found, if the XRF can be trusted, ended up in the hydroxides. 

This will not happen when you follow the steps we have outlined.

Edited. Changed the % gold figure which was entered on an iPhone and added too many zeros.


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## Gold.refinery (Jun 2, 2022)

4metals said:


> A 55 gallon drum of prepared hydroxides weighs around 500 pounds and refiners who do not cement their wastes (foolish but yes there are a few) typically will get about 2 ounces of Gold out of a drum. That works out to 0.00027% gold. A bit different than 2.8%


1920 gr of hydroxide was obtained from refin 5300 g of scrap. 
According to your calculations, 500 pounds of hydroxide in a 55 gallon drum is obtained approximately after refining 560 kg of scrap, which is two months of operation. 
You said that in this volume you get almost two ounces Gold, so the percentage is 62/226000 = 0.00027 equal to 0.027 %.



4metals said:


> The only way I can see that happening is if you did not add sufficient precipitant to a lot and, did not test with stannous, and did not drop all of the metals with aluminum. That material was treated with caustic and the gold you found, if the XRF can be trusted, ended up in the hydroxides.


We did not do the stannous test in the first operation, nor did we add a small amount of aluminum to the cement, but I guess because of the use of ammonia to wash the gold powder then add it to the mother solution, all the precipitated metals dissolved again and reached to the hydroxide station. 
Of course, the manufacturer was present and he did it, Unfortunately.


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## Gold.refinery (Jun 2, 2022)

4metals said:


> It would be interesting to hear what the manufacturer suggests you do with those tanks.


The second cylindrical tank you mentioned for cementing with *copper sheet*, the manufacturer recommended *aluminum sheet*. 

The third tank you mentioned was cemented with *copper powder*, the manufacturer recommended again with *aluminum sheet*. 

The first waste water station you mentioned Re-cementing with copper powder, the manufacturer recommended aluminum. 
The second station you do not consider necessary , the manufacturer advised to add iron.


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## Gold.refinery (Jun 2, 2022)

4metals said:


> the liquids and solids generated in the waste treatment room should not have payable values other than copper if you can find a buyer.


If 
1)enough precipitate is added, 
2)the stannous test is done correctly, 
3)the cementing is done in several stages, 
4)the filters are modified. 
do you hope that hydroxides will contain more copper ??? 

Can not platinum in hydroxides be extracted ???


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## Yggdrasil (Jun 2, 2022)

Gold.refinery said:


> If
> 1)enough precipitate is added,
> 2)the stannous test is done correctly,
> 3)the cementing is done in several stages,
> ...


The reason we recommend Copper is that no base metal will cement out.
Only PMs like Gold, Silver, Palladium, Platinum and so forth, with one exception... Mercury.
Mercury on the other hand is highly unlikely to find in scrap.

Additionally even if it was, it would still be in the cement from Aluminum, including Iron, Zinc, Copper, Tin or what ever else was in the scrap.
Aluminum will for all practical purposes give no separation of values vs no values.


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## Gold.refinery (Jun 2, 2022)

*I must say, you explain very well. clear , with details and step by step. Thanks*


4metals said:


> Add the Hydrochloric Acid according to the spreadsheet and then add 1/3 of the calculated Nitric Acid. As the reaction diminishes, add the second third of nitric, followed by the balance of the nitric as the reaction allows. The peroxide is an option, it will work well without it.


You mean to add the final 1/3 of nitric acid to see the reaction. To get the required amount, no more , right?
You do not think it necessary to help the AR react with peroxide, right ???



4metals said:


> if you only have the narrow paper, use 2 sheets at 90º to each other so the edges of the sheet do not expose the fabric filter support)


Is placing two paper filters 90 degrees relative to each other a good way? Isn't it better to make the ring that holds the paper filter bigger?


4metals said:


> Add urea to the tank without the mixer running. If you add too much urea and have a mixer running it may foam over so go easy with the urea. Again urea isn't my first choice but without heat and with cold acid there is no option for you. Slowly add urea prills, you will see it fizz and foam up so go easy, when it settles add some more until the emission of gas subsides. At the end, you will see little reaction and the prills of urea, added just a few at a time will float to the surface before dissolving and that is indication the addition is complete. Stir the liquid to make sure it will not foam up.


Excellent explanation


4metals said:


> Start the stirring mixer and sprinkle the metabisulfite on the surface


The gold tank does not have a mixer Now. we have a tube with air injection at the end. Most likely to do mixing with the pipe will need to open the tank, SO2 gas will bother. What do we really do?



4metals said:


> Continue to add metabisulfite to the well mixing solution slowly allowing it to react before adding more


Is it better to add powder sulfite or dissolve it in water?


4metals said:


> Is there a bottom drain to completely drain all of the solids into the filter through? I hope there is or that is something you will be mentioning to the manufacturer as well.


The bottom of the tanks is sloping towards a large valve that opens from the bottom of the tank. The same valve that you recommended to be filled from the inside with a solid pvc to prevent the gold powder from being trapped.



4metals said:


> The air needs to bathe the bar to dislodge any displaced values and expose more clean copper.


Is it enough if I put a few copper plates in the tank and put an air injection tube into the solution to move the solution?



4metals said:


> Any discharge line from either of the copper cementation tanks should be passed through a cylindrical canister filter to catch any fines.


Like the cylindrical filter that came after the silver chloride filter and you did not like it. Is that right?


4metals said:


> The liquid leaving these tanks should be through the side wall outlet of the tanks and always leaving liquid and settled solids on the bottom. They are collected periodically for processing and that is the only time you will need a filter under the tank to collect all of the values for processing. And processing 20 kg a day the frequency of running the solids cemented will likely be quarterly. Time and experience will determine that.


We have a valve at 18 cm top of the bottom of the cylindrical tanks (as shown), as well as a valve at 7 cm top the bottom.
When the solution comes in contact with the copper plate and the copper powder, do the value particles settle or stick to the copper plate?


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## Gold.refinery (Jun 2, 2022)

4metals said:


> but I do not believe the drains will drain these tanks completely so for cemented liquids that can contain values I think you are better off with the round tanks. Let's hope they have a large bottom drain


All tanks have a cylinder valve from the bottom of the tank. The first and second waste water stations also have a drain valve from the bottom of the tank.


4metals said:


> It is not a pleasant job mixing caustic flake and paddling it in a drum to dissolve it but tank #1 with a mechanical mixer can make easy work of it for you. So if it were me, I'd be mixing my own liquid caustic in tank #1.


We first add the flaky caustic to the third tank as a solid slowly, when the pH is about 5, the dosing pump pumps the caustic dissolved in water from a bucket until the pH reaches 8.
Is it right?


4metals said:


> I prefer to cycle from the hydroxide tank #3 through the press and back to tank #3 until the discharge runs clear, then divert some valves to pump it out,


Do you mean that the solution passes through the press filter twice?


4metals said:


> The filter press will fill up and slow considerably until it stops flowing because it is full of hydroxide cakes


When the water drains from the press filter, is it time to drain? What is the barometer that shows the pressure of the hydraulic jack for?


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## 4metals (Jun 2, 2022)

Gold.refinery said:


> Is it enough if I put a few copper plates in the tank and put an air injection tube into the solution to move the solution?


The air needs to knock the cemented metal off the copper sheet so it needs to physically contact the hanging copper, otherwise it will blind itself to further cementation. 

The air is inside the white tube with the copper slab, if you don’t move enough solution and cause enough current to break off the cemented metal that is adherent to the slab it will stop reacting. 

There is plenty of good information on the forum, some of which you have been told on this thread, to give you enough details to do this properly.


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## 4metals (Jun 2, 2022)

Gold.refinery said:


> We first add the flaky caustic to the third tank as a solid slowly, when the pH is about 5, the dosing pump pumps the caustic dissolved in water from a bucket until the pH reaches 8.
> Is it right?


That is the hard way if you have a tank that can mix it for you. You have a pH meter but it is not connected to a dosing pump? 


Gold.refinery said:


> Do you mean that the solution passes through the press filter twice?


I mean you want the liquid to flow clear before it is discharged. Often when you empty a press, the first solution through is not clear. By recirculating until it is clear you assure you are pumping out clear liquid. So, yes some solution passes through the pump twice.


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## 4metals (Jun 2, 2022)

Gold.refinery said:


> What is the barometer that shows the pressure of the hydraulic jack for?


Holy  didn’t the salesman show you how to work the equipment? 

A filter press has individual plates that are held together by a hydraulic press. When you drop the cakes from a full press you release the pressure and the hydraulic ram recedes allowing the plates to separate and the cakes to slip out. When you want to use the press again you pressurize the ram to push all of the plates tightly together. The barometer tells you what pressure you are exerting. When the press does not leak from between the plates when waste is pumped through, note the pressure and that is what you set it to each time.


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## Gold.refinery (Jun 2, 2022)

4metals said:


> You have a pH meter but it is not connected to a dosing pump?


Yep, dosing pump have ph meter, but very slowly.


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## Gold.refinery (Jun 2, 2022)

4metals said:


> The barometer tells you what pressure you are exerting. When the press does not leak from between the plates when waste is pumped through, note the pressure and that is what you set it to each time.


Is it enough that there is no leakage? I understood


4metals said:


> Holy  didn’t the salesman show you how to work the equipment?


I'm sorry


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## Yggdrasil (Jun 2, 2022)

I'm trying to make a reply. I just don't know how.......


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## 4metals (Jun 2, 2022)

Gold.refinery said:


> Like the cylindrical filter that came after the silver chloride filter and you did not like it. Is that right?


I did not like it where they placed it on your system, they tend to trap solution which you verified with a stannous test. Since the solution where they had the filter has dissolved gold in it it wasn’t good there. On the discharge from cemented solutions the solution has no value so a little trapped liquor is no issue but any fines which may be cemented values will be trapped. 
Same filter, where they located it, bad because it traps liquid holding gold. Where I suggested it, good because it retains unsettled values you don’t want to lose.


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## 4metals (Jun 2, 2022)

Gold.refinery said:


> According to your calculations, 500 pounds of hydroxide in a 55 gallon drum is obtained approximately after refining 560 kg of scrap, which is two months of operation.


