# Getting Ag from AgNO3 using Cu powder



## hrushi

Hello 
I have been trying this for past few months and found it to be useful and easy to recover Ag from Ag NO3 using Cu powder
I tried for few days and now i want to share with all of you 
I could recover 15-25Kg of Ag in just 15-20mins

This is my precipitating vessel


This is my precipitating vessel with stirrer





on left side of vessal there is stirrer which has black handle with PP sheet at its bottom 

After putting AgNO3 in vessel and add Cu powder. and stir the sol you will see Ag in tank
you can check Ag is fully recovered by adding Hcl to it if white spots apper after adding Hcl means Ag is Still In Sol 
so add Bit more Cu These you hav to do till all Ag is precipitated 
I may not be clear in above process
I will try to add video soon.
If any queries ple feel free to ask
Hrushi


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## Harold_V

Hrushi,
An interesting process---but you do realize that you can accomplish the same thing with copper pieces, don't you? It's much simpler---all you have to do is put pieces of copper in the silver nitrate solution and wait. The more copper you use, the faster the conversion. Once finished, you simply remove the undissolved pieces of copper, and rinse the copper nitrate from the cemented silver. 

The real advantages to using copper pieces is that no particular equipment is required, and it's a lot easier (and likely one hell of a lot cheaper) to obtain solid copper than it is to obtain copper powder. 

I'm not trying to detract from your accomplishment---just hoping to point others in a direction that is far easier and not demanding of equipment. 

Harold


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## hrushi

> Hrushi,
> An interesting process---but you do realize that you can accomplish the same thing with copper pieces, don't you? It's much simpler---all you have to do is put pieces of copper in the silver nitrate solution and wait. The more copper you use, the faster the conversion. Once finished, you simply remove the undissolved pieces of copper, and rinse the copper nitrate from the cemented silver.



True recovering with Cu bars is much easy but it takes much more time. Every time we have wash Cu rods properly or for long time ow if we keep Cu bars in open air they either turn black or green and if we use those for recovering Ag then we cannot achieve purity



Harold_V said:


> The real advantages to using copper pieces is that no particular equipment is required, and it's a lot easier (and likely one hell of a lot cheaper) to obtain solid copper than it is to obtain copper powder.



true equipment is not required.
we don't have to buy Cu powder we can use Cu powder which we can easily get from CuNO3 which is left with us. Its completely free.
I found this process more easy than electrolytic recovery or recovery using Cu bars
Thanks
Hrushi


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## goldsilverpro

Although you'll never get 999 from a cementation process, I would think the purity would be less with Cu powder than with Cu bars, due to possible Cu entrapment. Of course, if you're purifying it further, it wouldn't make much difference.


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## Oz

This sounds similar to what I was suggesting to Manuel in another silver thread, only hrushi is not casting his copper sponge to bar form to use in cementing.

The copper sponge would certainly speed things up due to the greater surface area, but I share the concerns of excess copper contamination. Perhaps there is a way around that, that is the best of both worlds. If the material being processed is already bought and paid for, you would know the silver content. Knowing the silver content digested in your solution, you could calculate in grams 90% of the silver content and add 3.4 grams of copper sponge (dry weight) for every gram of that 90%. With good agitation, that should be low enough to assure complete use of the copper sponge in a timely manner and give you 90% recovery as cement silver. After separating your cement silver from your solution, the remaining solution could be put into settling tanks with copper bars to finish recovering the last 10% of your silver. That should give you 1% or less copper contamination if you wash your cement silver well.

It is worth noting that it is the final stages of cementing out you silver that are the slowest. Trying to get that last bit of silver nitrate in a mostly copper nitrate solution to physically touch the copper and cement is the problem. Some method of agitating or stirring the solution will help greatly. 

Something to keep in mind when speeding up the cementation process with either greater surface area of copper or by adding heat. The faster you drive the reaction the more NOX fumes it will off-gas. Not a big deal with proper fume control, but it may make a difference if you are re-using your nitrate solutions after reclaiming your copper from them to digest more silver. It depends on if loss of time or nitric costs you the most.

Ps; hrushi, I would enjoy seeing that video of your process.


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## rbramsey

Oz said:


> The faster you drive the reaction the more NOX fumes it will off-gas. Not a big deal with proper fume control, but it may make a difference if you are re-using your nitrate solutions after reclaiming your copper from them to digest more silver. It depends on if loss of time or nitric costs you the most.



How do you go about reusing your nitrate after copper cementation? and how are you reclaiming your copper?

