Abstract：Phosphogypsum is a by-product of the phosphate fertilizer industry. If it is stored for a long time, it will cause environmental pollution. To achieve high-value utilization, this paper uses phosphogypsum as the sulfate excitation source, combines steel slag and mineral powder to prepare a full-waste-triple-component super sulfate cement, and systematically evaluates its mechanical properties, dry shrinkage behavior, hydration products, microstructure, environmental safety and carbon emission levels. Seven sets experiments are configured using the simple centroid design method, and mechanical, dry shrinkage, XRD, SEM, leaching toxicity and carbon emission tests are carried out. The results show that when the phosphogypsum content is 20%~25%, the steel slag content is 15%~20%, and the mineral powder content is 60%~65%, the 28-day compressive strength is more than 45 MPa, the dry shrinkage strain is controlled within 1 300~1 500 με, which exhibits good mechanical and volume stability. XRD and SEM reveal that under the optimized ratio, a large amount of calcium aluminosilicate and C-(A)-S-H are formed, which significantly densifies the microstructure. The supersulfated cement system can effectively solidify F-, PO3- 4 and other ions, which meets the GB 8978—1996 standard, demonstrating environmental friendliness. The carbon emission is minimized to 35 kg/t, reducing by 95.6% compared to Portland cement, demonstrating significant low-carbon advantages
2025, Vol. 0 
