Preparation of No Burning Building Materials by Phosphogypsum Heat Treatment

This is an article in the field of ceramics and composites. Phosphogypsum has a large discharge and low utilization rate,and resource utilization is imminent. The heat treatment of phosphogypsum under different temperatures was studied. The influence of heat treatment temperature on the physical phase and microstructure of phosphogypsum, and the compressive strength, phase and microstructure of non burningsample of building materials by the treated phosphogypsum were studied. The results show that with the increase of heat treatment temperature, the crystallinity of gypsum increases and the crystal form changes. After heat treatment at 80 ℃, the crystal of gypsum is dense, and part of it is converted into hemihydrate gypsum. The Gypsum dihydrate formed by hydration recrystallization of hemihydrate gypsum fills the void, forming the internal microstructure of dense and mutual bonding of crystals, so the compressive strength of no burning building materials is greatly improved. After curing for 7 days and 28 days, the compressive strength of non burningsample (the mass ratio of phosphogypsum to cement is 4∶1) reaches 36.45 MPa and 38.12 MPa. The compressive strength of the sample soaked in water for 24 hours is still 21.03 MPa.