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Abstract

Purification process for chromium metal is conducted on chromium metal powder which has been compacted without additives at a pressure of at least 50,000 psi (35.times.10.sup.7 Pa) into a compacted body having a critical diffusion dimension of less than or equal to 25 mm. The purification process uses a hydrogen gas treatment at a temperature of 1200.degree. C. to 1600.degree. C. for a period of 2 hours to 10 hours using 0.8 m.sup.3 per Kg chromium metal of hydrogen gas or more. The hydrogen treated chromium metal compacted body is then further treated under vacuum at a pressure less than or equal to 100 .mu.m of Hg (15 Pa) at 1200.degree. C. to 1600.degree. C. for 2 hours to 10 hours. The combined hydrogen and vacuum treatment reduces the oxygen, carbon, sulfur and nitrogen impurities in the chromium metal and results in a chromium metal suitable for metallurgical and electronic applications.

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First Claim