GB810822A - Process for purifying titanium tetrahalides or zirconium tetrahalides - Google Patents

Abstract

Titanium and zirconium tetrahalides are purified at least from vanadium by passage through a fluidized bed of particles at least the surface of which are metallic. Metals referred to are copper, zinc, iron, nickel, calcium, magnesium, aluminium, titanium, lead, antimony, tin, sodium and alloys containing at least one of these metals; sodium carbonate particles on which sodium has been deposited by rapid agitation in nitrogen at 160 DEG C. are also referred to. Such metals as iron and chromium will generally also be removed. The temperature of the purification should be such that decomposition of the halide to be purified does not take place; for the undiluted tetra bromides or chlorides of titanium and of zirconium temperatures under atmospheric pressure of 150-300 DEG C. and of 300 DEG to 400 DEG C. respectively are suitable. The halides may, if desired, be diluted, e.g. with nitrogen, carbon monoxide and/or carbon dioxide, and may come directly from the halogenation with a halogen and carbon of titaniferous or zirconiferous material. In the latter case it is desirable to remove solid matter such as ferric chloride, entrained in the gases; diluent gases, which may include chloride and silicon tetrahalide, may be separated by condensing out the metallic halides before or after purification in the fluidized bed. The particles of the bed should be periodically or continuously replaced or regenerated; two or more beds may be operated e.g. when using three beds, at any given time, a first bed may be removing a major part of the impurities whilst a second is removing the remainder and a third is being regenerated, said third bed having been employed as the bed removing the major part of the impurities in the preceding run. Specification 674,315 and U.S.A. Specifications 2,530,735, 2,416,191 and 2,396,458 are referred to.