Process for recovering metals from refractory ores
AssigneeChevron Research and Technology Company
InventorsMichael Dubrovsky, Paul J. Marcantonio
Life of this patent
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Abstract
The present invention is a process to recover metals from refractory ores. It involves the chlorination of an ore concentrate in the presence of solid salt at a temperature between 300.degree. and 650.degree. C. Thereafter, an oxidation step can be used to convert iron chloride to iron oxide. Subsequent separation steps remove the salt, gangue, and iron oxides. Separate pathways are described for precious and base metal recovery.
Claims53
A process for extracting precious and base metals from ore or ore concentrate, comprising:
- (a) contacting a metals-containing ore with solid salt to obtain an ore/salt mixture of solids;
- (b) chlorinating the mixture of solids by contacting the mixture with a chlorine-containing gas at a temperature between 300.degree. and 650.degree. C.;
- and
- (c) recovering the metals.
A process for recovering precious metals from ore or ore concentrates having metal sulfides and elemental metals comprising:
- (a) contacting a precious metal-containing ore or ore concentrate having metal sulfides, elemental metals, and iron or copper, with a solid particulate, alkali or alkaline earth metal chloride salt to form an ore/salt mixture of solids wherein the molar ratio of formed metal chlorides to solid salt is less than 4;
- (b) chlorinating the ore/salt mixture by contacting the ore/salt mixture with chlorine gas at a temperature between 300 and 650.degree. C. wherein the ore/salt mixture contains melted metal chlorides that comprise less than 10% of the ore/salt mixtures;
- (c) evolving sulfur;
- (d) ceasing the contact of the chlorine gas with the ore/salt mixture from step (b) after substantially all of the metals have formed chlorides;
- (e) brine leaching the ore/salt mixture;
- (f) separating precious and base metal chlorides from the brine;
- and
- (g) recovering the precious metals.
A process for recovering base metals from ore or ore concentrates having metal sulfides comprising:
- (a) contacting base metal containing ore or ore concentrate having iron or copper with a solid particulate, alkali or alkaline earth metal chloride salt to form an ore/salt mixture of solids wherein the molar ratio of metal chlorides that are formed to solid salt is less than 4;
- (b) chlorinating the ore/salt mixture by contacting the ore/salt mixture with chlorine gas at a temperature between 300.degree. and 650.degree. C. wherein the ore/salt mixture contains melted metal chlorides that comprise less than 10% of the ore salt mixture;
- (c) evolving sulfur;
- (d) ceasing the contact of chlorine gas with the ore/salt mixture from step (b) after substantially all of the metals have formed chlorides;
- (e) contacting the ore/salt mixture with an oxygen-containing gas at a temperature between 300.degree. and 650.degree. C.;
- (f) alcohol leaching the ore/salt mixture to form an alcohol solution and solid;
- (g) separating the alcohol solution from the solids;
- (h) separating leached metals from the alcohol solution;
- (i) brine leaching the solids at a temperature between 60.degree. and 103.degree. C.;
- and
- (j) separating leached metals from the brine.
Dependencies are inferred from the claim text.