# Washing process and no ice available.



## autumnwillow (Apr 13, 2016)

I'm pretty sure hoke's method is a bit outdated. And I've been trying to search the forum for hours now and could not find an answer.

1) How do you wash your fine gold from AR precipitated with SMB?
Hot water 3x, 
Boil to concentrated HCL
Hot water 3x
Ammonia ? boil? or what?
Hot water 3x
Dry. Melt with small amounts of borax.
Anything I've missed here?

I will be using sulfamic acid to neutralize the acid.

2) I don't have ice available. Can I just put the beaker in a cold stainless steel bowl?


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## Topher_osAUrus (Apr 13, 2016)

autumnwillow said:


> I'm pretty sure hoke's method is a bit outdated. And I've been trying to search the forum for hours now and could not find an answer.
> 
> 1) How do you wash your fine gold from AR precipitated with SMB?
> Hot water 3x,
> ...



Hot water yes
Hcl yes
Water yes
Ammonia-some do, some dont....some do dilute sulfuric instead
Hot water yes

When in this process are you needing ice?

It should be BEFORE you precipitate with smb, to dilute the solution out and chill it so the silver chloride being held in solution by the strong acid may precipitate out.
It also helps to add sulfuric acid before that step(then filter) to remove lead in solution as lead sulfate.

Hoke is still spot on for the most part (99.999%) -read Daves (frugalrefiners) pdf version where the very very few things have been changed (dont use gas...dont refine in a basement..)

Hoke is old, not obsolete

Ice is also used/preferred before adding the smb (after agcl removal) as the process of precipitation is exothermic, and, if highly concentrated (gold per L) can get VERY hot and make the precipitation hit a wall--harold has a few posts on the matter

Edit to add: ice is suuuuuper cheap... Also, quite easy to make... I might have a recipe around here somewhere if you need it


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## autumnwillow (Apr 13, 2016)

Chemical recipe? Not involving expensive stuff? Sure!

So as long as the beaker stays cool during SMB precipitation, ice doesn't have any other purposes?


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## Topher_osAUrus (Apr 13, 2016)

Water+freezer+time=ice
Its perfect!

Ice serves the purpose of diluting the solution to remove agcl that is with the gold.

Also when precipitating it helps keep the solution cool and dilute to keep the SO2 gas in solution longer to help reduce the auric chloride back to elemental gold.

There may be other reasons, but those are the most prominent i believe

Edit for spelling and to add: those 2 ice additions are at different times. One before filtering out the lead sulfate and agcl that has ppt from solution.
The second is after the solution has filtered to crystal clear before adding SMB


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## autumnwillow (Apr 13, 2016)

With your first two statements I think I could just dilute the gold chloride with distilled water then just put the beaker in a cold stainless steel bowl with cold water in order to keep it cool. 

I really do not have ice.


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## autumnwillow (Apr 13, 2016)

One more, why does everybody wait for the gold to settle (after precipitation in AR)? Why not just filter it right after checking negative for stannous? Are there any other chemical reactions happening while it is settling down?


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## rewalston (Apr 13, 2016)

autumnwillow said:


> One more, why does everybody wait for the gold to settle (after precipitation in AR)? Why not just filter it right after checking negative for stannous? Are there any other chemical reactions happening while it is settling down?


You want to let it settle so that you can decant the barren solution. You do not want to filter it. Keep your powder in the beaker you precipitated it in, so that you can wash it with HCl until clear and wash it with water. There are multiple wash steps. Only after it's washed and dried in the beaker do you move your powder to your melting dish. Constantly moving it to different containers you have a greater chance of loosing some of your gold.

Rusty


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## Topher_osAUrus (Apr 13, 2016)

rewalston said:


> autumnwillow said:
> 
> 
> > One more, why does everybody wait for the gold to settle (after precipitation in AR)? Why not just filter it right after checking negative for stannous? Are there any other chemical reactions happening while it is settling down?
> ...



+1, rusty nailed it with his words of wisdom.
The more you move your gold, especially filtering, the more you misplace.

And yes, i suppose you could dilute to 3x the volume with cold water snd allow it to chill and have the silver chloride settle out overnight.