The weight of hydroxides generated by any refining lot is totally dependant on the karat of the material. You said you started with 18 kt. material although it had cadmium which is odd. Anyway, a refiner processing 10 kt scrap will generate more hydroxides than a refiner processing 14 kt. So it is impossible to (well not impossible to but not worth the effort) figure out how many kilograms of scrap were processed to generate one full drum of dried and sifted hydroxides. And, all of the refiners I know of who process karat gold scrap process mixed scrap lots so the karat varies.


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## Gold.refinery (Jun 8, 2022)

4metals said:


> Start the stirring mixer and sprinkle the metabisulfite on the surface, it will darken as gold drops and may blow a little red until any remaining free nitric is consumed. Continue to add metabisulfite to the well mixing solution slowly allowing it to react before adding more. From time to time dip in a glass rod and test to be sure there is still gold in solution until you are experienced enough to notice the color shift from bright green to a dull green. When all of the gold is dropped and tested to confirm, shut the mixer and stir the mud to allow any pregnant acid under the mud to react. Agitate and test again. Now it is time to filter the acid into the funnel.


When adding smb we will turn on the scrubbers to absorb so2 gas. 
But after filtering the solution into the second tank and getting the gold powder, the cement-copper operation in the next tanks will take several days. Definitely can not stay on the scrubbers day and night. Will the next so2 gas tanks be released into the workshop environment? 

Of course we have an extra fan for ambient ventilation, but I do not think it is concentrated on top of each tank.
Each tank has a chimney to the scrubber, but no ventilation system.


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## 4metals (Jun 8, 2022)

From what you have said I take it you do not constantly run an exhaust over the tanks holding your acids or waste. Do you realize how corrosive the fumes coming off an open tank of spent aqua regia? Everything metal in your facility is slowly attacked by these almost imperceptible fumes. That’s the steel supports in most ceilings, I beams, anything not painted. And things often overlooked, like sprinkler tips in a sprinklered building. I had a client who chose not to protect his sprinkler tips and one let loose. Do you realize how much damage a 90 gallon per minute sprinkler tip can cause? 

Even when you are not processing anything but the tanks contain liquids you should have air moving through those ducts. You can shut off the scrubber pumps and controllers but keep the air moving. What I prefer for general exhaust is a tee in your exhaust so one way goes through the scrubbing circuit and the other goes to a direct venting blower. By switching the flow you can go through a scrubber or bypass it. 


Gold.refinery said:


> But after filtering the solution into the second tank and getting the gold powder, the cement-copper operation in the next tanks will take several days. Definitely can not stay on the scrubbers day and night. Will the next so2 gas tanks be released into the workshop environment?


These can safely go through the bypass and run while you are not there safely as no reactions are actively outgassing. 



Gold.refinery said:


> But after filtering the solution into the second tank and getting the gold powder,


I take this to mean you get the gold sponge as it drops out of the precipitating tank before the liquid gets to tank 2. Is this correct?


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## 4metals (Jun 8, 2022)

I should mention it is not recommended to
paint sprinkler tips. But a twice a year painting with molten candle wax (paraffin) will do the trick. It’s one of those things that it pays to do but those that do it never see the benefit because they never have a tip let loose from corrosion.


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## Gold.refinery (Jun 8, 2022)

4metals said:


> And things often overlooked, like sprinkler tips in a sprinklered building. I had a client who chose not to protect his sprinkler tips and one let loose. Do you realize how much damage a 90 gallon per minute sprinkler tip can cause?


What exactly do you mean by sprinkler?


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## FrugalRefiner (Jun 8, 2022)

He's talking about automatic sprinkler heads used in buildings in case there is a fire. They're designed so that if there is a fire, the sprinkler head is turned on and sprays water throughout the room.

Dave


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## 4metals (Jun 8, 2022)

The biggest mess I have ever seen in a refinery was made by the sprinkler system going off due to a corroded tip. 
The biggest loss I've ever seen in a refinery was due to having an unsealed concrete floor. 
Both of which I always advise clients to do, coat the sprinkler tips, and seal the floor. But not everyone listens.


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## orvi (Jun 8, 2022)

I am with 4metals on this 100%. If you are ever working with HCl or HNO3 anywhere, you mush have the fumehood running 24/7. And all the corrosive fumes must go through the fumehood - so all vessels bearing acids and acidic waste must be scrubbed. If you want to refine in nice clean rooms, not rusted and messy ones.

Chlorides, and espetially HCL (chloride, and also acidic) are promoters, or better said catalysts for corrosion. Seawater, using salt on the roads in the winter... All chlorides. And the iron is gone order of magnitude faster than in normal conditions. Even comparably acidic, but with different acid, say H2SO4 won´t be that bad as HCL.

You must protect everything in your shop from HCL fumes. For some time, nothing is obvious. It takes some time for the corrosion to appear, but when it accelerates, results are devastating. Precision scales, rebar in concrete, sink faucets, water pipes (often unnoticed and causing disstrous situations), doorframes... Everything. And it is often very difficult to stop it, because chlorides deposit on the material and promote further corrosion. And some things, you simply cannot wash.

If you cannot place everything into the fumehoods, best would be to concentrate the flow of air in the shop that way, it would go from the tanks straight to the some suction hose, leading to the exhaust motor/fan. So generally, any fumes possibly created have predetermined pathway, not affecting your expensive equipment and shop in general.


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## AMS-Pro (Jun 8, 2022)

4metals said:


> From what you have said I take it you do not constantly run an exhaust over the tanks holding your acids or waste. Do you realize how corrosive the fumes coming off an open tank of spent aqua regia? Everything metal in your facility is slowly attacked by these almost imperceptible fumes. That’s the steel supports in most ceilings, I beams, anything not painted. And things often overlooked, like sprinkler tips in a sprinklered building. I had a client who chose not to protect his sprinkler tips and one let loose. Do you realize how much damage a 90 gallon per minute sprinkler tip can cause?
> 
> Even when you are not processing anything but the tanks contain liquids you should have air moving through those ducts. You can shut off the scrubber pumps and controllers but keep the air moving. What I prefer for general exhaust is a tee in your exhaust so one way goes through the scrubbing circuit and the other goes to a direct venting blower. By switching the flow you can go through a scrubber or bypass it.
> 
> ...


There is a nifty trick for this, that will still allow the power bill to stay on the lower side. At one of my clients properties, we took an old 42U Server Cabinet, filled it top to bottom with UPS (uninterrupted power supplies), and connected the exhaust fan system to it.

Whether it was just the power being shut off for the night to keep the bill lower, or in the instance of a power loss, in either case, the exhaust fans always had power. The cabinet should not be located in the refine/recovery room for obvious reasons, but it is not hard to run the power to the exhaust system in sealed piping. In most cases, you should be able to set this up right next your utility box (breaker box), and install an ATS (automatic transfer switch) for the power on the supply end to the UPS, this way, if it is because of a power loss, the cabinet gets isolated for fan use only, and excess power doesn't get fed back into a dead power grid.


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## 4metals (Jun 8, 2022)

orvi said:


> rebar in concrete



I know a refiner in the south who bought a new building to build and move his refinery. He had to repair the building he was vacating and he quickly realized it was cheaper to buy it and take it down than to repair it. The hidden culprit, aside from the rust falling off every bit of steel superstructure, was the almost non existent rebar which had corroded away invisibly beneath the concrete. Small cracks in the concrete slowly allowed corrosive fumes to get to the iron rebar.


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## Shark (Jun 8, 2022)

Several years ago the plant where I worked decided to clean all the concrete floors and walls and paint them. Being so nasty someone decided to spray them with concrete cleaner called muriatic acid and leave it over the weekend. Luckily the equipment was stainless steel along with all the exposed piping. The steel joists and some retainers had to be painted afterwards due to heavy rusting. This was a bleaching facility for bleaching cloth that normally housed 50 gallon barrels of commercial powdered bleach. It could have been a lot worse than it was.


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## Palladium (Jun 8, 2022)

4metals said:


> I should mention it is not recommended to
> paint sprinkler tips. But a twice a year painting with molten candle wax (paraffin) will do the trick. It’s one of those things that it pays to do but those that do it never see the benefit because they never have a tip let loose from corrosion.


Back when i used to do Lowes construction we had to paint the ceiling. Walmarts too!
There are about 2,000 heads in a store. We used to cover them with aluminum foil so they didn't get paint on them. But as luck would have it a couple always got missed and painted. The fire marshal would fail them for inspection and lets not even talk about what the plumber will charge you to replace them. $250 a piece counting the head. I was cleaning one off one time and popped the head! Talk about a shower! Alarms going off. Fire department shows up. It got ugly! lol

When i built my house a few years back i actually installed a commercial sprinkler system in my house. Insurance rates are VERY favorable. 

Fans run 24/7/365 in my shop.


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## 4metals (Jun 8, 2022)

Palladium said:


> Fans run 24/7/365 in my shop


The only shops I know of that don’t do this are shops that close down for vacation and then any solution left in the shop has a pretty snug fitting lid. And one of those shops says the first day back from vacation none of the ladies in the office want to come back because of the smell!


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## orvi (Jun 9, 2022)

Shark said:


> Several years ago the plant where I worked decided to clean all the concrete floors and walls and paint them. Being so nasty someone decided to spray them with concrete cleaner called muriatic acid and leave it over the weekend. Luckily the equipment was stainless steel along with all the exposed piping. The steel joists and some retainers had to be painted afterwards due to heavy rusting. This was a bleaching facility for bleaching cloth that normally housed 50 gallon barrels of commercial powdered bleach. It could have been a lot worse than it was.


Concrete cleaner called muriatic acid... Nice 
Altough HCL is fast in wrecking anything metallic, even stainless steel... Chlorine is whole another level  AR fumes of chlorine mixed with NOCL and NO2 are somewhere in between HCL and HCL/Cl2.

