Question from first AP run....!

[Fragum]

Hey Guys,

OK, so I processed my first batch of PII and PIII fingers (600 grams). I successfully retrieved the gold mash without much problem (thanks to Steve's great vids).

I added SMB to the remaining solution (very dark green) and not much happened. After researching the site, I figured out that I had too much copper in the solution - so I suspended a BIG OLE piece of steel in the solution to precipitate the copper.

Now here is where I need a bit of guidance:

I would assume that I can take the total precipitated powder from the solution, wash it and then dissolve the powder in HCL-CL and then filter the AuCL. Will the copper remain in the filter, or do I need to perform some additional steps to the powder before the HCL-CL step?

Thanks for your help!

Mike

 

[Never_Evil]

Almost, but you didnt watch them all in the right order. After you poor off the AP solution to get your gold mash, you must wash it 2 or 3 times with straight HCL. After that, use regular water to rinse the gold to remove the HCL. This step is to remove any salts that form.

In a separate glass dish or ceramic bowl spread out the mash and add just enough HCL to cover it, maybe a slight more. *** this next step is to be done out doors or with great ventilation *** add about a table spoon of Chlorox (sodium hypochlorite 6%). If done right there will be very little fumes, but they will be nasty ones that will literaly choke the breath out of you. Allow the solution to work and stir with a glass rod ( glass stir sticks for alcohol work) After 2 or 3 min if you still have some gold, add another table spoon. The less chlorox you use, the less salt that will form and the more pure the AuCl will be.

From this add two parts water to one part AuCl, allow this to sit over night. Doing that will let some of the excess chlorine evaporate off. Next with your solution of SMB or PMB or what ever SULFITE (not sulfate) add it and stir. The solution will then clear and your gold will start to precipitate. Do this in a glass container, because it will be easier to syphon the liquid out and have the gold collect into the corner.


Your green AP solution can be reused for further processing and rejuvinate it by adding more peroxide or using a fish tank bubbler to add oxygen back to the solution. When the solution is completely spent, you would add the steel to precpitate out the copper.

 

[Fragum]

Thanks for the reply never, but I am not looking for the answer that you gave me.

My problem is not with dealing with the mash, my problem is dealing with the remaining gold that is in the AP (if any).

The AP solution was almost a pitch black color (after processing the mash out of the solution) and I could not even shine a flashlight through it. I added SMB to the solution, let the solution sit for 24 hours, and then siphoned out the solution into another container to find very little gold precipitated out. As I mentioned before, I added steel to the AP mixture to precipitate the copper out of the AP solution because other posts suggested that there was too much copper in the solution and that removing as much as possible would help.

Which leads to my problem. If I assume that I have both precipitated gold and copper in my AP solution, how do I process the precipitate to separate out the gold from the copper?

 

[lazersteve]

I would assume that I can take the total precipitated powder from the solution, wash it and then dissolve the powder in HCL-CL and then filter the AuCL. Will the copper remain in the filter, or do I need to perform some additional steps to the powder before the HCL-CL step?

Mike,

With regards to gold powder mixed with the spongy copper powder that has been precipitated from the AP with iron before disposing. Don't use HCl-Cl on the powders when large amounts of copper moss are mixed with very small amounts of gold powder. Use straight HCl to dissolve the fine copper powder first. This takes some time, but leaves behind the small amount of gold powder that was dissolved in the AP solution.

The remaining fine black powder will then need to be redissolved to purify it before melting.

The above procedure is costly with respects to the required HCl to dissolve the copper, but if you do not use SMB on the AP solution before you put the scrap iron in the spent AP solution, it's your only option to get the last little bit of gold out.

I always test my AP solutions for dissolved gold before I add the iron. If gold is present, it is a very small amount, and it can be precipitated with SMB as a fine brown/black powder which can easily be filter out and re-dissolved in HCl-Cl to purify.

Steve

 

[Fragum]

Thanks Steve!

Just so I understand you correctly:

I should take the gold powder/copper powder mix and add HCl to it to dissolve the copper. Filter that mixture to get the gold powder, then clean it and process it down to AuCl3 using HCl-Cl.

Am I on track with this?

 

[lazersteve]

Correct.

It's best to avoid this situation by precipitating the gold with SMB prior to adding the iron or steel.

Steve

 

[Fragum]

I would concur with you on that!

Mike

 

[Lino1406]

You'd be better off using H2SO4 instead of
HCl (v.sl. solvent for Copper) and also
can dissolve some silver, or silver salts

 

[lazersteve]

Lino,

Do you have the specifics on this reaction (concentrations and ratios)?

Sound interesting.

Steve

 

[Lino1406]

Silver, including salts will dissolve
up to 5%(env.) depending on
temp and H2SO4 conc.
Copper - more than that.
I use about 10%H2SO4
sparingly and assume (about)
2% silver dissolution when hot

 

[lazersteve]

Lino,

What specific concentration of sulfuric acid and peroxide (?) concentrations do you use?

What are the ratios of these two reactants to affect the dissoluiton?

Steve

 

[Lino1406]

Peroxide is not needed (in this case).
You can assist dissolution by heat