| 摘要 |
PURPOSE:To obtain a fine spindle-shaped goethite of >=0.5mu size and high in acicular ratio at low cost. CONSTITUTION:In a method wherein iron carbonate contg. slurry formed by reacting water solution of alkali carbonate and water solution of ferrous salt is oxidized with oxygen-contg. gas to produce spindle-shaped goethite, there are provided (1) a reaction step of 1st stage where equivalent ratios of alkali carbonate to ferrous salt are 1.5-3.0 and Fe concentration in the slurry is 0.2-0.6mol/l and the slurry is oxidized with oxygen contg. gas to generate seed and (2) a reaction step of 2nd stage where after the generation of the seed, while continuing the oxidation with the oxygen contg. gas, water solution of ferrous salt and alkali hydroxide or gaseous ammonia are added to perform growth reaction in the range of pH7-11. |
