# Separating Gold and Lead



## Rizingfire

I got a bunch of slag with a coating of gold and to get the gold off I used an oxygen/map torch to melt it, which it worked well and once in the crucible I heated it until the lil molten balls pulled together however there was a pocket of lead and I didn't realize it until I mixed everything together. I have seen in some processes a drop or two of sulfuric acid would eat the lead but any suggestions on how I can get the gold out of the lead because now I have a 9.9g chunk of lead and gold with about 4g of gold in it...and it is mixed thoroughly...so I will likely need to dissolve it and then precipitate the gold out, just looking for some advice.


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## Geo

ive only dealt with small amounts of lead in my processes. lead is used in refining when you cupel, but thats a small amount. try dissolving the lead using saturated sodium nitrate solution.


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## goldsilverpro

Lead will dissolve fairly readily in hot weak nitric - 7 parts distilled water and 1 part concentrated nitric acid. You can't use strong nitric because lead nitrate crystals will form on the surface and block the dissolving action. Lead nitrate is not very soluble in strong nitric. The distilled water will prevent your having to screw around with any lead chloride that might otherwise be formed. For the same reason, I would also rinse the gold well with hot distilled water before going into aqua regia. Use a little sulfuric in the aqua regia before filtering. Traces of lead are bad actors in refined gold. Anytime I know lead is present, I do what I can to get rid of all of it.


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## Rizingfire

awesome, thank you.


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## Harold_V

Alternately, although I do not advise this method, is to oxidize the lead to litharge, and bail it off. I've done it several times with a torch, in a melting dish. A fume hood is mandatory. All you have to do is heat the lead until it's quite hot (red heat), then turn off the fuel and play oxygen on the button. It will ignite and create more heat, keeping the reaction going until litharge buries the button. Bail off the litharge and repeat. When all lead is converted, the button will no longer support combustion. Clean it well and you have your gold back, sans lead. 

I heartily endorse what GSP said---when you dissolve the gold, do use some sulfuric acid, so you can remove any traces of lead that may follow the gold. It will then be eliminated in filtration as lead sulfate. 

Harold


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## lazersteve

If you have some cupels and a furnace you could also easily heat the button in your furnace with an oxidizing atmosphere and the lead would soak into the cupel leaving a gold button behind. Be cautious of the fumes from this process as Harold has already pointed out the dangers of lead vapors.

Steve


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## Lobby

I often recover the values off the papers I filter the auric chloride with after AR digestion, and typically find quite a bit of lead there. Even if I didn't add any sulfuric acid to drop the lead out.

Thanks for the advice, folks. Your answers to the original poster helped me, too.


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## butcher

Lobby, 
Here the lead is a lead chloride salt, it can be washed from the powder with boiling hot water, the lead chloride dissolves into the hot solution, silver salts will not, but the silver will take some time to settle, so after bringing the powders to a boil in water lower heat, but keep solution hot, letting silver settle, decant (suction bulb) the lead chloride solution to a cooling jar, when cool the lead precipitates out of the water, if there is a lot of lead in powders I will reuse the cooled water to pick up more lead chloride by returning to heating vessel, I collect and save the lead salts in a jar.


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## Lobby

Ah. Interesting.

I've been so fixated on gold yield that in the last few batches, I've been recovering the gold from the post AR filter papers. I guess I'm still trying to prove I'm a decent refiner...

Anyway, here's a pic with the XRF scan of the metals. I carefully collected the filter paper, cut it into pieces, placed it in a melting dish, covered it with 50:50 borax : soda ash, and burned it with a torch. I couldn't keep the metals in one button...

http://leo.smugmug.com/photos/i-D3CfWNj/0/L/i-D3CfWNj-L.jpg

I then added this metal to the subsequent batch (which I finished today).


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## SonuBhai

I am also facing the similar issue.
I am having an alloy of gold silver copper and lead.
Tested it on XRF gold is 2%, silver 57%, copper 7% and lead about 7%.
I want to extract gold and silver from it.
Can anyone help me out?


