NEUTRALIZAÇÃO DO FOSFOGESSO COM CAL E A SUA INFLUÊNCIA NA HIDRATAÇÃO E NO DESEMPENHO MECÂNICO DE MATRIZES CIMENTÍCIAS

Abstract

Phosphogypsum has the potential to be used as setting retarder for Portland cement, however P2O5 and F- in its composition delay cement hydration and reduce the mechanical performance of the matrix in the early ages. The objective of this study was to evaluate a simple process of neutralization (removal of impurities) of phosphogypsum through the mixture with hydrated lime. Cements were made with gypsum, phosphogypsum, and neutralized phosphogypsum. ICP-OES, isothermal calorimetry, and compressive strength tests were performed. It was observed that neutralization with lime reduced the concentration of impurities, reducing the delay in hydration and increasing the initial mechanical strengths.