粉末压片-X射线荧光光谱法测定过磷酸钙中硫含量

Determination of Sulfur Content in Superphosphate by X-ray Fluorescence Spectrometry with Powder Compression

硫是过磷酸钙中重要营养指标之一,为准确快速测定过磷酸钙中硫的含量,将过磷酸钙试样充分干燥后研磨至粒度小于74μm,采用硼酸镶边,在压力18 MPa条件下保压30 s,制成样片。通过在过磷酸钙样品中添加不同质量的纯物质硫酸钙(质量分数1.52%~17.21%),经过专用混匀设备混合均匀后,与试样压片相同条件下压制标准样片,作为过磷酸钙中硫的标准样品,制作硫标准曲线,曲线线性相关系数R 2为0.9995,采用经验系数法校正干扰,建立了粉末压片-波长色散X射线荧光光谱法测定过磷酸钙中硫含量的方法,方法检出限为0.002%;对3个不同硫含量的过磷酸钙样品重复测量7次,相对标准偏差(RSD)在1.4%~3.1%,方法精密度较好;同时用高温燃烧红外光谱法和电感耦合等离子发射光谱法测定样品,将测定结果进行对比,三者测定结果相对极差小于2.0%,无显著性差异。方法不需要对样品进行熔融或溶解,样品制备简单,数据准确度和稳定性好,分析效率高,适合于大批量样品中硫的测定。

Sulfur is one of the important nutritional indicators in superphosphate.In order to determine the sulfur content in superphosphate accurately and quickly,the superphosphate sample was fully dried and ground to a particle size of less than 74μm.Using boric acid edging and maintaining pressure for 30 seconds under a pressure of 18 MPa,a sample was prepared.By adding different masses of pure substance calcium sulfate(mass fraction ranged from 1.52% to 17.21%)to the superphosphate sample,mixing it evenly with a dedicated mixing equipment,and pressing the standard sample under the same conditions as the sample compression,the sulfur standard curve was established as the standard sample for sulfur in superphosphate.The linear correlation coefficient R 2 of the curve was 0.9995,and the interference was corrected using the empirical coefficient method.A method for the determination of sulfur content in superphosphate by powder compression wavelength dispersive X-ray fluorescence spectrometry had been established,with a detection limit of 0.002%.This experimental method was repeated 7 times for three samples of superphosphate with different sulfur contents,with RSD ranging from 1.4% to 3.1%.The precision of the method was good.At the same time,high-temperature combustion infrared spectroscopy and inductively coupled plasma emission spectroscopy were compared,and the relative range of the measurement results was less than 2.0%.There was no significant difference in the measurement results.This method does not require melting or dissolution of the sample.The sample preparation is simple,with good data accuracy and stability,high analytical efficiency,and is suitable for the determination of sulfur in large batches of samples.