Dangers of fine gold recovery

[LP13]

Most people know me as the guy who invented the Gold Well sluice. This sluice recovers very fine gold very well. The big problem as one of my customers indicated, was how to get the fine gold out once you recover it in the sluice. My preferred method is just add up the concentrates with the fine gold in it (after removing the larger gold) and when I have a bunch of it, to re-run it through the sluice again and get it to high enough concentration that it can form a line that can be sucked up.

Another method I use is aqua regia. I really like this method, and although it has some hazards, if you learn to do it properly it is not very difficult and the recovery is excellent. I prefer it over mercury or other methods.

Well, last weekend I decided to combine a few projects. Removing the gold from old computer boards I have AND recovering gold from a bunch of black sands with gold 400 mesh and finer in it. So I processed it in two batches. For the circuit boards i used acetone to remove the coating that covers the copper traces, then used hydrochloric and peroxide to eat away the copper, leaving just the gold foils floating around in the liquid. And I processed the black sands with some aqua regia. All in all it turned out well and I got several grams of gold for my efforts.

I also know a bit about things that go boom. And just today as I was thinking about the processes i use to recover gold, it dawned on me that the acetone-hydrochloric-peroxide technique (commonly described on the internet as the 'how-to' for e-gold recovery), creates a by-product. Acetone Peroxide explosive! This stuff is very powerful when dry and very sensitive. In addition if it is contaminated with other stuff it becomes even less stable! And that recovery of the silver?? Washing that silver with ammonia? Explosive silver!

I always take precautions to insure that these products are not formed or do not dry out and become explosive. In the case of the acetone-acid-peroxide, I wash off the boards with hot soapy water to remove the residue before i add the acid and peroxide, meaning that there is virtually no acetone left to form explosives. Also my batches are very small and so any resulting explosive powders that could possibly accumulate would me microscopic, if any.

So anyone who is new to fine gold recovery, using ANY chemical means to recover their fine gold, they should, -no-, MUST study up on the safety and possible dangerous by-products of the process they intend to use and how to deal with or avoid them. Even that lovely gold if allowed to form crystals from acids drying out, can become extremely explosive. Gold fulminate.

The fulminates can be found here:
http://lem.ch.unito.it/didattica/infochimica/2008_Esplosivi/Fulminate.html

There are other hazards also when you get down to recovery of gold by other than mechanical means. Leaching out arsenic from rock is one that comes to mind. And most people know the hazards of working with mercury.

Bottom line. Take gold recovery seriously enough to put time and effort into learning how to do it the RIGHT way AND the SAFE way... Don't cut corners or try out some new idea you have (unless you have a degree in chemistry and know what you are doing!) because it could blow up in your face!

 

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[Mitch Dickson]

Gee, and all these years I have just been dumping it in a crucible, adding a bit of flux and firing it and pouring a button Like dupont says "Better things for better living through chemistry" LOL!

 

[Hoser John]

Amen Mitch keep it simple and MUCH less dangerous-John

 

[LP13]

I smelt a lot too. You never get all the gold out though. If you dont believe me, give this a try (assuming you use borax and lead for example to smelt your gold.)

Take some of your old waste glass from smelting that you got a gold button out of. Put it in a crucible and melt it and add some baking soda. Add a teaspoon or two for a 30 gram crucible. Give it 20 or 30 minutes at around 1850 - 1900F and pour it into a bucket of water (wear safety glasses.) Then take out the bits of glass and crush them very fine. Put this in a beaker or plastic bucket and add water and hydrochloric acid. More hydrochloric works faster. All the glass will dissolve into the water. Pour it off and repeat until all the glass is gone. Stirring will help it dissolve faster.

When all the glass is dissolved, or at least almost all of it, rinse what remains with clean water a couple times to get rid of the acid then put it in a pan and pan it. Unless you have a perfect process of smelting, what you will see in that pan is all the gold, silver, lead, platinum, etc., that DIDN'T get into your button! I was amazed how much I got from a couple gallons of my old glass!

