Mitsui Minings & Melting Co., Ltd.

Masahiro Miwa

Masachika Hashiuchi

Takeshi Miyazono

Hiroyuki Shimamura

Iron oxide particles having the surface thereof coated with a layer of a complex iron oxide containing Al and Mg are disclosed. The total content of Al and Mg in the complex iron oxide layer is 0.1 to 2.5% by weight based on the whole iron oxide particles. The Mg content in the complex iron oxide layer is 0.05 to 1% by weight based on the whole iron oxide particles. The Al content in the complex iron oxide layer is 0.05 to 1.7% by weight based on the whole iron oxide particles. The Mg content in the complex iron oxide layer is 20% or more based on the total Mg content of the whole iron oxide particles.

Iron oxide particles and method for production thereof

Magnetite particles continuously contain a total amount of 0.2 to 1.2 wt. %, based on magnetite, of a silicon component and an aluminum component expressed as silicon and aluminum, in a region ranging from the center to the surface of the particle, a total amount of 0.01 to 0.5 wt. % of the silicon component and the aluminum component, expressed as silicon and aluminum, being exposed on the surface of the particle, and an outer shell of the particle being coated with a metal compound comprising at least one metal component bound to the silicon component and the aluminum component, the metal component being selected from the group consisting of Zn, Mn, Cu, Ni, Co, Cr, Cd, Zr, Sn, Mg, Ti, Ce, W and Mo and a process for their preparation.

Magnetite particles and process for production thereof

Magnetite particles continuously containing 0.2 to 1.0 wt. %, based on magnetite, of a silicon component expressed as silicon, in a region ranging from the center to the surface of the particle; 0.01 to 0.3 wt. % of the silicon component being exposed on the surface of the particle; and an outer shell of the particle being coated with a metal compound comprising at least one metal component bound to the silicon component, the metal component being selected from the group consisting of Zn, Mn, Cu, Ni, Co, Cr, Cd, Al, Sn, Mg, Ti and Ce, and a process for preparing the particles.

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Tamano, Japan

Masahiro Miwa