Verfahren zur Nachbehandlung von Titandioxidpigmenten

1,187,941. Coated TiO 2 . TITAN G.m.b.H. 18 Jan., 1968 [3 Feb., 1967], No. 2880/68. Heading C1N. TiO 2 pigment is coated with an oxide or hydrated oxide by separately introducing steam and one or more halides into a fluidized bed of the TiO 2 which is at a temperature of 100- 600‹ C. The halide may be AlCl 3 , TiCl 4 , or SiCl 4 . Air may be used to maintain the bed fluidized, and as a carrier for the steam and halide. The steam and halide may be introduced alternately, air being blown through in between. Two or more halides may be introduced successively or admixed. The process may be operated discontinuously, or continuously in several successive beds. The TiO 2 may be coated with 1-10% by wt. of oxide. The TiO 2 may have been produced by the vapour phase reaction of TiCl 4 with O 2 or by the sulphate process.