glot
Gold Digger
Posts: 75
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Post by glot on Jul 6, 2017 17:19:49 GMT 10
I have tried everything I can think of in a pan to separate super fine gold on sand grains from super fine chalcopyrite. The pyrites is cubic under a strong lens and the gold is stuck to the sides of silt grains. The latter is yellow in the shade and the former is hard to see. However, they seem to have a very similar SG and HE. Short of setting up a cyanide plant in my bathroom, does anyone have any suggestions. At this point I am only testing amounts. Could I perhaps burn off the pyrite?
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Post by shivan on Jul 6, 2017 20:53:55 GMT 10
This is where you have to look at the cost of processing it vs what gold you are going to get in return. There are a few chemical means, but i would leave them as last resorts and only if the gold looked to be good. You could try heating and quenching the concentrates to free the gold, though you need to make sure this is done outside in a well ventilated area (keep the neighbours in mind also) as some of the fumes could be toxic.
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rustyau
Panner
Prospecting is like fishing. Doing it is the best part. Finding a keeper..is a bonus
Posts: 39
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Post by rustyau on Jul 8, 2017 5:38:31 GMT 10
Hi Glot, Even after fine crushing the recovery rate from gravity separation will only be about 30-40% and that's using all of the good gear. You have to decide whether it’s really worthwhile even trying to recover the gold. The chemical route is expensive and takes a lot of knowledge and practise. In saying that, if you are like me and just want to try to see if you can do it, then give it a go by all means. I would suggest a Pyrometallurgical process as opposed to chemical. MUST BE DONE OUTSIDE. Pyrites can and do contain various amounts of Sulphides and Arsenic that vaporise when heated…..nasty stuff.
Ground to -200mesh (cement powder) Mix 50/50 with fine carbon powder (home brew supplies) Roast for 4-5 hours (you can use a Heatbead and charcoal mix) When cool pan off the carbon. Smelt with a bit of “Chapman flux” or Borax (hardware store)
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