选择印尼苏拉威西岛Kolonodale和中国云南元江两处红土型镍矿床中的硅酸盐型镍矿石作为研究对象, 利用X射线衍射和傅里叶红外吸收光谱分析技术, 系统对比研究了不同产地红土型镍矿石的矿物学属性。 研究结果表明, 不同类型的硅酸盐型红土镍矿石各自显示出独特的红外光谱特征, 这有助于指导对该类型矿石进行分类。 其中, 印尼Kolonodale矿床的硅酸盐型红土镍矿石可细分为蛇纹石类、 蒙脱石+蛇纹石类和硅镁镍矿类等三种不同类型, 中国元江矿床的硅酸盐型红土镍矿石可细分为蛇纹石类和滑石+蛇纹石类等两种类型, 且元江镍矿石中矿物结晶度普遍优于印尼镍矿石。 利用红外吸收光谱在区分矿物多型方面的优势, 明确了利蛇纹石是两个矿床中蛇纹石类红土镍矿石的主要矿物类型, 而未发现纤蛇纹石和叶蛇纹石存在的明显证据。 红外吸收光谱特征还指示, 矿石中蛇纹石类载镍矿物在OH摆动带的频率发生变化能指示Ni(Fe)对Mg的类质同象置换。 随着Ni(Fe)对Mg置换比例的增大, 蛇纹石矿物中的OH摆动带向高频移动。

The silicate nickel ores developed in the lateritic nickel deposit, from Kolonodale, Sulawesi Island, Indonesia, and Yuanjiang, Yunnan province, China, were selected for the present study. The X-ray diffraction and Fourier infrared spectra were used to analyze the mineralogical attribute of laterite nickel ores from two different places. The results show that these two different silicate nickel ores have unique infrared spectra characteristics individually, which contributes to the ore classification. The silicate nickel ores from Kolonodale deposit, Indonesia, can be classified as the serpentine type, the montmorillonite+serpentine type, and the garnierite type. While, the silicate nickel ores from Yuanjiang deposit, China, can be classified as the serpentine type and the talc+serpentine type. Moreover, the mineral crystallinity of Yuanjiang nickel ores is generally better than Kolonodale nickel ores. According to the advantage of infrared absorption spectra in distinguishing mineral polytypes, it can be determined that lizardite is the main mineral type in the silicate nickel ores of the two deposits, and there is no obvious evidence of chrysotile and antigorite’s existence. The characteristic of infrared absorption spectra also shows that frequency change of OH libration indicates Ni (Fe) replacing Mg in the serpentine type nickel-bearing mineral, that is, OH libration of serpentine moves to higher frequency, with the proportion of Ni (Fe) replacing Mg increasing.