| 摘要 |
PURPOSE:To produce acicular alpha-iron oxyhydroxide effectively used for producing magnetic metal powder capable of coping with the increase of the recording density of a magnetic recording medium without deteriorating the magnetic characteristics and having excellent dispersibility. CONSTITUTION:A ferrous hydroxide slurry having >=1.0mol/l concn. of excess alkali is oxidized with oxygen-contg. gas, an aq. aluminate soln. is added to the oxidized slurry in excess and they are mixed, stirred and oxidized again with oxygen-contg. gas to obtain a slurry contg. free aluminate ions and alpha-iron oxyhydroxide. This slurry is mixed, stirred, neutralized, aged, washed and dried, these the objective acicular alpha-iron oxyhydroxide is produced. |
