Reduction of Ilmenite with Coal in the Presence of Nitrogen

Abstract

In this study, the carbothermal reduction of ilmenite with coal was investigated in laboratory-scale experiments. Reactions were performed in nitrogen atmospheres in the temperature range of 1,225–1,325°C with a residence time of 6 h. The solid reaction products obtained in the investigation were characterised by ICP-EOS and LECO analysers, X-ray diffraction, and scanning electron microscope (SEM). The results show that temperature increase leads to an increase of reduction degree for constant bed depth but the reduction degree decreases with increase of bed depth. The reduction degree of 42.2% was obtained with a bed depth of 25 mm, at 1,350°C after 6 h of residence time. The reaction started with the reduction of ilmenite to titania, followed by the reduction of titania to suboxides. Titania was reduced to Ti3O5, which was later converted to titanium nitride or titanium oxycarbonitride depending on element reactivity and temperature. It was found that Ti2O3 does not appear as an intermediate reaction product due to its instability.