Simultaneous phosphogypsum recycling and CO2 mineralization: A potentially recyclable indirect mineralization route to high‑purity nano‑calcium carbonate

Phosphogypsum (PG) can cause severe water pollution and ecological risks. In this study, we developed a sustainable chemistry process that can simultaneously address PG pollution and carbon dioxide (CO 2 ) sequestration by integrating precise reaction control with advanced tail-end wastewater treatment. Through a secondary leaching process, over 99% of the active calcium ions in PG were efficiently recovered. Subsequent carbonation yielded high-purity nano-calcium carbonate (nano-CaCO 3 ), achieving a calcium utilization efficiency exceeding 99%. The synthesized nano-CaCO 3 exhibited a high purity of 97.18% with an average particle size of 72.05 ± 12.31 nm. This sustainable chemical strategy establishes a sustainable and scalable approach for reducing PG stock and capturing low-CO 2 -content industrial flue gas, followed by mineralization, demonstrating significant potential for practical PG disposal and high-value nano-CaCO 3 production. The commercialization of this process could serve as a viable reference for large-scale PG consumption, offering a promising solution for global PG management and carbon emission mitigation.