industrial metal Sn/Pb/Zn/Au powder

[Sucho]

i have few kilos of industrial mental powder

main metals are Sn/PB/Zn , a little of Cu,Ag
Au - about 8-10 g/kg

which chemical process would be the best for refining the gold from this powder in large shape?

except electrochemistry

i am thinking about parkes process (metal liquid/liquid extraction) or cyanide process(i dont have cyanide salt and i am a little bit affraid of this process)

i have whole laboratory available for use

any ideas/experiences ?

 

[aussco999]

Sucho:

Because of the Zn content, a cyanide leach won't work on your powder. Zinc is used as a precipitante of cyanide, and some of the other base metals are considered a cyanamide. The Park's process may work, but you should take a good look at the numbers (such as what percentage of the 8-10 grams/kg is valuable precious metals), to determine if it's economically feasible to attempt that process. Some one else on the forum may have a better idea on how to process this material, but always check the profit numbers first.

Good luck,

John

 

[4metals]

The easy way would be to digest the material in acid and use copper to cement out the values. Then the values can be refined classically once most of the base metals are gone.

I would try a small sample in 50/50 nitric and water to see what dissolves. That should leave the gold on the bottom to be filtered off. Any silver can be recovered by cementation. The gold will have to be aqua regia refined, possibly twice because of the tin to get it clean.

 

[HAuCl4]

How many Kilos or Kilos per day?.

How fine is the powder?.

Is the powder an alloy of the metals or a mixed powder of separate metals?.

What % of weight total is the lead?

 

[Sucho]

i have made some tests, nitric treatment included

i guess, theres a lot of metal oxide microparticles (Sn/Pb) because i thing only 30 % of each sample was dissolved (nitric, hydrochloric acid )
there was a lot of gel nitrates
it was a colloidal mixture, very hard to separate solid/liquid

nitric - AR process worked only in a high redundance/abudance of acids ( 15g sample - 100 ml 1:1 HNO3, vacuul filtered-enormous 2 hour filtration time of 100ml, 388 paper used,AR 100 ml 3:2:1 Cl-,H2O,NO3-)

without redundance of AR there was no Au precipitant(outgoing of electrochemical series of metals i think)

this isnt a good way for large shape refining

so i am asking ...

 

[Sucho]

to HAuCl4 : its about 100-200 kilos of powder

it was analyzed only with a laser pistol and me ..i didnt measure it with that machine

there is a lot of insoluble particles-about 70 percent

before acid treatment its greyish powder with very fine particles
after acid treatment its dirty white mega fine powder making colloidal shit

 

[HAuCl4]

to HAuCl4 : its about 100-200 kilos of powder

it was analyzed only with a laser pistol and me ..i didnt measure it with that machine

there is a lot of insoluble particles-about 70 percent

before acid treatment its greyish powder with very fine particles
after acid treatment its dirty white mega fine powder making colloidal shit

I would use a cupellation furnace before finishing the refining of the silver/gold with acid. The other metals have very little value in those quantities.

The colloidal white mess is tin paste. A wash of the solids in sulfuric acid, after the nitric cleans it up pretty good.

 

[Sucho]

i can try it, i have one furnance heating up to 1200 degrees but only 4 litre chamber
will liquid metal separate/leak/flow way from powder oxides well?
or there is any mechanical process needed with heating simultaneously ?

 

[Harold_V]

The easy way would be to digest the material in acid and use copper to cement out the values. Then the values can be refined classically once most of the base metals are gone.

I would try a small sample in 50/50 nitric and water to see what dissolves. That should leave the gold on the bottom to be filtered off. Any silver can be recovered by cementation. The gold will have to be aqua regia refined, possibly twice because of the tin to get it clean.

By incinerating the recovered solids after extraction via nitric, the residues could be given a wash in hot HCl, eliminating troublesome traces of tin. I would recommend that procedure highly regardless of one's intention to refine more than once, or not. The reward will be a gold chloride solution that readily filters.

Harold

 

[nickvc]

I'd strongly advise you to follow Harold advice and run a sample to check if there really is a decent amount of values there. If by laser gun you mean an xrf gun I'd be wary of believing the readings for trace amounts of values in a powder and only testing on a good representative sample or an assay on same will give you a true idea of what's actually there.

 

[Oz]

XRF is best performed on a bar or other homogeneous mass. They are also often calibrated to read incorrectly by buyers, so beware of the intentions of the operator.

 

[Joeforbes]

Why did you wash it in nitric before HCL? Wouldn't the HCL have removed all of the Zn and Sn and any of the Pb oxides? It seems like that should have come before the more expensive wash of nitric.

 

[goaldspektre]

I agree with joeforbes,I would wash with HCL first.The zinc will bubble like crazy though so use a large vessle to do the reaction.