Determination of magnesium oxide in rare earth magnesium ferrosiliconalloy by inductively coupled plasma atomic emission spectrometry afterleaching with potassium dichromate solution
LIU Xiao-jie1, 2, HAO Qian1, 2, JIN Si-qingaowa1, 2
1. Baotou Research Institute of Rare Earths, Baotou 014030, China; 2.National Engineering Centre of Rare Earth Metallurgy and Function Materials, Baotou 014030, China
Abstract：A method for the determination of magnesium oxide in rare earth magnesium ferrosilicon alloy was established. 40 g/L potassium dichromate solution was used as the leaching agent for magnesium oxide. The sample was shaken for 30 min at room temperature and filtered. One of three spectral lines 279.553 nm, 280.270 nm and 285.213 nm was selected as the analytical line, and under the optimized instrument parameters, inductively coupled plasma atomic emission spectrometry (ICP-AES) was employed for the determination of magnesium oxide in the filtrate. The method’s detection limits (mass fraction) were 0.003 0 % for 279.553 nm, 0.002 7 % for 280.270 nm and 0.004 3 % for 285.213 nm. The limits of quantitation (mass fraction) were 0.030 % for 279.553 nm, 0.027 % for 280.270 nm and 0.043 % for 285.213 nm. The maximum allowances (μg/mL) of iron, potassium, chromium and rare earths were 150, 2 000, 6 000 and 200 respectively, and the matrix effect produced by 2 g/L potassium dichromate in the sample solution on the determination was negligible. The method was applied to the determination of magnesium oxide in actual samples, the measured values were consistent with those obtained by atomic absorption spectrometry, and the relative standard deviation of the determination results were less than 5%.
