The present study conducted to investigate the potential use of PG in cement industry. This was accomplished by preparing mortar mixes contain Portland cement clinker (PPC) with thermally treated PG at different temperatures (200, 400, 600, 800 and 1000 °C) instead of raw gypsum (RG) at different proportions. The characteristics of prepared mortars were investigated after curing in water for different periods (3, 7, 28 and 90 days) by determination of setting time, compressive strength, bulk density, and total porosity. The hydration kinetics was evaluated by determination of free lime and chemically combined water contents. FTIR spectroscopic analysis was used to investigate the change in structure of some mortars after curing. The change in morphology and microstructure of hardened pastes was investigated using scanning electron microscopy (SEM). The results approved the possibility for the utilization of treated PG at 800 and 1000 °C instead of raw gypsum in cement industry.

Within approximately 50 years, 1.0 × 108 tons of Phosphogypsum have already been produced and collected. Nearly 85 percent PG byproduct has been stored, only15 percent has been reprocessed. Lowering disposal of waste materials offers both environmental and economic advantages. Physical and chemical characteristics of Blast furnace slag cement after partial and full replacing of raw gypsum with samples prepared from BFSC-PG at various temperatures (200–1000°C) are formed by blending different proportions with PG have been studied. The results validated the application of calcined Phosphogypsum at 800 and 1000 degrees Celsius rather than raw gypsum in cement manufacturing.

Micrographs of mixes (PPV) contain thermally treatment PG at 600 o C after 3(a), 28 (b) and 90 (c) days curing