Objective Determination of silicon dioxide in fluorite by alkali fusion-molybdenum blue spectrophotometry.Methods The method is melted with potassium hydroxide,extracted with water and acidified with sulfuric acid,then,in a weak acidic solution,silicic acid and ammonium molybdate form soluble yellow silicomolybdic heteropoly acids,to improve acidity,reduce silicomolybdate yellow to silicomolybdate blue by reducing agent,the absorbance was measured at 700 nm and the silicon dioxide content was measured.A large number of fluoride interference,the addition of aluminum salt to eliminate.Results Determination of silicon dioxide in fluorite by alkali fusion-molybdenum blue spectrophotometry,the silicon dioxide has good calibration curve linearity,the linear regression equation is Y=0.34733ρ+0.00228,the correlation coefficient was 0.999;the precision of the method is less than 1.5%,the accuracy was measured with the national reference materials,and the relative standard deviation(RSD)was less than 2% .Conclusion It was found that the precision and accuracy of this method for the determination of silicon dioxide in fluorite samples were satisfactory and met the requirements of relevant standards.
fluoritesilicon dioxidepotassium hydroxidemolybdenum blue spectrophotometer
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