METHOD OF PROCESSING COPPER-ELECTROLYTE SLUDGES Russian patent published in 1998 - IPC

FIELD: electrolytic processes. SUBSTANCE: method is intended for recovering lead and sulfate sulfur from sludges and transferring them into separate concentrates. Sludges are leached with saturated sodium chloride solution at solids to liquid ratio 1:3, resultant cake being separated and washed. Impurities are removed from solution using their cementation on lead. Cementate is separated and leached and lead is precipitated from solution when adding sodium hydroxide until reaching pH 7-8. Once lead concentrate is separated from solution by calcium chloride, calcium sulfate is precipitated and remaining solution with wash waters is recycled. All operations are carried out at 70 to 95 C. 98-100% of lead and 80-85% of sulfur is recovered. Contents of impurities in lead concentrate and calcium sulfate are reduced to the level below 1%. EFFECT: enhanced efficiency of lead and sulfur recovery. 1 tbl