REFINING METHOD OF BLISTER COPPER

PURPOSE:To remove impurities such as As, Sb, Bi, Pb in blister copper by bringing the blister copper as an anode to be used in electrolytic refining of copper into reaction in a molten state together with the chloride and oxide of an alkaline earth metal in the presence of oxygen. CONSTITUTION:As, Sb, Bi, Pb, etc. are contained as impurities in copper obtainable by oxidation refining of copper matter in a converter and therefore such blister copper is inadequate as an anode to be used for electrolytic refining of copper. The content of such impurities is consequently decreased considerably. The blister copper is melted in an alumina crucible in an atm. and while 0.1- 0.7% oxygen is dissolved therein CaCl2 as the chloride of an alkaline earth metal and CaO as the oxide of the alkaline earth metal are added thereto in such a way that CaCl2:CaO attains about 3:1. The blister copper is thus refined at >=1,200 deg.C. The greater part of the impurities are removed from the blister copper and the blister copper usable as the anode for electrolytic refining is easily obtd.