| 摘要 |
PURPOSE:To synthesize hydrous iron oxide consisting of high-quality goethite essentially at a low cost, by oxidizing a suspension consisting of iron (II) hydroxide with a gaseous oxidizing agent and a liquid oxidizing agent together. CONSTITUTION:A suspension consisting of iron (II) hydroxide is oxidized with a gaseous oxidizing agent, e.g. air, and a liquid oxidizing agent, e.g. NaClO3, together, and the liquid oxidizing agent is preferably used in the initial stage of the reaction and then changed over to the gaseous oxidizing agent to carry out the oxidation. In the process, the suspension is reacted at 30-60 deg.C with agitation. After the suspension turns yellow completely and the reaction is completed, a formed precipitate is washed with water, filtered and dried to give goethite powder in the form of fine needlelike crystal. According to the method, the amount of the liquid oxidizing agent of comparatively high price is reduced to half or less that in the case of the liquid oxidizing agent used throughout the reaction period, and the raw material cost can be saved. |
