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. 30, 1976
Filed:
Jan. 11, 1973
Applicant:
Inventors:
Lutz Leitner, Rumeln-Kaldenhausen, DT;
Franz Hund, Krefeld-Bochum, DT;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01G / ;
U.S. Cl.
CPC ...
423632 ; 252 6259 ; 423633 ; 423634 ;
Abstract
In the production of acicular, ferromagnetic iron oxide of high coercive force by oxidizing an iron (II)-hydroxide suspension with an oxygen-containing gas to form acicular iron (III) oxide hydroxide and dehydrating the iron (III) oxide hydroxide, optionally tempering, reducing and/or reoxidizing this into magnetic iron oxide, the improvement which comprises effecting the oxidation of the iron (II)-hydroxide suspension at a pH of at least about 13, the suspension including SiO.sub.2 in the form of a sol or soluble salt, the resulting iron (III) oxide hydroxide having SiO.sub.2 deposited thereon.