Patience is a key aspect of this field. Allowing stuff to settle well overnight will help your accountability per lot...if thats something you do anyways, everyone is different


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## Grelko (Apr 13, 2016)

autumnwillow said:


> With your first two statements I think I could just dilute the gold chloride with distilled water then just put the beaker in a cold stainless steel bowl with cold water in order to keep it cool.
> 
> I really do not have ice.



If it's still cold where you live, you could always dig a shallow hole in the ground, and set the steel bowl in it. The coldness of the ground would transfer through the bowl and help cool the solution down more.

Edit - My grandmother had an underground fruit cellar, which stayed right around 48-50 F all year long.


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## Palladium (Apr 13, 2016)

The cold solution will produce a slower nucleation of seed crystals which leads to larger grain and particle sizes. The larger grains will settle, filter and wash easier. A hotter solution will produce a more rapid formation of crystals leading to a smaller finer particle sizes which can be more difficult to settle and filter. This is from a cleaner solution with few contaminates. Add more contaminates to the equation with an addition of heat and the whole thing can get crooked sideways quick as far as nucleation goes.


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## nickvc (Apr 14, 2016)

The best method I have seen is to wash your precipitated powders with water until no colour is seen then add cold HCl and put on a stirrer plate to keep the powders moving, do this several times decanting and washing inbetween new additions of HCl until the HCl takes on no colour.
This was Lou's method and it works very well, much better than hot HCl.


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## Anonymous (Apr 14, 2016)

*coughs* where did you see the stirrer idea? 8) 8)


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## nickvc (Apr 14, 2016)

U tube :roll: :lol: 

Ok at yours, but it works and that's what matters 8)


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## Anonymous (Apr 14, 2016)

lol. 8)


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## autumnwillow (Apr 14, 2016)

Can I use my stirring rod for washing with HCL? I don't have a magnetic stirrer yet. Hehe

Almost there!! Could have finished it today if it wasn't for that very slow filtering process. Took me a while.
Gold has already settled at the bottom of the beaker. Tested negative for stannous. I think this AR waste has no more values?

Also, I though Platinum dissolves in nitric when alloyed with silver, this lot was from inquarted gold jewelry scrap. Or maybe the white powder is something else?


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## nickvc (Apr 14, 2016)

You can use your stirrer rod but it means spending time manually stirring the powder, you only need to add enough cold HCl to cover plus about 5 cm more.


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## autumnwillow (Apr 14, 2016)

nickvc said:


> You can use your stirrer rod but it means spending time manually stirring the powder, you only need to add enough cold HCl to cover plus about 5 cm more.



I'll shake the entire beaker then. Heh.


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## autumnwillow (Apr 14, 2016)

The cold water in a stainless steel bowl worked during gold precipitation with SMB dissolved in distilled water!


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## Topher_osAUrus (Apr 14, 2016)

Even if it shows negstive for stannous, id still throw it in my stock pot a couple days.

But, thats just me, i dont want to throw the baby out with the bathwater


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## autumnwillow (Apr 15, 2016)

On my cold HCL wash there was no color change at all, I did it twice just to be sure.
I also did cold ammonia wash twice. More than 4 distilled water rinses. What I did was 2 boiling rinses, then 2 cold rinses.

This is my first button by the way. Weighs 124.50g. Tried to alloy it to 14k as a 99.9 gold, then tested on a touchstone. It tested ok but I still need to find an assay lab as I want to know the exact purity of my work.


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## Aeon13 (Apr 15, 2016)

Beautiful button sir!


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## UncleBenBen (Apr 15, 2016)

Your FIRST button is 124.5g?!?!
Way to go autumnwillow!

I think I have button envy now!


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## Aeon13 (Apr 15, 2016)

UncleBenBen said:


> Your FIRST button is 124.5g?!?!
> Way to go autumnwillow!
> 
> I think I have button envy now!



True! My first button was 1.2 grams. 8)


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## nickvc (Apr 15, 2016)

I don't know of one near you but a good cheap and fast service is available off these guys .
Guardian laboratories Midlands Ltd. they are in the UK fax 0121 359 7281 phone 0121 359 8233
Know the guys well they are very good and a gold assay is around $15 and they only need around 1/2 gram to work with, I think you can pay them by PayPal or cash but ask them, hope this is of use to you.


