Phosphogypsum Utilization in Road Construction Becomes an Effective Path for Large-Scale Resource Recycling

Phosphogypsum is a solid by-product discharged during the wet-process phosphoric acid production, with calcium sulfate dihydrate (CaSO₄·2H₂O) as its main component. Due to the presence of soluble phosphorus and various harmful impurities, raw phosphogypsum cannot be directly utilized.

Currently, the comprehensive utilization of phosphogypsum mainly includes applications such as a cement retarder, manufacturing of gypsum boards and blocks for construction, soil conditioner, and road base material. Among these, using phosphogypsum in road construction has the advantages of large consumption and high utilization efficiency, making it one of the most effective pathways for resource recycling.

For every kilometer of road constructed, about 10,000 tons of phosphogypsum can be consumed, replacing 30%–50% of crushed stone and reducing overall construction costs by 10%–15%. In the Yunnan Chuxiong–Yao’an Expressway test section, 4,500 tons of phosphogypsum were used, and after two years of operation, no cracks or mud pumping were observed. The heavy metal leaching levels remained below national standards, achieving large-scale, safe, and high-value utilization of industrial solid waste.