Material Research Summary


, Volume 38, Issue 6, pp 18-22

First online:

Ferric Chloride, Thiourea and Brine Leach Recovery of Ag, Au and Pb from Complex Sulfides

  • R. G. Sandberg
  • , J. L. Huiatt

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The Bureau of Mines recently investigated a hydrometallurgical procedure to recover gold, silver, and byproduct lead from a complex lead-zinc sulfide ore. A ferric chloride (Fecl3) preleach, at 40°C for six hours extracted about 50 percent of the zinc and formed insoluble silver and lead chlorides. Subsequent acid thiourea leaching, for one to three hours at 40°C, extracted about 85% of the gold and silver. Lead chloride was solubilized from the remaining residue with NaCl brine solution at 55°C in one hour. Lead was recovered from the brine solution in an electrolytic cell with an anion perm selective membrane at a current efficiency of 95 percent and current density of 100 A/m2. Spent FeCl3 leach solution was reoxidized in the anode compartment at a current efficiency between 75 and 95 percent.