Thermodynamic Investigation of Titanium Hydride Formation from Reduction of Titanium (Ⅳ) Chloride with Magnesium Hydride in Presence of Hydrogen Atmosphere

Abstract

Thermodynamic assessment and experimental investigation for formation of titanium hydride (TiH2) from reduction of titanium tetrachloride (TiCl4) with magnesium hydride (MgH2) were carried out under hydrogen atmosphere. In this method, TiH2 production at low temperature was investigated, which can be used for further dehydrogenation process in titanium powder metallurgy. The effects of temperature, time, amount of titanium trifluoride (TiF3) as catalyst, and ball milling time of MgH2 on reduction process were evaluated. The range of each parameters were set to 250-350°C for temperature, 2-4 hr for reaction time, 4-10 wt% for TiF3, and 1-2 hr for ball milling time. The phase transformations after reduction process were studied by X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analyziz. The morphology of powders was analyzed by scanning electron microscope (SEM). The results showed that titanium trichloride (TiCl3) was formed as major product in experiments for the above conditions. However, with increasing the reaction time above 10hr, characterization study of the final products confirmed the formation of TiH2 as major product. Our findings indicated that producing of TiH2 from reduction of TiCl4 with MgH2 at low temperature was feasible and could lead to low cost synthesis method for TiH2 for titanium powder production.

Synthesis of Ti Powder from the Reduction of TiCl4 with Metal Hydrides in the H2 Atmosphere: Thermodynamic and Techno-Economic Analyses

“…In the current study, the TiH 2 was synthesized from TiCl 4 gas reacted with the MgH 2 powder at 500 • C for 12 h at the lab scale. Our previous attempts to synthesize TiH 2 at a temperature between 250 and 500 • C indicated that higher temperatures positively impacted the formation of TiH 2 [24][25][26][27][28]. The reduction products were then washed with water and diluted HCl to separate TiH 2 powder from the reaction byproducts.…”

“…The obtained TiO x C y N z is then chlorinated at 400 • C to produce TiCl 4 gas [22,23]. The author proposed directly reacting the obtained TiCl 4 gas with metal hydrides such as MgH 2 to produce TiH 2 powder at low-temperature ranges under the hydrogen (H 2 ) atmosphere [24][25][26]. The TiH 2 powder can then transform into Ti powder through the dehydrogenation process in a vacuum.…”