| 摘要 |
PURPOSE:To manufacture a magnetic metallic iron powder having excellent denseness and magnetic characteristics by adding a Zn or Al compound to a ferrous hydroxide suspension for manufacturing alpha-iron oxyhydroxide as a raw material. CONSTITUTION:An aqueous solution containing any one of a Zn compound, e.g., ZnSO4, etc., and an Al compound, e.g., Al2(SO4)3, etc., and FeSO4 is added to a NaOH aqueous solution while stirring. The Fe(OH)2 suspension of pH 11 or more, obtained thus, is heated, and then an oxygen-containing gas, e.g., air, etc., is blown into the suspension to separate the needlelike particles of alpha-iron oxyhydroxide (FeOOH). The needlelike particles are filtered, washed with water, dried, and then dispersed into a Na4SiO4 aqueous solution. Then, CO2 gas is blown into the suspension to form alpha-FeOOH whose surface is covered with deposited silicic acid sol which is in turn filtered, washed with water, and dried. Then, the particles so treated are reduced by hydrogen gas in an electric oven to manufacture metallic iron particles containing Al and Si and having excellent denseness and magnetic characteristics. |
