PROCESS CONDITIONING LEAD-CARRYING MATERIAL BEFORE SMELTING Russian patent published in 1999 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: process can be employed in processing of lead-carrying materials, for instance, anode copper electrolyte sludge. Process conditioning lead-carrying material before smelting to silver and gold alloy includes alkaline leaching of lead and sulfur from sludge with heating, separation of cake by filtration, winning of lead from filtrate with return of lead-free solution for leaching. Sludge leaching is carried out in one stage. Sulfate-ion is reduced to alkaline electrolyte till concentration of caustic soda and sodium sulfate equal (3.75:7.5):1.0 is obtained with maintenance of rate of temperature rise of pulp at level of 0.2-1.0 C per minute within interval from 45 to 95 C. After electrolytic precipitation 5-15% of recycled electrolyte is removed from cycle and the rest volume is fed to leaching cycle. EFFECT: increased degree of winning of lead and sulfur, diminished duration of smelting, reduced losses of noble metals and prevention of environmental pollution. 2 cl, 1 tbl