Richard


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## Oz

I made the assumption since they were getting their copper powder for free from leftover nitrate solutions that the were electrowinning the copper. This leaves you a nitrate that is reduced in copper and has free nitric available for digestions.

Electrowinning the copper is done with DC current with an inert anode (such as graphite) and a copper cathode. LaserSteve has written about this elsewhere on the forum.


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## rbramsey

Dah, I was having a brain loss moment. I read more into your post than was there. I was thinking you were doing some chemical method, that's what was confusing me.

Richard


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## hrushi

I was able to recover 100% of Ag every time without knowing content of Ag in sol and also 999 purity every time
I will surly add video soon 
Hrushi


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## hrushi

I have added small clip watch this link
http://www.youtube.com/watch?v=5UgWpz7Rhf8
I am going for vacation for few days I will add video of full process as soon as I come back .
Hrushi


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## 4metals

Are you adding a precise quantity of copper to stoichiometrically replace the silver?


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## goldsilverpro

This is a very interesting process and I see merit in it. The copper looked beautiful and pure and I would be very interested in knowing it's source and how you prepared it.

However, I think 4 metals hit on the crux of the situation in this statement:



4metals said:


> Are you adding a precise quantity of copper to stoichiometrically replace the silver?



If you are trying to maximize purity, any excess of copper would have a negative effect. Unlike copper buss bars, you can't pull out the excess copper powder and any remaining will contaminate the silver. Too little copper will leave silver in solution. You can't guess on this and there are no accurate visual clues. You need to know (a) The amount of free nitric in the solution and (b) The amount of silver in the solution. 

(a) is easily solved by using less nitric than is necessary to dissolve all of the silver in the batch. In other words, when all of the nitric is spent (preferably heating the solution at the end), there should be some undissolved silver remaining on the bottom of the container. Only by doing this will there be essentially zero free nitric. A liter of nitric, diluted to 2 liters with distilled water, will dissolve close to 821 g of Ag or 240 g of Cu. I would use enough nitric yo only dissolve 90-95% of the metal.

(b) is solved by knowing exactly how much silver is in the solution. This is known by either knowing exactly how much silver was dissolved (difficult) or by analyzing the solution. The latter is cheap (about $100 setup cost), fast (5 minutes), and easy to do using the Volhard titration method.

Here's how I would do this for maximum silver purity:

(1) Use only enough nitric (plus distilled water) to dissolve 90-95% of the silver alloy. Heat at the end. If too much nitric is used and all the alloy dissolves, add enough more alloy until all the nitric is spent and some metal remains. Put the remaining metal in the next batch.
(2) Accurately measure the total volume of solution, analyze the silver content, and calculate the total silver in solution.
(3) Depending on how good you are at this, add enough Cu powder to cement between 95 and 99% of the total silver. It takes about .294g of Cu to cement 1g of silver. Instead of mixing by hand, use a stainless paint mixer (one with a chopping action) chucked in a drill or a small motor.
(4) When all the Cu has reacted, remove the stirrer and hang some Cu buss bars or clean pipe in the solution to cement the remaining 1-5% of the silver. Remove and clean off the bars.

Steps (3) and (4) are added because it would be very difficult to determine exactly the amount of Cu needed to cement 100% of the silver. 

I doubt if all this will add more than 20-30 minutes of labor to each batch.


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## lazersteve

Chris,

You have the copper and silver ratios reversed:

2 AgNO3 + Cu --> Cu(NO3)2 + 2Ag

2 *107.8 = 215.6 g Ag
1 * 63.55 = 63.55 g Cu

215.6 / 63.55 = 3.39 g of Ag per gram of Cu used.

So 1 gram of Cu precipitates ~3.4 g of Ag.

Steve


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## goldsilverpro

lazersteve said:


> Chris,
> 
> You have the copper and silver ratios reversed:
> 
> 2 AgNO3 + Cu --> Cu(NO3)2 + 2Ag
> 
> 2 *107.8 = 215.6 g Ag
> 1 * 63.55 = 63.55 g Cu
> 
> 215.6 / 63.55 = 3.39 g of Ag per gram of Cu used.
> 
> So 1 gram of Cu precipitates ~3.4 g of Ag.
> 
> Steve



Sorry about that. I edited my post. Thanks, Steve.


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## Barren Realms 007

He had stated that he adds a little bit of HCL till he gets no white silver cloride reaction reaction and then he seperates the material and adds a copper bar to the liquid to finish the process.


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## HAuCl4

I wonder what hrushi's washing procedure is for the silver crystals and if he uses anything to leach the silver crystals after washing and before melting. An hour in ferric chloride with stirring cleans up pretty much any excess copper and leaves silver 999+ with iron traces as the main contaminant.

