X射线粉晶衍射基体清洗法在矿物定量分析中的应用

THE APPLICATION AND RESEARCH OF X-RAY POWDER DIFFRACTION MATRIX FLUSHING METHOD IN QUANTITATIVE ANALYSIS

为了消除层状硅酸盐矿物择优取向对检测结果的影响,本次X射线粉晶衍射定量分析采用基体清洗法,引入刚玉作为清洗剂,用滑石和绿泥石纯样品分别与刚玉以1∶1的比例配制成参比样,测试参比样中刚玉、滑石、绿泥石的主衍射峰强度值,根据参比强度公式计算出滑石、绿泥石的参比强度.再把刚玉与定值样(滑石和绿泥石混合样)按1∶1的比例配制成待测样,测试待测样中刚玉、滑石、绿泥石的主衍射峰强度值,把所得数据代入基体清洗法计算公式,剔除离散数据,计算出定值样中滑石的含量为81.5%,绿泥石的含量为14.6%;用EVA全谱拟合矿物半定量分析方法测试定值样中滑石的含量为92.9%,绿泥石的含量为5.8%.通过定值样中全岩化学分析铝元素含量换算,定值样中绿泥石的含量应在13%左右,接近基体清洗法的绿泥石矿物定值,与EVA全谱拟合矿物半定量分析方法绿泥石矿物定值相差较大.实验结果表明:利用基体冲洗分析混合物相中层状硅酸盐矿物含量是比较准确的.

In order to eliminate the influence of preferential orientation of layered silicate minerals on the detection results,matrix flushing method is adopted in X-ray powder diffraction quantitative analysis. Corundum is added as a flushing agent. Pure samples of talc and chlorite are used as references,with a ratio of 1 ∶ 1 to the corundum. The reference diffraction intensities of corundum,talc and chlorite are measured to calculate the reference strength of talc and chlorite by the reference strength formula. Then the corundum and the definite sample（talc and chlorite mixture）are prepared in the ratio of 1 ∶ 1 to test the main diffraction peak intensity values of corundum,talc and chlorite.Discarding discrete data,the contents of talc and chlorite are 81.5% and 14.6%,respectively. By EVA semiquantitative analysis,the contents of talc and chlorite are 92.9% and 5.8%,respectively. The content of chlorite in the definite sample is about 13%,which is close to the definite value of chlorite by the matrix flushing method,but with great difference to that by semi-quantitative analysis. The results show that the analysis of matrix silicate mineral content in the mixture phase by matrix washing is accurate.