Kozo Kitada1, Fumiyoshi Miyashita2, Giroku Miyatani2, Toshio Miyake3, Yamahiko Matuoka3 and Sumio Kamiyama3
1Graduate School, Kansai University, Suita. Present address: Osaka Seikei Gakuen, Osaka
Carbothermic reduction chromium oxide to metallic chromium was carried out in a high vacuum of 1×10-2∼10-3 mmHg at temperatures ranging from 1100 to 1400°C.
Mixture of 1 mole of chromium oxide and 3 moles of graphite was briquetted and reduced under above-mentioned conditions.
The experimental results were summarized as follows:
(1) The reaction starte at 950 to 970°C.
(2) At reaction temperatures of below 1100°C, the predominant reactions were chromium carbides formation. Metallic chromium cannot be almost detected in reaction product.
(3) At reaction temperatures of 1200 to 1300°C, metallic chromium was formed by reduction of chromium oxide by chromium carbides.
(4) At reaction temperature of 1300°C and reaction time of 3 hr, the reducing rate of chromium oxide to metallic chromium reached 75∼76%.
(5) At reaction temperature of 1300°C and reaction time of above 3 hr, vaporization of metallic chromium was detected.
(6) At reaction temperatures 1300 to 1400°C, vapolization rate of metallic chromium was higher than CO gas formation rate.
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