Troubleshooting Shor Products

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the_photon

Member
Joined
Apr 23, 2012
Messages
5
Sirs,

I am a chemist attempting to do a little hobbyist gold recovery -- although I must admit that I'm certainly not an inorganic chemist, and I'm working with extremely limited equipment in my back yard -- no access to a lab or any of my ordinary methods of troubleshooting for this project.

I am having a few problems with the Shor international kit. I have already read on here, as well as agree that Shor's instructions are rather oversimplified and misleading in many places, and that all of their chemicals are available elsewhere. However, given that I already have two complete kits of theirs (given to me, thankfully didn't have to pay), I'd like to use them if at all possible rather than go out and buy a whole lot of chemicals.

As per the Shor instructions, I added 1 lb (the entire bag) of Sub-Zero (which I suspect is simply sodium nitrate) to 1 gallon of muriatic acid. My source of scrap is several hundred slips of gold on what looks like polyethylene terepthalate plastic film -- electronics scrap from an R&D firm circa 1990. I suspect that each slip of film has about 0.0175 oz of gold on them, according to a variety of quantitative estimates that I have done, and I inserted 25 of them into the Aqua Regia that I concocted as above.

The gold on the plastic film strips turned rather dark blue. To the best of my knowledge (no pH meter in my back yard), I have neutralized most of the nitric acid with the Urea, and filtered out all solids resulting in about 3/4 of a gallon of extremely dark blue solution.

My question is this: when I add the "Storm precipitate", no obvious reaction happens, and no noticeable amount of "mud" (as Shor puts it) collects at the bottom of the bucket. Adding more storm precipitate seems to have no effect anything like what I see in the youtube videos of this process. Have I done anything obviously wrong? Should I just add more storm precipitate? Are there any major suggestions as to where to proceed from here, such as heating the dark blue solution to accelerate precipitation?

Thanks, and no flaming if you would be so kind.

the_photon
 
when you added the two chemicals together, did you heat? although a weak AR solution will result from passive association, it really takes heat to produce the nitric acid to form strong AR solution.

did you test the solution after dissolution with stannous chloride to determine if there was gold in solution?

you used WAY too much of each chemical for such a small amount of material, by your own estimate thats less than a half ounce of gold.there wouldnt be much of a change of appearance even if everything worked well.

did you test the solution with stannous chloride after you added the storm precipitant to see if gold was still present in the solution?

theres a very good chance that theres still free nitric in the solution considering the amount of chemicals you used and especially if you didnt use heat.
 
Sirs,

Thank you for your responses. And yes, I strongly suspected that I had used too much of each chemical for the amount of gold that I was trying to dissolve/recover.

I used the stannic(ous) chloride test. What tiny bit of gold dust that collected in the bottom DID turn rather blue with the test. The problem now is that trying to remove such a tiny amount of extremely fine gold dust is a bit challenging given the amount of AR, and yes I strongly suspected that I had not neutralized all the Nitric acid created, and thus still have quite a bit of gold Au3+ in the blue solution.

Any recommendations (or links to recommendations) with regards to the amounts of HCl and Sodium Nitrate that I should use on my next batch? I have read that it is better to dissolve the sodium nitrate into water first, then add the aqueous sodium nitrate to the HCl and then heat (not boil) the acid rather than just adding the pellets directly (as per the Shor instructions). I have quite a bit more of the scrap gold to work with -- this was just a practice run as I always do when attempting a new reaction.

Thanks again you all!

the_photon
 
http://tinyurl.com/mfnyhs

download this book and read it several times. reference it often.

the correct name of the process is "poor man's AR". do a search on the forum for poor man's AR.

you should first add the amount of hcl (muriatic acid) first to your material and heat. next you add the sodium nitrate in small increments (a spoon full at a time). be sure to cover your reaction with a watch glass or at least a heat resistant glass saucer. wait for the reaction to stop and and no more red fumes are produced. and add more nitrate.repeat until all the metal is dissolved and stop adding nitrate.

this is the most efficient way to use these chemicals.
 
Hoke teaches us to evaporate the Agua Regia several times and dilute with HCl after each evaporation until the nitric acid has been expelled. There are many links to her book here on the forum.

Many here will suggest that you add this experiment's result to a stock pot to be kept in a safe place until you have digested Hoke's book.

Robert Jeffery, CWI

Edit to correct Calm's name... Sometimes my fingers have a mind of there own.
 
As color of your solution is Blue, I would suspect you have no gold in the solution. Are you sure the film strips are not copper?

Gold solution should yellow or orange if saturated. When you have both copper and gold in the solution yellow+blue=green.

I do not know of any color that will make following equation yellow + X = Blue true.
 

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