High-Titanium Slag Preparation Process by Carbothermic Reduction of Ilmenite and Wet-Magnetic Separation

Abstract

As the titanium industry rapidly develops, low-grade ilmenite resources are drawing global attention. The direct use of low-grade ilmenite can result in low production efficiency and heavy pollution. In addition, the production of high-titanium slag via electric furnace melting consumes significant energy and possesses low production efficiency. Therefore, a novel process with low energy consumption is necessary for producing ultra-grade slag (UGS) for chlorination. For low-grade ilmenite, semi-molten reduction and magnetic separation were suggested in this study. The effects of carbon content, reduction time, and Na2CO3 addition on the reduction and separation behavior were studied. The results showed that the addition of Na2CO3 favored the formation of a semi-molten state, which was more conducive for the diffusion, aggregation, and growth of the metal phase. In this regard, excess carbon was not helpful, and it weakened the growth of the metal phase. Wet grinding and magnetic separation were used for beneficiation of the reduced sample for efficiently separating the slag iron and preventing the formation of agglomerates between slag and metal. For the sample with a carbon dosage of 13 pct, Na2CO3 dosage of 8 pct, reduction temperature of 1673 K (1400 °C), and 90 minutes holding time, high-titanium slag with a TiO2 grade of 81.63 pct and iron content of 4.53 pct was produced, with the TiO2 recovery rate of 93.43 pct and the yields of 55.37 pct. High-titanium slag can be used as a high-quality raw material to produce UGS for chlorination by leaching.