Non-Chemical Recovering gold wire from ash with mercury

[kurt]

The idea of using mercury to recover the gold wires from the ash of incinerated flat packs/chips is the result of my being involved in some hard rock mining about 20 years ago when I lived in Northern California. We were running some ore that was only running about 2 – 3 oz per ton & crushing it down to about 800 & mercury is what we used to recover this “ultra” fine gold from the concentrates.

I happened to have a little mercury on hand that I recovered from some old mercury switches so decided to give it a try yesterday. I know some here will have an issue with this due to the health risk – but like every thing else we work with in refining PMs – with the proper precaution & handling I don’t think it is any more of a risk than other refining procedure. In fact I believe it is just another “very” useful tool in the refiners tool bag.

Here is a link to a “very good” explanation on using mercury to recover “fine” gold from concentrates. http://nevada-outback-gems.com/Reference_pages/Amalgamation.htm

What I did --- I started with about 2 heaping table spoons of gold wire ash concentrates. In a small dish I put a small ball of mercury, a bit of water with just enough soup to break the surface tension & about ¼ teaspoon of ash concentrates. ( I went with only a ¼ teaspoon at a time so I could inspect how well the mercury was doing at picking up the gold wire with my 10X loop) I then agitated the ball of mercury through the concentrates using the same motion used to settle gold when panning. It didn’t take very long at all for the mercury to pick up “all” of the gold wire – including wires with bits of epoxy still partly incasing them. (they don’t get sucked into the mercury like the free wire but cling to the out side – so a little finer crushing may be in order)

When the mercury becomes “loaded” with gold wire and no longer rolls freely through the concentrates it is no longer effective in picking up the gold. I then placed my amalgam ball on a wetted coffee filter & squeezed out the excess mercury & then removed the remaining mercury from the gold/mercury amalgam with nitric.

The Result - .25 grams (1/4 gram on the nose) from 2 table spoons of ash concentrates.

On a larger scale a chamois works best for squeezing the excess mercury out of the amalgam (coffee filter will tear) & you would need to use a retort if you want to recover your mercury.

I am of course wide open to any other ideas/suggestions on how to recover the gold wire from flat pack/chip ash. I just know that in this experiment the mercury worked “Very Well” --- it was quick (very quick) & as best as I could tell it got very close to – if not 100% of the wire.

Kurt

 

[rusty]

Looks like copper to me.

Regards
Rusty

 

[kurt]

Looks like copper to me.

Regards
Rusty

I used nitric to remove the mercury from my amalgam ball so copper would have gone into solution along with the mercury. --- It the gold wires I asure you.

Kurt

 

[geonorts]

It won't be long before you hear from Harold but I'll ask first, what do you now do with the mercury nitrate?

 

[Harold_V]

It won't be long before you hear from Harold but I'll ask first, what do you now do with the mercury nitrate?

That's certainly a reasonable question. I'm hoping he'll tell us he's recovering the mercury with copper, and not dumping it in the environment.

I'm not well versed on dissolving mercury with nitric, but I do know that it's not exactly a good idea. If any of the readers feel bound to use mercury, they should invest in a reliable retort. Best scenario is to not use mercury at all. There are other ways to achieve the same end.

Harold

 

[samuel-a]

That seems like a clever way to treat this kind of material. IMHO
Though it's herd for me to imagine it on a bigger scale then a few spoonful at the time....
The process has its safety issues for sure, but not somthing out of reach. To make things safe, I would work with mercury inside a glove box.

I'm hoping he'll tell us he's recovering the mercury with copper, and not dumping it in the environment.

I think that recycling of the mercury will be in his best interest anyway, beside the important environmental issue, buying new mercury is probably painful to the wallet... especially when the process is continuous with many pounds of material.

Nitric, in some cases, is also is expensive. That is way my first thought was to retort the mercury rather then part it with nitric, it will save you time any acid.

Then treat the left over powder with nitric to eliminate base metals and refining.

These are my thoughts only... i have never got the chance to recover with mercury and don't know if i ever will. but it sure looks straightforward to me.

 

[kurt]

I will post more details about using this method of “recovery” later this next week. Right now I am working on finishing up a batch of silver from contact points so I can have a pay day Monday or Tuesday.

This is what I know – using mercury to recover very fine gold is an age old tried & true method which is why we used it to recover the gold from hard rock ore concentrates that we crushed to 800 fine. We were running about 3 ton a day with a wash tub full of concentrates at the end of the day – so yes it works on a large scale.

