Production of small particle size titanium tribromide or trichloride

摘要

PICT:0886512/III/1 Finely subdivided metal halide i.e. having a surface area greater than 4 sq. metres/grm. and comprising TiCl3 or TiBr3 is prepared by passing an inert gas containing between 0,01 and 50,0% volume of TiCl4 or TiBr4 vapour over a reducing substance which is TiCl2, TiBr2, Ti metal or Al metal at between 500 DEG C. and the m.pt of the reducing substance, the space velocity of the inert gas being at least 20,000 volumes of gas/volume of reducing substance, to form the vaporous metal trihalide in the inert gas, thereafter cooling the resulting gaseous mixture to condense the vaporous metal trihalide and separating the condensed metal trihalide from the inert gas. In operation inert gas e.g. argon, at any temperature between the m.pt of the TiCl4 or TiBr4 e.g. ambient temperature for TiCl4 and 50-70 DEG C. for TiBr4, is fed at pressures of more than 1 atmosphere and less than 3, preferably 20 p.s.i.g, through pipe 10 and is divided into two streams, one through valve 20 into pipe 16 and the other through valve 18 into pipe 12. Pipe 12 connects with tube 21 and leads inert gas into vessel 14 and through liquid TiCl4 and TiBr4 maintained at a sufficient level in 14 to cover the bottom of tube 21 by fresh addition through pipe 26 and valve 32 from storage tank 28. When using TiBr4 it is held in a liquid state in tank 28 and vessel 14 by heaters 30 and 31, the temperature in 14 being registered by thermometer 33. Inert gas carrying TiCl4 or TiBr4 vapour is passed through pipe 34 into the inert gas stream in pipe 16 both streams being metered by valves 36 and 38 to produce a mixture containing preferably between 0,1 and 1,0 per cent by volume of tetrachloride or tetrabromide which passes through pipe 17 into retort 40 which may contain TiBr2, TiCl2, Al or Ti metal of particle size preferably 1/16 -a1/2 inch fragmented Ti sponge being preferred, heated to above 500 DEG C., for example, with Ti sponge to between 500-1000 DEG C. preferably 600-800 DEG C., by heater 44. Reaction gases comprising vaporous TiCl3 or TiBr3 contained in the inert gas together with small quantities of unreacted TiCl4 or TiBr4, by-product TiCl2 and TiBr2 or, when Al is employed in the retort, AlCl3 or AlBr3, leaving the retort are preferably rapidly cooled by passage through pipe 46 to say below 300 DEG C. but above the condensation temperature of TiCl4 or TiBr4. The outside of pipe 46 may be in contact with air at ambient temperature or be surrounded by a cooling coil. To avoid removal of reducing substance from retort 40 in suspension with the reactant gases a platinium sieve (not shown) may be placed at the outlet from the retort into pipe 46. Cooled gases containing solid TiCl3 or TiBr3 in suspension pass into electrostatic precipitator 48 where the solid product is precipitated and collects in vessel 57. In place of the electrostatic precipitator a filter bag or cyclone separator may be employed. Residual gases after removal of solid products may if desired be recycled through vent 52 pipe 65 and pump 68 to pipe 10. When Al is used as the reducing substance AlCl3 and AlBr3 may be removed from TiCl3 and TiBr3 by conventional methods. Specifications 722,901 and 723,879 are referred to.