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## autumnwillow (Apr 15, 2016)

Aeon13 said:


> Beautiful button sir!


Thank you. Feel free to visit my workshop anytime. Get your chemicals for free(as long as they are in small quantities) so you can get started. Just make sure you get a proper fume hood with scrubber. You should also read about waste treatment. Educate your miners and help them grow. They are doing most of the hard work so they deserve a good treat.



UncleBenBen said:


> Your FIRST button is 124.5g?!?!
> Way to go autumnwillow!
> 
> I think I have button envy now!


This button produced a lot of stains in my hand and my hood(I still need practice on the art of lab work and need to deal with the condensing of closed scrubber systems), as I was doing other work not related to refining, a lot of phone calls, etc. I had to remove my gloves often only to go back to the lab and forget my gloves. I even washed a 50% caustic containing beaker with my bare hand wondering why my hand feels hot. Good thing I was at the sink. If you will look at my hand right now, there's a gold chloride stain, nitric stain, h202 stain and caustic stain. In small amounts though. They still look presentable. Heh.



nickvc said:


> I don't know of one near you but a good cheap and fast service is available off these guys .
> Guardian laboratories Midlands Ltd. they are in the UK fax 0121 359 7281 phone 0121 359 8233
> Know the guys well they are very good and a gold assay is around $15 and they only need around 1/2 gram to work with, I think you can pay them by PayPal or cash but ask them, hope this is of use to you.


I live in Asia, so that won't work. I wonder if I could do the fire assay myself? I have access to a high precision balance and a furnace. Are there any other equipments required?


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## Aeon13 (Apr 15, 2016)

> Thank you. Feel free to visit my workshop anytime. Get your chemicals for free(as long as they are in small quantities) so you can get started. Just make sure you get a proper fume hood with scrubber. You should also read about waste treatment. Educate your miners and help them grow. They are doing most of the hard work so they deserve a good treat.


I will definitely visit you sir. I will also read topics about waste treatment. Spot on sir about the miners, they are the hardest workers I've ever seen in my life. They do deserve better. I will do my best to help them in any aspect as long as I can. 



> I wonder if I could do the fire assay myself? I have access to a high precision balance and a furnace. Are there any other equipments required?



Looking forward to this sir autumnwillow.

Regards
Mohammed


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## upcyclist (Apr 15, 2016)

autumnwillow said:


> Also, I though Platinum dissolves in nitric when alloyed with silver, this lot was from inquarted gold jewelry scrap. Or maybe the white powder is something else?


Did you ever figure this one out? If not, did you fully dissolve & then remove your silver from the nitric solution before adding HCl to make AR and dropping the gold? If you didn't, that white powder could be silver chloride. It'll form when the nitric is added because if there's silver left, it dissolves with the nitric, then reacts with the HCl to make AgCl. That in turn frees the nitrate, which then helps get your gold into solution. But it reacts with the silver first, because silver is more reactive than gold.


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## Topher_osAUrus (Apr 15, 2016)

upcyclist said:


> autumnwillow said:
> 
> 
> > Also, I though Platinum dissolves in nitric when alloyed with silver, this lot was from inquarted gold jewelry scrap. Or maybe the white powder is something else?
> ...



When this happens, doesnt the silver chloride tend to be more grey than white?
-i thought my AgCl from ar was grey from precious metal contamination, but, i forgot that the sun will also make it more grey than white.

But is this an applicable statement when it is being. actively processed in AR?

Since the grey coloring (from light) is actually the chloride being turned back into silver metal, since the AR has free Cl, Would it be continually turning from metal to chloride salt(if an abundance of lught was there to convert?)

Sorry if my train of thought isnt that concise. I have family over, and they are more than distracting

Edit to recant my statement a bit


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## nickvc (Apr 15, 2016)

My only other advice is to refine your metal twice using different precipitants which changes the possible drag down effect, if you have no access to fast cheap assays it's the only way to be sure of the quality of your finished product.
GSP or 4metals can advise on assays in house but the problem with fine metals is that you have to work almost backwards from what little I understand, I'm sure they can explain it better.


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## autumnwillow (Apr 15, 2016)

upcyclist said:


> autumnwillow said:
> 
> 
> > Also, I though Platinum dissolves in nitric when alloyed with silver, this lot was from inquarted gold jewelry scrap. Or maybe the white powder is something else?
> ...



