Application of porous TiAl intermetallic compound in purification of industrial TiCl4 liquid in Ti metallurgy

Abstract

Industrial TiCl _4 liquid, which is a key intermediate in Ti metallurgy, is hard to be purified by traditional porous metals or ceramics due to its characteristics of easy hydrolysis, toxicity and corrosivity. In this work, porous TiAl intermetallic filter tubes were fabricated through a reactive synthesis process, and their filtration properties in industrial TiCl _4 liquid were investigated. The cyclic corrosion kinetics of porous TiAl in TiCl _4 follows a parabolic rate law, in which the corrosion rate constant is 4.8%, 0.06% and 0.04% of that of porous Ti, Ni and 316L stainless steel, respectively. After the cyclic corrosion of 408 h, the maximum aperture reduction rate of porous TiAl is 3.9%, which is far lower than that of porous Ti, Ni and 316L, indicating good pore structure stability. Porous TiAl filter tubes exhibit clean filtration performance in the solid-liquid separation of raw TiCl _4 suspension with stable filtrate solid content of 0.1 wt% and high filtration flux of 8.17 m ^3 · m ^−2 · h ^−1 at the maximum aperture of 17.0 μ m. The filtration equation and the filter medium resistance of porous TiAl are determined.

Keywords

• TiAl
• intermetallic compound
• corrosion
• Ti metallurgy
• clean filtration
• porous material