Wednesday, January 19, 2011

Gold mines


3-5 ppm gold content is called gold ore
10 ppm gold ore is called good.
Mill the ore into 20 um particles.
Cyanide leach the Au(0) out to Au(II) in the presence of air . Several towers were used.
Activated charcoal is used to absorb gold-cyanide complexes. With air bubbles from the bottom, the foamy gold-charcoal-ligand is skimmed off.
Desorption. Basically burn them.
Exchange out with zinc
Electrochemical purify
Electrolysis again to purify to 99.99%
Gold, silver, rhodium, palladium, platinum can be harvested. 
Copper close to the surface of earth is oxidized to oxides, while at very deep of earth copper exists as copper sulfides.
CuO+HCl=CuCl2+H2O
CuCl2 is dissolved in water ect, electrolysis of Cu++ to copper metal
CuS+heat=Cu+S

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