公开(公告)号：JPH09188520A

公开(公告)日：1997-07-22

申请号：JP2055496

申请日：1996-01-10

Applicant: KAO CORP

Inventor： ARITA TOSHIHARU ,  ARIKITA SHIYUUHEI ,  YAMAMOTO YOSHIYASU

IPC: C01G49/02 ,  H01F1/06 ,  H01F1/11

Abstract: PROBLEM TO BE SOLVED: 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. SOLUTION: 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.

公开(公告)号：JPH1029819A

公开(公告)日：1998-02-03

申请号：JP20783796

申请日：1996-07-17

Applicant: KAO CORP

Inventor： YAMAMOTO YOSHIYASU ,  IGAKI MICHIHITO ,  FUJII SHIGEO ,  ARITA TOSHIHARU

IPC: C01G49/02 ,  H01F1/20

Abstract: PROBLEM TO BE SOLVED: To obtain a spindle shaped goethite particle uniform in particle size, free from the incorporation of a dendrite particle and the presence of particle aggregation by previously incorporating a specific compound in one of reaction solutions before the forming reaction of the goethite particle. SOLUTION: This spindle shaped goethite particle is produced by passing an oxygen-containing gas in a suspension having pH 8-11 and containing FeCO3 - or Fe-containing precipitate, which is obtained by the reaction of an alkali carbonate aq. solution or an alkali carbonate.alkali hydroxide aq. solution with a ferrous salt aq. solution, to oxidize. At this time, before the spindle- shaped goethite particle is formed, a carboxylic acid or the salt having chelating ability or further a 2-valent transition metal compound are previously incorporated in one or more solutions of the alkali aq. solution, the ferrous salt aq. solution and the suspension containing FeCO3 - or Fe-containing precipitate. The goethite particle has 0.05-0.25μm average major axis diameter and an average axial ratio of 4-10.