Research status and progress of hydrophobic modification of phosphogypsum
Phosphogypsum(PG)is a solid waste discharged in the production of wet-process phosphoric acid.Nearly 5 tons of phosphogypsum will be discharged for every ton of wet-process phosphoric acid produced.Phosphogypsum surface is hydrophilic,and it is prone to melt creep effect in high humidity environment or after contacting with water,which has a negative impact on mechanical properties and limits its application in building materials field.In this paper,three methods for preparing hydrophobic phosphogypsum-based materials are comprehensively reviewed:surface hydrophobic coating,internal hydrophobic agent and organic/inorganic composite.By comparing the advantages and disadvantages of each method,it is found that organic/inorganic composite can improve the hydrophobicity and mechanical properties of phosphogypsum-based materials as a whole.