The same applies to aqua regia I have found. Once I have precipitated my gold with SMB, I take the solution and use zinc on it and will recover more gold that wasn't precipated by the SMB. As far as I know there is no method where you can get 100% of the gold back in a single step.

 

[KevinInColorado]

Great point LP13. That's why I like both my vodka and my mercury triple distilled! LoL

 

[LP13]

The problem one runs into with mercury beyond the standard propaganda against using it, is that as the particle size decreases, it's ability to collect gold diminishes. One report I read stated that mercury is useful down to around 60 microns or so and below that it's collection of gold drops off dramatically. Also if the gold is not clean of manganese and elemental carbon, mercury may not pick up the gold. Some old timers clean their gold with nitric which won't dissolve gold. Pure gold in a lab that is. However, there are a lot of chlorides in nature, and the chlorides mixed in with the concentrates will help create aqua regia essentially, dissolving up some of the very fine gold. This amount might be negligible or it could be significant, depending how much gold there is in the cons, how long the nitric is let to sit, and the type and quantity of chlorides in the material.

But this is more about safety than collection. Nothing in life is entirely safe, I'm told. Look at all the fools driving deadly weapons around on the highways! Some of them couldn't spell the word IQ let alone pass the test with a score that has a net positive value. Yet they give them driver licenses!

Regardless of the method you choose to refine gold, there are always going to be inherent dangers, advantages and disadvantages. Whichever one a person chooses, they should study it well and fully understand what they are doing. If you put a good honest effort into the study, and seek help when stumped from qualified people or sources in the area you need help with (Yahoo Answers is not a qualified source), you are far less likely to have an accident.

Now there will always be those fools who will not study up on their method, and just jump in and 'wing it'. But hey, I guess the gene pool could use a good cleaning anyhow these days.

Time to get back to my drinking. Toss me another bottle of nitro while you are at the fridge, will ya Kevin?

 

[bedrock bubba]

I just got a report about a miner I know who was deplating metals from computer parts, and stuck his hand into a jar of aqua regia! Now, he has toxic metal poisoning, and is goofier than a fruit bat! We also suspect that he is a meth user, too.

Stupid people!

 

[KevinInColorado]

Eek, pro tip: don't put hand in acid

 

[2cmorau]

how many times has he stuck a hand in royal water, and how many times has this guy used meth, i would say the latter
if as had been claimed by the likes of CBD n TSF the effects of MeHg, humans should not be walkin the earth, so why r we still here

almost forgot, yeah like the others said, don't be a izzy and stick your hand in it

 

[Bonaro]

I just got a report about a miner I know who was deplating metals from computer parts, and stuck his hand into a jar of aqua regia! Now, he has toxic metal poisoning, and is goofier than a fruit bat! We also suspect that he is a meth user, too.

Stupid people!

I would suspect that his suspected meth use was a greater contributor to his nuttiness than a one time exposure to mercury, or in this case, mercuric acid. HG poisoning can be achieved with a single huge dosage but the symptoms are usually more physical than mental. Mental degradation is most often associated with long term exposure.

 

[LP13]

I call B.S on him putting his hand in aqua regia and getting mercury poisoning from it. The mercury compound would be mercury (I) chloride most likely, and although toxic in it's own right, I doubt would be sufficiently toxic enough to poison him on a single exposure to his skin, especially in aqua regia as he would very quickly be washing it off so it wouldn't even be on his hand for long. I agree with the rest. He's a tweaker and his story is 100% unadulterated B.S. and most likely his brain damage is from chronic use of meth.

Another inconsistency in the story is that most people that learn to de-plate gold from ram chips and computer parts do not want to use aqua regia as it dissolves everything including the tin and steel, cadmium and copper, etc. The usual way is to use hydrochloric acid and hydrogen peroxide, which eats away all the copper but won't eat the gold, leaving the gold as little floating foils that don't need to be precipitated from the acid. You just filter off the acid and collect up all the little gold foils and melt them down.

