Recovery of Titania Slag and Iron from Semi-molten State Reduced Ilmenite Concentrate: Liberation Characteristics and Magnetic Separation

The electric arc furnace (EAF) smelting ilmenite concentrate process which produces titania slag, is high energy consumption, high pollution, and low efficiency process. An economical and clean process for semi-molten reduction followed by magnetic separation to produce titania slag from Panzhihua ilmenite concentrate is proposed. In the present study, grinding and wet magnetic separation of the products from semi-molten state reduction of Panzhihua ilmenite concentrate was investigated. The separation aimed at producing a titania-rich slag and a metal phase containing most of iron. The effects of additives to the concentrate in reduction step and grinding time on liberation of metallic iron, and distribution of iron and titania in non-magnetic products were evaluated. The results show that the metallic iron particles agglomerate and grow significantly in the reduction process when sodium carbonate and sodium sulfate are present. An increase in grinding time is conducive to the liberation of iron particles from the slag. The addition of sodium carbonate and sodium sulfate effectively improves the liberation degree of metallic iron particles. The grade of TiO2 in the titania slag in the presence of sodium carbonate and sodium sulfate can reach up to higher than 75%, which is higher than that of the industry's conventional technology. Under the optimum conditions of additive type and grinding time, the recovery of titania reached 93%.

Automated summary

This study proposes an economical and clean process for producing titania slag from Panzhihua ilmenite concentrate through semi-molten reduction and magnetic separation. The results show that the addition of sodium carbonate and sodium sulfate improves the liberation degree of metallic iron particles and increases the TiO2 grade in the titania slag.