Comprehensive Properties and Application of Phosphogypsum Cement Composite Gangue

ObjectiveIn order to improve the applicability of gangue in filling mining, phosphogypsum and cement composite gangue was prepared. MethodTests were conducted to analyze the effects of the content of phosphogypsum and gangue on the comprehensive performance indexes such as slurry fluidity, dry shrinkage rate, mechanical properties and permeability, etc.. The hydration mechanism was discussed using mineral composition and microscopic image results. The application effect of the material in coal mine engineering is also evaluated. ResultThe addition of phosphogypsum increased the slump of slurry, decreased the bleeding rate, and decreased the drying shrinkage index. When the dosage is 15%, the compressive strength, flexural strength and permeability indexes of phosphogypsum cement compound gangue are the best. The chemical activity of phosphogypsum can promote the secondary hydration of cement, increase the density of slurry, and improve the indexes of gangue. ConclusionIn practical application, filling mining with phosphogypsum cement composite gangue can not only realize comprehensive utilization of solid waste and phosphogypsum in coal mining, but also bring remarkable economic benefits.