Scale-Up Study of Deoxidation of Off-Grade Titanium Sponge Using Magnesium Metal Under Argon and Hydrogen Mixed Gas Atmosphere

To develop an efficient and cost-effective process for recycling off-grade titanium (Ti) sponge, the scale-up study of deoxidation of off-grade Ti sponge using magnesium (Mg) metal under argon (Ar) and hydrogen (H₂) mixed gas was conducted. In the experiments, titanium hydride (TiH₂) produced by the hydrogenation of an off-grade Ti sponge was used as the feedstock. The deoxidation of TiH₂ was performed at 933 K for 12 h using Mg metal in magnesium chloride and potassium chloride molten salt under Ar and 10% H₂ mixed gas atmosphere. The influence of production scale on the concentration of oxygen (O) in the obtained residues was investigated by increasing the amount of TiH₂ feedstock up to 2500 g/batch. After the deoxidation process, a mixture of Ti and TiH₂ was obtained, and the O concentration in the mixture decreased from 11750 to 1480 ppm under certain conditions. The results demonstrate that the deoxidation of TiH₂ using Mg metal under Ar and H₂ mixed gas can decrease the O concentration in an off-grade Ti sponge below 1800 ppm, even though the production scale increased under optimal conditions. Graphical Abstract: [Figure not available: see fulltext.].