Thermo- and Mechanochemical Reduction of Ilmenite with H2, Mg, and CaH2

Abstract Ilmenite is an abundant raw material with a general composition of FeTiO 3 , mainly used as ore for TiO 2 production, which, among other applications, is used to produce titanium metal. This paper focuses on the direct reduction of ilmenite to iron–titanium alloys via thermochemical or mechanochemical processes. These processes were carried out in the presence of reducing agents such as magnesium, calcium, and gaseous hydrogen, as well as the combination of magnesium or calcium in a hydrogen atmosphere. The mixture of ilmenite and the reducing agents was ball milled for 80 h at 350 rpm and analyzed via X-ray powder diffraction (XRPD). The influence of particle size, by necessity reduced during the milling process, on the reduction is investigated via thermal analysis [differential thermal analysis (DTA) and differential scanning calorimetry (DSC)]. Additionally, the thermochemical reduction path is investigated via in situ synchrotron radiation XRPD. In this study, the mechanochemical reduction with magnesium and the thermochemical reduction with calcium yielded the highest conversion yield of ilmenite into iron–titanium alloy, forming primarily TiFe 2 and small amounts of TiFe. TiFe is a promising hydrogen storage material. All runs were deficient in Ti after the reduction, as calculated by XRPD Rietveld refinement, which suggests the formation of an additional amorphous Ti–rich phase. Graphical Abstract