What I didn’t know – some “substrates” will contaminate the mercury & make it ineffective in catching up the gold & what I didn’t know was if epoxy ash from chips would be such a substrate which was the reason for a very low level experiment to start with.

However – low level experiment results are not always conclusive to large scale application results & there still may be some contaminating problems here so I will do some more “small” but up scaled experiments & post those results

I am a newbe here to the actual process of “refining” & have MUCH to learn about that – but I actually have real hands on experience with using mercury to recover ultra fine gold due the 17 years I lived in Northern California & being involved in both hard rock & placer mining.

Harold – I moved home a little over a year ago to help take care of my mom & dad who are in there mid 80s & we live out in the country on a very beautiful 40 acre’s so our water comes from a well so I don’t just go dumping stuff out on the ground that is gong to leach into my own water supply. Its “my” environment & “my” health we are talking about here – so I do “all” that I can to keep it as clean & tidy as possible considering the type of work that it is.

Kurt

 

[kurt]

One thing I should mention in case anyone else wants to try this is that if you have tin paste (from solder) as a contaminant in your material, it will contaminate your mercury & render it non effective in its ability to pick up the gold.

Also go check out the link I provided in my first post – the guy did a “very” good job of covering using mercury including precautions needed to be taken when working with it.

One more thing that needs to be said about working with mercury is that the stuff has a mind of its own & it does not like to be controlled. It by nature wants to go where it wants to go & do what it wants to do. It can & “will” try to get away from you & when it does it likes to shatter into tiny little beads that are near to - if not impossible to recover. So “always” make sure you have some sort of larger catch basin to set the containers you want it to go into – into, --- A large deep sink that drains direct into a catch bucket works good for this

Mercury – like just about everything else we work with to recover & refine PMs – has a nasty nature about. But like every thing else we work with, it is only a problem if you are careless with it & if you don’t take charge & control with the use of proper precautions. It is only as dangerous as “you” allow it to be & like wise it will be as safe as “you” “make” it.

Mercury is an age old - “tried & true” method to the recovery of fine gold, - mercury & gold have a natural love affair going on, - they “want” to be together & if you put them together they will come together & in fact you can increase the natural desire to be together by charging the mercury & then you get mercury on Viagra. (the link in my first post gives detailed instructions on charging mercury)

Also – there is cheap way to recover your mercury by retorting – but – I “ONLY” suggest this as a “one time” small scale experiment to see if you want to go with this method before investing in & setting up a real properly set up retort. IT IS NOT A SAFE WAY TO RECOVER MERCURY (caps for emphasis not yelling) on a regular or large scale basis. --- take a good size potato cut it in half & scoop out a cavity in one half, take 3 or 4 coffee filters put them in a funnel wet them & drop your amalgam ball in & then squeeze out the excess mercury (wear gloves) (you will want to use a real chamois if you do this on a regular basis) be careful not to tear filters. Once you have squeezed out the excess mercury - take your remaining amalgam ball & put it in the potato cavity – then put the potato halfs together & pin them with some wire. Place the potato in an old stainless steal pot with a lid (do not use an aluminum pot) Then get a good camp fire going so you can get some good coals happening. Place the pot & potato in the coals like a Dutch Oven & bake the potato DO NOT DO THIS INDOORS the potato is porous enough & fibrous enough to catch the evaporating mercury & the gold stays in the cavity, so when the potato is done baking - take it off the fire & let it cool, take the top half of the potato off collect your gold out of the cavity, put plenty of water in the pan with your potato, mash the potato to a pulp & with a little banging the bottom of the pan, stirring & agitation the mercury will collect into a ball in the bottom of the pan to be recovered. --- again – I “ONLY” suggest this as a “one time” small scale experiment – after that – invest in a real retort.

This is not even my idea – it is a tried & true method thousands of years old (so I can’t take the credit) I just took the method (which I have worked with in the past) & applied it to the chip ash question (which I was not sure would work) some things will contaminate your mercury to prevent it from picking up the gold. Tin paste is one, heavy clay is another.

Kurt

 

[rusty]

Kurt I strongly suggest you do more research on the use of Mercury before promoting its use.

Mad as a hatter, http://en.wikipedia.org/wiki/Mad_as_a_hatter

Death following inhalation of Mercury vapor at home, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1272162/

Mercury Spills, http://www.epa.gov/mercury/spills/

 

[kurt]

Rusty – Never have I said – use mercury – its safe --- in fact I have said follow the precautions as you would any other of the things used in refining when using mercury. I even posted a link to a very good web page that covers the hazards & the precautions very well..