Not to mention issue chlorides vs. concrete. Calcium chloride is even better de-icing agent than regular salt - yet it is not used on roads, and specifically pavements. Even low percentage of CaCl2 in NaCl for de-icing roads will be much much more effective than plain NaCl - but it is hardly used anywhere - because it wreck concrete very fast (it is also more expensive, but for the effect well worth extra money). Because of the solubility of CaCl2, it could penetrate the concrete to the significant depth and mess up the whole structure of Ca-silicate matrix = concrete start to crack and fall down of wall.
Not the thing you want from the structure which should hold the roof above you


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## Gold.refinery (Jun 9, 2022)

Working with chemicals, Toxic gases, causes Cancer, Menial level of work, High energy consumption, Corrosion of metals, High risk, Low profit. 
in 2022, What are we looking for?


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## 4metals (Jun 9, 2022)

orvi said:


> Calcium chloride is even better de-icing agent than regular salt - yet it is not used on roads, and specifically pavements. Even low percentage of CaCl2 in NaCl for de-icing roads will be much much more effective than plain NaCl - but it is hardly used anywhere - because it wreck concrete very fast (it is also more expensive, but for the effect well worth extra money).


I live in the woods in rural Pennsylvania. The road I live on is a dirt road and in the summer it is quite dusty. The “fix” to the dust issue is calcium chloride spread on the roads to control the dust. Multiple treatments over the course of the summer assure that our cars rust out in 4 years.


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## 4metals (Jun 9, 2022)

We are not trying to discourage you by pointing these things out. With all you have spent on your setup it’s a bit late for that. 


Gold.refinery said:


> Working with chemicals, Toxic gases, causes Cancer, Menial level of work, High energy consumption, Corrosion of metals, High risk, Low profit.


We are trying to help you assure that you can minimize these effects with proper maintenance and precautions. You want to be proactive not reactive.


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## Yggdrasil (Jun 9, 2022)

4metals said:


> I live in the woods in rural Pennsylvania. The road I live on is a dirt road and in the summer it is quite dusty. The “fix” to the dust issue is calcium chloride spread on the roads to control the dust. Multiple treatments over the course of the summer assure that our cars rust out in 4 years.


In Norway they salt the roads to a salty flour every winter. Brake discs, undercarriage and chassis dies fast under these conditions.


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## Gold.refinery (Jun 9, 2022)

4metals said:


> You want to be proactive not reactive.


I will try not to be disappointed but…

There are other job opportunities, with less risk and better opportunities. 
Whenever losses are prevented, there is profit.

The mind both produces motivation and kills motivation.


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## orvi (Jun 9, 2022)

4metals said:


> I live in the woods in rural Pennsylvania. The road I live on is a dirt road and in the summer it is quite dusty. The “fix” to the dust issue is calcium chloride spread on the roads to control the dust. Multiple treatments over the course of the summer assure that our cars rust out in 4 years.


"Nice". Here the same issue, whole chassis of car is wrecked in few years, if not washed properly, or coated with protective layer of paint/epoxy/polymer.


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## orvi (Jun 9, 2022)

Gold.refinery said:


> I will try not to be disappointed but…
> 
> There are other job opportunities, with less risk and better opportunities.
> Whenever losses are prevented, there is profit.
> ...


Keep your head up, with your help, we will steadily get it together and it will work. We can only give you our best points and advice, it´s you who must do the work. And things we advise are often cheap to build/make/alter, or even for free. 
But I completely understand your dissapointment. I now face similar issues, but with other precious metal


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## Shark (Jun 9, 2022)

It can be hard to keep looking forward when your not sure where the road leads to. Once you reach your destination the next trip becomes easier.


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## Palladium (Jun 9, 2022)

Adversity builds character brother! It's what sets the winners apart from the losers. 
The things we are telling you and pointing out are from experienced refiners. They have already made the mistakes so you don't have to. The value of the wisdom you are given here will not only assure your success, but i would argue is worth more than the value of the gold you are refining. Your into this pretty deep at this point, keep your head up and moving forward. Reverse is not an option. You have the equipment and these guys have the knowledge. That's a winning combination!


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## Gold.refinery (Jun 9, 2022)

Orvi
Shark
Palladium
4metal

The conditions of our workshop have improved since the day we decided to share the issues. With each point we changed correctly, a light came on in the dark.

Some changes can be made quickly, but some take time and the equipment needs to be improved. 

We do not have enough refining knowledge, it seems that the equipment manufacturer also intended to impose his incomplete knowledge.

If a professional refiner is present in our workshop for a few days, many problems will be solved.


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## billgold (Jun 12, 2022)

Now you are getting the idea. Possibly one of the best investments you could make would be to hire one of the EU experts here, such as orvi, to spend a bit of time in your facility and help you develop both a step-by-step processing plan including what tests to perform before moving to the next step - as well as helping create a check list of what modifications/additions need to be done to make the machinery operate at its best.

I would NOT rely on the manufacturer or any of their representatives - for any advice/instruction. Their advice to use aluminum instead of copper told me they either do not follow best practices or the plant is designed to handle feed material only containing gold, silver and copper.


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## Gold.refinery (Jun 12, 2022)

billgold said:


> Their advice to use aluminum instead of copper told me they either do not follow best practices or the plant is designed to handle feed material only containing gold, silver and copper.


Other members said that aluminum was not a good choice because it was more reactive than all the base metals and cemented them all. But what do you mean our device is designed for gold, silver and copper. Is it permissible to cement with aluminum to refine gold and silver only?


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## EMRE (Jun 12, 2022)

Gold.refinery said:


> Orvi
> Shark
> Palladium
> 4metal
> ...


Dear gold.refinery,

I will share my two cents;
I am Turkish, you are probably Turkish too living in UK who wanted to get into commercial gold refining with no knowledge. Instead of going to Fiori or Italimpiant, you went to a Turkish fabricator ( I know most of them since I am in the business) and purchased whatever they told you to buy. You probably paid 25% of what you could have paid to Italians. The problem is non of those manufacturers have chemists on their payroll who specialize in gold refining. They do not even know how to refine gold properly. There are four major gold refineries in Turkey ( two are LBMA approved) and non of them use standart equipment that you have. They use Italian machinery because they can buy the knowhow too. Frankly, a gold refining equipment manufacturer who tells you to use ammonia in NOx scrubber, or make you 2 liters of Stannous is an idiot!! (edited for clarity!)
Here are the good news from what I gathered reading 5 hours of thread;
1. you are in good hands because there are very knowledgeable people here responding to your questions. I know 4metals in person and worked with him on some of my projects. He is as good as it gets. Although i do not know Lou in person, I know he is super good too.
2. You want to make 995 gold. That is great because your equipment will never yield 9999 ICP verifiable product. ( well, technically it is but it would bankrupt you )
3. Your equipment is capable of producing 99.87% fine gold in a single pass. Just cut it down to 995 with silver and be done with it.
4. Do not complicate it. 1:4 AR then kill it with urea, cool it down to10c if you can, drop it with SMB and you will get 99.87. All are explained to you.
5. Do not your aluminum to drop base metals. Turks recommend it but they do not even know why they recommend it. I will tell you why; it is cheaper than copper thats why!!! and you end up with more junk at the end.
6. Try to find your leakage. Mostly it will be in the Agcl. Rinse everything with water and rinse very well. You should not see any green color stains on your equipment after every batch.

I hope you can achieve a profitable business. This is a very low profit margin industry.

PS: I did not see it being mentioned here but I think our mentors should look into inquarting your feedstock with silver first, run it with nitric, then AR with your existing equipment. You test this out with 75% au and 6% Ag incoming material. In reality, at least in USA, your feedstock will be 55%Au and 8-11% ag with balance base material. Your reaction will stop and your will end up with 600 gr of insoluble material due to Agcl freeze.

Good luck..

PS: Try to hire a chemist if you can but I know it is not easy, it seems like you need need one for the time being. 4Metals fees would have been probably up to $30K by now. And I am not joking!! You are lucky you found this forum.


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## Yggdrasil (Jun 12, 2022)

Gold.refinery said:


> Other members said that aluminum was not a good choice because it was more reactive than all the base metals and cemented them all. But what do you mean our device is designed for gold, silver and copper. Is it permissible to cement with aluminum to refine gold and silver only?


Since you are processing and refining mostly karat gold??
You I’ll not achieve anything by Al cementing. You will cement out all the metals dissolved in the AR process.

Copper will cement out only PMs.
Then you will have a clean Au Ag PGM mix. 
Then AR and drop the Gold with SMB hen cement the Silver or create AgCl.


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## orvi (Jun 12, 2022)

billgold said:


> Now you are getting the idea. Possibly one of the best investments you could make would be to hire one of the EU experts here, such as orvi, to spend a bit of time in your facility and help you develop both a step-by-step processing plan including what tests to perform before moving to the next step - as well as helping create a check list of what modifications/additions need to be done to make the machinery operate at its best.
> 
> I would NOT rely on the manufacturer or any of their representatives - for any advice/instruction. Their advice to use aluminum instead of copper told me they either do not follow best practices or the plant is designed to handle feed material only containing gold, silver and copper.


In my life, the biggest batch of gold I refined was around 100g. In a 2L beaker. I am no expert in the field of the kilo scale refining in tumbler plants, altough I know the chemistry behind. As I would maybe capable of improving something in place, I don´t feel this will work as it would if somebody like Lou, 4metals or AMS-Pro would visit his facility


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## Gold.refinery (Jun 12, 2022)

orvi said:


> I sometimes encounter the need to concentrate dilute values (AuAg) - say 0,3-0,5g from 3 liters of solution. In these cases, I add like 10 grams of copper powder to the stirred solution and let it mix for like one hour. Then I filter the solution and redissolve the powder in AR.
> You can also use the same principle, but stirring is necessary.
> 
> Eventually, if you add aluminium, all the nickel, copper and also the gold will precipitate. What happen next is that good portion of the less reactive metals like nickel or iron will cement out even more copper - simultaneously passing to the solution as ferric or nickel ions. Sounds good, you say, I create copper in the solution, that´s what I wanted - *but you will precipitate awful lot of metal sludge which needs to be processed AGAIN.*
> Your intention is to GET RID OF THE BASE METALS, that is why you refine the gold. Not to just stick aluminium to the precipitation tank to get them back and repeating the process one more time, with values even more diluted.


We started the New refining operation and made some changes. I will submit the report as soon as it is completed. I am very interested in reporting as soon as possible. 

