高压密闭酸溶-电感耦合等离子体原子发射光谱法测定锑矿石中10种元素

Determination of 10 Elements in Antimony Ore by Inductively Coupled Plasma Atom Emission Spectrometry with Sealed Acid Digestion at High Pressure

采用高压密闭酸溶溶解锑矿石,用电感耦合等离子体原子发射光谱法(ICP-AES)测定锑矿石中As、Sb、Al、Fe、Ca、Mg、K、Na、Ti、Mn等10种元素的含量。在装有0.10 g样品的消解内罐中依次加入体积比为3∶1的盐酸-硝酸混合溶液1 mL和氢氟酸2 mL,在150℃烘箱中保温24 h。取出内罐,在电热板上以150℃蒸发至近干。加入体积比为3∶1的盐酸-硝酸混合溶液0.5 mL再次蒸发至干,此步骤重复一次。加入体积比为1∶3∶4的硝酸-盐酸-水混合溶液5 mL,在烘箱中130℃加热3 h。用体积比为1∶3∶36的硝酸-盐酸-水混合溶液定容至100 mL,按照优化的ICP-AES仪器工作条件测定。结果显示:10种元素的质量浓度均在一定范围内与其对应光谱响应值呈线性关系,检出限(3s)为1.98~77.20μg·g-1;按照试验方法分析4种标准物质,所得相对误差为-2.8%~10%;对2种标准物质平行测定12次,测定值的相对标准偏差(RSD)为0.25%~6.6%。

Sealed acid digestion at high pressure was used to decompose antimony ore, and the contents of 10 elements, including arsenic, antimony, aluminum, iron, calcium, magnesium, potassium, sodium, titanium and manganese in antimony ore were determined by inductively coupled plasma atom emission spectrometry(ICP-AES). Mixed solution(1 mL) consisted of hydrochloric acid-nitric acid with volume ratio of 3∶1 and 2 mL of hydrofluoric acid were added into the digestion inner tank containing 0.10 g sample, and the mixture was heated at 150 ℃ for 24 h in the oven. The inner tank was taken out and the mixture was evaporated to near-dryness at 150 ℃ on the electric hot plate. Mixed solution(0.5 mL) consisted of hydrochloric acid-nitric acid with volume ratio of 3∶1 was added and the mixture was evaporated to near-dryness again, and the operation was repeated once more. Mixed solution(5 mL) consisted of nitric acid-hydrochloric acid-water with volume ratio of 1∶3∶4 was added and the mixture was heated in a 130 ℃ oven for 3 h. The volume of the sample solution obtained was made up to 100 mL by mixed solution consisted of nitric acid-hydrochloric acid-water with volume ratio of 1∶3∶36, and the content of target elements were determined at the optimized ICP-AES instrument working conditions. The results showed that the mass concentrations of the 10 elements were linearly related to their corresponding spectral response values within certain ranges, with detection limits(3s) in the range of 1.98-77.20 μg·g-1. Four reference materials were analyzed by the prescribed method, giving relative errors ranged from-2.8% to 10%;two reference materials were analyzed 12 times in parallel, with RSDs of the determined values in the range of 0.25%-6.6%.