| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a spindle-like goethite having a uniform particle size distribution, not containing dendritic granules and excellent in dispersibility even in the case of obtaining a goethite of a fine particle diameter. SOLUTION: This method for producing a spindle-like goethite is composed of oxidizing divalent iron in a suspension containing FeCO3 by an oxygen- containing gas. In this case, the oxidation of divalent iron is performed in two steps of the first step in which the oxidation is performed at a 0.1-0.7mol/(L.hr) oxidation rate and the second step in which the oxidation is performed at an oxidation rate of 1.5-4.0 times of the oxidation rate at a start of the second step by increasing the oxidation rate at an increasing rate higher than 0.05mol/(L.hr) per 1min, and the second step is started at one point of time at an oxidation rate of the divalent iron is 50-85mol%. |
