# how do i extract gold from tailings via AR bath



## gengates (Mar 13, 2012)

Peace to all!

i have an idea in mind that gold tailings from a ballmill can be extracted by other method like AR bath of tailings..... i have an aprox. 400 grams of tailings/soil, dried and then bathed in AR....mixed it and let the AR work, after a few hours and some of the solid settled, i was very excited to see yellow/orange fluid on top of the sludge, i siphoned it and put some UREA as instructed,,,, then put some SMB as instructed also....but to no avail....nothing happens, i was waiting for the color to turns black as the reaction of smb to acid immediately (like the ones i saw on youtube), but nothing happens, i tried pouring more SMB but nothing happens....

is there really a gold in my solution since its came from a mined soil? i dont know..... forgive me, i cant afford yet to have tin solder, here in my area they sell it by volume and i cant find one that retails..... tin salt/powder is hard to find here, but soon this is in my priority list....

just in case......here in our place mining is done like this..
soil/ore is grinded for hours in a ballmill together with mercury at the mill (for hours it is grinded), solid gold is trapped inside the mercury called amalgam, the remaining soil/ore is called tailing, it is sent to secondary extraction via cyanide leach.......this is where i intervene, to have the micron gold extracted via AR bath.... is this really possible?

thank you.


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## Harold_V (Mar 14, 2012)

gengates said:


> is this really possible?


Possible?

Yes!

Practical?

No.

The problem you'd have is exactly what you experienced. AR will react with much of the contents of the ore, dissolving things of no value, and, if, by chance, there is a little gold present, it most likely would get dissolved and then cemented, ending up in the ore, just converted from its natural state to cemented gold. 

Without stannous chloride to test your solution, you may not achieve your goal except by chance. The problem then becomes one of how much money you must spend on acid to recover a questionable amount of gold, if any at all. Further, without proper elimination of free nitric acid, your test may not be representative of the real contents of the solution. 

Cyanide is used for extraction because, unlike acid, it reacts with only values, assuming there are no cyanicides present. That isn't always the case, but it most likely is in this one, otherwise they most likely would not be using the cyanide process. 

In my opinion, your chance of recovering gold without sustaining a loss is not good. I suggest you find a different source for values, and that would be especially true if the head assay of the ore is under an ounce per ton. I expect it probably is. 

Keep one thought in your mind as you explore options. It is almost never successful to process ores by acid. 

Harold


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## gengates (Mar 15, 2012)

thank you Harold,

anyway this are just for an experiment for a small scale.... i just to want get a hand of anything, exposure to such things as failures....

how about extraction of ore tailings via electrolysis? can it be posible and practical in a small scale?


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## Harold_V (Mar 16, 2012)

gengates said:


> thank you Harold,
> 
> anyway this are just for an experiment for a small scale.... i just to want get a hand of anything, exposure to such things as failures....
> 
> how about extraction of ore tailings via electrolysis? can it be posible and practical in a small scale?


Yes, but not by processing with acid. That's the point. Too many of the constituents of ores react with acid, so it is consumed without doing the desired work. You can end up with hundreds of gallons of waste material to deal with, all the while recovering only traces of gold. Electrolysis (electrowinning) has been used with success, as has activated carbon, but both with cyanide, not acid. For a guy working in a small lab, there's nothing quite as convenient as good old zinc dust, however. I highly recommend you give that some thought. It's fast and easy, and requires no special equipment, unlike the other two processes. Best of all, unlike electrowinning, you can effect a total recovery of values. 

What is really important is for you to understand how much gold is contained within the ore. Minute amounts can be recovered with cyanide, often for a buck a ton, because the cyanide, used dilute, doesn't interact with anything but values, very unlike acid. If the head assay is low, please lose the idea of processing. Lets assume, for a moment, that it assays 1 oz/ton. Assuming you processed a pound of ore, the best you could hope to recover would be about a quarter grain (1/60 gram, for you folks that talk metric). That wouldn't begin to pay for the cost of acid. It also would be virtually invisible to the naked eye. 

Harold


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## gengates (Mar 19, 2012)

For a guy working in a small lab, there's nothing quite as convenient as good old zinc dust, however. I highly recommend you give that some thought. It's fast and easy, and requires no special equipment, unlike the other two processes. Best of all, unlike electrowinning, you can effect a total recovery of values. 

------------------------------------------------------------------------------

Harold,

can you expand the "zinc dust" process a little more?....what is this method called?

thanks


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## Harold_V (Mar 19, 2012)

gengates said:


> For a guy working in a small lab, there's nothing quite as convenient as good old zinc dust, however. I highly recommend you give that some thought. It's fast and easy, and requires no special equipment, unlike the other two processes. Best of all, unlike electrowinning, you can effect a total recovery of values.
> 
> ------------------------------------------------------------------------------
> 
> ...


Simple. It's called cementation, whereby, if I understand the process properly, zinc gives up an electron, and is put in solution, while gold in solution, which requires an electron, is removed from solution. If I have it wrong, one of the more learned members are free to correct my errors. I am not a chemist. 

I have used zinc in extraction from cyanide and know that it works perfectly well, even without eliminating free oxygen. It's cheap and fast. 

