Development of deoxidation process for off-grade titanium sponge using magnesium metal with wire mesh strainer type of crucible.

Abstract

In this study, the deoxidation process for off-grade titanium (Ti) sponge using magnesium (Mg) metal with a wire mesh strainer type of crucible was developed. Ti hydride (TiH₂) feedstock, which was prepared by hydrogenating off-grade Ti sponge, was deoxidized using Mg in a molten magnesium chloride-potassium chloride salt at 933 K under an argon and 20% hydrogen (H₂) mixed gas atmosphere. After deoxidation, the residual Mg-containing salt was separated in situ from the crucible to investigate the feasibility of minimizing salt loss during the leaching and production of pure TiH₂. The results showed that the presence of residual Mg-containing salt inside the crucible strongly influenced whether a mixture of Ti and TiH₂ or pure TiH₂ was produced. When the salt was not sufficiently separated, a mixture of Ti and TiH₂ was obtained and its oxygen (O) concentration was 0.121 mass% under certain conditions. Meanwhile, pure TiH₂ was obtained by increasing the H₂ gas flow rate during deoxidation. Therefore, these results demonstrate that the decrease of O concentration to below 0.180 mass% and the minimal loss of the salt are feasible.