GB679537A - Improvements in or relating to the condensation of vaporised halides - Google Patents

Abstract

A vaporous mixture of halides issuing from a reduction furnace, containing a halide which condenses from the gaseous or vapour phase directly to the solid phase, and a more volatile halide, is treated for the separation of the halides, by first cooling the mixture, and then subjecting it, at a temperature of 300-600 DEG C to heat exchange with a vaporizable liquid distributed in sufficient quantity to effect complete vaporization thereof with simultaneous complete condensation of the solid phase component in a dry state, and the latter is separated from the residual gaseous mixture. The vaporous mixture may be obtained by the reaction of chlorine at 600-1100 DEG C on say ilmenite, rutile &c. in the presence of carbon, and contains primarily titanium and iron chlorides with small amounts of silicon and aluminium chlorides. The process is also applicable to the separation of iron chloride from tin and silicon chlorides, or of chlorides of chromium, zirconium and aluminium from chlorides of tin, silicon, sulphur &c. A suitable vaporizable liquid is the more volatile halide present, e.g. titanium tetrachloride, but other liquids, e.g. carbon tetrachloride, gasoline, toluene, may be used. The cooling liquid may be distributed by discharging it on to a rapidly rotating horizontal disc or discs, or through spray nozzles. The condensed solid, e.g. ferric, chloride is separated in a cyclone separator or glass cloth filter, and the gases whilst still at a temperature above the dew point of the liquid halide, say 140-180 DEG C in the case of titanium tetrachloride, are passed to a surface condenser for the liquid. Specification 550,750 is referred to.