METHOD OF REWOKING ELECTROPLATING PROCESS SLUDGES Russian patent published in 2001 - IPC

FIELD: reworking domestic and industrial wastes; extraction of metals from sludges of electroplating process. SUBSTANCE: proposed method includes leaching heavy metals by 5- to 15-% sulfuric acid, separation of solid phase from solution, separation of ferric hydroxide (III) and chromic hydroxide (III), hydroxide of copper and other heavy metals; leaching of heavy metals is effected by stepped counter-flow method in cassettes vibrating in vertical plane; cassettes are provided with filtering partitions; method includes also separation of copper, treatment of solution in oxidizing reactor for conversion of iron to trivalent state, passing the solution through cathode spaces of electrolyzers at intermediate separation hydroxides of metals after each stage of cascade, regeneration of sulfuric acid; leaching solution is passed in reverse order through anode spaces of all electrolyzers at subsequent concentration in low-temperature evaporator; sulfuric acid thus obtained is used at leaching stage and condensed vapors are directed for flushing procedures. EFFECT: enhanced efficiency of separation of all precious components; enhanced ecological safety and economical efficiency. 1 dwg, 3 tbl, 1 ex