Resource utilization and development of phosphogypsum-based materials in civil engineering

Phosphogypsum (PG), as a by-product of phosphoric acid and a bulk industrial solid waste, has increased sharply due to the development of the phosphorus chemical industry. Because of the increasing serious environmental problems caused by stockpiling of PG, an analysis of its utilization status and development trend in civil engineering is important to improve the PG utilization rate. In this review, the chemical compositions of different PG and pretreatment methods were compared and analyzed firstly. And then, the utilization of PG including cement retarder, building materials, cement raw materials, concrete raw materials, cementitious materials, and fillers and modifiers were summarized. Current review concluded that calcination as a pretreatment method has special advantages, and future work should aim to propose advanced calcination incorporating with the addition of effective admixtures, reduction of calcining temperature, and activation of inert minerals. Moreover, studies have confirmed the feasibility of adopting PG as a retarder, cementitious materials, filler and modifier. Future research is recommended to focus on improving the reactivity and long-term stability. Meanwhile, some new PG-based materials are proposed to promote the large-scale, environment-friendly and resourceful utilization of PG.