熔融制样-波长色散X射线荧光光谱法测定铜精矿中主次成分

针对铜精矿熔融制样时硫含量高带来的问题,实验以四硼酸锂-偏硼酸锂(m∶m=12∶22)为熔剂,碳酸钠、二氧化硅和硝酸锂为助剂,建立了同时测定铜精矿中铜、硫、铁、锌、铝、镁、钙、铅和锰等主次成分含量的熔融制样-波长色散X射线荧光光谱法。通过研究不同氧化剂、助剂配方,熔融温度和时间对固硫和制片效率的影响,选定称量0.1g样品,6.9g四硼酸锂-偏硼酸锂混合熔剂(m∶m=12∶22),1.06g碳酸钠,0.38g二氧化硅,1.38g硝酸锂的熔剂配比和熔融介质条件,从室温升至600℃预氧化15min后,在960℃熔融5~8min制得玻璃熔片,经重量法和X射线荧光光谱法检测,硫回收率达到99%以上。采用有证标准物质和高纯度氧化铜混合配制出合适含量梯度的校准样品,经测量计算后校准曲线线性关系良好,线性相关系数(R²)达到0.999;通过标准物质验证及方法间比对,结果表明实验方法测定值与认定值相对偏差在0.43%~6.9%,对同一样品的检测结果与传统方法基本一致,可以满足铜精矿的快速检测要求。

Determination of major and minor component in copper concentrate by wavelength dispersive X-ray fluorescence spectrometry with fusion sample preparation

The sulfur content was high in fusion sample preparation of copper concentrate. To solve this problem, lithium tetraborate-lithium metaborate (m∶m=12∶22) was used as flux, and sodium carbonate, silicon dioxide and lithium nitrate were used as auxiliary. The simultaneous determination method of major and minor components (copper, sulfur, iron, zinc, aluminum, magnesium, calcium, lead and manganese) in copper concentrate by wavelength dispersive X-ray fluorescence spectrometry after fusion sample preparation was established. The effects of oxidizer, auxiliary formula, fusion temperature and time on sulfur fixation and sample preparation efficiency were investigated. The experimental conditions were as follows: 0.1g of sample, 6.9g of lithium tetraborate-lithium metaborate (m∶m=12∶22), 1.06g of sodium carbonate, 0.38g of silicon dioxide, and 1.38g of lithium nitrate. The temperature was increased from room temperature to 600℃ followed by pre-oxidization for 15min. The sample was prepared by fusion at 960℃ for 5-8min and then determined by gravimetric method and X-ray fluorescence spectrometry. The recovery of sulfur was higher than 99%. The calibration samples with proper content gradient were prepared using certified reference material and high-purity copper oxide. The linearity of calibration curves was good with correlation coefficient (R²) reach 0.999. The standard substance verification and method comparison indicated that the relative deviation between determination values and certified values was 0.43%-6.9%. The determination results of same sample were basically consistent with those obtained by conventional method. The proposed method could meet the rapid detection requirements of copper concentrate samples.