# processing a failed batch



## Anonymous (Jan 3, 2009)

Hey everyone. I'm new to gold refining and have some questions. 

I came upon this project when my uncle asked if I could try and recover the gold from some DSL equipment racks he pulled from an apartment building. 

I started with a google search and found Shor International before having problems and then finding this site. I've read this forum extensively and the next time I do this I'll be much better informed. I'd like to thank the forum for that!

here is what I've done so far.

I removed all the gold plated fingers from the cards (approx 100 cards) and removed all the connector pins from the boards, jumpers, the boards on the back of the racks and all the cables) I don't know how much it all weighed but it was a dense volume of pins and fingers that filled about 3/4 of a 1/2 gallon container. 

I then dissolved Shore's SubZero nitric acid substitute (1/2 lb) to 1/2 gallon of muriatic acid and then add the scrap to the bath with a plastic mesh bag. there was some plastic although I was careful to remove most of it.

The reaction was slow at first and the slowly started to dissolve the metals. I did this in my garage at ambient temp between 55 and 60 deg. the solution warmed up and continued to dissolve for two days. when the solution no longer bubbled and lost temp I removed the bag of scrap and decanted then filtered the solution.

I Now have two containers. One with a clear (no murkiness) cola colored solution and one with the scrap (mostly all the pins and fingers were dissolved but there was still some visible gold leaf) and residue from decanting and filtering. 

Following the instructions I added some urea to the cola colored solution and nothing happened, in all I added about 1/8 pound of urea pellets. I then added Shor's Storm precipitant and it precipitated a very sticky black grey substance that was clumpy. I was able to filter it with a screen.

Not knowing what this was I took the remainder of the of the solution and set it aside.

I then mixed a second batch of Shore's SubZero nitric acid substitute (1/2 lb) to 1/2 gallon of muiatic acid. I then added the bag of scrap, the residue from decanting and filtering and the clumpy sticky substance from the failed precipitation attempt.

Keep in mind that I knew nothing of dissolving base metals first or incinerating or any other methods I've now come familiar with. Again thanks to this forum! At this point I'm operating on intuition and what little I remember from my one chemistry class in college way back.

Surprisingly the second time worked pretty well. All the visible gold left dissolved along with most of the sludge and that sticky clumpy substance. I then decanted and filtered the solution and this time there was almost no residue. The liquid was a clear emerald green. I added urea and this time it fizzed. I added urea a little at a time unlit it no longer reacted. Then I added the Storm precipitant. The solution turned brown and cloudy. I then let it sit overnight decanted and filled the container with tap water and repeated until I got no color change when adding a drop of ammonia. when all was done I yielded just over 0.5 gm of gold grain. I tested the acid for gold with the precious metal detection liquid before discarding.

I'm now left with the first batch, which is a 1/2 gallon cola colored clear, not murky. when I add a drop of detection liquid on a paper towel the spot turns black. I contacted Sh or and I must say they are very helpful over the phone. He told me to add aluminum foil to the acid until I no longer get a color change with the detection liquid. So I added small pieces of foil one at a time until I no longer detected gold in the solution.

Now I have decanted and filtered this solution and I'm left with a black brown sludge. Mostly brown with black in it. If you look closely enough you can see the different colors. This is where I stopped. I still have the solution , it is clear and dark and after sitting for a few days I can now detect a very light color change when adding the detection liquid. A light brown. I also have the sludge in a separate container where I suspect the remainder of the gold is.

First I'd like to know how to process the sludge. The guy at Shore tells me to reprocess the sludge with SubZero/muriatic acid and then precip with storm. I'm not sure I want to go with this method again. I'm leaning toward 
first: rinsing, filtering and incinerating
Second: dissolving base metals with nitric alone
Third: processing with Aqua Regia.
Fourth: precipitating with SMB

Second, how should I process the remaining solution. I'm not sure if I should add more aluminum and keep with the same process or doe anyone have a better idea.

Thank you everyone patient enough to read through this post!

Drayden


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## butcher (Jan 3, 2009)

wash powder Hcl, dry incenerate,but not melt.
treat with nitric 50/50, decant powder disolve Aqua Regia, rid nitric, and ppt gold,
I would dump the shore.
(alternatives Ap and HCl/clorox) are exellent also.

if you did not dissolve all the metals the first time your gold replates mostly back to copper metals undissolved not that much in solution.

copper would be better to have used to drop metals from solution than aluminum (it would not have precipitated as much of base metals and aluminum can start giving you trouble.

you are on the right track here.
find download for Hokes book, 
see Steves sight www.goldrecovery.us,
keep reading through the forum,
you are finding the answers just dont give up yet.


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## Anonymous (Jan 3, 2009)

butcher said:


> wash powder Hcl, dry incenerate,but not melt.
> treat with nitric 50/50, decant powder disolve Aqua Regia, rid nitric, and ppt gold,
> I would dump the shore.
> (alternatives Ap and HCl/clorox) are exellent also.


