摘要
提供了一种用于滑石粉中石棉检测和确证分析的振筛富集样品预处理方法.对经X射线衍射法检测含有疑似石棉的滑石粉样品,比较了325目和400目标准筛的振筛法富集倍数;通过电子显微镜法和偏光显微镜法比较了富集前后石棉纤维的定性观察结果.结果表明,在低放大倍数下（30～200倍）直接观察滑石粉原样,很难在视野范围内找到纤维状物质,而400目振筛上残留物中的石棉纤维在最低的放大倍数30倍时即清晰可辨;在放大倍数400倍以上,滑石粉原样通过调节观察位置在视野范围内能搜寻到几个纤维状石棉物质,而同放大倍数的400目振筛上残留物中的石棉纤维满视野,因此振筛富集技术可以显著提高滑石粉中石棉显微镜观察的准确性和可靠性.比较了未经研磨和研磨后富集前后样品（原样、筛上及筛下样品）中石棉类矿物的X射线衍射谱图,结果表明,富集前后样品中石棉类矿物的相对衍射强度即石棉类矿物的含量无明显变化.因此,振筛富集法仅可用于滑石粉中石棉的定性确证分析,不能用于定量或半定量分析.
A sample pretreatment method of sieve-vibrating enrichment for the determination and identification analysis of asbestos in talc powder was proposed.The talc powder sample,which contains suspected asbestos,was detected by X-ray diffraction.The sieve-vibrating enrichment factor of standard sieve （325-mesh and 400-mesh） was compared.The qualitative observation results of asbestos fiber before and after the enrichment were compared by electron microscope and polarizing optical microscope.The results showed that,the fiber materials were hardly found in view area if the original talcum powder sample was directly observed with low magnification （30-200）.However,the asbestos fiber in residue on 400-mesh sieve could be clearly observed even in the lowest magnification （× 30）.When the magnification factor was higher than 400,several fiber materials in original talcum powder sample could be found in view area by adjusting the observation position,which was similar to that of asbestos fiber in residue on 400-mesh sieve.Therefore,the sieve-vibrating enrichment technology could significantly improve the observation accuracy and reliability of asbestos in talcum powder by microscope.The X-ray diffraction patterns of asbestos minerals in samples before and after enrichment （original sample,the sample on the standard sieve and the sample passing the standard sieve）and grinding were compared.The results showed that,the relative diffraction intensity of asbestos minerals in samples before and after enrichment,i.e.,the content of asbestos minerals showed no obvious change.Therefore,sieve-vibrating enrichment could be only used for the qualitative identification analysis of asbestos in talc powder,but not be used for quantitative or semi-quantitative analysis.
出处
《冶金分析》
CAS
CSCD
北大核心
2013年第10期12-18,共7页
Metallurgical Analysis
基金
辽宁出入境检验检疫局科研项目(LK28-2009)
关键词
振筛富集法
滑石粉
石棉
the sieve-vibrating enrichiment
talc powder
asbestos
