Mitsui Toatsu Chemicals, Incorporated

Haruo Sekiguchi

Nobuhiro Fukuda

Kazushi Ohshima

Sadao Kobayashi

Kimiteru Tagawa

Kazuhiro Imaoka

Fujio Hayashi

Kazufuyu Sudoh

Mitsuro Matsunaga

Disclosed herein is a process for producing ferromagnetic iron powder, which process comprises adding and mixing boron oxide or a borate with .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 without dissolving the former, heating the thus-obtained mixture to 350.degree. C. or higher in a non-reducing atmosphere and then reducing the thus-heated mixture.

Production process of ferromagnetic iron powder

Disclosed herein is a process for producing ferromagnetic iron powder, which process comprises adding and mixing zinc borate with .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 without dissolving the former, heating the thus-obtained mixture to 350.degree. C. or higher in a non-reducing atmosphere and then reducing the thus-heated mixture.

Disclosed is a process for preparing fine needle-like, ferromagnetic iron compound particles for use in magnetic recording in which needle-like iron oxyhydroxide fine particles prepared by simultaneously co-precipitating or cladding iron compound particles with an element of group II of the Periodic Table and manganese at atomic weight ratios of the element of group II of the Periodic Table and manganese to iron of from 0.001/100 to 10/100 and 0.005/100 to 10/100 respectively are reduced and/or oxidized under heating.

Process for preparing iron compound particles for use in magnetic

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Chigasaki, Japan

Haruo Sekiguchi