氢氧化钠熔融-超声辅助-水蒸气蒸馏-离子色谱法测定高硅银精矿中氟和氯

直接采用水蒸气蒸馏-离子色谱法测定高硅银精矿中氟和氯时,样品中的硫以硫化氢气体形式溢出,对操作人员的身体健康不利,同时高硅银精矿不能完全消解导致氟和氯测定结果偏低。为解决上述问题,实验提出了氢氧化钠熔融-超声辅助-水蒸气蒸馏-离子色谱法测定高硅银精矿中氟和氯。先使用氢氧化钠高温熔融样品,再放置于热水中结合超声技术浸出熔块及残渣中氟和氯,然后采用水蒸气蒸馏的方法将氟和氯有效蒸出,再通过离子色谱法测定。对熔样方式、超声时间、熔融温度、熔融时间、接收液体积、色谱洗脱时间等进行了优化。结果表明,在优化的实验条件下,氟和氯的校准曲线线性相关系数分别为0.9998和0.9992;方法检出限分别为0.002%(质量分数)和0.005%(质量分数)。按照实验方法测定高硅银精矿中氟和氯,测定结果的相对标准偏差(RSD,n=6)为1.5%~4.3%;加标回收率为95%~105%。采用高温水解法进行方法比对,结果表明两种方法的测定结果基本一致。

Determination of fluoride and chloride in high-silicon silver concentrates by ion chromatography with sodium hydroxide fusion-ultrasound assisted-steam distillation

During the direct determination of fluorine and chlorine in high-silicon silver concentrates by ion chromatography with steam distillation, the sulfur in sample will be spilled in the form of hydrogen sulfide gas, which is harmful for the operator′s health. Meanwhile, the determination results of fluorine and chlorine would be lower due to the incomplete digestion of high-silicon silver concentrate samples. In order to solve this problem, the determination of fluorine and chlorine in high-silicon silver concentrates by ion chromatography with sodium hydroxide fusion-ultrasound assisted-steam distillation was proposed. The sample was melted at high temperature with sodium hydroxide and then transferred into hot water. The fluorine and chlorine in melt and residue were leached by combining with ultrasonic technology. Then, the fluorine and chlorine were effectively evaporated by steam distillation, and finally determined by ion chromatography. The methods of sample fusion, ultrasonic time, fusion temperature, fusion time, volume of receptor fluid, and chromatographic elution time were optimized. The results showed that the linear correlation coefficients of fluoride and chlorine were 0.9998 and 0.9992 under the optimized experimental conditions, respectively. The limit of detection was 0.002% and 0.005%, respectively. The contents of fluoride and chlorine in high-silicon silver concentrate were determined according to the experimental method, and the relative standard deviations (RSD, n=6) of determination results were between 1.5% and 4.3%. The spiked recoveries were between 95% and 105%. The proposed method was compared with the pyrohydrolysis method. The results showed that the measured results of two methods were basically consistent.