THE EFFECT OF ADDITION OF REFINED PHOPSPHOGYPSUM ON THE PROPERTIES OF CEMENT

Phosphogypsum is considered as the major byproduct in phosphoric acid production (wet-process). In recent years various methods for refining and utilizing this product in industry is suggested. In this research, phosphogypsum was manufactured out of domestic Apatite earth. The product went through two washing stages. The optimum washing time was proved to be 10 minutes. After washing, the product was exposed to heating process with different temperatures between 200 c◦ to 1000 c◦ . Heating time was 1 hour. The final product was applied in producing blended gypsum and that was used as a cement additive. The best result for the blended gypsum was gained when 40% two-stage-washed phosphogypsum and 60% natural gypsum were used and total gypsum consumption was estimated 3.4%. This product improved the bending strength of the produced cement.

کلیدواژه ها:

Bending strength ، Blended gypsum ، Cement ، Phosphogypsum ، Setting time