PURPOSE: To manufacture a high quality ingot at a low cost by adding a specified amount of P to molten Cu contg. impurities as raw material, oxidizing the molten metal, separating the impurities, oxidizing and removing the P, and regulating the oxygen content by reduction.
CONSTITUTION: Cu contg. metals which are oxidized more readily than Cu as impurities is continuously melted as raw material in a melting furnace 1, and 0.4W0.7wt% P is added to the molten metal and melted in a transfer path 2. The molten metal is oxidized in an oxidation zone 3 to regulate the oxygen content preferably to 500W3,000ppm, and it is held for about 20W120min so that part of the P and the impurities are oxidized and floated. After the resulting oxides are separated, the molten metal is highly oxidized in a high oxidation zone 4 to regulate the oxygen content preferably to about 500W2,000ppm and it is held for about 5W60min to oxidize and remove the residual P. The molten metal is then reduced with charcoal or the like in a reduction zone 5 to regulate the oxygen content to a prescribed value and it is poured into a casting machine 7 through a casting pot 6. An ingot having superior characteristics such as high electric conductivity is obtd.
NAKANO KOSAKU
TERASHITA MICHIAKI
SHIBATA MITSUYOSHI
