PURPOSE: To obtain the title α-iron oxyhydroxide having an excelent acicular form keeping property even in a reduction stage and capable of coping with the ferromagnetic particles having a desired magnetic characteristic by supplying an aluminum or silicon compd. in the oxidation process of ferrous hydroxide.
CONSTITUTION: An aq. soln. of a ferrous salt is allowed to react with an aq. soln. of an alkali metal hydroxide to obtain a suspension of ferrous hydroxide, and an oxygen-contg. gas is supplied to the suspension while adding an aq. soln. of an aluminum compd. and/or a silicon compd. to the suspension. A water- soluble compd. such as AlCl3, Al2(SO4)3, and NaAlO2 is preferably used as the aluminum compd., and a water-soluble compd. such as Na2SiO3 or Na2Si2O5 is preferably used as the silicon compd. The aq. solns. of an aluminum compd. and a silicon compd. can be continuously or intermittently added while supplying an oxygen-contg. gas.
| JPS63291820 | PRODUCTION OF HIGH-PURITY IRON OXIDE POWDER |
| JP5755176 | Contact and adsorbent granules |
KAWASHIMA KOICHI
OKAI MICHIJI
KUBO TOMIYOSHI
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