COMPREHENSIVE UTILIZATION OF PHOSPHOGYPSUM: ADSORPTION OF METHYLENE BLUE AND ITS APPLICATION IN BRICKS

In this work, comprehensive utilization of phosphogypsum was developed. Methylene blue (MB) in aqueous solution was adsorbed by waste phosphogypsum (PG), and then the MB-adsorbed PG was used to the fabrication of PG bricks. The adsorption mechanism and the strength of PG bricks also have been studied. The dye maximum capacity of PG monolayer adsorption was found to be 0.2[Formula: see text]mg/g. The kinetic behavior is more accordant with the intra-particle diffusion equation. The MB-adsorbed PG could be effectively used as a raw material for building material. The mechanical properties of PG bricks were little different from the one of the water-washed PG bricks. The 2h-flexural and compressing strengths were about 2.8[Formula: see text]MPa and 6[Formula: see text]MPa, the dry-flexural and compressing strengths were about 5[Formula: see text]MPa and 20[Formula: see text]MPa.