4metals formate method seems more straightforward though (haven't tried it yet).

edit: I just saw the video and his stirring tank is made of...steel, and he is adding HCl...voila ferric chloride is in there somewhere!. 8)


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## machiavelli976

Wow! Ferric chloride is been used for a long time for etching silver . The byproduct is silver chloride of course. Another mess :lol: Steel (iron) and HCl don't react resulting ferric chloride , but FeCl2. And that tank looks pretty stainless :roll:


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## 4metals

The thing that interests me about this is the ease of treating the waste acid. In a formic reduction a complex is formed which is a pain to break causing extra steps and specialty chemicals to clean up the acid. 

When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well. 

What I think Hrushi meant by adding hydrochloric was testing a drop of the blue acid in water containing a few drops of hydrochloric. Any silver still in solution will turn a cloudy white. I do not think he is adding hydrochloric to the silver nitrate.


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## Barren Realms 007

4metals said:


> The thing that interests me about this is the ease of treating the waste acid. In a formic reduction a complex is formed which is a pain to break causing extra steps and specialty chemicals to clean up the acid.
> 
> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.
> 
> What I think Hrushi meant by adding hydrochloric was testing a drop of the blue acid in water containing a few drops of hydrochloric. Any silver still in solution will turn a cloudy white. I do not think he is adding hydrochloric to the silver nitrate.



_



After putting AgNO3 in vessel and add Cu powder. and stir the sol you will see Ag in tank
you can check Ag is fully recovered by adding Hcl to it if white spots apper after adding Hcl means Ag is Still In Sol 
so add Bit more Cu These you hav to do till all Ag is precipitated

Click to expand...

_
His english in the thread seems to be pretty good, hopefully he will be back soon and clarify what he is doing


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## machiavelli976

I would be tempted to use some kind of ultrasonic device to shake like hell that mixture. I can imagine every silver crystal hiding a tiny grain of copper , larger than obtained from usual cementing. 99% silver purity, no way.


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## HAuCl4

4metals said:


> The thing that interests me about this is the ease of treating the waste acid. In a formic reduction a complex is formed which is a pain to break causing extra steps and specialty chemicals to clean up the acid.
> 
> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.
> 
> What I think Hrushi meant by adding hydrochloric was testing a drop of the blue acid in water containing a few drops of hydrochloric. Any silver still in solution will turn a cloudy white. I do not think he is adding hydrochloric to the silver nitrate.



Check Hoke's description of procedures for cementing/cleaning up the silver chloride at the Homestake mine after Miller processing. At the end there is a pretty thorough description of getting the silver crystals cleaned up with *ferric chloride* and washing with HCl. Those crystals are about the dirtiest cemented silver that can be had as feed by man or beast. And yes, there will be *some* AgCl at the end to deal with. I didn't learn it from there, but from trial and error. :shock:

From the video it seems the bucket on his left has HCl and leaves a little white cloud when added to the blue liquid.

Boy, am I glad that is Hoke claiming 9995-9997 silver and not me... :lol:


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## HAuCl4

4metals said:


> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.



Cementing the silver nitrate with silver foil or silver dust and filtration an option here do you think?. :?:

(Clarification: With the purpose of filtrating out all PMs except silver, before the silver drop).


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## Platdigger

You need a metal higher in reactivity than the metal you are trying to cement out.


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## goldsilverpro

HAuCl4 said:


> 4metals said:
> 
> 
> 
> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.
> 
> 
> 
> 
> Cementing the silver nitrate with silver foil or silver dust and filtration an option here do you think?. :?:
> 
> (Clarification: With the purpose of filtrating out all PMs except silver, before the silver drop).
Click to expand...


I see what you're saying. It may work. However, the potential differences are so slight on the PM end of the EM series, PM cementation may be incomplete or not happen. Also, the EM series chart is based on pure systems and, in practice, things like contamination, acid strength, temperature, etc., can produce deviation from the ideal.


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## Platdigger

OK, I see it now also Chris.
When I first read it I thought he was suggesting cementing out silver on or with silver.


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## goldsilverpro

Platdigger said:


> OK, I see it now also Chris.
> When I first read it I thought he was suggesting cementing out silver on or with silver.



Me, too.


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## Barren Realms 007

Thought the same thing then I read between the lines and figured it out and let one of you answer that one.


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## HAuCl4

In theory it should work, in practice I can see problems filtrating the bulky solution and retaining the fines. When using a cell this is no problem since the mud gets retained and concentrated slowly in the anode bags, but here there maybe practical problems or the filtration may take a very long time. The cementing could take a long time too. Only an experiment will tell the tale.


