| 摘要 |
PROBLEM TO BE SOLVED: To provide iron oxide particles which have high dispersibility and excellent environment stability. SOLUTION: The iron oxide particles are characterized in that the surface of each particle is covered with a multiple iron oxide layer containing calcium and phosphorus. The iron oxide particles are produced by adding/mixing a ferrous salt aqueous solution containing a water-soluble phosphorous compound and an alkali aqueous solution to a slurry of iron oxide core particles in a state that calcium ions are present, and then subjecting the resulting mixture to wet oxidation while adjusting the pH value to 8-13 so that the multiple iron oxide layer containing calcium and phosphorus is formed on the surface of each core particle. COPYRIGHT: (C)2006,JPO&NCIPI
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