Niw, We are making cement with copper. 
We have a tank after taking the gold from the solution. Two tanks that do not have a mixer, we want to cement with copper plates and air pipe (according to 4metal recommendation) 

and the other two tanks have a mixer, cement with copper powder. 

Since we are now doing small operations to gain experience, the volume of cement solution is small, on the other hand we want to complete the gold deficiency report and compare the results after the changes are made. 
For example, in our tank with a height of 66 cm, there is only 25 cm of solution. 

Is it possible to make cement with copper *plates* or just use copper *powder*? 
Should copper powder be *aotmize* or not? (We have copper powder from previous operations that has been removed from the solution with aluminum)


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## 4metals (Jun 12, 2022)

When cementing metals, the trick is contact. The gold and PGM's in solution need to physically contact the copper. When you use a tank that is only partially full, you are not utilizing the copper slabs optimally. 


Gold.refinery said:


> For example, in our tank with a height of 66 cm, there is only 25 cm of solution.


But the real question is why are you chasing a few grams of gold for every lot? Quantify your yields on a lot by lot basis and only spend your time searching for lost gold when your yield is off by 0.25% of your expected yield. And search the chlorides first because that is where it will likely be. 

If you do this you will be running the cementation tanks when they are full, your labor will be less and you will recover your lost values. 


Gold.refinery said:


> Is it possible to make cement with copper *plates* or just use copper *powder*?


Copper plates are slower but effective. Copper powder, *not* cemented copper from the aluminum drop but fine copper powder (atomized works best) requires good mixing because if those fine copper particles settle to the bottom they are not effectively contacting the solution and they are no more effective than the copper slabs. That is why we suggested using powdered copper in the tanks with good mixing, preferably with a propeller and shaft. 

If you quantify your losses for each lot you will have the luxury of time for cementation to work more effectively because you will not be chasing your tail looking for small quantities. If that much gold is getting into your waste it is from errors made in precipitation and testing or mechanical issues with your equipment. Look in your chlorides first, I'd bet the farm that's where you'll find them most of the time, barring mechanical failure.


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## Gold.refinery (Jun 13, 2022)

Since we want to use SMB in future operations, I need to explain more about the route of tank ventilation systems and a separate workshop ventilation system. Each tank has a 3-inch chimney that sucks the air fan towards the scrubbers. According to the photo.

On the other hand, we have a separate air fan that drains the air of the workshop 24hours/7days. 


I know that if smb is used, the solutions will accumulate for several days until they reach the cementing stage with copper and finally the filter press. We will have annoying gases in the workshop environment.
*Question: Should I pipe another new route for each tank to the air drain fan? Or is it better to turn on the Air Fan Scrubber when we have the solution in the tanks?*


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## Gold.refinery (Jun 13, 2022)

*Cu Cementation Stage:*

For two cylindrical tanks, we want to equip it with cementation with copper plates. 
let us know if there is a problem.

The solution is now 50 liters, after two more operations it is ready for cementation.

The place of the holes is suitable for sufficient contact of copper and solution?
What thickness of copper plate is better? At what height of the cylinder?


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## Yggdrasil (Jun 13, 2022)

Gold.refinery said:


> *Cu Cementation Stage:*
> 
> For two cylindrical tanks, we want to equip it with cementation with copper plates.
> let us know if there is a problem.
> ...


The upper holes are not necessary if the whole tube are suspended under the surface.
What is necessary is an air bubbling tube into approximately the lower end of the big tube, such that the air drags liquid up over the copper plate.


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## 4metals (Jun 13, 2022)

Gold.refinery said:


> Question: Should I pipe another new route for each tank to the air drain fan? Or is it better to turn on the Air Fan Scrubber when we have the solution in the tanks?


You can run a separate exhaust to each tank to run when you are not scrubbing the gasses or you can use the existing ductwork and switch to a non scrubbed exhaust through tee’s and blast gate shutoffs so you can either scrub or just exhaust when not running any noxious gasses in need of scrubbing. Like overnight.


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## EMRE (Jun 13, 2022)

If I were you, I would cancel the middle pipe with holes. Just take it out. I dont think air bubbles will create enough movement of liquid into the pipe and out from the holes. You would need kind of a propeller for that. I think as is it is restrictive.. I would get few copper sheets as wide ad possible and submerse them in to the tank and let the air do its job. the thicker the plate the better it is. technically you are replacing gold ions with copper so copper plate will disappear. We use two plates that are 6" wide, 3 feet long and 1/2 inch thick. we always keep them in it the tank and occasionally take it out and rub them off.


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## 4metals (Jun 13, 2022)

The pipe with the holes actually directs the air bubbles and maximizes their contact with the cemented particles that like to stick to the copper slab causing them to slough off. The air movement he has, as seen in the video, is aggressive and probably be more effective than a propeller on a shaft unless it is one big propeller. 

I would hang one of those cylinders, like the one he made and showed us in the video, around every slab in the cementation tank. 

Remember, the more surface area of copper that effectively contacts the values in solution, the faster it works.


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## Gold.refinery (Jun 13, 2022)

4metals said:


> The air movement he has, as seen in the video, is aggressive and probably be more effective than a propeller on a shaft unless it is one big propeller.


I have an idea, do you approve? Increase the diameter of the cylinder to 200 mm. Make holes at the highest level. 
That is, there should be no holes between the bottom holes and the top holes. 

Use two copper plates in the middle of the cylinder. 

I shared the video to build another cylinder if you have no advice.


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## Yggdrasil (Jun 13, 2022)

EMRE said:


> If I were you, I would cancel the middle pipe with holes. Just take it out. I dont think air bubbles will create enough movement of liquid into the pipe and out from the holes. You would need kind of a propeller for that. I think as is it is restrictive.. I would get few copper sheets as wide ad possible and submerse them in to the tank and let the air do its job. the thicker the plate the better it is. technically you are replacing gold ions with copper so copper plate will disappear. We use two plates that are 6" wide, 3 feet long and 1/2 inch thick. we always keep them in it the tank and occasionally take it out and rub them off.


I can’t say what dimensions this is, but there is only one pipe.

It is a tried and tested design, I use around 50mm and 300 mm long.
The longer the pipe is and it is completely submerged it will create a “draft” through it by the air.

Of course you can create circulation any way you want as long as the circulation around the copper is strong.

4metals beat me to it


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## 4metals (Jun 13, 2022)

Truth if the matter is the cementation you are doing with the rig you made is fine. In the long run the metals recovered from cementation will just bring you closer to overall accountability but not make or break you.

If you were to hang 2 slabs in the fixture you made, you would likely have substantially less circulation on the 2 slab sides facing each other. So in reality you would gain little.


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## Yggdrasil (Jun 13, 2022)

Gold.refinery said:


> I have an idea, do you approve? Increase the diameter of the cylinder to 200 mm. Make holes at the highest level.
> That is, there should be no holes between the bottom holes and the top holes.
> 
> Use two copper plates in the middle of the cylinder.
> ...


You want good speed around the copper slabs, increasing the diameter negates that.


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## Shark (Jun 13, 2022)

Maybe an air lift pump for a pipe that size. They will move large volumes of fluid with aggressive bubbles.


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## EMRE (Jun 13, 2022)

do not increase the diameter..


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## Gold.refinery (Jun 13, 2022)

4metal
Yggdrasil
Shark
Emre
Orvi

Do you have an opinion on the location of the holes and the number of holes?


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## Shark (Jun 13, 2022)

I have never used one that size. But, I am thinking near the top. As Yggdrasil mentioned the updraft caused by the air being pumped in will lift the cement up and out. So I would consider where that lift starts loosing its power to keep the cement in good motion to be the better location.
I also agree that larger pipe would not be the way to go. Adding additional pipes might not be a bad idea based on how much material needs to be cemented out.

Let’s see how the others feel.


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## 4metals (Jun 13, 2022)

Gold.refinery said:


> Do you have an opinion on the location of the holes and the number of holes?


This isn’t rocket science, what you have will do the job. You have bigger fish to fry!


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## Shark (Jun 13, 2022)

I missed that video the first time. It sure seems to be working well.


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## EMRE (Jun 13, 2022)

Gold.refinery said:


> 4metal
> Yggdrasil
> Shark
> Emre
> ...


Even no holes is fine as long as your bubbles create upward stream of liquid.. .


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## EMRE (Jun 13, 2022)

Gold.refinery said:


> 4metal
> Yggdrasil
> Shark
> Emre
> ...


Let me ask you something; what is your reason for refining? do you want to make gold bars? if so in what denominations? The reason I am asking is because you will need to have a labaratory with proof corrected fire assay capability. ICP is even better. This is to verify the purity of your work. You can not do this with XRF machines.. Just so you know..


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## orvi (Jun 14, 2022)

Gold.refinery said:


> 4metal
> Yggdrasil
> Shark
> Emre
> ...


As it was said, *as you have it, you are good to go*. You will see if it is working or not. 

You can do it like this with holes, or as EMRE said, without the holes. But when you are going without them, you need to submerge the pipe completely to allow uninterupted flow of liquid.

With all the suggestions and pictures, you now know that important variables is diameter of the tube => this largely impact flowrate through the tube. If diameter is big, flow will be less aggressive, and tend to break less cement down of the copper bar. 
Also important parameter is surface area of copper. That does not mean you immediately need 1x1 m piece of sheet copper rolled inside  but that if you make the solution to flow, this parameter could be reduced to effective minimum.


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## Gold.refinery (Jun 14, 2022)

4metals said:


> You can run a separate exhaust to each tank to run when you are not scrubbing the gasses or you can use the existing ductwork and switch to a non scrubbed exhaust through tee’s and blast gate shutoffs so you can either scrub or just exhaust when not running any noxious gasses in need of scrubbing. Like overnight.


To suck gases without purification (like overnight), could we turn on the air fan scrubber in Low frequency and 
keep the water circulation pump off?


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## 4metals (Jun 14, 2022)

Gold.refinery said:


> To suck gases without purification (like overnight), could we turn on the air fan scrubber in Low frequency and
> keep the water circulation pump off?


Yes. Shut the circulation of the scrubber liquid off and it is just a blower.


