Process for controlling acid in sulfide pressure oxidation processes
First Claim
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1. A method, comprising:
- (a) providing a precious metal-bearing material, the precious metal-bearing material comprising acid consumers;
(b) floating the material to form a first fraction comprising at least most of the precious metal in the precious metal-bearing material and a second fraction comprising at least some of the acid consumers in the precious metal-bearing material;
(c) pressure oxidizing at least portions of the first fraction but not the second fraction to form a pressure oxidized slurry comprising pressure oxidized residue and reactive sulfates and an off gas, wherein the pressure oxidized residue comprises at least most of the precious metal in the preciuos metal-bearing material;
(d) contacting the off gas with at least a portion of the second fraction to cool the off gas and heat the at least a portion of the second fraction;
(e) contacting the heated at least a portion of the second fraction with at least a portion of the pressure oxidized slurry to neutralize, at least partially, reactive sulfates in the at least a portion of the pressure oxidized slurry;
(f) contacting the pressure oxidized residue with an alkaline lixiviant to dissolve at least most of a selected precious metal in a pregnant leach solution; and
(g) thereafter recovering the dissolved selected precious metal from the pregnant leach solution.
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Abstract
The present invention is directed to flotation of refractory gold sulfide ores and to pressure oxidized residue neutralization using flotation tailings that have been contacted with an off gas of pressure oxidation.
103 Citations
20 Claims
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1. A method, comprising:
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(a) providing a precious metal-bearing material, the precious metal-bearing material comprising acid consumers; (b) floating the material to form a first fraction comprising at least most of the precious metal in the precious metal-bearing material and a second fraction comprising at least some of the acid consumers in the precious metal-bearing material; (c) pressure oxidizing at least portions of the first fraction but not the second fraction to form a pressure oxidized slurry comprising pressure oxidized residue and reactive sulfates and an off gas, wherein the pressure oxidized residue comprises at least most of the precious metal in the preciuos metal-bearing material; (d) contacting the off gas with at least a portion of the second fraction to cool the off gas and heat the at least a portion of the second fraction; (e) contacting the heated at least a portion of the second fraction with at least a portion of the pressure oxidized slurry to neutralize, at least partially, reactive sulfates in the at least a portion of the pressure oxidized slurry; (f) contacting the pressure oxidized residue with an alkaline lixiviant to dissolve at least most of a selected precious metal in a pregnant leach solution; and (g) thereafter recovering the dissolved selected precious metal from the pregnant leach solution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, comprising:
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(a) providing a precious metal-bearing material, the precious metal-bearing material comprising acid consumers; (b) floating the precious metal-bearing material to form a concentrate comprising at least most of the precious metal in the precious metal-bearing material and tailings comprising at least most of the acid consumers in the precious metal-bearing material; (c) pressure oxidizing a slurry comprising the concentrate to form a pressure oxidized slurry, the pressure oxidized slurry comprising pressure oxidized residue and reactive sulfates and an off gas, wherein the pressure oxidized residue comprises at least most of the precious metal in the precious metal-bearing material; (d) thereafter hot curing the pressure oxidized slurry to convert solid-phase reactive sulfates into liquid-phase reactive sulfates; (e) separating the hot cured slurry into a solid component and a liquid component, the solid component comprising the pressure oxidized residue and the liquid component comprising the liquid-phase sulfates; (f) contacting the off gas with at least a portion of the tailings and not the concentrate to cool the off gas and heat the at least a portion of the tailings; (g) contacting the heated at least a portion of the tailings with the liquid component of the hot cured slurry to neutralize, at least partially, liquid-phase reactive sulfates; and (h) thereafter recovering the precious metal from the solid component of the hot cured slurry. - View Dependent Claims (11, 12, 13)
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14. A method, comprising:
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(a) floating a precious metal-bearing material, the precious metal-bearing material comprising acid consumers, to form a concentrate comprising at least some of the precious metal in the precious metal-bearing material and tailings comprising at least some of the acid consumers in the precious metal-bearing material; (b) contacting the concentrate with an acid-containing wash solution to consume, at least partially, acid consumers in the concentrate and form a pre-treated slurry comprising the concentrate; (c) washing the pre-treated slurry to form a washed slurry and a liquid overflow, the liquid overflow comprising acid; (d) pressure oxidizing the pre-treated slurry to form a pressure oxidized slurry, the pressure oxidized slurry comprising a pressure oxidized concentrate and reactive sulfates and an off gas, wherein the pressure oxidized concentrate comprises at least most of the precious metal in the precious metal-bearing material; (e) separating the pressure oxidized slurry into a solid component and a liquid component, the solid component comprising the pressure oxidized residue and the liquid component comprising the liquid-phase sulfates; (f) contacting the off gas with at least a portion of the tailings and not the concentrate to cool the off gas and heat the at least a portion of the tailings; (g) contacting the heated at least a portion of the tailings with at least one of the liquid component of the pressure oxidized slurry and liquid overflow to neutralize, at least partially, liquid-phase reactive sulfates; and (h) thereafter recovering the precious metal from the solid component of the pressure oxidized slurry. - View Dependent Claims (15, 16, 17, 18)
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19. A method, comprising:
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(a) providing a refractory precious metal-bearing sulfidic material; (b) providing a slurry stream comprising acid consumers; (c) oxidizing the refractory precious metal-bearing sulfidic material to form an oxidized slurry comprising oxidized residue and reactive sulfates and waste heat, wherein the pressure oxidized residue comprises at least most of the precious metal in the preciuos metal-bearing material; (d) contacting the slurry stream with the waste heat to heat the slurry stream and not the refractory sulfidic precious metal-bearing material; and (e) contacting the heated slurry stream with the liquor component of the oxidized slurry to neutralize, at least partially, reactive sulfates in the oxidized slurry; (f) thereafter contacting the oxidized residue with an alkaline lixiviant to dissolve at least most of a selected precious metal in a pregnant leach solution; and (g) thereafter recovering the selected precious metal from the pregnant leach solution. - View Dependent Claims (20)
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Specification