Patent ID: 7435325
Filing Date: 2008-10-14
Classification: C22C,C23C,C25C,Y10T

Abstract:
1. A manufacturing method of high purity 5N (99.999 wt %) or higher nickel, wherein, upon separating an electrolytic bath with a diaphragm to define an anode side and a cathode side of the electrolytic bath and performing electrolysis with a solution containing nickel as the electrolytic solution, anolyte existing in the anode side is extracted intermittently or consecutively, and the extracted anolyte is adjusted to pH 2 to 5; impurity iron contained in the extracted anolyte is eliminated by adding an oxidizing agent to the anolyte and precipitating and eliminating said impurity iron as hydroxide; cobalt and copper impurities are eliminated by at least one of performing preliminary electrolysis to the extracted anolyte and performing displacement reaction by adding nickel foil to the extracted anolyte; impurities including precipitated oxides are thereafter eliminated with an activated carbon filter to provide a substantially impurity-free solution; the impurity-free solution is introduced intermittently or consecutively into the cathode side only of the electrolytic bath such that a concentration of iron within the electrolytic solution in the electrolytic bath is 1 mg/L or less; and the impurity-free solution is employed as catholyte to perform said electrolysis, said 5N (99.999 wt %) or higher nickel being obtained without method steps of ionic exchange and solvent extraction.