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## MIAMOTO

Dear SonuBhai,
If u have nitric acid than try too dissolve the "alloy" in it, the residue will be gold in a dark brown/black powder. If you havent got any Nitric than u must make a cupel first. 
To make a cupel is very easy get some bones, some dry wood and in a furnace burn it down (in the fire it should have an orange color for 30 min). U will be left with calcined bones, note that the bones should be very crumbly, if they arent than burn it a nother time. Next crush the bones to a fine powder (fine as flour), wash out carefull with water (salt like NaCl, Na2CO3, KCl ... will make trouble) and dry it half way, than press it together the upper side should have a depression where your lead alloy will be oxidized (and leave you with a nice snow white prill). 
Next dry it slowly min one week (best 2-3 weeks) than heat it up till its yellow than let it cool and its ready tho use ,if it cracks crush it down too powder press it in an iron/steel container. 
Place the raw gold/silver/copper/lead alloy in the cupel put about the same wheight of lead (best would be 4-5 times the weigh of your raw alloy if it contains many copper). Place it in a furnace heat it up to 900 Celsius( orange color, 880 too 950 Celsius max, over 960 Celsius Silver will melt and spit from atmosferic oxigen) and keep the temperature. U will notice that the lead will have a skin like surface wich will be sought in to the bone ash dish, finaly as the cupelation progresses there wont be any lead left and in that moment a courtain drag like phenomenon will occur>>>>> the orange alloy will cool down in an instant and there will be your noble metal prill with minor base metals (less than 0,5 %). 
To separate the gold from silver:
A. u will have too use nitric acid or hot/boiling sulfuric acid.
B. the cementation proces: 
1. make a very thin sheet from your metal prill, 
2.place it in a clay crucible 
3. 2 x salt, vinegar/urin and 2x powdered brick mix till it has a paste like consistency
4.Mix the paste and the thin metal foil/foils
5. Seal the clay crucible put it near the fire, max. cherry red or your silver is lost.
6. Let it there for 6 to 8 hours, 
7. Repeat till u have only gold left ( if u want pure gold), pan it out and there is your gold.
8. Get the residue separated from you gold, put 2 x weight Na2CO3 and 0,5 wheight borax, 0,2 flour/carbon, mix it, put it in a crucible heat it gently too 1100 Celsius (white hot, 1000 is enough), be carefull the temperature should be held for 20 min around 600 too 800 Celsius than heat it too 1100 pour too a mold and ther is your fine silver. 
I have used min. 4 gram silver, dont now how much u have, if it is less than a gram dont bother yourself whit it.
Hope it helps. 
P.s. Sorry for my spelling english is my 3 language. Be carefull at the cupellation process lead will vaporize (about 1 to 0.5 % or more) so make it outside far from your "kitchen", the wind should blow from your back, wear a gas mask or u will get a nice blue line next to your teeth, on your gum.


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## g_axelsson

SonuBhai said:


> I am also facing the similar issue.
> I am having an alloy of gold silver copper and lead.
> Tested it on XRF gold is 2%, silver 57%, copper 7% and lead about 7%.
> I want to extract gold and silver from it.
> Can anyone help me out?


Nitric acid, the gold will stay in the solids while copper, silver and probably the lead too will go into solution. Then filter and cement the silver on copper.
There will probably be a lot of lead left with the solids, so after dissolving the gold in aqua regia any dissolved lead is removed by adding sulfuric acid until all lead have precipitated, then filter and precipitate the gold with the chemical you prefer.

Göran


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## ayhan

hi. I have about 1KG lead that contains 980 gr lead and 2 gold and 2 pellatinum and 2 rhodium and silver and copper. I want to separate the gold and pellatinum . I want to eliminate lead in weak nitric acid. and filter it. I want to solve what remains in AR and deposite gold with so2 gas. then i will deposite pellatinum with amunium choloride. 
is this a good methode? do you have any idea??
thanks


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