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## 4metals (Jun 14, 2022)

orvi said:


> You can do it like this with holes, or as EMRE said, without the holes. But when you are going without them, you need to submerge the pipe completely to allow uninterupted flow of liquid.


This is not totally true, without some holes on the lower pipe you will not provide a flow thru setup. At least a ring of holes around the bottom so there is a place for liquid to flow in to displace what has flowed out the top.


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## orvi (Jun 14, 2022)

4metals said:


> This is not totally true, without some holes on the lower pipe you will not provide a flow thru setup. At least a ring of holes around the bottom so there is a place for liquid to flow in to displace what has flowed out the top.


I assumed that the pipe with copper bar is hanging from above and isn´t touching the bottom of the vessel. But yes, if it will be standing from the bottom, then some holes also in the bottom are necessary. Anyway, setup with holes at the top is best.


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## 4metals (Jun 15, 2022)

orvi said:


> But yes, if it will be standing from the bottom, then some holes also in the bottom are necessary.


When I first started using this style I started with about 5 feet of 6” diameter PVC and in the center drilled 4 equidistant holes around the pipe. Then I cut the pipe in half leaving 2 equal length pipes and 4 scallop shaped cutouts at the bottom to allow solution in. The first ones I made were for cementing silver from silver electrolyte loaded with copper. So much Silver came down the holes were blocked so I added a second line of holes around the circumference to maintain flow. 

I always liked to stand these on the bottom of plastic drums so they were easy to remove and clean out the cemented Silver after the solution was pumped out. Often we had a couple of these bubbling away processing solution so simplicity of use entered the design.


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## Gold.refinery (Jun 25, 2022)

4metals said:


> This isn’t rocket science, what you have will do the job. You have bigger fish to fry!


We made two pvc cylinders according to the recommendations (you can see in the video). We put them in the mother solution, about 110 liters. For 3 hours. We have not yet filtered the solution, but no particles have settled. 
Did they react? 
what is the problem?


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## 4metals (Jun 25, 2022)

Nice job on the cementing fixture. That will do the job. 

The problem is there isn’t a lot to cement out, the solution looks pretty clear (blue is mostly copper, and that will not drop). Did the solution show positive results with stannous chloride? One or 2 grams of precious metal may come out of solution and it is barely detectable. If you used aluminum you would think you got a lot out but most of it isn’t precious and it’s a mess to separate. 

I still think your missing gold is in the silver chlorides. Have you separated the gold from the reduced chlorides yet?


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## Gold.refinery (Jun 25, 2022)

4metals said:


> Nice job on the cementing fixture. That will do the job.
> 
> The problem is there isn’t a lot to cement out, the solution looks pretty clear (blue is mostly copper, and that will not drop). Did the solution show positive results with stannous chloride? One or 2 grams of precious metal may come out of solution and it is barely detectable. If you used aluminum you would think you got a lot out but most of it isn’t precious and it’s a mess to separate.
> 
> I still think your missing gold is in the silver chlorides. Have you separated the gold from the reduced chlorides yet?


We have not yet recovered the silver chlorides and collected them all in gallons. The stannous test for the solution showed nothing.

But, important point, our least lost gold is related to the operation that we added the AL -sludge from the previous process to Tumbler in new operation . Our efficiency was 99.81 %.


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## 4metals (Jun 25, 2022)

Gold.refinery said:


> The stannous test for the solution showed nothing.


You mean the waste acid after the precipitation process showed nothing on the stannous I assume. If that is the case you can skip the process entirely and go right to waste treatment. If there is Platinum in the solution 
the stannous will indicate it. 

I always preferred to have a cementation tank always bubbling. Every lot processed went into it even if it exceeded the 99.75% recovery standard. With jewelry related feed, there can always be a touch of Platinum or Palladium and cementation will catch it. But you should not be running it on a lot by lot basis. It takes a while for values to accumulate to justify processing. Only concentrate on lots with losses in excess of 0.25% to find losses and then only after processing the silver chlorides for that lot.


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## 4metals (Jun 25, 2022)

4metals said:


> only after processing the silver chlorides for that lot.


If you are processing 25 kilo lots with a silver content of 7.5% it is relatively quick and easy to quickly reduce the chlorides to metal using either the sugar and caustic or the sulfuric and iron. You will only be looking at 60 or so ounces of chlorides, a manageable volume. Once it is reduced you can re-dissolve the metallic silver in nitric and filter out the gold. This is one of the things I would recommend doing in a hood. Another option is to melt the reduced silver into a bar and take a dip sample and part an accurately weighed sample to determine the gold content. Then when you have enough gold worth going after you can do it on a larger scale. The ability to find the gold content in the chlorides quickly allows you to put the lot to rest and move on. Chasing small quantities of gold is too costly but determining that you haven't lost it is important.


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## Gold.refinery (Jun 28, 2022)

4metals said:


> You mean the waste acid after the precipitation process showed nothing on the stannous I assume. If that is the case you can skip the process entirely and go right to waste treatment. If there is Platinum in the solution
> the stannous will indicate it.
> 
> I always preferred to have a cementation tank always bubbling. Every lot processed went into it even if it exceeded the 99.75% recovery standard. With jewelry related feed, there can always be a touch of Platinum or Palladium and cementation will catch it. But you should not be running it on a lot by lot basis. It takes a while for values to accumulate to justify processing. Only concentrate on lots with losses in excess of 0.25% to find losses and then only after processing the silver chlorides for that lot.


The last efficiency of our operation was 99.64%. 

As I said before, nothing was achieved after working with copper plates. 
We have about 200 liters of solution. 
For the test, we reacted about 8 liters of solution with 50 g of AL. No sludge was obtained and only a very small amount. 
We tested the small sludge, showed:
1.6/1000 Au
0.8/1000 Pd
986/1000 Cu
4.3/1000 Fe
5.3/1000 Cd
0.7/1000 Rh

There are 200 liters of solution left and I am undecided.

I'm confused and very tired. I hardly get through the days.

From previous operations, we have several hundred grams of copper powder containing 2/1000 gold. 
Can they be recovered? 
Is there an economic justification?


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## 4metals (Jun 28, 2022)

Gold.refinery said:


> From previous operations, we have several hundred grams of copper powder containing 2/1000 gold.
> Can they be recovered?
> Is there an economic justification?


Several hundred grams, let's call it 500 grams. 2/1000 as gold. So you are getting burnt out over 1 gram of gold? At today's prices that is worth about $60. 

There are many reasons that small amounts of values will get through the system. foremost will be the filtration medium or the equipment you use to filter it. We discussed adding the in line vertical spiral wound filter to the discharge line after you precipitate the precious metals. That tightly wound, often under 1 micron filter should trap any fines. But you will never be able to quantify it but some day that filter will be worth processing. 

How did you arrive at the values you showed for the sludge of copper powder? I hope it was by dissolution followed by instrumentation. I would never rely on XRF for that analysis.

I again recommend you start processing some silver chlorides. I would bet the farm they are the hiding place for your missing gold, but you insist on chasing rather insignificant values in sludges. 

Process the chlorides, it isn't difficult. We can work you through simple questions here and once you find the gold that you are obviously being whipped for "losing" you will rest better. 

Also, keep in mind the sludges you recover from your filter press are typically dried, incinerated, crushed and sifted to make a product to ship to a copper smelter. That is where any lingering PM's will be found. Although if it is high in Cadmium, the incoming penalties will exceed the recovered value.


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## orvi (Jun 28, 2022)

0,1-0,2 % in sludges is relatively OK, much much better than previous 2% 

As 4metals say, focus on processing the silver chloride. Depending on quantity, you want to go lye/sugar, or better iron/sulfuric. For Fe/H2SO4, you need to construct the system for continous tumbling of iron and AgCl. So maybe classic ca 20L bucket in cement mixer, or some more sophisticated turning system similar to standard drum-ball mill. Lye/sugar also need mechanical stirring, for both conversion to silver oxide and reducing of silver oxide with sugar. In bigger quantity, lye/sugar can become impractical. But with good stirring and temperature management, you can push it maybe to 10kg for a batch, but I never processed more than 2 kg batch.


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## Palladium (Jun 28, 2022)

Several hundred grams, let's call it 500 grams. 2/1000 as gold. So you are getting burnt out over 1 gram of gold? At today's prices that is worth about $60.

I'm just sitting back having my coffee. We both have tried and tried to explain this. I even did a breakdown of the number in the very beginning. I have ask question after question without any clear or concise answers that could give clues to efficiency. I bet he's getting burnt out. On the equipment issues he seems to follow pretty well, but when it comes to the processing he's still chasing ghost. The thought has crossed my mind that either he is the manufacturer of the equipment or knows the manufacturer pretty good and we are doing nothing, but feeding the monster here.

Fine don't take our advice. I'll just have my coffee everyday and read the stories until they come to a logical conclusion of the end. Ignore me until you're broke.


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## Palladium (Jun 28, 2022)

orvi said:


> In bigger quantity, lye/sugar can become impractical. But with good stirring and temperature management, you can push it maybe to 10kg for a batch, but I never processed more than 2 kg batch.


For my scale size using 55 gallon drums 25 lbs per batch is a good number. I've pushed bigger lots, but it becomes a P.I.T.A. past that. That's when i go to multiple barrels to process bigger lots. 4 drums x 25 lbs = 100 lb lots. I can push 100 lbs a day using that system, 500 lbs a week, about a ton a month. I can do that with 100 sq ft floor space.


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## Palladium (Jun 28, 2022)

See above ^^^^^


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## 4metals (Jun 28, 2022)

Ralph,
Nobody has to tell you the value of the often overlooked Silver. From the quantities expected to process at Gold Refineries place and the Silver assay he is looking at upwards of $5,000 a week in Silver value. Yet he is looking for grams of Gold. Kind of like the kid who spills the whole bowl of Cheerios while trying to scoop up the one Cheerio on the floor! 
With the relatively small 2 kg a day of Silver Chloride to reduce, redissolve and collect the gold then drop as Silver Chloride again to reduce to 999+ silver to sell he can, by adding a simple process, know exactly how much gold is in the chlorides and recover a sale able product which he can also vacuum cast into kilo bars.


