The U.S. Bureau of Mines investigated a hydrothermal sulfidation (hts) and chloride leaching procedure to recover lead and silver from plumbojarosite. The plumbojarosite, generated during pressure- oxidatve leaching of zinc concentrate in a commercial operation, contained, in percent, 25.4 PB, 18.8 Fe, 1.4 Zn, 29.5 Sulfate (so4 2- ), 3.2 Elemental sulfur (s0), 13.4 Total s, and 7.4 Tr oz/st ag. The hts was conducted in an autoclave and converted the plumbojarosite into amorphous iron oxide and liberated the pb and ag as sulfides (s2-). The best operating conditions were 50 g of plumbojarosite and 7 pct s0 (2.04 G s0 added) in 500 ml of 2.0-Mol/l nh3 at 150 deg c for 1 h. 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- pct pulp density and 2.4 Lb/st of isopropyl xanthate as collector. The flotation concentrate contained 43 pct pb, 25 pct fe, and 13 tr oz/st ag. Fecl3 leaching of the sulfidation product in a resin kettle extracted 98 pct pb and 97 pct ag from the sulfidation product, and hcl-02 leaching in a shaker glass bottle extracted 99 pct pb and 98 pct ag. Both leach residues met the Environmental Protection Agency's toxicity characteristic leaching procedure (epa- tclp) standards for nonhazardous wastes. The hts and chloride leaching procedure is a potentially effective method for detoxification of plumbojarosite-bearing residue from the zinc pressure-leaching circuit.