电感耦合等离子体发射光谱法应用于锑矿石化学物相分析

锑矿石化学物相分析涉及三个矿物相:锑华、辉锑矿和难溶锑酸盐,不同锑矿物相提取的溶剂不同、共存离子复杂、浓度梯度差别大,这些因素影响了电感耦合等离子体发射光谱法(ICP-OES)对锑化学物相的准确测定。本文以锑华、辉锑矿和锑酸盐的选择分离溶剂为研究对象,测试了盐酸、硝酸和硫酸钾-硝酸-硫酸不同介质对ICP-OES测定锑的影响。结果表明:同浓度的盐酸和硝酸介质对锑的测定没有影响,锑华和辉锑矿中锑含量的测定可使用同一标准溶液系列,盐酸或硝酸的浓度控制在15%～20%可避免锑的水解;混合酸介质(4g/L硫酸钾-15%硝酸-3%硫酸)对锑的测定有影响,可采用基体匹配方法解决,在测定锑酸盐相锑含量时,锑校准溶液的配制加入锑酸盐浸出剂相同量的混合酸。选择206.833nm谱线作为分析线,在优化的分析方法流程和测定参数条件下,锑华、辉锑矿和锑酸盐中锑的检出限分别为0.0006%、0.0012%和0.0021%;对不同浓度原生矿和氧化矿12次分析,测定值的相对标准偏差(n=12)为0.16%～5.76%,相态加和与全量的相对偏差绝对值为0.07%～7.38%。本方法精密度和准确度满足锑矿石化学物相分析的质量控制要求,解决了锑矿石化学物相快速准确的测量问题。

Determination of Antimony Content in Antimony Ores by Inductively Coupled Plasma-Optical Emission Spectrometry

BACKGROUND:Chemical phase analysis of antimony ores involves three mineral phases:valentinite, stibnite and insoluble antimonate. Solvents used for extracting various antimony mineral phases are different. In addition, coexisting ions are complex and concentration gradients vary greatly. These factors affect the accurate determination of antimony chemical phases by inductively coupled plasma-optical emission spectrometry (ICP-OES).
OBJECTIVES:To solve the problem during rapid and accurate measurement of chemical phases of antimony ore.
METHODS:The effects of hydrochloric acid, nitric acid and potassium sulfate-nitric acid-sulfuric acid on the determination of antimony by ICP-OES were studied with valentinite, stibnite and antimonate as selective separation solvents.
RESULTS:The same concentration of hydrochloric acid and nitric acid medium had no effect on the determination of antimony. The same standard solution series can be used to determine antimony in valentinite and stibnite. Hydrolysis of antimony can be avoided by using 15%-20% hydrochloric acid or nitric acid of. Mixed acid medium (4g/L potassium sulfate-15% nitric acid-3% sulfuric acid) had an effect on the determination of antimony. The matrix matching method can be used to solve the problem. In determining the amount of antimony in antimonate, the calibrated solution was formulated to add the same amount of mixed acid as the antimonate leaching agent. The detection limits of antimony in valentinite, stibnite and antimonate mineral phases by ICP-OES were 0.0006%, 0.0012% and 0.0021%, respectively, by choosing the 206.833nm line as the analytical line, under optimized analytical method flow and measurement parameters. The relative standard deviations (n=12) of the method were 0.16%-5.76%, and the absolute relative deviations of phase addition and total amount were 0.07%-7.38%.
CONCLUSIONS:The precision and accuracy of the method meet the quality control requirements of antimony ore chemical phase analysis, and provide fast and accurate measurement of antimony ore chemical phase.