Preparation and properties of phosphogypsum based plastering mortar

Abstract

In order to reduce the negative impact of phosphogypsum accumulation on the environment, this paper uses phosphogypsum, magnesium slag, potassium dihydrogen phosphate, fly ash and calcium carbide slag to prepare gypsum based plaster mortar as a cementing material, and explores the optimal ratio of the composite cementing material through orthogonal experimental design. The mechanical properties of the test block were analyzed by the flexural and compressive strength of the test block, and the slurry properties were evaluated by the initial and final setting time, stability measurement, fluidity test and water resistance test. The experimental results show that when phosphogypsum: potassium magnesium phosphate: fly ash: When titanium gypsum =50:25:20:20, the strength of the composite system can reach 2.98Mpa in 60 days, and the initial setting time is 118min and the final setting time is 223min, which meets the requirements of GB/T25181-2019 building gypsum plaster mortar that the initial and final setting time is greater than 60min and less than 480min. Its fluidity is 237mm, which meets the requirement that the fluidity of GB/T25181-2019 building gypsum plaster mortar is greater than 100mm.