埋孤自动焊及电渣焊用熔剂(简称熔剂)中,氟化钙的测定是比较麻烦的,往往不易测准。我们曾用氟氯化铅-硝酸银容量法和硝酸钍容量法,但都要先经过碳酸钠熔融,测出氟的含量后再换算成氟化钙。由于熔融不透,沉淀条件掌握不好,以及洗涤不完全,对氟氯化铅-硝酸银容量法来说,会得到偏高或偏低的结果。如果氧化铝含量高,必须进行分离,否则对硝酸钍容量法来说,也会得到偏低结果。我们也作过蒸馏法使氟成氟硅酸蒸出,然后用硝酸钍滴定。但是为 Buried Solitary Welding and Electroslag Welding flux (referred to as flux), the determination of calcium fluoride is more troublesome, often difficult to align. We have used lead chlorofluoride - silver nitrate volumetric method and thorium nitrate volumetric method, but have to go through sodium carbonate melting, measuring the content of fluorine and then converted into calcium fluoride. Insufficient melt penetration, poor settling conditions, and incomplete washing lead to high or low results for the lead chlorofluoride-silver nitrate volumetric method. If the alumina content is high, it must be separated, otherwise the thorium nitrate capacity method, it will get low results. We also made the distillation of fluorine into fluorosilicic acid, and then titrated with thorium nitrate. But for