Amalgamated material

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stampeden

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Dec 16, 2013
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I am a new member - and one who has had a few missed opportunities. We processed a gold flotation concentrate with an electrolytic amalgamator. After pressing the mercury, we had a cake larger than any I had seen from only 250 pounds of feed material. Our chief chemist simply would take the cake and dissolve it in nitric acid to leave the gold. The huge cake got smaller and smaller until only a small gold button was left. What was in that cake? To this day, I do not know. But I have the feeling that we were holding a viable site but we did not know how to handle it. Any thoughts. there were 6,000 tons of this material. It was from the Argonaut mine in Jackson, CA. Thanks for your time. Stam Peden
 

Swissgoldrefiner

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I am not sure, but i wounder if mercury dont amalgam Silver too. In that case, it s normal that the cack desapear.
 

nickvc

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Virtually all metals will form an amalgam with mercury so without an assay we will never know.
 

orvi

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Mercury is strange metal. And yes, it form amalgam with practically all metals, except iron alloys. Some amalgams are liquid, some are solid. You need to study phase diagrams to understand this. Interestingly, gold isn´t that much soluble in mercury at room temperature.

You need basic fire assay of the concentrates. Or at least one production smelt of the cons without that mercury (say 1-2 kg roasted sample), which could be zapped with XRF at least.
Quite a bit of metals dissolve in nitric. Only few noble metals don´t. So it isn´t surprising that the cake practically "disappeared" :)

Why mercury ? Aside of the ease of the work ? In 21st century, we can do better :)
 

stampeden

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Mercury is strange metal. And yes, it form amalgam with practically all metals, except iron alloys. Some amalgams are liquid, some are solid. You need to study phase diagrams to understand this. Interestingly, gold isn´t that much soluble in mercury at room temperature.

You need basic fire assay of the concentrates. Or at least one production smelt of the cons without that mercury (say 1-2 kg roasted sample), which could be zapped with XRF at least.
Quite a bit of metals dissolve in nitric. Only few noble metals don´t. So it isn´t surprising that the cake practically "disappeared" :)

Why mercury ? Aside of the ease of the work ? In 21st century, we can do better :)
I worked on this in 1981. We refined mercury from a variety of sources - batteries, ore, waste materials, etc. The ore in question was flotation concentrate from the Argonaut mine. It was stockpiled next to the mine, almost in town. There were over 20,000 tons. On the same site were the millions of tons of mine run tailings. Gold values in the large tailings pile was low, but every pan had mercury and gold. The tails from the Argonaut have never been extracted further. The Kennedy main tailings were leached with cyanide in the 1930's by Amador Metals Reduction company. There was a glass sand pilot plant put into operation in the 1960's. Material was attrited and washed with cyclones. The market for glass sand is very good. Budweiser in Fairfield was always in the market to buy sand. Basic Minerals owned the operation. That is how they obtained both the Kennedy tails and the Argonaut tails. They sold the Kennedy tails , keeping the Argonaut material. I worked for Morse VanHorn, one of the principals of Basic Minerals. He owned Van Gas. Why did we use mercury? Because that is the business we were in. The smaller (20,000 ton) pile was removed. I left VanHorn around 1983. To this day I regret that I was not capable of understanding what we had. Even though I was just a worker bee, I knew we were going down the wrong road. Last I heard, Calaveras Cement was buying sand from the large tailings pile for concrete.
 
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