need help on Gold Salts

nickvc said:

Gold salts sounds like gold cyanide salts to me, if so do not try anything to recover them unless you have a very good fume hood and a good knowledge of what your doing. Cyanide is deadly and gives no second chances and should be handled with extreme caution, don't even open the container if it is cyanide based, there are ways to recover the gold from them but I'm not willing to tell you how unless you can prove you have the right equipment or knowledge.

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jd12586 said:

Hi, I'm new to gold refining. My uncle has some gold salts I would like to know how to extract gold from gold salts.

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patnor1011 said:

You will be much better served to struck a deal with someone who is familiar with processing this. You are not going to learn process overnight and you are not going to benefit from some step-by-step manual. If that is only something like one thing you want to do and just extract that gold out of it contact some professional. If you plan to do more in future then you need to put a lot of effort in studying this field and get some experience before you will be ready to deal with deadly poisonous stuff as cyanide certainly is one.

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In its purist form, which is usually used in acid gold baths, the PGC will contain about 68.3% gold. If it is used for alkaline cyanide baths, it might also contain some potassium cyanide, which would lower the gold percentage. If it is used for acid baths, it could also contain a little nickel or cobalt and will have a green or pink color. The presence of these won't interfere with the recovery of the gold.

(1) Dissolve the PGC in water. At room temperature, you can dissolve about 143 grams of PGC in a liter of water. This would contain about 3 troy oz of gold, if it is the 68.3% variety. Since the solubility of PGC varies considerably, based on temperature, I would only dissolve about 2/3 of that in the water or, about 2 oz of gold per liter.

(2) To prevent the very dangerous evolution of hydrogen cyanide gas in the following steps, first adjust the pH to 12 with potassium hydroxide. Try not to exceed this pH, since too much hydroxide will increase the amount of zinc needed in the step below.

(3) If the PGC is of the 68.3% variety, it would help the gold precipitation to also dissolve about 15 grams of potassium cyanide per liter in the solution. Without the extra cyanide, you may or may not have a problem dropping the gold. The gold may finally drop, but it will be slower. It is best to add the extra cyanide.

(4) With constant stirring, add 325 mesh zinc powder until all the gold has dropped out. This should take from 1 to 2 oz of zinc per oz of gold. The gold will drop out and appear as a brown powder. To insure all the gold has dropped out, you'll need a slight excess of zinc, which is of a gray color. Add the zinc in increments, allow it to work for a couple of minutes, and observe the color. When the observed powder is of a uniform gray color, all the gold should be out.

The zinc powder tends to clump when stored and must be broken up before adding. The easiest way to break it up is to weigh out what you think you'll need and place it in one of those small flour sifters that has a squeeze handle on it. Add the zinc to the solution directly from the sifter.

(5) Allow the powder to settle overnight. To prevent any gold from re-dissolving, hang a couple of zinc bars in the solution.

(6) Either siphon or dip off most of the solution without disturbing the settled solids.

(7) Filter the solids and rinse several times with hot water in order to remove any cyanide solution.

(8) Remove all the solids from the paper and put them into a plastic bucket. Keep the paper(s) for future incineration.

(9) Cover the solids with water and stir a bit to break up the solids and create a slurry.

(10) UNDER A FUME HOOD!, add a small amount of concentrated nitric acid. You should see an immediate reaction. When the reaction subsides, give it a stir and add a little more nitric. Repeat until an addition of nitric produces no reaction. You MUST use a fume hood for this, just in case you didn't rinse out all of the cyanide. The combination of acid and cyanide will produce deadly hydrogen cyanide gas

(11) Transfer the solids to a beaker, cover with water, and heat to a little below boiling. Add some nitric and heat for about 15 minutes.

(12) Filter the solids and rinse several times with hot water. Remove the solids from the paper and slowly dry.

(13) At this point, you should have 99+% gold powder. To purify it further, you can use the standard aqua regia method.

NOTES:
(1) Wear rubber gloves and a full face shield for all operations.
(2) In the above, I suggested using Potassium hydroxide and Potassium cyanide because the solution is Potassium to start with. It would work as well using Sodium hydroxide and Sodium cyanide instead.

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A few additional notes on the process I outlined above.

The purpose of the nitric acid, in steps (10) and (11) is to leach out all of the excess zinc. Also, if any Ni or Co is present, it will also be leached out with the nitric. Step (11) is done to insure all the zinc, etc. is leached out.

This process can also be used for any acid or cyanide gold baths, already in solution form, that contain PGC. Also, it can be used for cyanide/H2O2 or most cyanide/m-NBSS gold stripping solutions. In these cases, just start at step (2). For cyanide baths or gold strippers, eliminate step (3).

The process will NOT work for baths containing sodium gold sulfite. These sulfite baths are rarer than PGC baths, but there's a lot of them out there.

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goldsilverpro said:

jd12586 said:

Hi, I'm new to gold refining. My uncle has some gold salts I would like to know how to extract gold from gold salts.

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Need much, much more info. What kind of gold salts? Who is the manufacturer? What color are the salts? What quantity, in grams? Are the containers marked and sealed? What does the label say? Etc., etc.? How gutsy are you?

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