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Process for recovering gold and silver from refractory ores

  • US 7,922,788 B2
  • Filed: 09/11/2008
  • Issued: 04/12/2011
  • Est. Priority Date: 09/18/2007
  • Status: Active Grant
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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