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## hrushi

Well I had a long vacation now finally back at work
I would be answering all your doubts
I really appreciate all of you for your great study and experience in this field
I am totally new I hardly have experience of few years.
I am not technically sound as you people are.
I don't want to challenge any body or test anyone.
I would be posting all my replies based on my practical experience.
SO please don't feel offended.
I have learned a lot from all you guys.
Thank You all 
Hrushi


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## hrushi

goldsilverpro said:


> Although you'll never get 999 from a cementation process, I would think the purity would be less with Cu powder than with Cu bars, due to possible Cu entrapment. Of course, if you're purifying it further, it wouldn't make much difference.


Hello GSP
I would say every time I get 999+ Ag with the process.
Yes Cu entrapment is there but if we stir it well Cu entrapment is not there and slowly all Cu is dissolved.
Hrushi


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## hrushi

4metals said:


> Are you adding a precise quantity of copper to stoichiometrically replace the silver?


No.
Firstly we have to thoroughly stir the sol.
It completely depends on how much thick is the AgCl spot appears after add HCl.
If AgCl spot is thick after good stirring then add Cu powder and don't add large quantity of Cu at a time add in small parts it is really helpful. Slowly AgCl spot will faint. And finally there would be no AgCl spot even after adding HCl all Ag will be cemented.
If after adding HCl if Dark or black spot appears then it indicates that we have added excess Cu no need to worry. Excess Cu can be removed by add some AgNO3 if we have or take 5lts of H2O add 250mL of H2SO4 and put in cemented Ag and stir it for some time you can do this for 1-2 times more.
Please be careful while adding Cu powder it is very important that we small parts of Cu powder.
Hrushi


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## hrushi

Hello GSP


goldsilverpro said:


> This is a very interesting process and I see merit in it. The copper looked beautiful and pure and I would be very interested in knowing it's source and how you prepared it.


I recovered Cu from left over CuNO3 using Fe 


goldsilverpro said:


> If you are trying to maximize purity, any excess of copper would have a negative effect. Unlike copper buss bars, you can't pull out the excess copper powder and any remaining will contaminate the silver. Too little copper will leave silver in solution. You can't guess on this and there are no accurate visual clues. You need to know (a) The amount of free nitric in the solution and (b) The amount of silver in the solution.
> 
> (a) is easily solved by using less nitric than is necessary to dissolve all of the silver in the batch. In other words, when all of the nitric is spent (preferably heating the solution at the end), there should be some undissolved silver remaining on the bottom of the container. Only by doing this will there be essentially zero free nitric. A liter of nitric, diluted to 2 liters with distilled water, will dissolve close to 821 g of Ag or 240 g of Cu. I would use enough nitric yo only dissolve 90-95% of the metal.
> 
> (b) is solved by knowing exactly how much silver is in the solution. This is known by either knowing exactly how much silver was dissolved (difficult) or by analyzing the solution. The latter is cheap (about $100 setup cost), fast (5 minutes), and easy to do using the Volhard titration method.
> 
> Here's how I would do this for maximum silver purity:
> 
> (1) Use only enough nitric (plus distilled water) to dissolve 90-95% of the silver alloy. Heat at the end. If too much nitric is used and all the alloy dissolves, add enough more alloy until all the nitric is spent and some metal remains. Put the remaining metal in the next batch.
> (2) Accurately measure the total volume of solution, analyze the silver content, and calculate the total silver in solution.
> (3) Depending on how good you are at this, add enough Cu powder to cement between 95 and 99% of the total silver. It takes about .294g of Cu to cement 1g of silver. Instead of mixing by hand, use a stainless paint mixer (one with a chopping action) chucked in a drill or a small motor.
> (4) When all the Cu has reacted, remove the stirrer and hang some Cu buss bars or clean pipe in the solution to cement the remaining 1-5% of the silver. Remove and clean off the bars.
> 
> Steps (3) and (4) are added because it would be very difficult to determine exactly the amount of Cu needed to cement 100% of the silver.
> 
> I doubt if all this will add more than 20-30 minutes of labor to each batch.



