Reduction mechanism of natural ilmenite with graphite
(1. State Key Laboratory of Multi-phase and Complex Systems,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. Institute of Ironmaking Research, Baoshan Iron and Steel Co., Ltd, Shanghai 201900, China;
3. Department of Energy and Resources Engineering, College of Engineering, Peking University,Beijing 100871, China;)
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. Institute of Ironmaking Research, Baoshan Iron and Steel Co., Ltd, Shanghai 201900, China;
3. Department of Energy and Resources Engineering, College of Engineering, Peking University,Beijing 100871, China;)
Abstract: Reduction of Bama ilmenite concentrate containing 49.78% TiO2 and 27.96% total Fe by graphite was studied using thermogravimetric analysis system under argon gas ambient from 850 to 1 400 ℃. The reduction degree of Bama ilmenite is enhanced with increasing temperature and the molar ratio of carbon to oxygen, and the reaction rate varies with temperature and reduction time simultaneously. The phase transformation, chemical composition, microstructure and morphology of reduced samples were investigated by using X-ray diffractometry, scanning electron microscopy, and energy disperse spectroscopy, respectively. The high content of impurities in Bama ilmenite evidently bates the reduction of ilmenite. Forming the enrichment zone of manganese prevents complete reduction of Fe2+. The reduction products are mostly reduced iron, rutile, reduced rutiles, Ti3O5 and pseudobrookite solid solution. The reduction kinetics was also discussed. The results show that the reduction temperature is a key factor to control reaction rate.
Key words: Bama ilmenite; reduction; thermogravimetry; impurity; kinetics