Phosphogypsum is a waste by-product of the phosphate fertilizer industry, which is usually disposed in the environment because of its restricted use in industrial applications. The aim of this study is to reduce this environmental risk by producing calcium fluoride and sodium sulphate from phosphogypsum and sodium fluoride. To optimize this reaction, many factors have been considered such as temperature, reaction time, NaF/phosphogypsum molar ratio, stirring speed, reagents adding mode and phosphogypsum mass. The obtained results have shown that the NaF/phosphogypsum molar ratio, the reaction time and the phosphogypsum mass were the most influential parameters. Optimal conversion conditions were obtained with the NaF/phosphogypsum ratio between 1.5 and 2, at an average reaction time between 30 minutes and 120 minutes and at room temperature. In these conditions, the results are very satisfactory, in terms of quantity and quality of the obtained CaF2 and Na2SO4 , the conversion rate has exceeded 95%.
H. Douahem, H. Hammi, A.H. Hamzaoui, A. M’Nif
phosphogypsum, calcium fluoride, conversion, conditions