How to get disseminated gold from mud?

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Zolotov

Well-known member
Joined
Feb 21, 2017
Messages
62
Hi,
I miner gave me some kilos of mud with (supposedly) disseminated gold in it. The origin of the mud is from gold refining machines. How do I extract it ? The gold particles are invisible to human sight. I have been watching this video (https://www.youtube.com/watch?v=yb6xPB6IHGA) but I am not sure if I have to use electricity. The pictures of the mud are attached.

I have almost no experience in getting disseminated gold so I will appreciate your help.
 

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Have you ad had Assay?It is the only way to know what is where.
Can tell very little from a picture!I regularly pay up to £100 for assay and M.G.S. so I know where the goal lines are and if I am preforming a fair service.
 
I would dry out a small spoonfull of the mud and heat it to a red glow with a torch. Then I would add some aqua regia to dissolve a the small sample and test the solution with stannous chloride.

I never heard of disseminated gold before so I am unsure of what it is exactly, and what type of machines it came off of.

But the heating the sample to a red glow will take care of any cyanide if it is from a leach setup so a small dissolve under a fume hood should get you your answer.
 
4metals said:
But the heating the sample to a red glow will take care of any cyanide if it is from a leach setup so a small dissolve under a fume hood should get you your answer.
Thanks for your tips. About cyanide, are you suggesting that my sample could be deadly poisonous? In that case, if I heat the cyanide it will vaporize and I may inhale it in gaseous state. Or not?
 
Cyanide decomposes with heat but still use some form of fume exhaust. After you have gotten a small sample to glow red test it for gold by digesting it. If it has gold we can do a few more tests
 
4metals said:
I
I never heard of disseminated gold before so I am unsure of what it is exactly, and what type of machines it came off of.
I used there term "disseminated" because it is a way to say that gold particles of very tiny size and are sparsed all over the place (http://www.minelinks.com/alluvial/goldDeposits3.html) however my sample comes not from nature but from machinery and gold in it is barely visible to human eye. I hope your idea works for me. Thanks again.
 
4metals said:
Cyanide decomposes with heat but still use some form of fume exhaust. After you have gotten a small sample to glow red test it for gold by digesting it. If it has gold we can do a few more tests

Thanks agian. Should I add borax to the heating process ?
 
I cannot speak for 4metals, but, when heating to red heat borax is not necessary.

Generally borax is used just to glaze the melt dish, or when melting impure gold.

His suggestion was to heat to redness -to drive off any cyanide or other leach based compounds (if they are there), then to dissolve the remaining mud in aqua regia. Which, the heating to redness would be absolutely necessary as a precursor to dissolution (if CN is present). Else you would create poisonous gas.

Its better to be more cautious than careless
 
No borax, you are not melting this you are heating it to drive off potentially harmful elements. Borax would coat the material and it wouldn't get "wetted" by the acid, preventing a reaction. With borax coated material you could have gold but not react with the acid and think it was worthless and be wrong.

No borax or any flux material
 
4metals said:
No borax or any flux material

Great advices, many thanks!
BTW, may I ask why stannous chloride and not nitric acid? Because I went to jewellery repair services and asked for stannous chloride (I thought they had it already made for sale) but none of them use it. They use nitric acid only.
 
4metals said:
Then I would add some aqua regia to dissolve a the small sample and test the solution with stannous chloride.

Unfortunately there is no aqua regia in my town,but there is 98% of sulfuric acid, do you think sulfuric acid can be used instead of aqua regia?
 
Zolotov said:
4metals said:
Unfortunately there is no aqua regia in my town,but there is 98% of sulfuric acid, do you think sulfuric acid can be used instead of aqua regia?

Actually, I at the store I was asking for 98% concentrated nitric acid, and 98% of hydrochloric acid, because I thought aqua regia was made with 98% concentrated liquids. But now I am reading at wikipedia that hydrochloric acid only has to be at 30% and nitric acid only at 65%. At the store, they have hydrochloric acid at 30% but nitric acid only at 50%. So I may try to mix aqua regia from those myself.
 
You should wait until you have a fundamental knowledge of the chemicals that we would tell you to use.
Aqua regia is a mixture of nitric acid and hydrochloric acid (HCl). The ratio is 1 part nitric acid and 3 parts HCl. This mixture will dissolve gold into solution. It generates toxic fumes when when it dissolves metal. You would heat the soil sample and then leach it in aqua regia to dissolve any gold that might be there. Stannous chloride is a liquid test solution for detecting dissolved gold in solution. Stannous chloride (SnCl2) will turn the sample of solution purple if gold is dissolved. The greater the amount of gold, the darker the purple will be until it is completely black.
 
Zolo,

The questions you ask and the assumptions you have made scare me. Why would anyone give some material suspected to contain gold to someone who has never done this before?

Do yourself a big favor and click on the link in my signature line below and go to the library and download a copy of Hoke's book for free,. It is written to teach a non chemist how to refine. Please do a little reading before you jump into this.

Best of luck.
 
