Effect of reducing agents on reducing atmosphere in coal-based direct reduction of beach titanomagnetite

Abstract

Beach titanomagnetite (TTM) provides a cheap alternative source of Fe and Ti, but this ore is difficult to process to make suitable concentrates for the blast furnace. Recently studies showed that it is feasible to separate Fe and Ti by coal-based direct reduction. In this study, beach TTM was selected as the research object, the effects of reducing agents on reducing atmosphere in coal-based direct reduction of beach TTM were analyzed, and the role of volatiles was also studied. The results showed that when bitumite and coke were used as reducing agents of TTM, the CO produced from volatiles was involved in the reduction reaction, and the generated CO₂ provided the raw material for the reaction of TTM. The reduction effect of bitumite was better than that of coke. The reason is that bitumite+TTM had a higher gas generation rate and produced a higher CO partial pressure, while coke+TTM had a lower gas generation rate and produced a lower CO partial pressure. When graphite was used as a reducing agent, there was a solid-solid reaction in the early stage in the reaction. With the continuous accumulation of CO₂, the Boudouad reaction started and accelerated. Graphite+TTM also produced a higher CO partial pressure.

Keywords

beach titanomagnetite / coal-based direct reduction / magnetic separation / reducing agents / reducing atmosphere

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