Harold


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## gene carr (Mar 23, 2012)

i have filters full of gold powderand need to process into clean gold that was left on my paper filters. i tried to water the filter but had no sucess.how you can help with zinc dust process
regards,
gene carr


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## Harold_V (Mar 24, 2012)

gene carr said:


> i have filters full of gold powderand need to process into clean gold that was left on my paper filters. i tried to water the filter but had no sucess.how you can help with zinc dust process
> regards,
> gene carr


It's not clear to me that you need zinc. If you have gold in filters, all that is required is to incinerate the filters, then to process the ash with AR (aqua regia). 

I don't understand what you mean by "i tried to water the filter but had no sucess."

Harold


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## gengates (Mar 29, 2012)

Finally i had my hand on a 90%tin solder, i cut a number of this solder in mm intervals and boil it in muriatic acid 29%....(i dont have a hcl 32%), is this ok?....
then i tested my previously AR from computer scraps, it reacted with almost black color...... but the tailings in AR, tailings in Acid Peroxide and tailing from
Clorox Method..... all, nothing reacted when i test my tin solution.....

questions:
-is my tin test solution acceptable to use with muriatic, boiled? i heard others mixed tin solder in AR for testing, is this ok also?
-is there really no gold in my tailing, even a micron one that tin test can detect?

now, this are my thought, since the complexity of the solution in an ore using AR..... i plan to dissolve first the base metal via nitric maybe or acid peroxide (without heating)....discard the liquid then dissolve the "gold" (if there is any) in AR or Acid Peroxide.....then drop it with smb or electrolysis....

another question:
-can i test gold presence using tin from other chem. solution like Acid Peroxide or Clorox Method, or is it only for AR solution?

thank you all!
---your humble chemist to be.... 8)


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## Oz (Mar 29, 2012)

That is what I would expect. Harold mentioned cementation with zinc and likely that is what is happening with your tailing solutions. Even if they have gold, the gold will cement on any remaining base metals and be non-detectable with stannous chloride. This is why it is not advised to process ores by acid, it typically takes more acid than your gold is worth.

You did do one thing right, you checked your stannous against a known gold bearing solution.

You really need to do more reading before you go blindly about with mixing chemicals.


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## gengates (Mar 30, 2012)

ok....then what are this guys doing?..
http://www.treasurenet.com/forums/geophysics/1425-would-simple-field-gold-test-kit-under-1-per-test-help-anyone.html

also...
this...http://acta.chem-soc.si/54/54-4-907.pdf


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## Oz (Mar 30, 2012)

I am not saying it cannot be done, I’m saying it is exceedingly rare for it to be cost effective recovering ores with acids.

Your top link is an acid digestion then a stannous test. Yes it can work and has value as a test, but only if you have dissolved all of the base metals. Easier to do on a small sample, however it is not cost effective on large quantities.

On the second link they did karat gold and a refractory ore. Karat jewelry is very high grade that you will not find in nature unless metallic nuggets or fines. The refractory ore is a realistic sample at 50ppm. Said another way it is .005% gold or 50 grams per ton.

Try this test, make yourself a super ore that is 1% gold (that is 5,000 grams per ton or 5,000ppm). Take your 1 gram bead of gold and add 14 grams of copper clippings and 85 grams of black sands. I am making this easy as normally you would have silver and copper directly alloyed with your gold which would cause other problems. Digest this in acid until you can get a positive stannous result and recover your gold. Your gold will start to digest in AR right away not being alloyed, but will keep cementing back out until you have digested all of the base metals.

When you are done get back to me and tell me if you still believe it is cost effective how you wish to proceed.


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## Harold_V (Apr 2, 2012)

It is my opinion that inquires such as this one will be satisfied only when the individual in question gets the answer he hopes to get (yeah, sure, you can process your ore with acid. Hell I do that everyday). 

What he seeks is approval, not guidance. He isn't interested in the truth. So then, he most likely should attempt to process with acid. He'll quickly come to understand what he's been told, and if he doesn't, he's one of the lucky few who have an ore that can be processed economically with acid. It is my opinion that that will not be the case. 

Harold


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## handypur (Jul 25, 2014)

I have chalcopyrite ore that contains 15 ppm gold. I leaching chalcopyrite with h2so4 47.5% + hno3 2.5%+ water 50%. Can anyone give me a suggestion an effective method to get the copper and the gold? Thanks before for the advice and sorry for my bad english. I hope you understand what i means. GBU


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## goldsilverpro (Jul 26, 2014)

Harold_V said:


> It is my opinion that inquires such as this one will be satisfied only when the individual in question gets the answer he hopes to get (yeah, sure, you can process your ore with acid. Hell I do that everyday).
> 
> What he seeks is approval, not guidance. He isn't interested in the truth. So then, he most likely should attempt to process with acid. He'll quickly come to understand what he's been told, and if he doesn't, he's one of the lucky few who have an ore that can be processed economically with acid. It is my opinion that that will not be the case.
> 
> Harold


Good insight, Harold!


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## Reno Chris (Jul 27, 2014)

H2SO4 + HNO3 + water will dissolve chalcopyrite and put the copper in solution, but it will *not* dissolve the gold in your ore. Any gold present will remain with the insoluble fraction. Hope you have lots and lots of acid and very large containers. It will almost certainly cost you much more money for the acids than the value of the copper you will get out.


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