PHOTOCHEMICALLY REACTIVE TITANIUM DIOXIDE AND ITS METHOD OF PREPARATION

摘要

1370309 Photo-reactive TiO2 AMERICAN CYANAMID CO 25 Nov 1971 [25 Jan 1971] 54870/71 Heading C1N Photo-reactive particles of TiO2.xH2O, where x is 0-1, having an average diameter of less than 100Š, and a sulphur content of less than 0À3% by wt., may be produced by treating an alkali metal titanate with a monobasic acid to neutralize the titanate, then filtering, washing, and heating at below 600‹ C. The alkali metal titanate may be obtained by refluxing an aqueous pulp of TiO2 hydrolysate with NaOH or K2CO3. The titanate may then be washed, reslurried, and treated with HNO3 or HCl to give TiO2.H2O, which may be heated at 100-600‹ C. to remove at least the free water. The product preferably has a sulphur content of less than 0À03% and a P2O5 content of less than 0À14%. In comparative examples (A) the TiO2.H20 is heated at 400‹ C. and then at 700‹ C. to give rutile particles of size 400Š, and (B)-(E) hydrous TiO2 precipitated from T : sulphate (obtained from ore or slag) is subjected to the same heat treatment and yields TiO2 of similar particle size but higher S content.