| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a particle not intentionally containing an element to be added to an environment, having high electric resistance, slight aggregating of powder, improved dispersibility and handleability, preventing deterioration of FeO and reduction in blackness and having stability by making the particle have an electric resistance of a specific value or higher than it and not include an element on and after a specific atomic number. SOLUTION: This iron oxide particle requires >=1×104Ω.cm electric resistance. The iron oxide particle contains no element of an atomic number on and after 21 except Fe. Especially the lower content of transition metal is preferable so as to suppress a load to an environment. The iron oxide particle has a coated layer consisting essentially of Fe3+ as a metal component and <=50% degree of aggregation. The shape of the iron oxide particle is a hydroxide, oxide, etc. The content of Fe3+ in the coated layer is preferably 0.1-10 wt.% based on the total of iron oxide particle. The iron oxide particle is produced by neutralizing and mixing an aqueous solution of ferrous salt with an aqueous solution of an alkali to give a slurry, adding an aqueous solution of Fe3+ to the slurry and adjusting the slurry to pH >=2.</p> |
