Preparation of high-purity cobalt by anion-exchange separation and plasma arc melting

Masahito Uchikoshi, Hideka Shibuya, Junichi Imaizumi, Tamás Kékesi, Kouji Mimura, Minoru Isshiki

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20 Citations (Scopus)


High-purity Co was prepared with valence-controlled anion-exchange separation, oxidation refining using plasma arc melting, and H2-Ar plasma arc melting on a pilot scale. The result of a laboratory-scale experiment indicated that the slower flow rate is more effective to remove the impurities by anion-exchange separation. However, the separation efficiency is reduced by scaling up the column from the laboratory to pilot scale. The discussion of the decrease in the separation efficiency implies that the distribution coefficient increases as the concentration of the adsorbate is lowered, but a reduced slower flow rate might increase the final purity of Co. In addition to anion-exchange separation, Co oxidation refining using plasma arc melting was useful. Consequently, a high-purity Co of 99.9998 pct by mass excluding gaseous elements was prepared, which represents the highest purity reported.

Original languageEnglish
Pages (from-to)448-455
Number of pages8
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Issue number2
Publication statusPublished - 2010 Apr


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