Process for the recovery of noble metals from ore-concentrates
OwnerEberhard Gock, Elias Asiaminventors
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Abstract
A process for the hydrometallurgical recovery of gold and silver by direct oxidizing sulphuric acid-digestion of arsenopyrite-concentrates (FeAsS.sub.2) containing carbonaceous materials with a silicate gangue, and/or a silicate and pyrite gangue whereby arsenic and iron are fully solubilized and the noble metals are quantitatively enriched in the silicate-residue. The concentrate is subjected to mechano-chemical stress to produce structural deformations before being digested in the presence of oxygen. After decarbonization of the residue, gold and silver can be recovered by cyanide leaching without losses due to adsorption. A bulk process for preparing gold and silver rich concentrates is also disclosed.
Claims36
A process for the wet-chemical recovery of gold and silver from pyrite-free arsenopyrite ore concentrates, which, in addition to silicatic gangue, particularly carry carbon-containing substances, by means of cyanide leaching of the carbon-free residue of the acid decomposition and subsequent precipitation of the noble metals, comprising the steps of:
- mechano-chemically treating by vibratory milling the ore concentrates with predominantly impact-stressing with an energy expenditure of 50 to 500 kWh/ton ore concentrate;
- oxidizingly decomposing said ore concentrate, in one step, with sulfuric acid with a reaction duration of from 15 minutes to 6 hours at temperatures from 50.degree. to 150.degree. C. in the presence of oxygen with a partial pressure of 0.2 to 20 bar, whereby the arsenic and iron components are almost completely solubilized, whereas the gold, silver and carbon-containing substances almost completely accumulate in the silicatic residue;
- and
- decarbonizing the silicate residue at temperatures from 400.degree. to 1000.degree. C.
A process for the wet-chemical recovery of gold and silver from pyrite-containing arsenopyrite ore concentrates, which, in addition to silicatic gangue, in particular carry carbon-containing substances, by means of cyanide leaching of the carbon-free residue of the decomposition and subsequent precipitation of the noble metals, comprising the steps of:
- chemically treating by vibratory milling the ore concentrate with predominantly impact-stressing with an energy expenditure of 50 to 500 kWh/ton ore concentrate;
- oxidizingly decomposing the ore concentrates, in one step, at temperatures from 50.degree. to 150.degree. C. and with a reaction duration of 15 minutes to 6 hours in the presence of oxygen with a partial pressure of 0.2 to 20 bar, whereby the arsenic and iron components are almost completely solubilized, whereas the gold, silver and carbon-containing substances almost completely accumulate in the silicatic residue;
- and
- decarbonizing the silicatic residue at temperatures from 400.degree. to 1000.degree. C.
A process for the wet-chemical recovery of an iron-, arsenic, and cabon-free silicatic concentrates with gold and silver contents, from pyrite-free arsenopyrite concentrates which, in adition to silicatic gangue, in particular carry carbon-containing substances, comprising the steps of:
- mechano-chemically treating by vibratory milling the arsenopyrite concentrate with predominantly impact-stressing with an energy expenditure of 50 to 500 kWh/ton ore concentrate;
- oxidizingly decomposing the arsenopyrite concentrates, in one step, with sulphuric acid with a rection duration of 15 minutes to 6 hours at temperatures from 50.degree. to 150.degree. C. in the presence of oxygen with a partial pressure 0.2 to 20 bar, whereby the arsenic and iron components are almost completely solubilized, whereas the gold, silver and carbon-containing substances almost completely accumulate in the silicatic residue;
- and
- removing the carbon by heating to temperatures from 400.degree. to 1000.degree. C.
A process for the wet-chemical recovery of an iron-, arsenic- and carbon-free silicatic concentrate with gold and silver contents, from pyrite-containing arsenopyrite concentrates which, in addition to silicatic gangue, particularly carry carbon-containing substances, comprising the steps of:
- mechano-chemically treating by vibratory milling the arsenopyrite concentrates with predominantly impact-stressing with an energy expenditure of 50 to 500 kWh/ton ore concentrate;
- oxidizingly decomposing the arsenopyrite concentrates, in one step, with a reaction duration of 15 minutes to 6 hours at temperatures from 50.degree. to 150.degree. C. in the presence of oxygen with a partial pressure of 0.2 to 20 bar, whereby the arsenic and iron components are almost completely solubilized, whereas the gold, silver and carbon-containing substances almost completely accumulate in the silicatic residue;
- and
- removing the carbon by heating at temperatures from 400.degree. to 1000.degree. C.
Dependencies are inferred from the claim text.