I do not follow any of above things 
It is quite simple and very easy process believe me.
I really don't know amount of Ag present in sol.
And also I really don't how much Cu by WEIGHT I am adding in sol. Never did that.
I simply check that by adding HCl
Thank you 
Hrushi


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## hrushi

lazersteve said:


> Chris,
> 
> You have the copper and silver ratios reversed:
> 
> 2 AgNO3 + Cu --> Cu(NO3)2 + 2Ag
> 
> 2 *107.8 = 215.6 g Ag
> 1 * 63.55 = 63.55 g Cu
> 
> 215.6 / 63.55 = 3.39 g of Ag per gram of Cu used.
> 
> So 1 gram of Cu precipitates ~3.4 g of Ag.
> 
> Steve


Hi Steve
got UR DVD the great you have taken tonnes of efforts on making them.
great calculation above they are very precise
Hrushi


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## hrushi

Barren Realms 007 said:


> He had stated that he adds a little bit of HCL till he gets no white silver cloride reaction reaction and then he seperates the material and adds a copper bar to the liquid to finish the process.



Barren
No
I complete the process using Cu powder ONLY NO CU BARS ARE USED its quite simple.
Hrushi


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## hrushi

HAuCl4 said:


> I wonder what hrushi's washing procedure is for the silver crystals and if he uses anything to leach the silver crystals after washing and before melting. An hour in ferric chloride with stirring cleans up pretty much any excess copper and leaves silver 999+ with iron traces as the main contaminant.
> 
> 4metals formate method seems more straightforward though (haven't tried it yet).
> 
> edit: I just saw the video and his stirring tank is made of...steel, and he is adding HCl...voila ferric chloride is in there somewhere!. 8)


Iron traces can be removed at the time of melting bu adding flux. As Fe doesn't melt even at 1050C it can be removed bu using graphite rod. One thing is sure it needs good cleaning while melting.
Hrushi


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## hrushi

4metals said:


> The thing that interests me about this is the ease of treating the waste acid. In a formic reduction a complex is formed which is a pain to break causing extra steps and specialty chemicals to clean up the acid.
> 
> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.
> 
> What I think Hrushi meant by adding hydrochloric was testing a drop of the blue acid in water containing a few drops of hydrochloric. Any silver still in solution will turn a cloudy white. I do not think he is adding hydrochloric to the silver nitrate.



All cementation is done after filtration of solution so any Au or PGM is left behind.
I am adding HCl to AgNO3 Sol check amount Ag still present in sol.
Hrushi


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## hrushi

HAuCl4 said:


> 4metals said:
> 
> 
> 
> The thing that interests me about this is the ease of treating the waste acid. In a formic reduction a complex is formed which is a pain to break causing extra steps and specialty chemicals to clean up the acid.
> 
> When treating old sterling silver it is not uncommon to find 0.5 parts per thousand of gold in the silver. In this method the lack of filtration before adding the copper would leave the gold in with the silver. Also any palladium, which can also be in old sterling, will be in the silver as well.
> 
> What I think Hrushi meant by adding hydrochloric was testing a drop of the blue acid in water containing a few drops of hydrochloric. Any silver still in solution will turn a cloudy white. I do not think he is adding hydrochloric to the silver nitrate.
> 
> 
> 
> 
> Check Hoke's description of procedures for cementing/cleaning up the silver chloride at the Homestake mine after Miller processing. At the end there is a pretty thorough description of getting the silver crystals cleaned up with *ferric chloride* and washing with HCl. Those crystals are about the dirtiest cemented silver that can be had as feed by man or beast. And yes, there will be *some* AgCl at the end to deal with. I didn't learn it from there, but from trial and error. :shock:
> 
> From the video it seems the bucket on his left has HCl and leaves a little white cloud when added to the blue liquid.
> 
> Boy, am I glad that is Hoke claiming 9995-9997 silver and not me... :lol:
Click to expand...


True
but according to my experience when i recovered Ag from AgCl there are more losses, more efforts and even after melting some amount of AgO is present in ingots and more time I can recover near about 25 Kg of Ag( Sorry I am not used to pounds and Kg ratio) in just 25-30 min and of 999+ purity.
hrushi


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## 4metals

First I would like to thank Hrushi for his follow up on this thread. 

Although you are not adding a stoichiometric quantity of copper to the process vat by calculating the exact quantity of silver, in essence you are doing it by adding until the solution tests silver free to chlorides and adding extra silver nitrate if you overshoot it. 

The powdered copper you use must be very fine, do you know what the mesh size is?

I do not know why you add the HCl to the process vat to test for silver instead of adding a few drops of the process solution to a HCl solution out of the process vat. Apparently the presence of a small quantity of silver chloride is converted into silver metal when melting the silver. 

What analytical method are you using to determine the .999+ purity. Have you ever had it assayed by ICP?

Any more video's would be appreciated, you have an interesting setup. I would especially enjoy a video of the silver nitrate HCl testing step.


