PRODUCTION OF STABILIZED FERROMAGNETIC METALLIC POWDER

PURPOSE:To produce ferromagnetic metallic powder which is subjected to a stabilizing treatment and has good dispersibility in the stage of preparing a paint by bringing the ferromagnetic metallic powder formed to granules having an adequate grain size and bulk specific density into contact with an oxygen- contg. gas with a fixed bed in an org. solvent. CONSTITUTION:The ferromagnetic metallic powder such as iron oxyhydroxide is granulated or lumped to form the granules 6 having >=1mm, more preferably 1-10mm, more par- ticularly preferably 2-7mm grain size and 0.4-1.2 bulk specific gravity. Such granules are packed into a reaction vessel 12 immersed in a heating chamber 11 to form the fixed bed. An org. solvent 7 such as ben zene inert with the above-mentioned ferromagnetic metallic powder is added thereto at 2-15 times by weight the granules 6 and if necessary an antistatic agent is added thereto at 0.1-5% with respect to the granules 6. The oxygen- contg. gas formed by mixing air or gaseous oxygen with an inert gas such as nitrogen, helium or argon to dilute the same to about 1-10vol% is blown through a gas blowing pipe 1 and a preheater 2 into the vessel 12 to oxidize the surface layer of the ferromagnetic metallic powder as the granules 6, by which the stabilized ferromagnetic metallic powder is obtd.