Back to results
US 4,226,843 AGranted
Process and apparatus for production of spherical grain ferrite powder
AssigneeDowa Mining Co., Ltd.
InventorsYasuo Watanabe, Seizi Isoyama, Yoshikazu Yamamichi
Life of this patent
Estimating the term…
Abstract
There is disclosed a novel type of spherical grain-ferrite powder as well as a process and apparatus for the production thereof. A slurry of ferrite-forming powdered raw materials in alcohol is sprayed under applied pressure through a spray nozzle into a high temperature atmosphere of between 700.degree.-1500.degree. C. to allow the combustion of sprayed alcohol therein thereby instantaneously producing spherical grain-ferrite powder.
Claims17
A process for the production of spherical grain ferrite powder which comprises the steps of:
- suspending impalpable powder of (1) pre-formed ferrite powder or (2) ferrite-forming material, in methyl alcohol to form a suspension consisting of said impalpable powder in said alcohol,
- said ferrite-forming material being selected from the group consisting of the oxides, hydroxides and carbonates of (i) iron and (ii) at least one ferrite-forming metal element M selected from the group consisting of Mn, Ni, Zn, Co, Mg, Cu, Ba and Sr, and wherein said pre-formed ferrite powders have the formula MO.Fe.sub.2 O.sub.3 ;
- spraying said suspension into a high temperature zone at a temperature of from about 1200.degree. to about 1300.degree. C.;
- whereby granulation, and ferrite formation when said impalpable powder is said ferrite-forming material, and sintering of said impalpable powder occurs while they are in said high temperature zone to form spherical ferrite particles with at least 80% of said spherical particles being of a size between 30 and 250 microns.
1 more element
Dependencies are inferred from the claim text.