Producing titanium powder by continuous vapor-phase reduction

Abstract

One of the goals of the U.S. Department of Energy’s Albany Research Center is to reduce the cost of titanium parts by developing a continuous titanium process. In this work, titanium powder was produced by feeding liquid TiCl4, with argon as a carrier gas, and magnesium wire into a shaft reactor at 1,000°C. The magnesium and TiCl4 vaporized and reacted to produce a mixture of titanium, MgCl2, and magnesium powder. Ti/Mg/MgCl2 powder was removed from the argon gas stream by an electrostatic precipitator, and the titanium powder was separated from the magnesium and MgCl2 by either vacuum distillation or leaching. Vacuum distillation produced sintered titanium powder with lower oxygen levels, but unacceptably high levels of magnesium and chlorine. Leached powder was spherical and free-flowing with low levels of magnesium and chlorine, but the oxygen content was no lower than 0.82%. The high oxygen content of the leached powder is caused by surface oxidation of the submicrometer titanium powder.