Okay let me explain the process I did. I was doing this in a newly built fume hood and vacuum scrubber setup. You can see the poorly designed hood here: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=23529

When I first processed the inquarted gold in nitric diluted with H202/distilled water. I never turned the heat up because I was testing the scrubber whether it could scrub properly or not. This process took almost 4 hours until I decided to decant the liquid and smashed the corn flakes to powders so the nitric can attack the base metals further. Note that not all of the corn flakes were turned into powder/mud, some were a bit hard to smash so I left them as is. I then repeated the process with nitric/h202 distilled water. This time under high heat. I then washed multiple times with distilled water, boiled it in distilled water then washed again multiple times with distilled water until the wash liquid was clear.

I then add about 500ml of h202/distilled water, 500 ml of HCL, separate additions of 120ml nitric. After the digestion stopped, I diluted the solution and added sulfamic acid dissolved in hot distilled water, mixed the solution, added more until there was no fizzing, then just a little bit more. I then filtered the solution, which took hours because I had to change filter papers as they were clogging up. Diluted the solution further then added 120g SMB dissolved in distilled water to the solution.

Note also that I do not think the heat really goes up because of the fume hood design. The room is at negative pressure, I was able to check this by shutting the door of the room and feeling the small gaps on the sides of the door, there was a pressure of air being sucked in the room. With this I think that the heat is being sucked out by the fume hood/scrubber setup. I will turn off the fume hood exhaust next time when vacuum scrubbing digestions.

From my understanding, platinum only dissolves under very high heat. My nitric digestion was only under high heat on the second set and my AR digestion was never under high heat.

One way I could check is to melt the powders. I have about 3-4 of this filter paper. Now I highly doubt that this is silver chloride, but melting it to check (if this is silver chloride) would produce chlorine gas which is not good for me. Another method would be to try and convert the powders as if they were silver chloride but I'm not sure if the silver chloride conversion techniques would have different reactions to this suspected PGMs which would further complicate things. I will try to take a sample and do it in a test tube. Maybe next week, as I have other jobs not related refining to do.


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## nickvc (Apr 16, 2016)

If you inquart with silver the PGMs will go into solution with the silver, so test your nitric solutions for PGMs, some may also go into your AR again test with stannous.
If you do have PGMs in your nitric solutions then you have to make a decision of the route to follow.
You can convert the silver to chloride decant and filter the solution off and then cement the values using copper, in my opinion the easiest route.
You can cement all the values with copper and put the silver and any PGMs cemented through a silver cell and collect the values from,the slimes, not so easy and a pain dealing with the slimes.
If you have values still in your AR either add to your stock pot or cement with copper.
I know I repeat this regularly but be very careful with PGMs in solution or as chlorides as they are highly toxic and dangerous.


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## autumnwillow (Apr 16, 2016)

nickvc said:


> If you inquart with silver the PGMs will go into solution with the silver, so test your nitric solutions for PGMs, some may also go into your AR again test with stannous.
> If you do have PGMs in your nitric solutions then you have to make a decision of the route to follow.
> You can convert the silver to chloride decant and filter the solution off and then cement the values using copper, in my opinion the easiest route.
> You can cement all the values with copper and put the silver and any PGMs cemented through a silver cell and collect the values from,the slimes, not so easy and a pain dealing with the slimes.
> ...



I have already cemented my nitric waste. I have forgotten to drop the Pd first though, I'll do that on the next batch. It also cemented faster than I could filter that grey powder. The problem that I have now is what is in the filter paper? This filter paper contents are the solids before I precipitated the gold.


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## Topher_osAUrus (Apr 16, 2016)

autumnwillow said:


> upcyclist said:
> 
> 
> > autumnwillow said:
> ...



In AR, yes Pt requires very high heat, but when nuking your inquarted material with nitric, if platinum is in minimal % of the makeup, it will readily go into solution with silver and Pd. Which then must be recovered by cementing (easiest way...im sure you could go about it differently, but...)


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## nickvc (Apr 17, 2016)

A picture of that filter and its contents will help so we can advise further but if you melted all your scrap together when you inquarted it's possible any larger solid pieces of platinum did not melt into the mix fully or even at all, post that picture and let's see what's happening.


