Abstract：The content of calcium fluoride in fluorite was the most important index to evaluate its quality level, so the determination method of calcium fluoride in fluorite had attracted much attention. The content of total calcium in sample was determined by EDTA titration, and a kind of determination method of calcium carbonate in sample was proposed. Then the content of calcium fluoride in fluorite could be calculated based on the content of total calcium and calcium carbonate. Two samples with different mass were leached with certain amount of calcium chloride-hydrochloric acid solution. The pH of solution was adjusted to about 7 with phenolphthalein as indicator. Then the two sample solutions was diluted to the same volume. After placing for a period of time, the dissolution of calcium fluoride reached the equilibrium. At this time, the content of dissolved calcium fluoride as well as reagent blank in the two solutions was the same. After dry filtration, the mass difference of total calcium (in calcium carbonate) in the two solutions was determined by EDTA titration. This difference was the mass of calcium carbonate contained in the difference of sampling mass. The proposed method was applied for the determination of total calcium, calcium carbonate and calcium fluoride in certified reference materials and production samples of fluorite. The determination results of total calcium were consistent with the certified values of certified reference materials or those obtained by standard method GB/T 5195.1-2006. The relative standard deviations (RSD, n=5) were between 0.11% and 0.23%. The determination results of calcium carbonate were consistent with the certified values of certified reference materials or those obtained by standard method GB/T 5195.2-2006. The RSDs (n=5) were between 4.9% and 7.6% for the sample with calcium carbonate mass fraction not lower than 0.30%, and the RSDs (n=5) were between 12.6% and 28.1% for the sample with calcium carbonate mass fraction lower than 0.30%. The determination results of calcium fluoride were basically consistent with the certified values of certified reference materials or those calculated by the found of the above two standard method. The relative error was not more than 0.40%.
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