Process for recovering gold and silver from refractory ores
First Claim
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1. A method, comprising:
- (a) providing a refractory feed material, the refractory feed material comprising gold, sulfides, a carbonaceous preg robbing component, and a clay;
(b) comminuting the refractory feed material to form a comminuted feed material having a first size distribution;
(c) during comminuting, adjusting chemical conditions of the refractory feed material by adding a sulfide activator and a polymeric clay dispersant;
(d) after the comminuting step (b), contacting the comminuted feed material with a carbonaceous component depressant, collector, and frother;
(e) floating the comminuted feed material, in the presence of the sulfide activator, the polymeric clay dispersant, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about pH 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to form first and second fractions, the first and second fractions each comprising at least some of the gold and sulfides in the refractory feed material;
(f) comminuting the second fraction to provide a comminuted second fraction, the comminuted second fraction having a second size distribution finer than the first size distribution;
(g) during comminuting, adjusting chemical conditions of the second fraction by adding the sulfide activator and polymeric clay dispersant;
(h) after the comminuting step (f), contacting the comminuted second fraction with the carbonaceous component depressant, collector, and frother; and
(i) further floating the comminuted second fraction, in the presence of the polymeric clay dispersant, the sulfide activator, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to produce third and fourth fractions, the third fraction comprising at least most of the gold and sulfides in the second fraction.
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Abstract
The present invention is directed to flotation of refractory gold sulfide ores in which the ore is ground, floated, the tailings reground, and refloated to produce gold-bearing concentrates.
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Citations
26 Claims
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1. A method, comprising:
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(a) providing a refractory feed material, the refractory feed material comprising gold, sulfides, a carbonaceous preg robbing component, and a clay; (b) comminuting the refractory feed material to form a comminuted feed material having a first size distribution; (c) during comminuting, adjusting chemical conditions of the refractory feed material by adding a sulfide activator and a polymeric clay dispersant; (d) after the comminuting step (b), contacting the comminuted feed material with a carbonaceous component depressant, collector, and frother; (e) floating the comminuted feed material, in the presence of the sulfide activator, the polymeric clay dispersant, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about pH 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to form first and second fractions, the first and second fractions each comprising at least some of the gold and sulfides in the refractory feed material; (f) comminuting the second fraction to provide a comminuted second fraction, the comminuted second fraction having a second size distribution finer than the first size distribution; (g) during comminuting, adjusting chemical conditions of the second fraction by adding the sulfide activator and polymeric clay dispersant; (h) after the comminuting step (f), contacting the comminuted second fraction with the carbonaceous component depressant, collector, and frother; and (i) further floating the comminuted second fraction, in the presence of the polymeric clay dispersant, the sulfide activator, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to produce third and fourth fractions, the third fraction comprising at least most of the gold and sulfides in the second fraction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising:
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(a) providing a refractory feed material, the refractory feed material comprising gold, sulfides, a carbonaceous preg robbing component, and a clay; (b) comminuting the refractory feed material to form a comminuted feed material having a first size distribution; (c) during comminuting, adjusting chemical conditions of the refractory feed material by adding a sulfide activator; (d) after the comminuting step (b), contacting the comminuted feed material with a carbonaceous component depressant, collector, and frother; (e) floating, in the presence of air bubbles, the comminuted feed material, in the presence of the sulfide activator, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about pH 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to form first and second fractions, the first and second fractions each comprising at least some of the gold and sulfides in the refractory feed material; (f) comminuting the second fraction to provide a comminuted second fraction, the comminuted second fraction having a second size distribution finer than the first size distribution; (g) during comminuting, adjusting chemical conditions of the second fraction by adding the sulfide activator; (h) after the comminuting step (f), contacting the comminuted second fraction with the carbonaceous component depressant, collector, and frother; and (i) further floating, in the presence of air bubbles, the comminuted second fraction, in the presence of the sulfide activator, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to produce third and fourth fractions, the third fraction comprising at least most of the gold and sulfides in the second fraction, wherein an amount of sulfide activator added during steps (b) and (f) is insufficient to oxidize substantially the collector. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method, comprising:
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(a) providing a refractory feed material, the refractory feed material comprising gold, sulfides, a carbonaceous preg robbing component, and a clay; (b) comminuting the refractory feed material to form a comminuted feed material having a first size distribution; (c) during comminuting, adjusting chemical conditions of the refractory feed material by adding a sulfide activator and a polymeric clay dispersant; (d) after the comminuting step (b), contacting the comminuted feed material with a carbonaceous component depressant, collector, and frother; (e) floating, in the presence of air, the comminuted feed material, in the presence of the sulfide activator, the polymeric clay dispersant, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about pH 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to form first and second fractions, the first and second fractions each comprising at least some of the gold and sulfides in the refractory feed material; (f) comminuting the second fraction to provide a comminuted second fraction, the comminuted second fraction having a second size distribution finer than the first size distribution; (g) during comminuting, adjusting chemical conditions of the second fraction by adding the sulfide activator and polymeric clay dispersant; (h) after the comminuting step (f), contacting the comminuted second fraction with the carbonaceous component depressant, collector, and frother; and (i) further floating, in the presence of air, the comminuted second fraction, in the presence of the polymeric clay dispersant, the sulfide activator, the collector, the frother, and the carbonaceous component depressant, at a pH ranging from about 3.5 to about pH 6.5, and at an Eh ranging from about 25 to about 100 millivolts, to produce third and fourth fractions, the third fraction comprising at least most of the gold and sulfides in the second fraction, wherein, in each of steps (b) and (f), from about 10 to about 250 g/tonne of sulfide activator and from about 25 to about 250 g/tonne of polymeric clay dispersant are added and wherein, in each of steps (e) and (i), flotation is performed in the presence of from about 1 to about 50 g/tonne of the carbonaceous material depressant.
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Specification