Determination of barium in tungsten concentrate by inductively coupled plasma atomic emission spectrometry with alkali fusion
Tungsten concentrate is an important raw material of tungsten products.Barium in tungsten con-centrate could form insoluble precipitate with tungsten,so the content of barium will directly affect the quality and yield of tungsten products.0.500 0 g of sample was weighed and transferred into a silver cruci-ble containing 2 g of anhydrous sodium carbonate,then covered with 1 g of sodium hydroxide,1 g of sodi-um peroxide and 0.1 g of strontium chloride.The mixture was melted at 700 ℃ for 15 min.After water leaching and filtration,the residue was dissolved with nitric acid and perchloric acid.Consequently,a method for determination of barium in tungsten concentrate was established by inductively coupled plasma atomic emission spectrometry(ICP-AES)with Ba 455.40 nm as analytical line.The results showed that the mass concentration of barium in range of 0.5-10.0 μg/mL had a linear relationship with its correspond-ing emission intensity,and the linear correlation coefficient was greater than 0.999 9.The coexisting ele-ments such as iron,calcium,magnesium,manganese and nickel in tungsten concentrate did not interfere with the determination of barium.The limit of detection and the limit of quantification was 0.000 78%and 0.002 6%,respectively.The contents of barium in tungsten concentrate samples were determined accord-ing to the proposed method.The relative standard deviations(RSD,n=11)of determination results were between 1.4%and 1.6%,and the recoveries were between 92%and 105%.The proposed method was used in 8 laboratories for determination of barium in tungsten concentrate samples.The results of statisti-cal data analysis showed that its precision could meet the requirements of product testing,and a national standard method was formed for promotion.