Energy consumption in the selective reduction of iron from ilmenite concentrate

Abstract

The main pyrometallurgical methods are single–stage electric melting and a two-stage method according to the “tubular furnace – melting unit” scheme. Both processing schemes involve the use of carbon as a reducing agent, which in turn leads to the formation of iron metal products and titanium oxide concentrate based on anosovite – Ti3O5. Reducing firing of ilmenite concentrate allows selectively reducing iron from ilmenite concentrate with both carbon and hydrogen to produce soft iron and a concentrate of titanium oxides with a rutile – TiO2 structure. It is shown that the process of carbothermic reduction of iron from ilmenite at a temperature of 1300 ℃ proceeds by the reaction: 3FeTiO3 + + 4C = 3Fe + Ti3O5 + 4CO. At a temperature of 900 ℃, the reduction of iron from ilmenite with carbon and hydrogen proceeds by the reactions: FeTiO3 + C = Fe + TiO2 + CO, FeTiO3 + H2 = Fe + TiO2 + H2O. The results of calculating energy costs for carbothermic reduction reactions at 1300 and 900 ℃ and hydrogen at 900 ℃ are presented. According to the calculation results, the lowest amount of costs is fixed when reducing iron with hydrogen at a temperature of 900 ℃ and amounts to 215.81 kJ. At the same temperature and carbon reduction, the total energy consumption is 341.29 kJ. The total energy consumption for the reaction of ilmenite with carbon at a temperature of 1300 ℃ is 484.51 kJ. When comparing the calculation results, it was found that the reduction of iron with hydrogen at a tempera-ture of 900 ℃ is 1.58 times less expensive than carbothermic reduction at the same temperature, and 2.25 times than carbothermic reduction at a temperature of 1300 ℃. Carbothermic reduction of iron at a temperature of 1300 ℃ re-quires even greater energy consumption due to heating the charge to a higher temperature and partial reduction of tita-nium to a lower oxide – Ti3O5 anosovite