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## teclu

Hello Hrushi, 
Have you tried before the Au cementation(from AR) with Cu powder?
It could be a reasonable alternative for remove Au from AR solution? AR solution which besides gold contains base metals(Cu, Ni, Fe and Sn) 
Thanks!
teclu


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## eeTHr

How about a small, slow, motor, with a long shaft and a copper bar attached to the shaft as a stirrer blade? For faster results, make a bank of four motors with stirrers.

The motors would need to be sealed air tight, like motors used in explosives areas.

When the copper bar blades get too small, replace them, and re-process the old blades.

This would solve the "contact all the silver nitrate" problem, _and_ the "too much copper" problem.

I would recommend gloves and eye protection, though. And strong exit ventilation behind the vat.


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## 4metals

Just thought I'd bump this thread to see if Hrushi is still out there to fill in some details.


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## Barren Realms 007

4metals said:


> Just thought I'd bump this thread to see if Hrushi is still out there to fill in some details.



His profile shows he was on here Friday. Hopefuly he will update us with some info and new pictures.


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## hrushi

sorryn guys I was away for so many days 
what else u want to know
hrushi


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## 4metals

> The powdered copper you use must be very fine, do you know what the mesh size is?
> 
> I do not know why you add the HCl to the process vat to test for silver instead of adding a few drops of the process solution to a HCl solution out of the process vat. Apparently the presence of a small quantity of silver chloride is converted into silver metal when melting the silver.
> 
> What analytical method are you using to determine the .999+ purity. Have you ever had it assayed by ICP?
> 
> Any more video's would be appreciated, you have an interesting setup. I would especially enjoy a video of the silver nitrate HCl testing step.
> [ P


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## hrushi

4metals said:


> The powdered copper you use must be very fine, do you know what the mesh size is?
> 
> I do not know why you add the HCl to the process vat to test for silver instead of adding a few drops of the process solution to a HCl solution out of the process vat. Apparently the presence of a small quantity of silver chloride is converted into silver metal when melting the silver.
> 
> What analytical method are you using to determine the .999+ purity. Have you ever had it assayed by ICP?
> 
> Any more video's would be appreciated, you have an interesting setup. I would especially enjoy a video of the silver nitrate HCl testing step.
> [ P
Click to expand...

I have not checked mesh size of copper powder but it is very fine
I had HCL to check how much Ag is still left for recovering
I am using Volhards analytical method to determine the .999+ purity and also Spectrophotometer 
Video are not ready but as soon as they are ready I will surly post them 
Hrushi


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## golddie

In my shop I Cemented some silver in a 4 inch jar and I have 2 blowers and I couldn't stand that smell.
I know that my system has faults but I think it was pulling that small amount of air
Here hrushi is doing the same but in a container that is about 100 times bigger and I didnt see any blowers anywhere
I appreciate the video but I say be careful Hrushi


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## Barren Realms 007

golddie said:


> In my shop I Cemented some silver in a 4 inch jar and I have 2 blowers and I couldn't stand that smell.
> I know that my system has faults but I think it was pulling that small amount of air
> Here hrushi is doing the same but in a container that is about 100 times bigger and I didnt see any blowers anywhere
> I appreciate the video but I say be careful Hrushi



Some people are more sensitive to this stuff than others this may be the case with you. If you have worked with it for years you get to the point you don't notice it.


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## 4metals

> Video are not ready but as soon as they are ready I will surly post them



Thanks for following up with this thread, the video's will be interesting. I still do not know what benefit you get from adding the HCl directly to the bath to test for silver, but apparently it is doing no harm.


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## hrushi

4metals said:


> Video are not ready but as soon as they are ready I will surly post them
> 
> 
> 
> 
> Thanks for following up with this thread, the video's will be interesting. I still do not know what benefit you get from adding the HCl directly to the bath to test for silver, but apparently it is doing no harm.
Click to expand...


True there is no harm in doing it in testube as there is no need to take out the sol and check
The purpose of adding HCl is to check how much silver is still present in sol and nothing else
As the amount of silver reduces the white spot after adding Hcl becomes less thinner Initially it is quite thick and as Ag is precipitated it goes on becoming thin and thin and when all Ag is recovered it will show black spots after adding HCl 
But last stage of adding Cu powder is very important and we have to be very cautious while adding it. We have add it in small quantity and stir more.
Hrushi


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## hrushi

golddie said:


> In my shop I Cemented some silver in a 4 inch jar and I have 2 blowers and I couldn't stand that smell.
> I know that my system has faults but I think it was pulling that small amount of air
> Here hrushi is doing the same but in a container that is about 100 times bigger and I didnt see any blowers anywhere
> I appreciate the video but I say be careful Hrushi




try adding little of urea brown fumes wont come out and some kind of smell will come.
Brown fumes comes as free nitric is present and when we add Cu to the Sol reaction takes place and brown fumes are liberated
Hrushi


