Abstract:

Phosphogypsum has poor gelation,which hinders its resource utilization in the field of building materials.By study-ying the phase and microstructure of phosphogypsum after alkali-excited pretreatment,the building materials of high content and high compressive strength were prepared by adding reinforcements.The results showed that the strength of the specimen was greatly improved when the amount of enhancer was 3 mL,its strength of 7,28 d and immersion was 13.75,28.30,17.56 MPa respectively.Compared with the blank sample,the growth rate of strength of 7,28 d and immersion was 62.3%,62.0%,36.8% respectively,and the maximum density of the specimen was 2.42 g/cm³,the water absorption was 11.10%,there was no frosting.Meanwhile,the internal structure of the specimen 28 d specimen was relatively compact,the porosity was small,and the CaSO₄·2H₂O peak strength was low.The CaSO₄·2H₂O main crystal phase structure became weaker and the crystallinity was poor,which was beneficial to improve the strength and compactness of the gypsum specimen and thus optimize the mechanical properties of the non burning building materials.

Key words: phosphogypsum, alkali excitation, enhancer, non-burning building materials, compressive strength