Simultaneous determination of fluorine, chlorine and bromine in cement with ion chromatography after pyrolysis.

A rapid method for simultaneous determination of fluorine, chlorine and bromine in cement with ion chromatography after pyrolysis was proposed for routine quality control analysis. The elements were separated from cement sample by pyrolysis, and were subsequently determined with ion chromatography. A pyrolysis method was investigated for the separation of micro amounts of these elements from cement. Total time taken to determine these elements is about 45 min including 25 min for the pyrolysis and 18 min for ion chromatography. The results of recovery tests ranged 95% or above. The limits of detection for F, Cl and Br are 0.2, 0.3 and 0.5 mg kg(-1), respectively. The method was successfully applied to the simultaneous determination of F, Cl and Br in commercial ordinary Portland cements.

Differences of fluorine in cements determined by photometric methods after distillation and pyrolysis.

Using a spectrophotometric method after distillation separation is a standard test method widely employed for the determination of fluorine (F) in cement. Using a flow injection (FI) method after pyrolysis separation for quantification of fluorine in cement has recently been developed. Differences between the fluorine content values obtained by each method have been noted. This paper documents the differences between fluorine content (distillation F) measured spectrophotometrically after distillation and that (pyrolysis F) determined using the FI method after pyrolysis for fourteen commercial Portland cements and identifies a factor contributing to the differences between distillation F and pyrolysis F values. A highly significant relationship existed between distillation F and pyrolysis F values for fourteen cements (r(2) = 0.998, p < 0.001).