Recovery of Lead and Silver from Plumbojarosite by Hydrothermal Sulfidation and Chloride Leaching

摘要

The U.S. Bureau of Mines investigated a hydrothermal sulfidation (HTS) and chloride leaching procedure to recover lead and silver from plumbojarosite. The HTS was conducted in an autoclave and converted the plumbojarosite into amorphous iron oxide and liberated the Pb and Ag as sulfides. The best operating conditions were 50 g of plumbojarosite and 7% S (2.04 g S added) in 500 mL of 2.0-mol/L NH3 at 150 C for 1 hour. The sulfidation product contained, in percent, 37 Pb, 28 Fe, 2 SO4(2-), 7 total S, and 11.2 tr oz/st Ag. Flotation of the sulfidation product was conducted at pH 3 with 15% pulp density and 2.4 lb/st of isopropyl xanthate as collector. The flotation concentrate contained 43% Pb, 25% Fe, and 13 tr oz/st Ag. FeC13 leaching of the sulfidation product in a resin kettle extracted 98% Pb and 97% Ag from the sulfidation product, and HC1-O2 leaching in a shaker glass bottle extracted 99 percent Pb and 98 percent Ag. The HTS and chloride leaching procedure is a potentially effective method for detoxification of plumbojarosite-bearing residue from the zinc pressure-leaching circuit.