REDUCTION OF LIME CONSUMPTION WHEN TREATING REFRACTORY GOLD ORES OR CONCENTRATES
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Abstract
The present invention is directed to a precious metal recovery process in which basic ferric sulphates and/or jarosites are controlled by a number of mechanisms, including control of the oxidation reaction conditions in the first autoclave compartment, hot curing of the autoclave discharge slurry, and/or contacting of the autoclave feed slurry with the hot cured discharge liquid.
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Citations
41 Claims
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1-14. -14. (canceled)
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15. A precious metal recovery process, comprising:
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inputting a precious metal-containing feed slurry into a first compartment of a multi-compartment autoclave, the precious metal-containing feed slurry comprising a precious metal-containing material comprising sulphide sulphur; providing, in the first compartment a slurry temperature that is at least about 5°
C. less than a slurry temperature in a second compartment of the autoclave, the second compartment being adjacent to and downstream of the first compartment;removing, from the autoclave, an aqueous discharge slurry comprising discharge solids and aqueous discharge liquid, the discharge solids comprising at least a portion of the precious metal and basic iron sulphate, wherein at least most of the sulphide sulphur is oxidized to sulphate sulphur, wherein the aqueous discharge slurry comprises sulphuric acid, and wherein the discharge slurry comprises less than 10 wt. % (dry basis) of the basic iron sulphate; contacting the discharge solids with an acid consumer to consume at least a portion of the sulphuric acid and dissolved metal sulphates; and contacting a lixiviant, at a pH above about pH 7.0, with the discharge solids to solubilize at least most of the precious metal; and recovering the solubilized precious metal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A precious metal recovery process, comprising:
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(a) inputting a precious metal-containing feed slurry into a first compartment of a multi-compartment autoclave, the precious metal-containing feed slurry comprising a precious metal-containing material comprising sulphide sulphur; (b) operating the first compartment, but not at least a second autoclave compartment downstream of the first autoclave compartment, under conditions favoring hematite formation; (c) removing, from the autoclave, an aqueous discharge slurry comprising discharge solids and aqueous discharge liquid, the discharge solids comprising at least a portion of the precious metal and basic iron sulphate, wherein at least most of the sulphide sulphur is oxidized to sulphate sulphur, wherein the aqueous discharge slurry comprises sulphuric acid, and wherein the discharge slurry comprises less than 10 wt. % (dry basis) basic iron sulphate; (d) contacting the discharge solids with an acid consumer to consume at least a portion of the sulphuric acid and dissolved metal sulphates; and (e) contacting a lixiviant, at a pH above about pH 7.0, with the discharge solids to solubilize at least most of the precious metal; and (f) recovering the solubilized precious metal. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A process, comprising:
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(a) inputting a valuable metal-containing feed slurry into a first compartment of a multi-compartment autoclave, the valuable metal-containing feed slurry comprising a valuable metal-containing material comprising sulphide sulphur; (b) at least partially oxidizing the sulphide sulphur to sulphate sulphur in the first compartment to form a first oxidized slurry; (c) transporting the first oxidized slurry to an adjacent second compartment of the autoclave, wherein the first oxidized slurry passes through a lower portion of a first weir separating the first and second compartments; and (d) thereafter recovering the valuable metal from a slurry output by a final compartment of the autoclave. - View Dependent Claims (37, 38, 39, 40, 41)
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Specification