Objective Determination of silicon dioxide in fluorite byalkali fusion-molybdenum blue spectrophotometry. Methods The method ismelted with potassium hydroxide, extracted with water and acidified withsulfuric acid, then, in a weak acidic solution, silicic acid andammonium molybdate form soluble yellow silicomolybdic heteropoly acids,to improve acidity, reduce silicomolybdate yellow to silicomolybdateblue by reducing agent, the absorbance was measured at ${700}\mathrm{\;{nm}}$ and the silicondioxide content was measured. A large number of fluoride interference,the addition of aluminum salt to eliminate. Results Determination ofsilicon dioxide in fluorite by alkali fusion-molybdenum bluespectrophotometry, the silicon dioxide has good calibration curvelinearity, the linear regression equation is $\mathrm{Y}= {0.34733}\mathrm{p}+{0.00228}$ , the correlation coefficient was 0.999; the precisionof the method is less than 1.5%, the accuracy was measured with thenational reference materials, and the relative standard deviation (RSD)was less than 2%. Conclusion It was found that the precision andaccuracy of this method for the determination of silicon dioxide influorite samples were satisfactory and met the requirements of relevantstandards.

fluorite  /  silicon dioxide  /  potassium hydroxide  /  molybdenum blue spectrophotometer