Have you ever read the hazard warnings &/or the safety data on nitric, HCL, sulfuric, SMB, ammonium chloride, sodium chlorate, sodium hydroxide, etc. etc.

Most of that stuff is way more nasty then mercury – especially when you start mixing them together &/or using them to dissolve metals.

Throw some straight SMB in some AR – then take a big wiff of those fumes & hope you don’t get burned by the acid when it erupts out of the container as you hit the ground gasping for air.

My point is if it is a question “only” of something being hazardous – then refining in & of it self should not be promoted because it is ALL hazardous --- but its not “just” a question of is it hazardous – because the hazards only exist if proper safety precaution are not followed - & mercury is no different – its only a hazard if you don’t follow the precautions when working with it.

Another words – its only dangerous if “you” allow it to be dangerous – but it is also safe if “you” make it safe.

Kurt

 

[rusty]

Rusty – Never have I said – use mercury – its safe --- in fact I have said follow the precautions as you would any other of the things used in refining when using mercury. I even posted a link to a very good web page that covers the hazards & the precautions very well..

Have you ever read the hazard warnings &/or the safety data on nitric, HCL, sulfuric, SMB, ammonium chloride, sodium chlorate, sodium hydroxide, etc. etc.

Most of that stuff is way more nasty then mercury – especially when you start mixing them together &/or using them to dissolve metals.

Throw some straight SMB in some AR – then take a big wiff of those fumes & hope you don’t get burned by the acid when it erupts out of the container as you hit the ground gasping for air.

My point is if it is a question “only” of something being hazardous – then refining in & of it self should not be promoted because it is ALL hazardous --- but its not “just” a question of is it hazardous – because the hazards only exist if proper safety precaution are not followed - & mercury is no different – its only a hazard if you don’t follow the precautions when working with it.

Another words – its only dangerous if “you” allow it to be dangerous – but it is also safe if “you” make it safe.

Kurt

I'm perhaps one of a handful of forum members that have actually retorted mercury. A friend of mine purchased a commercial building once used as a Dental lab, in the basement there were box and box's of used filters that were half full of muck containing bone ships along with precious metals and yes plenty of mercury.

After building a retort, distilled the mercury out of the muck, even using a retort some mercury can remain behind. It's nasty stuff to work with as you stated above and I hope that your not speaking from experience when you say the mercury spreads into little beads when spilled.

I do not advocate the use of mercury at home or in Industry.

Regards
Rusty

 

[Juan Manuel Arcos Frank]

Kurt:

Harold´s,Rusty´s,Samuel-a´s and Geonorts´ advices are wise and useful.There are better ways to recover gold than mercury process.

Anyway,if you decide to use mercury then make your own retort,this is the better way to recover(and reuse) mercury.

Dissolving mercury in nitric acid is not a good idea...but if you have formed mercury nitrate(which is very soluble and very toxic) then you must add some salt to your solution,a white mud will be formed,this is mercury chloride(higly insoluble),let settle down,filter and put the white mud in an hermetic container(a tupperware,in example).

Regards.

Manuel

 

[butcher]

Will mercury collect gold? Yes
Are there better ways? Yes
Can it be used safely? Yes
Is their more risk than benefits? Yes
Will this metal vapor at room temperature into the air you breathe? Yes
Are you risking your health, others health, everything you own including your freedom from prison, with this metal? YES
Are there any good reasons to use mercury to recover or refine gold? NO

My advice study and find a better method.
This metal almost cost me my home, and my freedom, it did cost me more than I have ever made in gold, believe me, you should adjust your thinking about this metal, it is not fun having federal marshals, detectives, EPA, DEQ, and others wake you from sleep knocking on your door wanting to search your premises with sniffing machines.

There are much better methods.

 

[goldsilverpro]

Will mercury collect gold? Yes
Are there better ways? Yes
Can it be used safely? Yes
Is their more risk than benefits? Yes
Will this metal vapor at room temperature into the air you breathe? Yes
Are you risking your health, others health, everything you own including your freedom from prison, with this metal? YES
Are there any good reasons to use mercury to recover or refine gold? NO

My advice study and find a better method.
This metal almost cost me my home, and my freedom, it did cost me more than I have ever made in gold, believe me, you should adjust your thinking about this metal, it is not fun having federal marshals, detectives, EPA, DEQ, and others wake you from sleep knocking on your door wanting to search your premises with sniffing machines.

