Heat stable yellow iron oxides
AssigneeTitan Kogyo Kabushiki Kaisha
InventorsJihei Senda, Yoshihiro Inoue, Toshiaki Uenishi, Hidefumi Harada, Kouji Nakata, Akio Akagi
Life of this patent
Estimating the term…
Abstract
Synthetic yellow iron oxide (.alpha.-FeOOH) is dispersed in an aqueous ferric solution, and an adequate alkali solution and an aqueous aluminum salt solution are added. The resultant dispersion is subjected to a hydrothermal treatment at 150.degree.-250.degree. C. By this treatment, the surface of the synthetic yellow iron oxide is covered with a (FeAl)OOH (solid solution). Yellow iron oxides treated thus have an elevated resistivity to heat of about 50.degree. C. The modified synthetic yellow iron oxide thus obtained is non-toxic and can be used as a pigment in plastics and melt-type traffic paint.
Claims7
A method of preparing a yellow iron oxide having improved heat stability, comprising the steps of:
- (a) forming an aqueous slurry of yellow iron oxide (.alpha.-FeOOH), ferric sulfate, an alkali-metal hydroxide, and sodium aluminate,
- (b) subjecting the resultant mixture to hydrothermal treatment,
- (c) separating the treated mixture into a solid phase and a liquid phase, and
- (d) recovering the solid phase, consisting essentially of yellow iron oxide having at least a partial coating of (FeAl)OOH solid solution.
A method of preparing FeAl(OOH), comprising the steps of:
- (a) forming an aqueous slurry of ferric sulfate and an alkali metal hydroxide,
- (b) curing the slurry, until .alpha.-FeOOH seeds are formed,
- (c) adding sodium aluminate to the cured slurry,
- (d) subjecting the resultant slurry to hydrothermal treatment, and
- (e) separating the treated slurry into a solid phase and a liquid phase, with the solid phase consisting essentially of solid solution (FeAl)OOH.
A composition of .alpha.-FeOOH having at least a partial film or coating of (FeAl)OOH solid solution.
The solid solution of the compound (FeAl)OOH.
Dependencies are inferred from the claim text.