Can phosphogypsum utilization in China be sustainable? An integrated life cycle environmental and economic evaluation

Phosphogypsum (PG), as the major solid waste from the phosphate chemical industry, has become a significant challenge due to its massive annual generation-approximately 70-80 million tonnes in China. Although there are several utilization approaches, determining the best available approach remains highly controversial. Based on field investigations to collect foreground data, this study combines life cycle assessment and economic evaluation methods to examine and compare four typical PG utilization and disposal pathways. Results show that PG stockpiling disposal causes serious burdens in all six impact categories, whereas cement retarder route achieves the largest environmental benefits, with net reductions of up to 2.1 t CO₂ eq per tonne of PG. Gypsum products provide the highest profitability among the utilization routes. Environmental monetization analysis indicates that both gypsum products and cement retarders are promising options, generating profits of 8.0 (±5.5) USD and 23.0 (±0.4) USD per tonne, respectively, compared to a cost of 40.0 (±6.0) USD per tonne for the stockpiling disposal. These findings highlight the necessity of integrating environmental and economic assessments to support sustainable PG management strategies and provide actionable insights for industry and policymakers.