Abstract: The large−scale stockpiling of phosphogypsum poses a significant environmental challenge, mainly due to its high impurity content and low whiteness, which critically limit its potential for high−value applications. This study investigated phosphogypsum from a plant in Hubei Province, integrating process mineralogy with graded flotation for efficient purification. The results showed that the use of hydrochloric acid, water glass, collector ZX−4−4 and frother Q1 in a closed circuit flotation process − consisting of one rougher flotation, two cleaner flotations and a sequential middle return−significantly improved the quality of the material. Specifically, the CaSO₄−2H₂O content of the phosphogypsum was increased from 89.65% to 98.15%, while the whiteness improved from 37.10% to 52.44%. The overall recovery rate reached 83.47% with a significant reduction in impurities: silica content decreased from 6.16% to 0.58% and iron content was minimized to 0.0062%. The whiteness of the β−hemihydrate gypsum produced by direct calcination of the purified phosphogypsum exceeded 80%, significantly exceeding the first grade specifications of the national standard GB/T 23456−2018 for phosphogypsum. Thus, the flotation process significantly improved both the quality of the phosphogypsum and the performance of the derived products.