 

[KevinInColorado]

I agree with LP13. Hydrochloric and Suphuric (eats rust real well) are cheap, available and more useful for separating gold from scrap. I've used both very successfully to retrieve gold. Nitric and therefore Aqua Regia are special use only.

 

[timemachine]

Yeah, no, yeah, ummm, no... I too have seen those YouTube vids with ram chips, and making a mess all over creation, and then what of the byproducts, ya just flush it, errr what?
I'll stick with nugget shooting via plain old metal detecting...thanks.

 

[KevinInColorado]

Yeah, no, yeah, ummm, no... I too have seen those YouTube vids with ram chips, and making a mess all over creation, and then what of the byproducts, ya just flush it, errr what?
I'll stick with nugget shooting via plain old metal detecting...thanks.

Good point. Proper handling of the byproducts is challenging and requires knowledge of chemistry. I have that knowledge and care enough to do this properly (safe for me and the environment) and anyway, this isn't something I do regularly. Like you I prefer to be out in the field rather in my shop most times. The other reality is it's very easy to spend more on the chemicals than the value of the gold you get, very easy.

 

[augoldminer]

I will stick to using mercury after removing other metals with acid.

I worked for a number of years for a chemical company and learned how to work with toxic chemicals safely.

My last mine job i did a lot of work grinding cons with mercury and retorting.
and i had blood test done for mercury and they only found normal background levels and i have a number of mercury fillings.

Wear the safety gear and the right respirator and there is very low chance of problems.

 

[bedrock bubba]

I knew a little Indian man who worked at the Kate Hardy mine near Alleghany, CA. He says he used to sit in a vat of mercury where the crushed ore went. He was mad as a hatter! I coined him; "Mad Max the Miner". He used to do some crazy stuff, like cave in a whole bank of boulders onto me! He was absolutely fearless! And stupid, too! Even tho he had ephephesema, he would go out every day with his Vac-Pac and bring home nice gold. Well, he lived in his car as home. He had a hair trigger temper, and when he yelled, you could hear him from far away! Ranger Rick busted him one day at the S.Yuba State Park(Bridgeport) for caving in a bank. He would toss lit cigarettes out the window of his car while driving onto dead weeds, and stood up to a biker gang with loaded shotguns pointed at our heads, and lecture them, loudly!

I realized, he was not one to hang out with!

 

[Bonaro]

Mercury is a demon because people don't understand it. It's toxicity is comparable to lead but it can enter the body is invisible ways which are hard to easily understand.
When electricity was first introduced to homes, people were afraid of it because they didn't understand it and couldn't see it. They believed that something had to be plugged into every outlet or the electricity would run out on the floor and shock you

 

[LP13]

Well that was my original point: That some methods of gold recovery have hidden or subtle dangers, that if you don't know what you are doing, can in some cases be deadly, whether it's instant death by breathing deadly poison, or explosion; or long term death caused by mercury or lead accumulation in your body. That no matter what method you choose, you need to study it well to fully understand the inherent dangers in the method you chose, and if you don't do foolish things, and practice the proper safety for that method, that the risks are manageable and become minimal to non-existent when done properly.
And if you are a fool or too impatient, or have a learning impediment making it impossible for you to learn what you need to, you will likely end up being an example for others to point at to prove how dangerous that method is, and clean up the gene pool at the same time. So it's not all bad

And trust me, the anti-chemicals for mining people are always prowling for examples of misuse and inherent dangers of chemical means of gold recovery! The other day I saw an article that mentioned that a "miner had died, surrounded by extremely dangerous and potentially lethal chemicals..." ... of course he died from natural causes and the chemicals had no actual role in his death and caused no damage to any life or property. They were just present where he died! But to read it how they worded it it made a lay person believe that somehow mining=deadly chemicals=death.

Personally I believe this kind of reporting and fear mongering should be prosecutable as a crime...