离子交换分离-电感耦合等离子体原子发射光谱法测定锰矿中铊

锰矿用盐酸、硝酸、氢氟酸和高氯酸溶解,以氢氧化钠溶液调整试液酸度至pH 1.7~2.0,用溴水氧化Tl(Ⅰ)为Tl(Ⅲ),过D401离子交换树脂柱,经0.015 mol/L硝酸淋洗后,用2mL 3g/L亚硫酸溶液还原柱上的Tl(Ⅲ)为Tl(Ⅰ),再用0.015 mol/L硝酸洗出Tl(Ⅰ),选择Tl 190.857nm为分析谱线,电感耦合等离子体原子发射光谱法(ICP-AES)测定分离后溶液中的铊。方法中铊的检出限为1ng/mL,测定下限为0.8μg/g。干扰试验结果表明,测定0.1μg/mL铊,不大于50μg/mL铁、2μg/mL锰、10μg/mL铝、镉、铬、镍、铅、锌不干扰。一般锰矿样品按实验方法分离和测定,铁、锰、铝、镉、铬、镍、铅、锌不影响铊的测定。按照实验方法测定锰矿样品中的铊,测定结果的相对标准偏差(RSD,n=8)在1.6%~11%之间,加标回收率为90%~108%。

Determination of thallium in manganese ore by inductively coupled plasma atomic emission spectrometry afterion exchange separation

The manganese ore was dissolved with hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid. The pH of sample solution was adjusted to 1.7-2.0 with sodium hydroxide solution. The Tl(Ⅰ) in solution was oxidized to Tl(Ⅲ) with bromine water. After D401 ion exchange resin column and elution with 0.015 mol/L of nitric acid, the Tl(Ⅲ) on column was reduced to Tl(Ⅰ) with 2 mL of 3 g/L sulfurous acid solution. Then, the Tl(Ⅰ) was eluted with 0.015 mol/L nitric acid solution. The Tl 190.857 nm was selected as the analytical line. The content of thallium in solution after separation was determined by inductively coupled plasma atomic emission spectrometry. The detection limit of method was 1 ng/mL, and the lower determination limit was 0.8 μg/g. The interference test results showed that tolerant amount of co-existing ions for 0.1 μg/mL of thallium was listed as following (in μg/mL): iron (50); manganese (2); aluminum, cadmium, chromium, nickel, lead and zinc (10). The general manganese ore samples were separated and determined according to the experimental method. The iron, manganese, aluminum, cadmium, chromium, nickel, lead and zinc did not interfere with the determination of thallium. The thallium in manganese ore sample was determined according to the experimental method. The relative standard deviations (RSD, n=8) of determination results were between 1.6% and 11%, and the recoveries of standard addition were between 90% and 108%.