| 摘要 |
Powd. goethite, for the manuf. of magnetic recording tapes, was made by oxidn. of an Fe hydroxide suspension obtained by reaction of aq. solns. of alkali metal hydroxides and Fe salts. Thus, 392g KOH in 800mg H2O was mixed with a soln. of 279g Fecl24H2O in 400ml H20. After blowing 3th with N2 at 80≦̸C, the resulting colloidal Fe oxide was blown 4.5hr with air at 80≦̸C to give 120g 0.5μ long yellow goethite particles of acicularity 20, and oxidized for l hr by air at 230≦̸C to give powd. goethite.
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