4metals said:
Zolo,

The questions you ask and the assumptions you have made scare me. Why would anyone give some material suspected to contain gold to someone who has never done this before?
Well, it happens that I went to a mining city (here in Mexico) looking for alluvial gold (the gold in rivers), but there was a guy at an old mine (non-functioning mine), and we talked a lot about gold. After about 1 hour of conversation he told me that they have a big pile (about 1 ton) of waste from the mining company and it has a lot of gold. He said "there is about 500 grams of gold there and only I know about it". So, he said the owner of the mine can sell it to him as dirt because nobody suspects this pile could be worth $17k , but he is not interested in money so he can give it to me. And for such amount of money I will definitely learn chemistry if I can extract this gold somehow. When I started to question him if such amount of gold would lie there just like that, he told me "go and take a sample, and see it for yourself". I took 3kg of this dirt and here I am , trying to find out if the old guy is telling the truth, because if he does, it is going to be a very profitable deal.

Thanks for the book! I will definitely read it.
 
Geo said:
Stannous chloride (SnCl2) will turn the sample of solution purple if gold is dissolved. The greater the amount of gold, the darker the purple will be until it is completely black.

Thanks for the info! But what if this sample solution is already black? Because it the dirt is already gray, and I suspect the acid is going to give it more darkness.
 
Put a small sample of the liquid you want to test in a white plastic spoon. Add a bit of stannous chloride to the sample and let it react for a minute. Then pour the liquid out of the spoon. If there is a purple stain in the spoon, it indicates there is gold in the material.

Personally, I would get a professional assay done first. Most people don't leave thousands of dollars of gold lying around or give it away unless there is a catch. What worries me most is when you said "they have a big pile (about 1 ton) of waste". There could be any number of toxic chemicals in their waste. If it's worth $17 thousand dollars, it's worth getting an assay.

Dave
 
Auric chloride is very sensitive to stannous chloride. The color change is enough to be seen with very low concentrations of gold in solution. Leach the sample with aqua regia. If the sample is black, add enough fresh HCl to the sample to make the sample transparent. Let the sample settle completely. Draw the clear solution off with a pipette or dripper. The solution may be discolored but must be clear. Place a single drop in a spot plate cavity or use a white plastic spoon. Add a single drop of stannous chloride. Watch the sample closely as you add the stannous. You are looking for a color change to the purple or beyond.
 
At this time I think it is good to talk about sampling. An assay on a given sample will only tell you what's in that sample. It could easily be salted with some gold dust so it assays as high or even higher than what the guy said. Then when you come for the rest of the mud you hear that he can "buy it cheap" from the mine, so you pay him the small fee and then when you have a ton of mud you discover that it doesn't contain any gold.

If it comes to that, then demand to take another sample, but use your own shovel and use the coning and quarting method that 4metals described in this thread.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=25196&p=267043#p267028
If they don't allow you to sample it by yourself I highly suggest that you back away from the deal.

Göran
 
Well, it happens that I went to a mining city (here in Mexico) looking for alluvial gold (the gold in rivers), but there was a guy at an old mine (non-functioning mine), and we talked a lot about gold. After about 1 hour of conversation he told me that they have a big pile (about 1 ton) of waste from the mining company and it has a lot of gold. He said "there is about 500 grams of gold there and only I know about it". So, he said the owner of the mine can sell it to him as dirt because nobody suspects this pile could be worth $17k , but he is not interested in money so he can give it to me. And for such amount of money I will definitely learn chemistry if I can extract this gold somehow. When I started to question him if such amount of gold would lie there just like that, he told me "go and take a sample, and see it for yourself". I took 3kg of this dirt and here I am , trying to find out if the old guy is telling the truth, because if he does, it is going to be a very profitable deal.

This has all of the markings of a typical set up. If you took the sample did you take a little from here and a little from there or was there a 3 kg bag conveniently taken for you? And if you did take the sample, did you stuff it in your bag and make sure no one switched it for different spiked bag while you were celebrating over a bottle of Dos Eques with your new found friend? Stay thirsty my friend!

If the ton of material has 500 grams of gold in it then each pound has 500/2200 = .227 grams since you have 6.6 pounds you are looking for 1.5 grams of gold. That much gold, 1.5 grams, is worth just under $60. The way scams like this work, this guy gets you to take this sample so you can check it out. Send it out for assay and come back with a result. So it comes back assaying 16 ounces per ton, which is what 1.5 grams per 3 kilo's works out to and you are so psyched you can't wait to get back there and scoop up your ton.

So your buddy in Mexico says OK let me talk to the owner and the owner comes back and says I know it has some gold or some story and asks you for $2,000 (or something I am making this up) you say whoa, I know this is worth ten times that and you pay. Smiles all around
and your friend even helps you scoop it into your pickup truck.

As it will turn out, the only gold in that pile is the 1.5 grams that were in your sample. guarantee, I've seen it many times with guys who bought piles of African ore that assayed high. This scenario is a classic.

The moral of the story, there is no Santa Claus! Sorry to break your bubble. Actually you are pretty lucky, you have stumbled on the one place on the internet where you will get the straight scoop to recover all of the gold that is supposed to be in there, but this time, my friend, I'm not optimistic.
 
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