The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1977
Filed:
Jun. 22, 1976
Norbert L Piret, Duisburg, DT;
Hans Joachim Rabben, Duisburg, DT;
Herbert Kudelka, Duisburg, DT;
Siegbert Schmidt, Moers-Vinn, DT;
Duisburger Kupferhutte, Duisburg, DT;
Abstract
Copper sulfate solution obtained by the sulfuric acid leaching of cupriferous material and containing impurities such as Fe, As, Sb, Bi, Se, Te, Sn, Pb, Cl, Ag, Hg, and PO.sub.4, are subjected to a two step purification process. In the first step, the pH is adjusted to 2.7-3.3 with, e.g. Ca(OH).sub.2, and the potential in relation to the standard hydrogen electrode is adjusted to at least 575 mv with an oxidizing agent, e.g. air. The temperature is 50.degree.-90.degree. C. Impurities precipitate and are separated. Se, Cl, and possibly Ag and Hg remain in solution and are removed in the second step, wherein the potential is reduced to below 350 mv by addition of a cupriferous reducing agent, e.g. Cu or Cu.sub.2 O. The pH is below 3 and the temperature is below 50.degree. C. Impurities precipitate as copper (I) compounds, and are separated to provide the solution in condition for the electrolysis. The copper produced is of high purity, having a conductivity of at least 58.8 mho .times. m/mm.sup.2 and a maximum semi-hard temperature of 200.degree. C.