| 摘要 |
<p>PURPOSE:To produce ultrahigh purity copper having a specified elongation and a specified hardness at ordinary temp. by using high purity copper as raw material to ge refined and carrying out primary electrolytic refining in a copper sulfate soln. acidified with sulfuric acid and secondary electrolytic refining in a copper nitrate soln. acidified with nitric acid. CONSTITUTION:High purity copper is electrolytically refined as the anode in a copper sulfate soln. acidified with sulfuric acid at <=100A/m<2> cathode and anode current densities to obtain primarily refined copper on a starting sheet as the cathode. This refined copper is electrolytically refined again as the anode in a copper nitrate soln. acidified with nitric acid at <=100A/m<2> cathode and anode current densities to obtain secondarily refined copper on a starting sheet as the cathode. This refined copper is ultrahigh purity copper having >=99.99999% (7N) purity, >=30% elongation and <=42 Vickers hardness at ordinary temp. The electrolytic solns. in the 1st and the 2nd stages are preferably kept at 30-50 deg.C. Ag and S can be remarkably removed by shifting the potential of each of the electrolytic solns. to an extremely low potential region.</p> |
