珪ニッケル鉱石の構成鉱物について-フェロニッケル製錬に関する基礎的研究(第1報)- Constituent Minerals of Siliceous Ni Ores-Fundamental study on Fe-Ni smelting(1st Report)-

The Oheyama plant of Nippon Yakin Kogyo Co., Ltd. produces ferro-nickel granules by the Oheyama Process (the worlds only method for smelting siliceous nickel ores with a rotary kiln) for self-consumption to make finished stainless steels in Kawasaki plant. Siliceous nickel ores imported from New Caledonia, Indonesia and Philippines are composed of various minerals and their chemical compositions largely vary depending on mines as well as working places, which causes smelting operations very vulnerable. Constituent minerals of New Caledonian ores were investigated by X-ray diffraction method to understand the properties of the siliceous nickel ores and the following results were obtained. (1) Main constituent minerals are garnierite, serpentine, goethite and silica. (2) Garnierites are consisted of such types as 7 A°, 10 A°, 14 A° and 12 A° which represent X-ray reflection positions from the base planes of phyllo-silicates, while serpentines are consisted of 7 A° and 14 A°. (3) Ni in the ores is concentrated in phyllo-silicates such as garnierites and serpentines, while Fe is concentrated mainly in laterite ore whose main constituent mineral is goethite. (4) A good relationship between Ni content and crystal structure is observed.