偏光显微镜法检测工业矿物粉料中石棉  

Testing of asbestos in industrial minerals powder by polarizing microscope

作　　者：汤晓萍 刘超 韩欣怡 

机构地区：[1]苏州电器科学研究院股份有限公司,江苏苏州215011

出　　处：《冶金分析》2015年第4期44-48,共5页Metallurgical Analysis

摘　　要：采用偏光显微镜法测定了某未知工业矿物粉体样品中的微量石棉纤维。样品通过450℃高温热处理及酸洗过程去除大部分干扰物质,经乙醇分散后均匀沉积在玻璃片上,滴加具有固定折射率的浸渍液制成试片。在正交偏光系统下观察到粉体中存在纤维状颗粒,且纤维呈现四次平行消光特性,干涉色为白色,即具有中等折射率,插入石膏试板后根据纤维在不同象限的颜色判定其具有正延性。单偏光系统下纤维无多色性现象。在离散染色系统下经尝试不同折射率的浸渍液,观察可知纤维的折射率接近1.618 0。综合所有光学性质分析可测定样品中含有少量的透闪石石棉纤维,同时可估算出该种石棉纤维的质量分数约为1%。The content of micro asbestos fiber in one unknown industrial mineral powder sample was deter- mined by polarization microscope. The sample was treated by high-temperature heating at 450℃ followed by acid washing to remove most interference materials. After dispersion with ethanol, the sample was uni- formly deposited on glass sheet to prepare test piece by dripping impregnation liquid with certain refractive index. The fibrous particles were observed in powder under orthogonal polarization system. Moreover, the fibers exhibited the characters of quartic parallel extinction. The interference colors were white, indicating the medium refraction index. After inserting the gypsum test plate, the positive elongation was evaluated according to the color of fibers in different quadrants. The fibers had no pleochroism in plane polarized light system. The impregnation liquid with different refractive indexes was investigated in dispersion stai- ning colours. It was found that the refraction index of fiber was closed to 1. 618 0. The analysis results of optical properties proved that the sample contained little tremolite asbestos fiber. Moreover, the mass fraction of this asbestos fiber was about 1%.

关 键 词：石棉 透闪石 偏光显微镜 工业矿物粉料 

分 类 号：P575[天文地球—矿物学]