Simulating experimental study of phosphate and fluoride on the influence of phosphogypsum properties and microstructure

In this paper, phosphate and fluoride were added into the gypsum, respectively, to simulate phosphate and fluoride in the phosphogypsum. The affect of adding different impurities on setting time, compressive strength, and bulk density were inspected by simulation experiments. The pore structure of hardened gypsum was analyzed by mercury intrusion porosimetry, and the micromorphology of hardened gypsum was observed by scanning electric micrograph in sequence to get the influencing rule of different impurities and its contents on the performance and micromorphology of phosphogypsum. The results indicate that phosphate prolongs the setting time, while the fluoride shortens it. Meanwhile, the strength gets lower because of the coarsening crystal resulting from the phosphate and fluoride. CE Database subject headings: Phosphate; Fluoridation; Simulation; Microstructure; Gypsum.