| 摘要 |
PURPOSE:To produce high-purity chromium halide, chromium oxide, chromium nitride, chromium carbide, and metallic chromium with superior productive efficiency by subjecting medium-carbon or low-carbon ferrochrome to nitriding and then to iron removal by means of acid treatment and further carrying out respective treatments of halogenation, oxidation, nitriding, carbonization, and decomposition. CONSTITUTION:Medium-carbon or low-carbon ferrochrome is nitrided by a solid nitriding method. It is desirable to perform this nitriding sufficiently by repeating a process consisting of nitriding, crushing, and nitriding plural times. The resulting nitrided ferrochrome is subjected to iron removal by means of acid treatment. The resulting chromium nitride is subjected to halogenation treatment at about 350-500 deg.C, by which chromium halide is prepared. This chromium halide is treated by a hyrolysis method, a neutralizing sedimentation method, an oxidizing roasting method, etc., by which chromium oxide is prepared. Further, the above chromium halide is nitrided by using ammonia gas to form chromium nitride. Carbon is added to the above chromium oxide, and these are treated at high temp. under reduced pressure to form chromium carbide. Moreover, the above chromium halide is allowed to react with carbon, Al, Na, Mg, etc., at high temp. or thermally decomposed, or the above chromium oxide is treated by an aluminum thermit method, or the above chromium nitride is thermally decomposed in vacuum, by which metallic chromium is prepared. |
