The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 08, 1988
Filed:
Jan. 20, 1987
Yasushi Matsui, Yokohama, JP;
Norio Koike, Tokyo, JP;
Kunio Takahashi, Yokohama, JP;
Hiroshi Matsue, Hiratsuka, JP;
Showa Denko Kabushiki Kaisha, Tokyo, JP;
Abstract
Lepidocrocite (.gamma.-FeOOH) with an large specific surface area and a uniform particle size is provided by a method comprising preparing a suspension of ferrous hydroxide at a pH of 6.5 to 7.5 by adding a ferrous salt solution with an alkali solution in an amount of 0.4 to 0.7 times the theoretical amount for converting all the ferrous salt to ferrous hydroxide, blowing an oxygen-containing gas into the suspension to form a seed crystal of .gamma.-FeOOH, completing the generation reaction of .gamma.-FeOOH by blowing an oxygen-containing gas into the suspension while adding an alkali solution to keep the pH of the suspension within a range of 3 to 5, in which an Si concentration of the suspensions for seed reaction and for generation reaction of .gamma.-FeOOH is controlled to be within 5 to 30 ppm.