separating gold plating from iron/nickel alloy

Martijn

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Are you sure there is gold in the second solution? Did you test with stannous chloride? iron gives a nice yellow color as well.
If all fails, you can cement any values on copper in your solution. Collect the powder, re-dissolve and drop again. As described in the section 'Dealing With Waste"
boiling off HCL? why? I believe you need a little HCL in solution to make the SBM work, but that will be confirmed or debunked really fast here :)
How did yo make the second batch? the same way as the first one? it could help explain what happened.
Martijn.
 

Yggdrasil

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I think what is precipitating the Gold, at least the major factor is the formation of SO2 from the SMB.
One can drip HCl into the SMB and bubble the SO2 formed through the liquid instead of adding SMB directly to the liquid.
But that means a lot more equipment and is not needed, unless you are trying to make ultra pure gold.
So in short, the SMB need an acidic environent to work, at least as far as I know.
 

millgold

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the second solution was basically the same as the first, it was another portion of the grindings treated in the same way. the only reason I heated it was to drive off any residual chlorine gas. assuming a chlorine free solution, it should be diluted a few times over with water and smb added right? in theory gold will precipitate, it did once.

is there a certain target ph I need?

thank you

Mg
 

millgold

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A thought has been running through my mine for a bit now, Can the iron nickle gold metal grindings be dissolved quickly in the HCl/bleach solution and then the Iron and nickle be precipitated first? Or the gold, then cemented out on copper powder, then processed later to separate the gold from copper by AP? Does SMB behave in a slective manner such that mostly pure gold could be precipitated and refined later to higher purity?

I am figure to learn if there is a way to recover the gold, without a weeks long leaching process? I have read a fair bit that leads me to think this may be possible?

Thank you for your thoughts

MG
 

FrugalRefiner

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millgold said:
A thought has been running through my mine for a bit now, Can the iron nickle gold metal grindings be dissolved quickly in the HCl/bleach solution and then the Iron and nickle be precipitated first? Or the gold, then cemented out on copper powder, then processed later to separate the gold from copper by AP? Does SMB behave in a slective manner such that mostly pure gold could be precipitated and refined later to higher purity?

One way experienced members have processed certain materials, like ICs, is to use AR or poor man's AR. The material is placed in a beaker or other suitable vessel. AR or poor man's AR is added, but not enough to totally dissolve all the metals. The process is allowed to exhaust the acids. Any gold that is dissolved will cement out on the remaining base metals. The spent acid is decanted off, tested with stannous to be sure no values are discarded, then processed as waste. Fresh acid is added to the feed material, and the process is repeated as needed till all the base metals have been dissolved and the values go into, and stay in, solution.

SMB is relatively selective for gold, but may drop some base metals from dirty solutions. If your gold is precipitated or cemented from a dirty solution, doing a second refine is a good way to purify it to your requirements.

Dave
 

etack

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just use nitric if you cant buy it make it as poormans with sulfuric and nitrate of soda.

Your gold and abrasive will be left with some residues of the soda. collect and just add HCl there will be enough of the nitrates left to dissolve your gold filter the part that wont dissolve will be the abrasive then precipitate.

No need to over complicate it.

Eric
 

kurtak

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etack said:
just use nitric if you cant buy it make it as poormans with sulfuric and nitrate of soda.

no need for nitric - HCl will dissolve both the iron & nickel - preferably hot

No need to over complicate it.

I agree

However - that said - being this is a "grinding" dust/fines the problem is going to be getting the acid to all the metals in the dust/fines - that will require stirring to keep the dust/fines in suspension so that free acid can "stay in contact" with the metals

grinding sludge

Sludge - that tells me this came from a "wet" grinding process - rather then a dry grinding process --- is that right ?

if so - is it still a wet sludge - or has it dried to a hard cake ? --- pics would be helpful

Sludge - if it is truly a "sludge" you are likely going to have filtering problems - no matter how you go about leaching this

In other words - we need to know more about the material - before trying to figure out how to leach it (&/or other wise process it) --- as in smelting - or combination of leaching the base metals & then smelting for the gold - due to the abrasive

Please answer the above questions (including pics) - plus one more ------

How much of this material do you have ?

Kurt
 

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