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## golddie

I have mixed in lye in my scrubber and it smells like pesticide and I dont like it and hrushi said he uses urea to kill the brown fumes and I am wondering if I can use urea in my scrubber and is what is urea is it a safe thing

hrushi
How much urea do you add 
In what quantities do you add the urea

Also 


> we don't have to buy Cu powder we can use Cu powder which we can easily get from CuNO3 which is left with us


Lets say I have copper nitrate solution left over from refining silver how can I make it so that I will be able transform this into powder so it is of acceptable quality 
If I just boil it than that wont work if I cement it with another metal like steel that wont work
It would be nice if you can tell me this
Thanks


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## golddie

> Lets say I have copper nitrate solution left over from refining silver how can I make it so that I will be able transform this into powder so it is of acceptable quality
> If I just boil it than that wont work if I cement it with another metal like steel that wont work


Can I cement this with steel and than wash it with hcl


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## hrushi

golddie said:


> Lets say I have copper nitrate solution left over from refining silver how can I make it so that I will be able transform this into powder so it is of acceptable quality
> If I just boil it than that wont work if I cement it with another metal like steel that wont work
> 
> 
> 
> Can I cement this with steel and than wash it with hcl
Click to expand...


Better than steel is iron as it is cheap than steel.
I use iron strips to get Cu powder out of CuHNO3
Believe me it is very economical.
Hrushi


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## golddie

Hi Hrushi
Thanks for your help I appreciate it


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## shyknee

golddie


> I have mixed in lye in my scrubber and it smells like pesticide and I dont like it and hrushi said he uses urea to kill the brown fumes and I am wondering if I can use urea in my scrubber and is what is urea is it a safe thing
> 
> hrushi
> How much urea do you add
> In what quantities do you add the urea


I think hrushi was referring to adding a little urea to the nitrate to neutralize the nitric to prevent the NOx from developing .
As for the use of urea in a scrubber to reduce NOx, I'm not sure but I would like to here some opinions on the use of urea in the scrub solution. Will it produce copious amounts of ammonia or would it just not work at all.
I understand that in a diesel engine's exhaust that uses urea to convert NOx works, because the urea is converted into ammonia, in the heat of the exhaust, in just the right amount .The ammonia then converts the NOx to less harmful stuff.
If it did work as a scrub solution, then DEF ( DIESEL EXHAUST FLUID) by the jug would be an option for some.
Golddie is your lye solution to concentrated .I was under the impression that the solution should only have to stay above neutral ph as in ph8 and that this is done with regular checking and additions of lye as necessary.


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## Palladium

I like 4metals would have liked to learned more and seen more video. I find his methods both simplistic as well as functional for practicality purposes. I liked it because like them i rely on known methods and instinct to guide me more that fancy equipment and phd science.


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## 4metals

It seems in his posting Hirushi told us what he did so I tried it. I dissolved clean copper, not copper recovered from cementing with scrap iron which has other base metals in it, but clean copper. Then I added enough nitric acid to digest the copper and added some extra just so the acid was completely consumed. 

Then I added iron slab, not steel but iron, and what came down was nice finely divided copper metal. Wash it dry it and it is just like in Hirushi's video. 

I did not follow up and use the copper powder to drop silver from spent silver electrolyte, instead I used it for PGM's in spent aqua regia. 

The only thing I would do differently than Hirushi would be to test for completeness of the silver drop with HCl in a test tube rather than in the tank with the silver nitrate. I can imagine some of the people I've worked with dumping in too much HCl and having a white soupy mess and saying "What happened man, I just added a little!"


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## Palladium

I found it interesting that when they added to much copper they added active silver nitrate to consume the extra copper which makes good sense. Like a two step washing procedure i guess you could say. Once the excess copper is consumed the excess silver nitrate can be wash free of the cemented powder. Since i run continuous batch processes for clients i always have silver hung up in the process some wheres. After i finish a drop and remove the copper slab i add some fresh nitric to the batch, chop it up, and let it settle. This consumes any excess copper that may be trapped in the powder. When i wash the powder the wash water is used to dilute the next incoming batch for refining at the beginning of the process so it continuously repeats over and over.