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## autumnwillow (Apr 17, 2016)

nickvc said:


> A picture of that filter and its contents will help so we can advise further but if you melted all your scrap together when you inquarted it's possible any larger solid pieces of platinum did not melt into the mix fully or even at all, post that picture and let's see what's happening.



The filter is at page 1 nickvc.


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## nickvc (Apr 17, 2016)

Looking at the picture it looks like silver chloride, if you can't see any true metallic flakes or pieces the chances are the PGMs went into solution in your nitric digest, you can gently incinerate the filter papers and put the remains in a beaker wash with ammonia to remove any silver chloride and then check to see if there is any material left, if there is simply dissolve in hot AR, if you do wash this powder with ammonia makes sure to add some HCl after to avoid explosive hazards. 
If you do need to dissolve in AR you can then use stannous to see what you have.


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## autumnwillow (Apr 24, 2016)

nickvc said:


> Looking at the picture it looks like silver chloride, if you can't see any true metallic flakes or pieces the chances are the PGMs went into solution in your nitric digest, you can gently incinerate the filter papers and put the remains in a beaker wash with ammonia to remove any silver chloride and then check to see if there is any material left, if there is simply dissolve in hot AR, if you do wash this powder with ammonia makes sure to add some HCl after to avoid explosive hazards.
> If you do need to dissolve in AR you can then use stannous to see what you have.



Wouldn't the silver chloride produce chlorine gas upon incineration or does this chlorine gas only happen when the material is melted?
How do you recover the silver chloride dissolved in ammonia? Add HCL then cement with Cu?


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## nickvc (Apr 24, 2016)

Virtually all incinerations produce nasty fumes so decent extraction is advised whenever you do it.
You could just put water through the filter several times to remove as much acid as possible and then place your filter whole into a beaker and wash with ammonia which will remove any silver chloride, as I said you need to add HCl after to your ammonia which will produce silver chloride again.
Whatever is left after the ammonia wash is now visible either in the beaker or on your filter paper, wash off any residues from the filter paper with your water bottle and put the filter with any others you have to treat later, if you have any metallics they should now all be in the beaker so just dissolve in AR and test with stannous.


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## g_axelsson (Apr 24, 2016)

Silver chloride doesn't break down when melted, it starts to give off silver chloride fumes.

There are several methods to recover silver from silver chloride, check the library, read Hoke and search the forum... hint, cementing on copper isn't one of them.

Göran


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## autumnwillow (Apr 26, 2016)

nickvc said:


> Virtually all incinerations produce nasty fumes so decent extraction is advised whenever you do it.
> You could just put water through the filter several times to remove as much acid as possible and then place your filter whole into a beaker and wash with ammonia which will remove any silver chloride, as I said you need to add HCl after to your ammonia which will produce silver chloride again.
> Whatever is left after the ammonia wash is now visible either in the beaker or on your filter paper, wash off any residues from the filter paper with your water bottle and put the filter with any others you have to treat later, if you have any metallics they should now all be in the beaker so just dissolve in AR and test with stannous.



Thank you for the advice, I really hate the ammonia smell, I have a technical grade one which I dilute to 3% content. I dislike opening the 1 gallon bottle even under the fume hood it stinks.

I haven't bothered to put filter papers in any of my AR process as I think this would contaminate the gold. What happens to the filter paper when you put it in AR?



g_axelsson said:


> Silver chloride doesn't break down when melted, it starts to give off silver chloride fumes.
> 
> There are several methods to recover silver from silver chloride, check the library, read Hoke and search the forum... hint, cementing on copper isn't one of them.
> 
> Göran



There are a lot of methods, Lou's method, saltlakemetals method, formaldehyde method, etc. I find Lou's method to be the best if it wasn't for the formaldehyde toxicity.
To be honest with you, I have read Hoke's book so many times that I think it is already outdated and the processes there generate too much waste. I already have about 25gallons of copper nitrate, 5 gallons has already been processed with iron (which is a pain to do). I would go for HCL addition to make silver chloride this time, then just process the solution remaining in the stock pot. The remaining 20 gallons, I'll just save it and I believe I could use it somewhere sometime.