There are much better methods.

Good post, Richard! I couldn't have said it better! I hope no one gets sucked into using mercury. Listen to Richard - he knows and you don't.

 

[rusty]

Credits: C.W. Ammen

When melting values extracted from a mercury amalgam that you retorted by vaporizing off the mercury, you should work under the hood. In the event that any mercury remained with the values (because of incomplete distillation), it surely will vaporize at the melting temperature of the values, and mercury vapor is very
toxic.

Some authorities recommend separating the mercury from gold and platinum values by heating the amalgam in nitric acid, thereby putting the mercury into solution with the nitric acid as mercuric nitrate (mercury pernitrate—Hg(N0 ) -H 0). This does work; however, if any silver is present, you will have put the silver and mercury into solution together.

No one advocating this method mentions the problems or additional operations required to separate the silver and recover the mercury. If you dissolve the mercury amalgam in nitric acid, so that the gold and platinum sink to the bottom, undissolved, what is the liquid?

It is highly toxic (human beings have a tolerance of only 0.05 milligrams per cubic meter of the compound in air), a very dangerous fire risk, and—in the presence of alcohol—produces mercury fulminate (Hg(CNO) ), which explodes readily when dry and is used in blasting caps and detonators.

Mercury is not entirely safe to handle or to retort under any circumstances, but dissolving it in nitric acid is exceptionally hazardous.

Mercury is also called quicksilver (hydrargyrum). It freezes at -38.85°C, boils at 356.6°C, has a specific gravity of 13.59. and is noncombustible. Its chief ore is cinnabar (HgS), which is mercury sulphide.

Mercury is highly toxic by absorption through the skin and by inhalation of fumes or vapors. It can be absorbed by the respiratory and intestinal tract. Inorganic compounds (amalgams) of mercury are highly toxic.

When a mercury amalgam is left in moisture or water, it can be converted to methyl mercury by bacteria in the water. Methyl mercury is an extremely toxic material. Human beings have a tolerance of 0.01 milligrams per cubic meter of methyl mercury in air, against 0.05 for mercury vapor alone.

Human tolerance for alkali compounds of mercury is also 0.01 milligrams per cubic meter in air.

It is unfortunately relatively easy to get into trouble with methyl mercury by spilling regular mercury. Spillage can create havoc due to mercury's droplet proliferation. Clean-up of any spillage, regardless of how minor, requires special care and must be complete.

As mercury has a vaporization point of between 671° and 680°F, it is easy to separate from values by distilling. Home-made retorts, how- ever, unless very carefully made on the basis of a good leak-proof design, are very dangerous. The same goes for mercury condensers.

The old pipe and pipe cap home-brew retorts, along with the potato retort of the old prospectors, are excessively dangerous.

Purchase a commercial mercury retort, and follow the directions carefully. The most common problems are using a retort that is improperly sealed (and leaks) and opening the retort too soon, with your nose in the path of the mercury fumes.

A more serious problem can result from having the discharge from the condenser immersed in water in the catch bowl. When the condenser starts to cool, a vacuum forms in the retort, drawing water into it, with a resulting explosion that under the right conditions is as violent as a hand grenade.

Retorting at too high a temperature, with an insufficient water flow through the condenser can cause the mercury not to condense or to condense incompletely, resulting in mercury fumes discharging from the condenser.

 

[goaldspektre]

Have you thought about trying an HCL wash to remove tin from any solder residue,filtering the solution and safely disposing of it and then dissolving any values with HCL/Cl.Then after dropping values out of solution a few washes with Harolds' HCL technique?Tried and true works the best 99% of the time.Hopefully you try it and give us the results.Good luck!

Rob

 

[patnor1011]

I see problem with mercury in this process. Chips powdered will smear fine gold wires on small copper particles and mercury will pick them up alongside with gold. You will have to purify that anyway.

 

[mrpazu]

cucl2 solution/au amalgam?

 

[g_axelsson]

cucl2 solution/au amalgam?

Is that an answer or a question?

Göran

 

[kernels]

Great thread, thanks for sharing Kurt. I have been thinking about Mercury for recovering bond wires for a while now. My limited research has indicated that a pipe-retort is probably the way to go to after you finish the amalgam.

For all the contributors saying that there are better ways to process super fine bond wires, are you just referring to HCl -> Incinerate -> HNO3 -> Wash -> Aqua Regia ?