自动电位滴定法测定锑矿石中锑

Determination of total antimony in antimony ores with an automatic potentiometric titration method

建立了自动电位滴定法测定锑矿石样品中锑含量,确定了相关滴定参数和等当点识别标准。该方法用H2SO4-K2SO4分解样品,用硫酸肼将样品中的Sb（Ⅴ）还原为Sb（Ⅲ）,以硫酸铈为滴定剂,滴定反应在HCl介质中进行。用该方法对3种锑矿石标准样品GBW07280,GBW07279和GBW07176进行连续5次测定,相对标准偏差范围为0.40%-0.84%;并且用于5种铁含量较高的锑矿石样品中锑含量的测定,回收率在96.1%-102%。本法适用于1.80%以上锑含量的测定。与手动滴定法相比,该方法不受样品溶液颜色限制,锑含量为33 mg/L时,铁含量超过1.40 g/L也不干扰测定,解决了手动滴定使用甲基橙指示剂判定终点难的问题,有推广价值。

It can save a 10t of manpower to useautomatic potentiometric titrator instead of manual titration, and thus greatly improve the analysis efficiency. In this paper, a method for the determination of antimony content in antimony mines with automatic potentiometric titration was developed. The related titration parameters and the equivalence point identification standards were identified. In this method, H2SO4-K2SO4 was used to samples decompose , and H4N2·H2SO4 to reduce antimony（V） to antimony（ Iii）, and Ce（ SQ ） 2 as a titrant. The titration reactions were carried out in hydrochloric acid. Five GBW07279 and GBW07176 standard samples showed 0. 84%. The method was applied to the determination times of determination of antimony on GBW07280, relative standard deviations varying from 0. 40% to of antimony in two samples with high iron, and the recoveries were 96. 1% - 102%. The method is suitable for the detection of antimony above 1.80%. Compared with manual titration, the method was not limited by colour of sample solution, so it was not interfered by 1.40 g/L iron, and solved the problem to determinate titration end-point with methyl orange in manual titration.