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## Palladium (Jun 28, 2022)

The value of silver chlorides is crazy at times. I squeeze the pig until it sequels! If he's buying or processing based on just the gold value the chlorides are a free added bonus. I've ask detailed questions about the cost, profit margins, and other efficiency question with no answers. Like what is his accountablity to the client. I give 99%. That other 1% is mine. I'm not chasing that 1%. It's not worth it to me in cost and time. Now once that 1% adds up from so many lots then i'm chasing it. Numbers numbers numbers! That's what drives my processing. Every thing after that procedure wise is based on value both seen and unseen. I don't know if he can't give those numbers or if he don't want to give those numbers. There's a difference. He came here for processing information chemical wise and that's fine, but unless you can see and understand the operation as a whole that alone will not guarantee your success.


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## Shark (Jun 28, 2022)

Having never ran more than 1/2 ounce of karat gold at a time even I know that silver chloride can hide quite a bit of gold. I learned this early on by processing gold filled. I have settling “tanks” or beakers where I leave my wash fluids for extended settling periods. Out of boredom and curiosity I decided to run a small batch and see what was there. Using a 100ml beaker I managed to recover just shy of .1 gram of gold. All this from a 1L beaker with enough material to still be able to see light through it. I also learned that day that not all gold filled is made up of base metals. I have over three gallons of silver chloride to process now and I have no idea how much that will produce in silver metal, but it is going to be an interesting learning experience.


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## Palladium (Jun 28, 2022)

I built my whole business off of gold filled. One mans trash is another mans treasure.
Chris taught me that! I LOVE gold filled!


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## 4metals (Jun 28, 2022)

Although I have never needed to know on a lot by lot basis the gold quantities hiding out in the Silver Chloride unless the lot loss exceeded 0.25%, I never had to chase it daily. But I also did a lot of refining in the time, After the Hunt Brothers made Silver hit $50, when Silver fell to $3 an ounce. But today, when it averages $21 $22 an ounce and you can generate 50 to 60 ounces a day, a small operator in the same or similar position as the OP could set up a dedicated hood with a tumbler for sulfuric and iron to reduce the dirty chlorides to metal. A bucket to digest the metallic silver (stainless steel, it doesn't break) and a buchner funnel with a vacuum to filter out the gold that was trapped in the chlorides. Then add chlorides (salt or Hydrochloric Acid ) and filter it out. Rinse it well and reduce with the caustic and sugar to yield high purity silver. Start to finish, this would take an employee maybe 3 or 4 hours total. And the quick turn around of the "lost" Gold, combined with the "found" income of the Silver would likely pay the salaries of a 4 or 5 man shop. 
Then the OP can rest easy, knowing the accountability within 24 hours of finishing a lot and accounting for all of the gold. Then he can, maybe, answer some of the valid questions members have asked to add even more value to this series of threads.


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## Shark (Jun 28, 2022)

I would think 50 to 60 ounces of silver would be the economical way to go versus 1/4 percent of gold. Based on shear volume of material run and volume of silver chloride recovered it makes sense that the tiny bit of missing gold would most likely be in the silver. But for .25% I would move on. If time is money, that little bit is very expensive to chase.


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## 4metals (Jun 28, 2022)

Truth be told at the quantities the OP is expecting to process major refineries would quote him 1 or 2 dollars an ounce incoming and 99.9 to 99.95% accountability. So less than the 0.25 that is an acceptable loss. Even though it isn’t truly a loss it is more a deferred payment as most of it is found later. Of course they will take a few days to sample and assay but advance you 90% of the value on XRF results and you pay interest on that money until the job settles. So really the majors are more bankers than refiners. 

That means there is a reason it isn’t shipping out and I suspect it is the high Cadmium. There are penalties at most majors for Cadmium and above 1% they won’t even accept it.


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## Shark (Jun 28, 2022)

What ever it is holding it back my next question would be how to deal with it. If it is cadmium then that is my target for removal. 

Would an xrf not detect the cadmium upfront?


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## 4metals (Jun 29, 2022)

Shark said:


> Would an xrf not detect the cadmium upfront?


An XRF absolutely would pick up the Cadmium in the unrefined alloy coming into the refinery. 

But there are multiple reasons why people choose to refine on a smaller scale so we will always see refining operations like this thread is about popping up. 

Given the rates that this quantity of material can be refined for, I would have invested in a furnace to melt the entire lot in one melt and gotten a bag house to catch any particulates coming off the melt (Cadmium) and melted the lot and, using flux and oxygen sparging, cleaned up the incoming alloy. The precious values and copper will not oxidize out of the melt and the Iron, Cadmium, and Zinc in the alloy will either volatilize (hence the bag house) or oxidize and be in the slag. The remaining metal can be cast into bars and shipped to major refiners without incoming penalties for the Cadmium.


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## Shark (Jun 29, 2022)

So if the material is properly melted into shot it could remove much of the base metals (including cadmium). Is there any good reason for not melting it before processing, especially since it seems to provide a beneficial step in the over all goal of purifying the gold.


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## 4metals (Jun 29, 2022)

Most small refiners will not melt material with Cadmium, or at least admit they did it. Without bag house type cleaning of the smoke and Cadmium will be generously shared with the neighborhood. Aside from eliminating Cadmium, the process will not remove copper from the precious metals so the benefit of removing small amounts of zinc and iron will be small. And since the slimes contain Cadmium as per the OP, it does not all pass off in the melting and some remains in the alloy to refine. That leaves the refiner dealing with it as a waste.


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## Shark (Jun 29, 2022)

We can use sulfamic or sulphuric acid to drop lead from AR. At what point would cadmium come out of solution? As a filtering process or is something similar to lead and sulfamic/sulphuric helpful. I am thinking there isn’t much more than the melting since it seems to leave remnants in all areas including the refined metal, waste and bag houses.


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## 4metals (Jun 29, 2022)

Shark said:


> We can use sulfamic or sulphuric acid to drop lead from AR. At what point would cadmium come out of solution?


Both lead and cadmium have a sulfate chemistry, lead is only slightly soluble as a sulfate so it comes out of solution. Cadmium is highly soluble so it stays in solution as a sulfate.


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## orvi (Jun 30, 2022)

I was processing cadmium containing material before, and yes, when you melt it down, Cd could be removed fairly quickly, even without sparging the melt with oxygen. Just simply hold it for hour or so in fairly oxidative furnance (flame) or partially opened electric furnance, and periodically dip graphite rod into the melt and shot with XRF. Eventually, all Cd and Zn will be gone. Cadmium even quicker than zinc, altough not always. Keep the surface of the melt nice and clean, this will speed up the process.

This could, as 4metals say, reasonably cut the toxic waste volume, because you are scrubbing only the "goodies" 
I hope I needn´t to mention that melting cadmium material anywhere without a scrubber is very dangerous not only for you, but also for your neighbors.


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## Gold.refinery (Jun 30, 2022)

We are ready to recover gold and silver from silver chlorides. We kept them wet in gallons. We have two recommendations, 
caustic and sugar - caustic and hydrazine. 
*Both will work, but which is better?* 

If we want to do caustic-sugar, I would like to explain my perceptions, please guide me. 
We have about 2 cm of silver chloride on the bottom of a 12-inch gallon. 
According to previous recommendations, we should dissolve 500 grams of caustic in one liter of water. Then add slowly to the gallons of chlorides (exothermic reaction). 
Then use the reaction heat to add about 400 grams of sugar syrup. Fiz until it is not visible. Stirring is also very important in these steps. 

*Am I right so far?* 

We now have a thick, viscous black solution where silver and gold have settled. 

*Can I use the vacuum filter that I used for gold to wash silver from caustic? 

Can I add HCl to dilute and wash better?* 

*If so, how much am I allowed to add?*


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## 4metals (Jun 30, 2022)

For reasons we discussed earlier, I have avoided using hydrazine whenever possible. So I would choose the caustic sugar method.

Before you drain off the liquid try to use a scoop to scoop up some of the solid you have reduced. Look at the color closely. Any bits of white indicate poor stirring and incomplete conversion of Silver Chloride to Silver Oxide. Silver Oxide is black and the Silver metal you wish to have when this process is complete is silver-gray in color. 

Before you filter it, make sure you have had a complete conversion.



Gold.refinery said:


> Can I use the vacuum filter that I used for gold to wash silver from caustic?


Use a filter that you do not use for refined gold. That filter should be a single use filter to avoid contamination. Since you will be re-dissolving the Silver metal to get the Gold, you do not have to be concerned with a little cross contamination. When you process the silver a second time after recovering the gold, you want a clean filter.



Gold.refinery said:


> We have about 2 cm of silver chloride on the bottom of a 12-inch gallon.


This is a small quantity, your filters are made for much bigger lots. consider a buchner funnel with a vacuum suction, or for this small quantity a speed funnel with folded paper and gravity draining. Gravity draining will not be the best for rinsing but that is not critical for the first run where the Silver contains Gold.

If you put this small quantity of Silver nitrate from dissolving the first reduction through your big filters you will lose values. Use a filter system appropriate for ths size you are working with.


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## Palladium (Jun 30, 2022)

I'm sure you have kept up with the numbers. If you give us how much silver your numbers say is there we can give you estimates on the amount of water and chemicals you need. You use to much an amount of water and your not going to produce a lot of heat which aids in the process.


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## Gold.refinery (Jun 30, 2022)

Palladium said:


> If you give us how much silver your numbers say is there we can give you estimates on the amount of water and chemicals you need


The percentage of silver in our input was 6%. We refined 14,000 grams of gold feed. We should probably get about 800 grams of silver and hopefully the trapped gold will also be recovered.


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## Palladium (Jun 30, 2022)

It takes about 20g of NaOH, 133ml of tap water, and 13.3ml of light Karo per troy oz of silver (41.3g of AgCl). I like to use about 10% extra of each. 1ml of syrup = 3 grams sugar.