If I understand you correctly, first step is to wash the black/brown powder with Hcl. I'm assuming that it is a mixture of base metals and the gold I'm trying to recover. second step is to pour off the excess Hcl through a filter and then let dry.

I don't think I've had any trouble with the incinerating process but your comment not to melt concerns me. Is there anything specific I need to avoid? I've been using a map gas soldering torch so far.



butcher said:


> treat with nitric 50/50, decant powder disolve Aqua Regia, rid nitric, and ppt gold,


I've read some more about AP and HCL/clorox and watched the videos. If I'm not missing something here, would that let me omit the treatment with nitric acid and using aqua regia?


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## qst42know (Jan 3, 2009)

Incinerate to destroy the remaining HCL so the nitric can act alone. By not melting the powder the acids act quickly and more thoroughly.

The steps he summarized will eliminate most of the remaining base metals, which is always preferred.


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## butcher (Jan 4, 2009)

you can incenerate off the acids on a gas hotplate, we are cooking off the acids and they have alot of fumes and are very corrosive, some acids like sulfuric take >700 degrees to get rid of, if using a torch you can use stainless steel and a torch on bottom of pan, (careful torch's can blow away the fine powders easily), 
main reason for the hcl wash was the aluminum, the Hcl probably best somewhat dilute.
I didnt give a step by step explaination, just general idea's, if you are not sure about a step try and find discussions on it, and ask questions about it.


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## qst42know (Jan 4, 2009)

Drayden7937 said:


> I've read some more about AP and HCL/clorox and watched the videos. If I'm not missing something here, would that let me omit the treatment with nitric acid and using aqua regia?



AP is good on copper, but nitric is better on mixed base metals. The HCL/chlorine can be substituted for AR.


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## Anonymous (Jan 4, 2009)

butcher said:


> you can incenerate off the acids on a gas hotplate



I have a stainless steel sauce pan and an outdoor gas stove. Would that work If I use Hcl to wash?



butcher said:


> the Hcl probably best somewhat dilute.



I'm using off the shelf 31.45% Muriatic acid. how much should I dilute?

On another note. I have some other scrap I've yet to process. I'm thinking of trying the AP process after watching the video on Steve's site. (great site by the way!)
Did I hear him correctly when He said that some of the gold was desolved with the copper in the AP solution? If so wouldn't it be the same ppt with SMB process I'd use with a aqua regia with desolved gold? 



qst42know said:


> AP is good on copper, but nitric is better on mixed base metals. The HCL/chlorine can be substituted for AR.



What is the difference with AP and Hcl/clorox? I understand that AP works well with copper. What metals do Hcl/clorox desolve?

Still reading, and reading...

Thanks again for all the help.


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## qst42know (Jan 4, 2009)

Drayden7937 said:


> What is the difference with AP and Hcl/clorox? I understand that AP works well with copper. What metals do Hcl/clorox desolve?



AP is HCL/hydrogen peroxide. Regular first aid peroxide. It will dissolve gold if you add too much peroxide. Once started a fish tank air pump will keep it working until the solution is saturated.

HCL/Clorox is used to dissolve your cleaned gold without the nitric fumes of AR and then can be dropped with SMB after it is filtered clean.


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## Anonymous (Jan 5, 2009)

Thanks for all the answers to my questions. You guys have helped clear up a lot for me! I pretty sure I'm armed with all the info I need to get to the point where I'm ready to precipitate.

As for the ppt process, I've read lots of info on SMB and Ferrous sulfate. So much that my head is still spinning. I read somewhere that SMB is good but can also ppt copper. could someone clear this up for me.

specifically, what situations are best suited for ppt with either SMB or ferrous sulfate. 

Also I read somewhere I could use stump remover to substitute SMB. Is this so? If so does it's use add another step or complication I should be aware of? I have a brewers supply in town I'm going to try to get SMB, Just thinking ahead a bit.

And lastly, other than making it myself, are there any common sources of Ferrous sulfate?


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## qst42know (Jan 5, 2009)

Both SMB or ferrous sulfate are considered selective for gold. 

I don't know if ferrous sulfate will work with HCL/Clorox, it is used with AR. 

If you followed the preliminary cleaning steps there should be very little copper or other base metals left to interfere.

As long as I can get SMB locally and cheaply online I haven't had need to look into stump remover.

Well stocked Garden centers should have ferrous sulfate (copperas) as an iron supplement. The crystals should still be green not brown.


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## butcher (Jan 5, 2009)

stump remover come in several different chemicals, be careful of which chemical you get.
Sodium Metabisufite will precipitate copper chloride if too much SMB is used, ferrous sulfate doesnt have this problem.
ferrous sulfate will work with HCl/bleach solutions.
brewery supply is good source for SMB.
good job reading Drayden, the more you learn the more you see there is to learn,


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