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## Barren Realms 007

4metals said:


> It seems in his posting Hirushi told us what he did so I tried it. I dissolved clean copper, not copper recovered from cementing with scrap iron which has other base metals in it, but clean copper. Then I added enough nitric acid to digest the copper and added some extra just so the acid was completely consumed.
> 
> Then I added iron slab, not steel but iron, and what came down was nice finely divided copper metal. Wash it dry it and it is just like in Hirushi's video.
> 
> I did not follow up and use the copper powder to drop silver from spent silver electrolyte, instead I used it for PGM's in spent aqua regia.
> 
> The only thing I would do differently than Hirushi would be to test for completeness of the silver drop with HCl in a test tube rather than in the tank with the silver nitrate. I can imagine some of the people I've worked with dumping in too much HCl and having a white soupy mess and saying "What happened man, I just added a little!"



The difference in the two should be the make up of their elements that are added.


http://www.explainthatstuff.com/ironsteel.html


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## FrugalRefiner

Palladium said:


> After i finish a drop and remove the copper slab i add some fresh nitric to the batch, chop it up, and let it settle. This consumes any excess copper that may be trapped in the powder. When i wash the powder the wash water is used to dilute the next incoming batch for refining at the beginning of the process so it continuously repeats over and over.


I've used the same technique to clean up cement silver. It only takes a tiny amount of nitric, agitation, and time. Any silver dissolved by excess nitric is recovered in the next batch.

I mentioned it in the Fuzz Button Interconnects, need some advice thread, but never saw any comments.

Dave


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## Palladium

Sorry Dave i sometimes am guilty of speed reading the forum and i miss things. That's exactly how i do it!
I also don't use reclaimed copper for the process like i do with the stock pots. Only clean copper slabs, but theoretically if you have a copper nitrate solution with contaminants lower than copper in the solution also and you add iron without over doing it to the point of cementing all the copper out then the copper that falls should be of relatively clean purity. At least that's what i've observed. When i take the copper out of my stock pots for using in the upstream stock pots i never wait until the cementing is complete before i draw the first copper off, then the process is completed to finish it off for neutralization. I've never tried it for cementing silver, but i might just do some experimenting to see where it leads me.


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## FrugalRefiner

It's great to know I came up with a technique that one of the Pros uses!

The idea of doing a _partial_ cementation with iron to avoid all the other possible nasties is interesting too. I suppose the same techniques of adding just a bit of acid to the wash water might be able to be used to clean up the cemented copper as well. Very interesting!

Dave


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## Lou

golddie said:


> I have mixed in lye in my scrubber and it smells like pesticide and I dont like it and hrushi said he uses urea to kill the brown fumes and I am wondering if I can use urea in my scrubber and is what is urea is it a safe thing
> 
> hrushi
> How much urea do you add
> In what quantities do you add the urea
> 
> Also
> 
> 
> 
> we don't have to buy Cu powder we can use Cu powder which we can easily get from CuNO3 which is left with us
> 
> 
> 
> Lets say I have copper nitrate solution left over from refining silver how can I make it so that I will be able transform this into powder so it is of acceptable quality
> If I just boil it than that wont work if I cement it with another metal like steel that wont work
> It would be nice if you can tell me this
> Thanks
Click to expand...



Urea is fairly innocuous stuff. Often used in cremes for debriding dead skin and softening callouses and such.
You can not use it to scrub however especially in an alkaline environment--it will hydrolyze and turn into ammonia!

Most NOx scrubbers are multiple stage--peroxide first to oxidize NO to NO2 which then gets further oxidized by the peroxide into nitric acid which can be re-used. Very important here to remember to have a mist eliminator to keep metal salts from making it to the peroxide--which will cause it to decompose, perhaps spectacularly. The second and/or third stage is alkali with sulfide, or alkali with a sulfite (BioNox solver, which is GREAT stuff, can't recommend it highly enough).

Lou


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## 4metals

> relatively clean purity



Is that something like almost virgin copper?


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## Palladium

Once removed ! :twisted:


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## MarcoP

Lou said:


> Most NOx scrubbers are multiple stage--peroxide first to oxidize NO to NO2 which then gets further oxidized by the peroxide into nitric acid which can be re-used. Very important here to remember to have a mist eliminator to keep metal salts from making it to the peroxide--which will cause it to decompose, perhaps spectacularly. The second and/or third stage is alkali with sulfide, or alkali with a sulfite (BioNox solver, which is GREAT stuff, can't recommend it highly enough).
> 
> Lou


Would lime sulfur be ok instead of BioNox (not available anywhere in Europe) [stt]ans[/stt] and I'm still trying to figure out how to make a mist eliminator but I had an idea from a Palladium's post.


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## Lou

I would try sodium metabisulfite, pH 10-11 first and see how that goes.


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