| 摘要 |
PURPOSE:To prepare fine acicular yellow iron oxide, by introducing an oxygen- containing gas into an aqueous suspension of ferrous hydroxide having a specific molar ratio of ferrous hydroxide to ferrous sulfate and specific molar ratio of total iron to sulfuric acid radical, at or below a specific temperature. CONSTITUTION:An oxygen-containing gas, e.g. air is introduced into a suspension of ferrous hydroxide containing ferrous hydroxide and ferrous sulfate at a molar ratio of 2:1-4:1 and total iron and sulfate radical at a molar ratio of 3:2-5:1 (especially 2:1-4:1) to obtain wet cake composed of fine acicular yellow iron oxide having uniform particle size. The cake is washed with water and dried to obtain the objective iron oxide. The reaction mothor liquid left after the separation of the wet cake is mixed with an alkali, especially sodium hydroxide or potassium hydroxide, and the precipitated ferrous sulfate and ferrous hydroxide are separated and recovered. |
