KOH亚熔盐体系中用CuO催化氧化浸出铬铁矿.pdfVIP

Trans. Nonferrous Met. Soc. China 27(2017) 891−900 Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst 1,2 1,2 1 1 1 Long-jie LIU , Hao DU , Yang ZHANG , Shi-li ZHENG , Yi ZHANG 1. Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China Received 8 November 2015; accepted 13 June 2016 Abstract: CuO was used as a catalyst in the concentrated KOH solution to enhance the leaching of chromium from the chromite ore. The impacts of temperature, KOH-to-chromite ore mass ratio, CuO-to-chromite ore mass ratio, and gas flow rate on the chromium leaching rate were investigated. The results indicated that CuO played an important role in improving the chromium leaching rate . The leaching rate reached 98% after leaching for 6 h when CuO was applied, whereas it was only 60.8% without CuO under the same reaction conditions: temperature 230 °C, KOH-to-ore mass ratio 6:1, stirring speed 700 r/min, gas flow rate 1 L/min. According to the kinetics study, the catalytic oxidation was controlled by surface chemical reaction and the activation energy was calculated to be 15.79 kJ/mol when the temperature was above 230 °C. In contrast, without CuO, the rate-determining step was external diffusion and the apparent activation energy was 38.01 kJ/mol. Key words: chromite ore; copper oxide; leaching; catalytic oxidation