Solid state reduction of Panzhihua titanomagnetite concentrates with pulverized coal

摘要

Titanomagnetite concentrates and pre-oxidized titanomagnetite concentrates were reduced isothermally at 1000–1200℃ by pulverized coal. XRD, SEM and EDS were used to characterize the samples. The influence of reduction conditions on the metallization degree of the samples, such as reduction temperature, C/Fe molar ratio, pre-oxidation and additives were studied. It was found that the pre-oxidation and additives played a considerable role in the metallization degree of titanomagnetite concentrates. During the pre-oxidation of titanomagnetite concentrates in air, the magnetite was oxidized to hematite and ilmenite was oxidized to hematite–ilmenite solid solution, hematite and TiO_2. The pre-oxidation destroyed the crystal lattice of raw titanomagnetite concentrates and formed pores in the particles, which accelerated the reduction process. The effect of different additives on the metallization degree of pre-oxidized titanomagnetite concentrates was also discussed. The results show that when 1.5 wt.% Na_2CO_3 is used as an additive, the metallization degree of pre-oxidized titanomagnetite concentrates reaches 96.4%, after heating for 1 h at 1200℃. The final reduced sample was composed of metallic iron, pseudobrookite solid solution and TiO_2.