Keita


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## nickvc (Apr 26, 2016)

You can use salt to precipitate silver chloride and converting that back to silver metal is very easy, I like Lou's method add some sulphuric a few piece of iron and tumble or use a mixing rod attachespd to a drill.
You need to filter all your gold solutions, it's so easy to contaminate your gold at the final stage or pour a little silver chloride into your solution from the dregs at the bottom.
With filter papers you simply save them until you have enough to process then it's a careful incineration a good HCl wash and then into AR, very simple.
Hoke is an old book but gives you the basics for recovery and refining and how to test your solutions, remember it was written for those with little or no chemistry background, that's the reason we try to get newbies to read it, it gives you the basic understanding of most processes.
With high 14k+ scrap you can go direct to AR but will be left with silver chloride and a few rogue pieces that always seem to crop up, the one good thing in some ways are that any PGMs present should also be in solution, solid pieces of Pt are not likely to dissolve completely but if you melt and cornflake the metal first it helps to dissolve the Pt into the rest of the metals.


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## butcher (Apr 26, 2016)

autumnwillow
To be honest with you, I have read Hoke's book so many times that I think it is already outdated and the processes there generate too much waste. I already have about 25gallons of copper nitrate, 5 gallons has already been processed with iron (which is a pain to do). I would go for HCl addition to make silver chloride this time, then just process the solution remaining in the stock pot. The remaining 20 gallons, I'll just save it and I believe I could use it somewhere sometime.



Copper nitrate can be reused, to make nitric acid, in recovery to dissolve base metals, to make other copper salts, you can also recover gold and make another useful copper salt or solution in the same process, for me copper nitrate is almost as valuable as nitric acid, I do not consider copper nitrate a waste, I consider it a useful byproduct.

If you precipitate silver from a solution of silver/copper nitrate with NaCl or HCl acid, you will still have a waste product to deal with. This time it will be a mixture of copper chloride and nitrates, which I see as less useful as a byproduct than the copper nitrate. Unless if you were dealing with a more pure solution of AgNO3 where the byproduct with Nacl would be sodium nitrate and sodium chloride, that could be separated as salts, or with HCl and a byproduct of HNO3.

I have to disagree, I do not see Hokes book as outdated at all, in my opinion it is as relevant today as it was almost a hundred years ago, besides maybe in a few minor areas or details, there may be better or safer options in some instances, or processes for some materials, that we know more about now. Hokes book was not written today, so it will not reflect the times it was written in. Not what we know or use today. The chemistry, basics or principles have not changed in all of these years, I am sure if she would have been able to re-write her book today it would have most of the things we discuss today, or at least mention or touch on them. She did not write her book on mining or recovery of values from mining, but she did touch on the subject. She would not have written the book on recovery of electronics if written today although I am sure she would touch on the subject, if she was to rewrite her book "Refining Precious Metal Waste" today. Her book was written mostly for jewelers to help them in that trade to recover and refine their scrap.


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## Anonymous (Apr 26, 2016)

I agree Richard

The chemistry doesn't change, and it's wholly valid when taken within that perspective. The added metals involved in e-waste do put a different perspective on things though because as you rightly pointed out the book was written to help jewellers.


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## autumnwillow (Apr 26, 2016)

Okay. I agree. Let me re-state that. Hoke's book is just a little bit outdated. Books get revised all the time. I think it should be re-written by Lou/4metals whom I find is very experienced and knowledgeable in this field.

The 20 gallons that I saved is for your killing with two birds in one stone method. Which I will do once I get my hands on materials to process. Nitric is cheap in my place, distilling it would cost more as electricity is very expensive here.

My silver nitrates from inquarted gold contains trace PGMs which I think could be recovered after removing the silver chloride thru HCL then stock pot copper cementation.


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## autumnwillow (May 7, 2016)

The contaminant is primarily iridium with a little silver chloride. 

How does one go about setting aside iridium so it does not keep on being part of your refining cycle?


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## nickvc (May 7, 2016)

Are you sure it's iridium?
I ask because it's not normally associated with karat jewellery, it can and has been used in platinum alloys, if it's dissolved you can cement it out with copper, when I actually had some in my system it really wasn't keen to dissolve if I remember correctly, very like rhodium, I think HCl and hydrogen peroxide will have a better chance at dissolving it, check for gold before cementation and if present precipitate that first and then cement.