800 grams of Metallic silver expected..... 800/31.1 = 25.7 oz
NaOH = 25.7 oz X 20 = 514 + 10% = 566 grams
133ml water X 25.7 oz = 3,418 + 10% = 3,760ml
Sugar 25.7 oz X 13.3ml (syrup) = 342 + 10% = 375 ml syrup ( 1,127 grams sugar )


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## 4metals (Jun 30, 2022)

How many grams of gold are you missing in total? And does that include the larger chunks of chloride encrusted gold you were able to remove from the finer particles of Silver Chloride?


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## Palladium (Jun 30, 2022)

You should be able to do this in a 5 gallon plastic bucket in a fume hood. Use a drill and a stainless paddle mixer. Mixing and chopping is essiential to break it up and insure a complete reaction. Since you're going to do a double refine on the silver this will be a good learning lesson. The chlorides you don't convert will be left over with the gold when you redissolve it into nitric the second time.


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## Palladium (Jun 30, 2022)

Gold.refinery said:


> *Am I right so far?*
> 
> We now have a thick, viscous black solution where silver and gold have settled.


Just for *clarity* here. The solution will be black when you add the NaOH because the silver will be an oxide BEFORE you add sugar to convert it. Then the silver will turn grey and the solution will be a brown syrupy color like Coca-Cola. Don't pour the silver and waste solution into the vacuum filter at once. Once the silver packs down in the funnel it will be harder to wash. Pour the excess solution into the filter leaving the silver in the container. Then add water (Hot) and wash it again. Pour that through the filter still leaving the silver in the vessel. After a couple of washes you can then pour the silver into the funnel to complete the rinsing.


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## Gold.refinery (Jun 30, 2022)

Palladium said:


> It takes about 20g of NaOH, 133ml of tap water, and 13.3ml of light Karo per troy oz of silver (41.3g of AgCl). I like to use about 10% extra of each. 1ml of syrup = 3 grams sugar.
> 
> 800 grams of Metallic silver expected..... 800/31.1 = 25.7 oz
> NaOH = 25.7 oz X 20 = 514 + 10% = 566 grams
> ...


Thank you sincerely, very helpful. Like a lamp in the dark.


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## Palladium (Jun 30, 2022)

Gold.refinery said:


> Thank you sincerely, very helpful. Like a lamp in the dark.


WEAR EYE PROTECTION! Caustic acid will PERMANENTLY damage your eyes. Fear caustic more than acids! This process will have small aerosol particles that will get in your eyes if not careful.


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## Gold.refinery (Jun 30, 2022)

4metals said:


> How many grams of gold are you missing in total? And does that include the larger chunks of chloride encrusted gold you were able to remove from the finer particles of Silver Chloride?


When washing silver chloride in each operation, we separated the undissolved fine particles. 

We did not get *50.6* grams of gold in total *13,595* grams of refining operations. 
This deficit includes :
chemical operations, 
analysis Mistakes, 
initial and final melting operations.


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## Gold.refinery (Jun 30, 2022)

Palladium said:


> Just for *clarity* here. The solution will be black when you add the NaOH because the silver will be an oxide BEFORE you add sugar to convert it. Then the silver will turn grey and the solution will be a brown syrupy color like Coca-Cola. Don't pour the silver and waste solution into the vacuum filter at once. Once the silver packs down in the funnel it will be harder to wash. Pour the excess solution into the filter leaving the silver in the container. Then add water (Hot) and wash it again. Pour that through the filter still leaving the silver in the vessel. After a couple of washes you can then pour the silver into the funnel to complete the rinsing.


We have an old italimpanti filter. 
In the previous operation we used to filter the *gold sponge*. It worked well. 

After rinsing the Coca-Cola solution twice with hot water, *can we use this filter to finally wash the silver with 2 filter paper?*


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## Palladium (Jun 30, 2022)

I can't tell the dimensions on that, but it looks pretty large for less than 2 lbs of silver. Do you have a smaller Buchner?


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## Palladium (Jun 30, 2022)

Quick question i never heard answered. Do you have a fume hood and glassware such as a 2,000ml beaker? I personally, and this is just me, would take the crusted pieces of gold and add some NaOH to the pieces. This will convert the crust to metallic silver. Then wash a couple of times. Then when you do ar don't add any hcl at first. Add the Nitric. This will dissolve and penetrate the gold deeper. If you add hcl and nitric you will create another crust barrier. Once you add the Nitric let it work on a warm hotplate for a few minutes. Then you can add your hcl which will turn any silver into silver chlorides. Filter your gold from the chlorides and drop it. You can then put the chlorides right back into the process again with the next batch. You are going to need a smaller Buchner funnel to filter the gold solution with. This will also give you visual references to go by that shows you what is happening on larger scales.


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## Gold.refinery (Jun 30, 2022)

Palladium said:


> I can't tell the dimensions on that


Dimension us 35 cm.


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## Palladium (Jun 30, 2022)

13 inches. A little bigger than a 5 gallon bucket. Yeah that should work if it's all you have, though it would be harder to clean out verses a smaller Buchner you can physically dump. You will still need a smaller Buchner for the solutions though.


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## Gold.refinery (Jun 30, 2022)

Palladium said:


> Quick question i never heard answered. Do you have a fume hood and glassware such as a 2,000ml beaker?


We have not glassware and fume hood


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## 4metals (Jun 30, 2022)

Gold.refinery said:


> After rinsing the Coca-Cola solution twice with hot water, *can we use this filter to finally wash the silver with 2 filter paper?*


The Italimpianti filter is the best filter you have, you should reserve it for your precipitated gold and nothing else. You don't want to contaminate it with silver. 


Gold.refinery said:


> Dimension is 35 cm.


That's a big filter for the relatively small quantity of silver you will recover. And for less than 2 ounces of gold you will have a hard time cleaning it all out. 

Get a porcelain 2000 ml capacity Buchner funnel and a vacuum jug and it will handle all of your smaller lots and cleanups. It uses inexpensive 18cm filter papers available in a wide variety of filtration speeds.


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## 4metals (Jun 30, 2022)

Gold.refinery said:


> We have not glassware and fume hood


Having one will make your routine silver cleanups simple and you have the scrubbing capacity to add some scrubbed drops to handle any noxious fumes. Without a hood you will be forced, as you were when you converted the silver chlorides, to work in the open shop or use the tumbler for lots too small to handle effectively. The hood will be a welcomed addition for the folks that have to work in the shop daily.


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## AMS-Pro (Jul 1, 2022)

Looks like someone needs to make a trip to Yamato, or Kalstein.


Get one of these type of setups, and run it parallel with your filter press if you're not changing your setup around.


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## orvi (Jul 1, 2022)

It is very good for lye-sugar conversion of AgCl to have a vessel that is able to be heated. Sometimes I found very helpful to heat the solution near boiling point and the conversion is done (with good mechanical stirring) under hour or two.*

Be aware of the fact that this is extremely exothermic reaction, which HAS INDUCTION PERIOD*. So if you dump all of the syrup/sugar at once to the hot silver oxide suspension, it will spatter out of the vessel in less than a minute. Hot caustic eat flesh in seconds, trust me.

With bigger quantities, you absolutely want a thermometer sticked in the suspension. You will watch a temperature rise - it always have induction period, so max temperature is reached after some time, so be patient. When temperature stop climbing and start to go down, you can add another portion of syrup/sugar. To the 110°C it is usually fine, than it start to boil.
When you add portion of syrup/sugar and temperature stop rising, reaction is over.

I never experienced like 10 kg of AgCl in one batch, but I have done 2 kg of AgCl and you absolutely don´t want to overadd the sugar


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## Gold.refinery (Jul 3, 2022)

After performing the initial operation and obtaining the silver metal powder, 
in order to dissolve the silver powder in nitric acid and obtain the trapped gold, 
for example, 
*how much nitric acid is needed for 1 kilo of powder? 
What is the Specification of the reaction? 
Is it hot?* 
*Does it have fume?*


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## Gold.refinery (Jul 3, 2022)

Which one is better for mixing silver chloride with caustic and sugar? 
Vertical mixer or magnet stirrer


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## Gold.refinery (Jul 3, 2022)

Since a vacuum pump is needed for the *Buchner funnel*, 
is a manual vacuum pump sufficient or should we get a separate pump? 
Can we use the vacuum pumps of Refine device?


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## orvi (Jul 3, 2022)

Gold.refinery said:


> Which one is better for mixing silver chloride with caustic and sugar?
> Vertical mixer or magnet stirrer


For AgCl conversion, you definitely need mechanical stirrer. Or stirring at least with drill bit for stirring cement attached to a drill. It need agressive mixing, otherwise it wont react and silver chloride will be left in the silver at the end of the process.
Magnetic stirrer can stir AgCl only up to 100-200g, 300 max. Then it just stop, because it is very difficult for the magnet to turn such a mass.


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## Palladium (Jul 3, 2022)

Gold.refinery said:


> After performing the initial operation and obtaining the silver metal powder,
> in order to dissolve the silver powder in nitric acid and obtain the trapped gold,
> for example,
> *how much nitric acid is needed for 1 kilo of powder?
> ...


It takes 1.2 ml of 67-70% nitric acid to dissolve 1 gram of pure silver.
1000 grams X 1.2ml = 1200ml of Nitric to dissolve 1 kilo. You will also add the same amount of water as you need nitric acid. So a total of 1200ml of Nitric acid and 1200ml of water.
Will it get hot? Yes, Boiling hot!
Yes it will fume.


For future reference....... For copper It takes 4.15 ml of 67-70% nitric acid to dissolve 1 gram of pure copper. When using copper to cement silver from nitric acid (Not needed for agcl) it takes 1 gram of copper to drop 3.4 grams of silver from solution. But if you have excess Nitric in the solution it will chew up the copper and put off red fumes, before it will start dropping the silver. The silver that drops from excess Nitric will also be dirtier. That's a lot of extra copper and cost. That's why it important to watch the Nitric numbers when using the cementation process. With agcl excess Nitric is not a problem except for wasted chemicals.


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## Gold.refinery (Jul 3, 2022)

Palladium said:


> For future reference....... For copper It takes 4.15 ml of 67-70% nitric acid to dissolve 1 gram of pure copper.
> When using copper to cement silver from nitric acid it takes 1 gram of copper to drop 3.4 grams of silver from solution.


