| 摘要 |
<p>PURPOSE:To enable the mass production of the high-purity copper having an excellent low-temp. softening characteristic at a lo cost by combining a crystal fractionation method by a difference in solubility of an aq. acidic copper sulfate soln. and a two-stage electrolytic refining method. CONSTITUTION:The aq. acidic copper sulfate soln. is prepd. by using electrolytic copper and a proper volume of water is evaporated therefrom to crystallize the copper sulfate. While the solubility of the anhydrous sulfate of the main metal impurity contained in the electrolytic copper in the water is about equal to or larger than the solubility of the copper sulfate, the solubility of the lead sulfate or silver sulfate is fairly small. However, the lead sulfate or silver sulfate has the large solubility in an aq. acidic soln. and the metal impurity of even the electrolytic copper which is available at a low price hardly exceeds 0.1wt.% and, therefore, the high-purity copper sulfate is crystallized without precipitating the sulfate of the metal impurity such as silver by the above-mentioned operation. Cations such as Ag<+>, Pd<2+>, Au<3+>, etc., having the smaller tendency to ionization than Cu<2+> are removed by electrolytic collection from the electrolyte obtd. by remelting the copper sulfate and thereafter, the cathode is set at a suitable electrode potential and only the Cu<2+> is electrolytically collected.</p> |
