| 摘要 |
PURPOSE:To obtain the titled acicular crystal having narrow particle size distribution range and being suitable to prepn. of ferromagnetic powder by introducing O2-contg. gas into liquid suspension of a mixture of aq. soln. of ferrous salt and an aq. soln. of alkali in the presence of hydroxy carboxylic acid. CONSTITUTION:O2-contg. gas is introduced into liquid suspension obtd. by mixing aq. soln. of ferrous salt with aq. soln. of alkali having >=1.0 equivalent ratio R of alkail to the ferrous salt in the presence of hydroxy acid or its salt or ester to carry out oxidation reaction. Aimed acicular crystals of alpha-oxy iron hydroxide is thus obtd. The amt. of the hydroxy carboxylic acid or its salt or ester to be added is generally 1/10,000-5/100 mole per 1 mole of the ferrous salt. Particularly preferred hydroxy carboxylic acid or salt or ester thereof is hydroxy dicarboxylic acids, its salts, or its esters. |
