Research Progress of Phosphogypsum-based Backfill Technology

Phosphogypsum-based backfill is an important way for bulk solid waste disposal and safe and efficient mining of phosphorus mines, which responds to the national development strategy of ecological civilization construction, meets the requirements of sustainable development of green mines, and has a broad application prospect. This paper systematically analyzes the material properties of phosphogypsum and filling preparation process, filling performance, filling pollution risk and control: (1) Bibliometric analysis of phosphogypsum-based backfill, introduces the output of research results in the field and the related policy dynamics; (2) Collated the chemical composition and physical properties of phosphogypsum from different regional sources both at home and abroad, analyzed the types of cementitious materials and the range of theoretical optimal stoichiometric composition. The factors influencing the rheological and mechanical properties of phosphogypsum-based backfill and the evolution mechanism are described. (3) The potential risk of environmental pollution by phosphogypsum was analyzed, and the existing pretreatment technology of phosphogypsum and the immobilization mechanism of toxic elements were summarized; (4) The future research was prospected according to three aspects: pretreatment technology, targeting materials, and in-situ monitoring.