To profitably obtain fusiform goethite particles uniform in particle distribution and having a high axial ratio by lowering an oxidation rate to a specific range in a time specific in the oxidation degree of a ferrous compound in a suspension, when a suspension containing FeCO3 is subjected to an oxidation reaction treatment comprising blowing an oxygen-containing gas in the suspension.
A suspension containing FeCO3 is oxidized with an oxygencontaining gas to produce the fusiform goethite. Therein, the following means is employed: the oxidation reaction of the suspension is started at an oxidation rate (γ1), and subsequently lowered to 20-80% of the (γ1), when the oxidation degree of the ferrous compound in the suspension is 4-20%. The suspension containing FeCO3 is obtained by reacting a ferrous salt aqueous solution with an alkali carbonate aqueous solution or its mixture with an alkali hydroxide. A means for lowering the oxidation rate includes a method for controlling an oxygen-supplying rate and/or a method for controlling a stirring rate.
ARIKITA SHIYUUHEI
YAMAMOTO YOSHIYASU
Next Patent: SUPPLY OF MOLTEN GLASS AND DEVICE FOR SUPPLYING THE SAME