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Innovations in Gold Metallurgy.
Secondary Raw Mater 1974 Mar; :24-30
Low-cost methods of cyanidation have been developed for gold ore deposits too small, too low grade, or unsuited chemically or physically for treatment by conventional procedures. Applicability of heap leaching has been demonstrated to suitably porous and permeable ores, both in the laboratory and on a commercial scale, for recovering 60 to 95 percent of the gold from crushed or mine-run ore containing 0.06 to 0.6 Ounce gold per ton. An expanded-bed, multiple-compartment, activated-carbon column developed by the Bureau of Mines is in use to recover the gold from recycling leach solutions. Recent engineering advances in handling pulp and carbon have made the carbon-in-pulp process more attractive for cyanidation of ores requiring fine grinding. Gold is removed from solution and the carbon is loaded by counter-current flow of carbon and leach pulp through a series of about four stirred contactors with a vibrating screen in each stage to separate the pulp and carbon. Loaded carbon is stripped of gold by hot caustic cyanide solution and reactivated by heating to 60 deg. C before recycle to the gold absorption step, and gold is removed from the cycling strip solution by electrowinning.
Secondary Raw Mater., March 1974, PP. 24-30
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