US 5,667,665 A · Process of producing high purity cobalt

Abstract

A process for producing a high purity cobalt is provided comprising the following steps. An aqueous solution of cobalt chloride having a hydrochloric acid concentration of 7 to 12N is provided. The solution includes either or both of Fe and Ni as impurities. The solution is contacted with an anion exchange resin so that cobalt is adsorbed on the resin. Cobalt is eluted from the resin with hydrochloric acid at a concentration of 1 to 6N. The solution containing the eluted cobalt is dried or otherwise concentrated to produce a purified aqueous solution of cobalt chloride having a pH of 0 to 6. Organic materials are preferably removed from the purified solution by active carbon treatment. Electrolytic refining is conducted with the purified aqueous solution as an electrolyte to obtain electrodeposited cobalt. A high purity cobalt sputtering target can be obtained wherein Na content is 0.05 ppm or less; K content is 0.05 ppm or less; Fe content is 1 ppm or less; Ni content is 1 ppm or less; Cr content is 1 ppm or less; U content is 0.01 ppb or less; Th content is 0.01 ppb or less; C content is 50 ppm or less, preferably 10 ppm or less; and O content is 100 ppm or less, the balance being cobalt and unavoidable impurities.

Claims11

Dependent claims

A process for producing a high purity cobalt comprising the steps of:

(a) preparing an aqueous solution of cobalt chloride having a hydrochloric acid concentration of 7 to 12N by dissolving a crude cobalt comprising Fe and Ni as impurities in an aqueous solution of hydrochloric acid at a temperature of 50.degree. to 100.degree. C.;
(b) contacting the prepared aqueous solution of cobalt chloride with an anion exchange resin so that cobalt is adsorbed on the anion exchange resin together with Fe;
(c) eluting the cobalt with hydrochloric acid as an eluting solution having a concentration of 1 to 6N to form an eluted cobalt solution while retaining Fe on the anion exchange resin;
(d) vaporizing and drying or otherwise concentrating the eluted cobalt solution to provide a purified aqueous solution of cobalt chloride having a pH of 0 to 6;
and
(e) conducting electrolytic refining of cobalt in an electrolyte cell with said purified aqueous solution of cobalt chloride as an electrolyte and a crude cobalt as an anode to obtain electro-deposited cobalt.

3 more elements

Dependencies are inferred from the claim text.

Process of producing high purity cobalt

Life of this patent

Process of producing high purity cobalt

Life of this patent

Abstract

Claims11