| 摘要 |
1356846 Iron oxide pigments; TiO 2 concentrates BAYER AG 3 June 1971 [13 June 1970] 18785/71 Headings C1A and C1N Iron oxide pigments are prepared by treating a metallic iron-containing material having a particle size less than 500 Á with an oxygencontaining gas (e.g. air) in an aqueous slightly acid ferrous salt reaction medium wherein the metallic iron containing material is added to the reaction medium in such quantities that the pH of the reaction medium during the formation of the pigment is 1 to 6, the medium being agitated to maintain the metallic iron in suspension. The iron containing material may be a reduced iron containing ore (e.g. reduced ilmenite, in which case a TiO 2 concentrate is obtained and separated from the pigment). The medium may contain crystal forming modifying substances e.g. an aqueous suspension of α- FeOOH, γ-FeOOH, #-FeOOH or α-Fe 2 O 3 . |