After adding nitric acid and water to the silver powder, the gold remains undissolved after the reaction is over. 
We filter the solution and get gold. 
Then we react silver nitrate solution with hydrochloric (HCl)acid to obtain silver chloride. 
*Right? *(How much HCl?) 

Caustic / sugar method again and obtaining pure silver powder.


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## Palladium (Jul 3, 2022)

I don't use hcl. I use regular salt for mine. Don't know those numbers. But if using hcl you can add about 500 ml while stirring vigorously. Give it a minute to stir. It's almost immediate. Then add about 10ml more and watch for a white cloud reaction. If you see the milky color of agcl add more. Keep running the same test until no more white milk is seen. At that point the silver is out of solution. Get you a notebook and keep track of all these formulas you will be using for future reference. It will serve you the rest of your refining career. That way using hcl you can a reference for your numbers.


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## 4metals (Jul 4, 2022)

Palladium said:


> Yes it will fume.


And it will produce nasty, red, NOx, not something you want wafting about the shop and not a fume that I have ever found an effective mask to filter NOx out of the air column you breathe. This is a good example of the need for a fume hood in your shop.  You will be doing this procedure routinely, it will never be advisable to do it in your tumbler plant which is connected to a fume scrubber. When considering what the daily operations are in a refinery such as the OP set up, I am surprised the manufacturer of the equipment didn't recommend putting a hood in place. And, the more experience you gain in refining, the more you will realize just how important it is to have a fume hood for testing and for small lots which will come in once you are established, and potential customers know you are a refiner. 



Gold.refinery said:


> Then we react silver nitrate solution with hydrochloric (HCl)acid to obtain silver chloride.
> *Right? *(How much HCl?)


This is one of the procedures a refiner learns to do by eye. Surely, we can calculate the exact stoichiometric quantity of either salt or Hydrochloric Acid but experience and simple testing will prove more practical in the end. 

To test the solution to see if the silver is all out, simply take a single drop of the solution and drip it into a small beaker of chlorinated tap water. If the water coming out of your tap is chlorinated it will have a slight odor of chlorine, if not, a few grains of table salt or a milliliter or so of Hydrochloric Acid will give you the chlorine needed. If the drop of solution has no silver in it, the drop will disperse without a cloud left behind. But if Silver is present, a cloud of white silver chloride will be seen. This is a quick test which can detect very slight quantities of Silver. It is advisable if you use this test to try it on solutions you know to contain a decent quantity of Silver as well as diluted solutions containing very little Silver. Then you can see what to expect from the test.


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## 4metals (Jul 4, 2022)

Gold.refinery said:


> Since a vacuum pump is needed for the *Buchner funnel*,
> is a manual vacuum pump sufficient or should we get a separate pump?
> Can we use the vacuum pumps of Refine device?


The double diaphragm pumps on the Italimpianti filters are plumbed such that you can either provide suction to the filter or shut off that side and open the other inlet port to provide suction as needed elsewhere. 

Provide the details and a photo of the double diaphragm pump on your filters and we can determine if they can do the same thing.


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## Palladium (Jul 4, 2022)

4metals said:


> And, the more experience you gain in refining, the more you will realize just how important it is to have a fume hood for testing and for small lots which will come in once you are established, and potential customers know you are a refiner.


That's where the real butter comes from percentage wise. I have clients whom i charge 5-7% and then i have clients who i charge 20% for the same materials. Volume gets the discount, but i can make the same profit spread on smaller lots with less chemicals, processing, and time. I can make a $1,000 on a small lot or i can make $1,000 on a large lot, but at the end of the day i'm eating!

NUMBERS NUMBERS NUMBERS!


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## Palladium (Jul 4, 2022)

4metals said:


> The double diaphragm pumps on the Italimpianti filters are plumbed such that you can either provide suction to the filter or shut off that side and open the other inlet port to provide suction as needed elsewhere.
> 
> Provide the details and a photo of the double diaphragm pump on your filters and we can determine if they can do the same thing.



That's one i didn't know how to answer once i got to thinking about it. I mean i do, but i don't because i don't know what type of Buchner he's going to use it with. With my diaphram air pumps there is just a second between the cycles where the pressure or suction drops as it cycles from one side to the other. I have two different types. One has balls that check the flow and the other ones have fingers like a pyramid that opens on three sides and that closes to check the flow. Using a big filter with a hold down ring it doesn't matter, but with a filter that requires suction to seat the filter i was wondering about the filter paper floating at the edges and not sealing.


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## 4metals (Jul 4, 2022)

Palladium said:


> Using a big filter with a hold down ring it doesn't matter, but with a filter that requires suction to seat the filter i was wondering about the filter paper floating at the edges and not sealing.


Good point Ralph. You could put a vacuum jug or a fat section of pipe with an inlet and outlet to hold a vacuum reserve and with valves keep the flow through the filter slower than the actual flow the pump can generate. Then you can assure suction to seat the paper. 

I don’t know if I mentioned this, to many it is obvious, but with a buchner funnel you suck into a vacuum receiver which holds the liquid. The diaphragm pump will not be passing liquid in this application, just air.


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## orvi (Jul 5, 2022)

Gold.refinery said:


> After adding nitric acid and water to the silver powder, the gold remains undissolved after the reaction is over.
> We filter the solution and get gold.
> Then we react silver nitrate solution with hydrochloric (HCl)acid to obtain silver chloride.
> *Right? *(How much HCl?)
> ...


Here, I would proceed slightly differently. Lye/sugar is much much more labor intensive than copper cementation. 

I would advise to convert gold containing AgCl with lye/sugar to silver, RINSE IT VERY WELL FROM CHLORIDES, dissolve the silver in nitric acid in such way you do not use excess. Then filter the remaining undissolved gold, and cement the silver solution on copper to get the silver in one step without any big efforts.


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## 4metals (Jul 5, 2022)

orvi said:


> Here, I would proceed slightly differently. Lye/sugar is much much more labor intensive than copper cementation.


I think this is all a matter what Gold Refinery is going to do with the silver.

It is absolutely true that for ease of obtaining a silver concentrate nothing is as easy as cementation. But the best he can hope for is 99% purity.

The first time around, with the silver chlorides from the aqua regia process the options all revolve around reducing the chlorides. So the options are either the Lye/sugar or the sulfuric/iron. 

It's the re-dissolve silver, after the insoluble gold is recovered, and we have silver nitrate in a pretty clean clear solution as the base metals are out already from the aqua regia. 

When considering all of the refining toys Gold Refinery has, we cannot forget he has a vacuum casting setup to make gold bars for sale. That same machine can produce (in different molds) silver bars for sale. Since this is an option, Gold Refinery can get the best price for his Silver bars. So I would choose Lye/sugar because it has the potential to make 999 silver for resale as bars. Why would he choose to use cemented Silver at 99% (on a good day) to cast bars for resale? 

My first choice for the Silver bars would be electrolytic refining of Silver followed by recovery of the Gold from the slimes, but the volume seems too low for this and, to be honest, we have written over 20 pages on the refining and waste from Gold Refinery for a simple process like karat gold refining. I cannot imagine how long the thread would become for a soup to nuts description of electrolytic silver refining.


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## orvi (Jul 5, 2022)

4metals said:


> I think this is all a matter what Gold Refinery is going to do with the silver.
> 
> It is absolutely true that for ease of obtaining a silver concentrate nothing is as easy as cementation. But the best he can hope for is 99% purity.
> 
> ...


Yes, now I see it. You are absolutely right. Added value would be much higher in comparison with work.
I was considering he will somehow manage to setup small cell to refine to 4N Ag. But yeah, we still don´t have refining right


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## 4metals (Jul 12, 2022)

Looks like Gold Refinery has washed his hands of us, he hasn't posted any follow up in 9 days. A shame really, I think we gave him a lot of valuable information which will undoubtedly help his business, but a follow up with real information would be nice to complete the topic.


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## Yggdrasil (Jul 12, 2022)

4metals said:


> Looks like Gold Refinery has washed his hands of us, he hasn't posted any follow up in 9 days. A shame really, I think we gave him a lot of valuable information which will undoubtedly help his business, but a follow up with real information would be nice to complete the topic.


Well we have seen that before. A simple thank you would have been nice though.


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## AMS-Pro (Jul 12, 2022)

Yggdrasil said:


> Well we have seen that before. A simple thank you would have been nice though.



At the very least, a thank you for our time is in order.
Unknown answer to questions, and an unknown resolve to problems. It's like leaving us with the equivalent of a 2/3s completed puzzle, and no more pieces left in the box to finish it. Frustrating.


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## Shark (Jul 12, 2022)

I can say Thank You, I have learned a lot from this and the related threads. 

Thanks, for all the input.


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## AMS-Pro (Jul 12, 2022)

Shark said:


> I can say Thank You, I have learned a lot from this and the related threads.
> 
> Thanks, for all the input.


Thank you, and thank you as well to everyone one else for your contributions too.

It was certainly an interesting project to work together on, if at the least for a little while. Hopefully the OP has just gotten into a groove, and that they will return to continue, and maybe provide some closure on the subject.


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## Palladium (Jul 12, 2022)

I've been wondering where he's at myself. Sometimes things happen that are not within our control. This may be one of those times. The worlds a crazy place right now. Time will tell the tell. I do wish him success and hope we will see his return. His education and ours is not complete yet. The time we invested not only serves his interest, but those of future generations that may read this thread. The purpose of our contributions will serve many long after we are gone. That's my main motivating factor regardless of the here and now.


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## FrugalRefiner (Jul 12, 2022)

Palladium said:


> I've been wondering where he's at myself. Sometimes things happen that are not within our control. This may be one of those times.


Very true. I was offline for 5 days due to an EF2 tornado hitting our area last Wednesday. We're fine. In fact, there were actually no significant injuries during the storm, though there were several during the clean-up. I hope he returns to give these threads proper closure.

Dave


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## Gold.refinery (Jul 19, 2022)

Hi guys; 
Although your expectations are right, you made a quick judgment. 
Sometimes there are problems that make you tired of working. Of course, it has already been with me
I had many problems and I don't go to work at all. 
(I haven't done anything to the chlorides yet) 
I'll be active as soon as I fix the issues. 

I will not forget your support without any expectations.


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