新疆喀拉通克铜镍矿贵金属矿物定量研究

QUANTITATIVE STUDY OF PRECIOUS METAL MINERALS OF KALATONGKE Cu-Ni DEPOSIT IN XINJIANG

喀拉通克铜镍矿床产于漏斗状基性岩体中下部的橄榄苏长辉长岩相中,矿石类型分特富铜镍矿石(Ⅰ)、富铜贫镍矿石(Ⅱ)、贫铜贫镍矿石(Ⅲ)及富镍富铜矿石(Ⅳ).由于矿床物质成分复杂特别是金银铂钯矿物颗粒细、品位低、种类多,故首先在进行矿物定性研究的基础上,确定目的矿物的特殊富集流程.然后在人工重砂大样中富集目的矿物,并制成砂光薄片,有代表性的排定视域,引入电子探针—图象分析—计算机联机定量并辅以显微镜定量的综合方法对贵金属元素和矿物进行定量.联机方法是用电子探针以扫描方式提供颗粒电子象和元素X射线面分布象信号给出元素或共存元素的化学信息,对矿物颗粒进行分类,统计出个数及面积百分比.这种方法对微细杂矿物的定量工作颇有成效.

This Cu-Ni deposit occurs in hyperite-gabbro fades of the mid-lower part of mafic rock mass. According to industrial grade, the ores are classified into four types of high-grade Cu-Ni ores ( Ⅰ), Cu-rich and Ni-poor oires (Ⅱ), low-grade ores (Ⅲ) and Ni-rich and Cu-high ores (Ⅳ). Because of complex composition, low content of associated elements of Au, Ag, Pt and Pd, small size of most precious metal grains and hardly determining the optical character of the minerals, the method of determination and quantitative analysis should be chosen in study of its occurrence. The minerals of Au, Ag, Pt and Pd are high in reflectance, large in specific gravity and generally nonmagnetic. Therefore, after qualitative study, the first is to decide the special concentration process of the object minerals and then the large panned sample is treated to separate and concentrate.It is safisfied to solve the quantitative analysis of precious elements and minerals with comprehensive method of combining electron microprobe, image analyzer and computer assisted with microscope on the given field in the special polished thin sections of sand. The average coefficent of elements in the four types of ores are as follows. Au: 99.23%, 106.90%, 95.59%, 105.90%; Ag: 90.83%, 99.19%, 90.65%, 92.54%; Pt: 108.16%, 96.53%, 91.16, 102.65%; Pd: 85.32%, 82.38%, 92.18%, 97.32%. The comprehensive method is getting chemical information of the elements or associated elements by analysis of scanning electron image grains and scanning distribution image of X-ray surface of the elements by electron microprobe and classifying the mineral grains to calculate number, area and area percentage of various-size grains of differant element association. This comprehensive method is successful in quantitative analysis of mixed fine or microscopic mineral grains for mineral research.