PRODUCTION OF INORGANIC POWDER

PURPOSE:To obtain an inorg. powder excellent in storage stability and dispersibility by heating and dehydrating an inorg. powder, chemically adsorbing carbon dioxide gas to the surface of particles, removing carbon dioxide gas, bringing water vapor into contact with the powder to adsorb water content so that specified amts. of carbon dioxide gas and water are chemically adsorbed to the particle surface. CONSTITUTION:An inorg. powder such as metal magnetic powder is heated and dehydrated so that the amt. of adsorbed water becomes 4/nm per unit area expressed by BET specific surface area. Then the powder is brought into contact with carbon dioxide gas to chemically adsorb carbon dioxide gas to the particle surface, and then the carbon dioxide gas is removed by vacuum deaeration or gas substitution, and then water vapor is brought into contact with the powder to adsorb water. Thus, 0.5-4/nm carbon dioxide gas and 4-12/nm water per unit area expressed by BET specific surface area are chemically adsorbed and adsorbed, respectively, to the particle surface. The obtd. magnetic powder has excellent stability and dispersibility in a binder resin.