超细地质样品的谱学特征及矿物分布形态研究

Study on Spectral Characteristics and Mineral Morphological Distribution of Ultra-fine Geological Samples

地质样品粒度已成为制约提高分析精度的关键因素,近年来超细地质样品的制备已越来越多地受到地质分析实验室关注,目前仍广泛采用74μm的地质样品粒度水平已越来越不能满足高精度、高灵敏度、小取样量和微区现代分析技术的要求,迫切需要发展适应地质实验室批量生产的超细地质样品制备技术。采用X射线粉晶衍射、扫描电子显微镜、差热分析等测试技术获得了地质样品超细化前后的谱学特征、并对超细地质样品中矿物分布形态进行研究。结果表明:超细加工使矿物结晶度降低,晶体产生晶胞畸变;矿物粒度分布主要集中于0.5~30μm,随矿物粒径减小,颗粒棱角逐渐消失,颗粒边界变模糊;矿物超细化后脱吸附水的热效应范围变宽,吸热效应变宽缓;矿物在超细地质样品中有单颗粒、集合体、团聚、包裹四种分布形态,影响地质样品超细化程度的主要因素是不易粉碎的矿物单颗粒和矿物集合体。基本查明了超细地质样品的谱学特征和矿物形态分布特点,为改进超细地质样品制备工艺和开发先进制备技术提供科学依据,对解决地质样品超细化均质性问题,提高地质样品分析准确性具有重要意义。

The grain size of geological samples has become a key factor restricting the improvement of analytical accuracy.In recent years,the preparation of ultra-fine geological samples has been paid more and more attention by geological analysis laboratories.Currently,widely used geological samples with grain size of 74μm are increasingly unable to meet the requirements of high precision,high sensitivity,small sampling volume and micro-area modern analysis technology.Therefore,it is necessary to develop the preparation technology of ultra-fine geological samples suitable for mass production in geological laboratories.X-ray powder diffraction,scanning electron microscopy and differential thermal analysis were used to obtain the spectral characteristics of the geological samples before and after the ultra-fine,and the distribution and morphology of minerals in the ultra-fine geological samples were studied.The results showed that ultrafine processing leaded to a decrease in the crystallinity of minerals and distortion of crystal cells.The particle size distribution of minerals was mainly concentrated between 0.5 and 30μm.As the particle size decreased,the edges and corners of mineral particles gradually disappeared,and the particle boundaries became blurred.After the mineral was ultrafine,the thermal effect range of losing adsorbed water became wider,and the endothermic effect became wider and slower.In ultrafine geological samples,minerals had four distribution forms:single particle,aggregate,aggregation,and encapsulation.The main factors affecting their ultrafine degree were the difficult to crush mineral single particles and mineral aggregates.This study basically identified the spectral characteristics and mineral morphology distribution characteristics of ultra-fine geological samples,which can provide scientific basis for improving the preparation process of ultra-fine geological samples and developing advanced preparation technology,and is also of great significance for solving the homogeneity problem of ultra-fine geological samples and improving the accuracy of geological sample analysis.