Abstract: To meet the demands on low CO₂ emission and resource utilization of phosphogypsum, this paper is guided by the academic principle of coupling CO₂ mineralization and phosphogypsum utilization, exploring the reaction of ammonia-strengthened phosphogypsum leaching solution to produce high-purity CaCO₃ in a NH₄Cl-H₂O system. The effects of process parameters on the leaching efficiency of CaSO₄·2H₂O in phosphogypsum were discussed systematically. The crystal phase and morphology of the carbonated product were characterized. The maximum value of dissolved CaSO₄·2H₂O was 0.945 g/100 mL with the mild reaction conditions. Pure spherical vaterite was produced. The content of calcium carbonate in the product was 99.80% and the whiteness of the product was 99.2%, which satisfied HG/T 2226-2010. The product mixed with cubic calcite and spherical vaterite could be formed by adjusting the reaction conditions. A probable reaction process of CaCO₃ production and polymorphism transformation was also proposed through chemical analysis of the liquid-solid-gas reaction. This paper provides a new idea for resource utilization of phosphogypsum and preparation of high purity calcium carbonate.