Method for manufacture of iron oxide flakes
AssigneeAgency of Industrial Science & Technology, Ministry of International Trade & Industry
InventorsKazuaki Ado, Soichiro Nobuoka, Takashi Asai
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Abstract
In the manufacture of iron oxide flakes by the steps of mixing an aqueous ferric salt solution with an aqueous alkali solution for thereby inducing an amorphous precipitate and subjecting the precipitate to a hydrothermal treatment, iron oxide flakes of an increased flake size are obtained by adding boric acid or a salt thereof to the mixture prior to the step of hydrothermal treatment.
Claims4
In a method for the manufacture of micaceous .alpha.-iron oxide by the steps of mixing an aqueous ferric salt solution with an aqueous alkali solution thereby producing an amorphous precipitate and subjecting the precipitate to a hydrothermal treatment at a temperature of more than 150.degree. C. under pressure of more than 5 kg/cm.sup.2, the improvement which comprises the step of adding boric acid or a salt thereof in an amount of 0.1 to 10% by weight, based on the ferric salt computed as an anhydride, prior to the hydrothermal treatment.
Dependencies are inferred from the claim text.