Direct carbothermic reduction of ilmenite concentrates by adding high dosage of Na2CO3 in microwave field
(1. School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China;
2. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China;
3. Shanghai Key Laboratory of Advanced Ferro-metallurgy, Shanghai University, Shanghai 200072, China)
2. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China;
3. Shanghai Key Laboratory of Advanced Ferro-metallurgy, Shanghai University, Shanghai 200072, China)
Abstract: A clean and efficient route for the utilization of ilmenite concentrates was proposed by direct carbothermic reduction in microwave field. High dosage of Na2CO3, which can be recycled, was added to accelerate the reduction reaction of ilmenite concentrates. After microwave heating in the temperature range of 1073-1123 K for 20 min, the main products were Na2TiO3 and metallic Fe with the metallization ratios being as high as 92.67%-93.21%. The reduction products were processed by water leaching, ball-milling in CO2 atmosphere and magnetic separation in turn. The final products after magnetic separation were Fe-rich materials and Ti-rich materials (90.04 wt.% TiO2), which can be used to produce iron and TiCl4 or TiO2. The optimized heating temperature was 1123 K in terms of metallization ratios, magnetic separation and caking property of the reduction products. Besides, the reduction mechanism of ilmenite concentrates with the addition of Na2CO3 in microwave field was also proposed.
Key words: ilmenite concentrates; microwave; Na2CO3; carbothermic reduction