PRODUCTION OF HIGH PURITY COPPER MATERIAL

PROBLEM TO BE SOLVED: To obtain high purity granular copper for producing electrolytic copper foil without contg. a chlorine ion by electrolyzing a copper etching waste soln. such as an aq. cupric chloride-hydrochloric acid soln., recovering chlorine-contg. copper deposited on a cathode, melting the copper at a high temp., dechlorinating it and thereafter, bringing the copper into contact with water to rapidly cool the copper. SOLUTION: A copper lined laminated sheet or the like is etched by using a copper etching soln. such as a cupric chloride-hydrochloric acid aq. soln. to form a circuit conductor or the like and the copper etching waste soln. having the increased concn. of copper which is produced thereby is electrolyzed. This electrolysis is preferably carried out using titanium, nickel, copper or the like as a cathode material and lead, titanium coated with a metal compd. of a platinum group, graphite or the like as an anode material at about 30-60 deg.C and about 0.5-30 A/dm current density. The chlorine-contg. copper deposited on the cathode is recovered, sufficiently washed and dried, thereafter, melted at about 1,100-1,400 deg.C in a melting furnace and dechlorinated. The resultant molten copper is brought into contact with water and water-crashed granulated by rapidly cooling to obtain the objective high purity granular copper having a nearly spherical shape and about 0.5-10 mm diameter.