Kinetics and mechanism of hydrogen reduction of ilmenite powders

• Published in: Journal of alloys and compounds 2015-01, Vol.619, p.443-451
• Main Authors: Dang, Jie, Zhang, Guo-hua, Chou, Kuo-chih
• Format: Article
• Language: English
• Subjects: Analyzers; Diffraction; Hydrogen reduction; Ilmenite; Iron; Isothermal; Kinetics; Non-isothermal; Reduction; Scanning electron microscopy; Titanium dioxide; X-ray diffraction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.09.057

Both isothermal and non-isothermal reduction experiments of Panzhihua ilmenite powders by H2 were carried out. It was shown that in the temperature range of 1146–1201K, the main reduction products were Fe, TiO2 and MgTiO3 with the iron being embedded in TiO2 matrix. The reduction reaction was controlled by the chemical reaction with the apparent activation energy being extracted to be 98.35–99.02kJ/mol by using a new kinetic model. However, under the non-isothermal condition, as gradually increasing the temperature to 1493K, TiO2 and MgTiO3 could be reduced, and the final products were metallic iron and MgxTi3−xO5 (x was in the range of 0.45–1). [Display omitted] •Both isothermal and non-isothermal reduction experiments of Panzhihua ilmenite powders by pure hydrogen were carried out.•A new model was applied to describe the reduction kinetics of ilmenite powders.•The rate controlling step and the corresponding activation energy for hydrogen reduction of ilmenite powders were obtained. Both isothermal and non-isothermal reduction experiments of Panzhihua ilmenite powders by pure hydrogen were carried out using a thermo-gravimetric (TG) analyzer. Results of X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopic (EDS) analyses showed that in the temperature range of 1146–1201K, the main products were metallic iron, TiO2 and MgTiO3 with the iron being embedded in TiO2 matrix. It was found that the reduction reaction was controlled by the chemical reaction at the reaction interface and the apparent activation energy was extracted to be 98.35–99.02kJ/mol by using a new kinetic model. However, under the non-isothermal condition, as gradually increasing the temperature to 1493K, TiO2 and MgTiO3 could be reduced, and the final products were metallic iron and MgxTi3−xO5 (x was in the range of 0.45–1).