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## autumnwillow (May 15, 2016)

A theory perhaps.

Gold chloride readily vaporizes when incinerated.

By putting all the filter papers containing trace amounts of gold chloride and silver chloride in a ferrous sulphate solution, we are able to convert gold chloride to metallic gold and silver chloride to silver in the presence of iron.

Wash, dry then incinerate.

Proceed with nitric digest, then hot AR. Drop Platinum, then drop Gold.
Whats left should be iridium and trace amounts of other metals.

I'll try these next week on my free time.


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## g_axelsson (May 15, 2016)

I don't think ferrous sulfate will turn silver chloride back into silver.

Göran


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## 4metals (May 15, 2016)

Take the silver out as a chloride with salt.


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## autumnwillow (May 19, 2016)

g_axelsson said:


> I don't think ferrous sulfate will turn silver chloride back into silver.
> 
> Göran



Correct me if I am wrong.

Iron and 10 percent sulfuric acid will. Ferrous sulfate.



4metals said:


> Take the silver out as a chloride with salt.



Thank you for the advice, if it wasn't for the advice I could have lost some silver.

My theory worked.
The process was:

Put all the used filter papers in a beaker.
Add recycled ferrous sulphate. Mix until the filter paper crumbles to pieces.
Add HCL to precipitate any dissolved silver as AgCl. Mix.
Add iron, mix.
Filter the sludge until pH is equal with wash water. I used tap water here.
Incinerate.
Digest in Nitric.
Filter again in a filter paper.
Melt.
Digest in AR.
Wash and Melt.

I would prefer this method over immediate incineration as gold chloride is easy to vaporize and no accidental AgCl fumes to deal with.


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## g_axelsson (May 19, 2016)

autumnwillow said:


> g_axelsson said:
> 
> 
> > I don't think ferrous sulfate will turn silver chloride back into silver.
> ...


Yes, that is a well known method.

What I think is that some silver is dissolved and then it is cemented on the iron. Iron and sulfuric acid is not the same thing as ferrous sulfate.

I haven't tried this yet but what I think is happening is that the iron will form an electrolytic cell. When the iron goes into solution the silver chloride is turned into silver and chloride ions.
From what I have heard, the transformation starts at the iron and moves outward. (Unless it is tumbled.)

Göran


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## autumnwillow (May 22, 2016)

I wonder if just iron in a chloride solution will convert silver chloride to silver metal. I will try and test this on a test tube.

Are you the same Goran from the finishing website?


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## Topher_osAUrus (May 22, 2016)

autumnwillow said:


> I wonder if just iron in a chloride solution will convert silver chloride to silver metal. I will try and test this on a test tube.
> 
> Are you the same Goran from the finishing website?



I dont think it would?

Since its above silver in the reactivity series, i think it would be a fruitless venture.

Not trying to be a nay-sayer, or negative nancy. But, trying to think pragmatically.

FeCl + AgCl would end up with the exact same things i believe, as there isnt anything to give up an electron or to catalyze the conversion.

Maybe i misunderstood the "iron in a chloride solution" though.
As i know iron has many oxidation states.


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## g_axelsson (May 22, 2016)

autumnwillow said:


> I wonder if just iron in a chloride solution will convert silver chloride to silver metal. I will try and test this on a test tube.
> 
> Are you the same Goran from the finishing website?


No, I've never registered there.

Göran


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## upcyclist (May 23, 2016)

Topher_osAUrus said:


> autumnwillow said:
> 
> 
> > I wonder if just iron in a chloride solution will convert silver chloride to silver metal. I will try and test this on a test tube.



I wouldn't think so. For the reactivity series to come into play, the solid has to be soluble in the solution. Copper will dissolve in nitric, thus you can cement out silver or gold in solution when the copper replaces those metals in the solution itself. Because the silver chloride is insoluble in nitric and hydrochloric acid, there is no option for it to be in solution at all, which means no cementation.

That's why the iron & sulfuric acid works--AgCl is slightly soluble in sulfuric, and once it's in solution, the iron knocks it back out, and it cements onto the iron. (usual caveat: I think so, and the big brains will tell me if I'm off or not, hehe)

--Eric


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