[Abstract] 

In recent years, a novel method for producing titanium (Ti) with a low oxygen (O) concentration has been developed to overcome the limitations of the commercial Ti production process, the Kroll process. This method involves the reduction of titanium dioxide (TiO₂) using magnesium (Mg) in a hydrogen gas (H₂) atmosphere. In this study, the effects of the sieving method and the particle size of the TiO₂ feed on the O concentration in the reduced Ti product were investigated, based on a thermodynamic analysis of the magnesiothermic reduction mechanism. Titanium hydride (TiH₂) powder containing 0.415 – 0.480 mass%O was directly produced by reducing dry-sieved TiO₂ feed, with a size range of 45 – 300 μm, using Mg under a 10 % H₂ mixed gas atmosphere at 973 K. Furthermore, by comparing the magnesiothermic reduction results of wet-sieved TiO₂ feed, the influence of the sieving method on the O concentration in the TiH₂ product was evaluated.