Preparation of TiCl4 from Ilmenite Concentrates via Carbothermal Reduction and Boiling Chlorination for Different Carbon Proportions

Low-temperature boiling chlorination is the most common approach used to achieve a clean preparation of TiCl₄ from ilmenite concentrates with high contents of calcium and magnesium impurities. However, this process did not systematically investigate the impact of the Ti/C ratio of the raw materials on the chlorination efficiency of Ti, Ca, and Mg elements. Thus, the influence of the carbon allocation proportion on the carbothermal reduction and boiling chlorination process of ilmenite concentrates with high contents of calcium and magnesium impurities was investigated in this study. The results show that the reduction products of ilmenite concentrates are mainly Mg-rich Ti₂O₃ impurities at a low carbon proportion. However, with increasing carbon proportion, Ti₂O₃ is gradually reduced to TiC_xO_1–x, and Mg₂TiO₄ appears. The Ti₂O₃ content in the acid-insoluble matter of the reduced products decreases after acid washing, while the TiC_xO_1–x content increases with increasing carbon allocation proportion. With increasing carbon proportion, the chlorination rate of the acid-insoluble matter increases, and the corresponding chlorination rates of titanium, magnesium, and calcium also increase. The residual carbon produced by acid-insoluble chlorination at high carbon proportions exacerbates the chlorination of Mg and Ca impurities.