关键词: 无机非金属材料;石膏;三氧化硫;容量法

Abstract: The gravimetric method is a classical method for the determination of sulfur trioxide ( SO3) in gypsum, and it has high accuracy and wide range of application.However, it is not suitablefor a large number of testing tasks and field test due to the low efficiency.In this study, the sulfate ion was precipitated with excess solution of barium chloride, and then the remaining barium chloride solution was titrated by EDTA instantly.In this way, the content of SO3 was obtained indirectly.Compared with the gravimetric method, the absolute error of the volumetric method is less than 1%, and the relative error can be kept below 0.5%.Therefore, this method can enhance the determination speed of SO3 in gypsum without the interference of other factors.The developed method is simple and reliable, and provides an ideal method for determinationof SO3 in Gypsum .

Key words: inorganic non-metal material;gypsum;sulphur trioxide;volumetric method