Abstract
A simple preprocessing method to allow the analysis of the fluoride content of gypsum is proposed for use in gypsum board recycling. The perchloric acid distillation method is well established as a method to quantify the fluoride content of gypsum. However, this method is a long, complex operation using hazardous chemicals. As an alternative, we propose a simple preprocessing method, using cationic and anionic ion exchange resins to allow the analysis of the fluoride content of gypsum using a commercially available kit based on the Lanthanum-Alizarin complexone (La-ALC) method. This preprocessing technique results in greatly increased solubility of calcium sulfate coupled with the separation of fluoride contaminants for quantitative analysis. This makes the determination of fluoride in gypsum by the La-ALC method possible because the preprocessing process does not remove the fluoride ionic species. This method is proposed as a suitable technique for on-site fluoride analysis.
