The comprehensive utilization of phosphogypsum has important implications for protecting the environment and pro-moting the sustainable development of enterprises.Phosphogypsum utilization is affected by impurities such as phosphorus,fluorine and silicon dioxide in phosphogypsum.In order to solve the problem of high silicon dioxide content in phosphogypsum from Yunnan,the experimental study on improving quality and reducing impurity of phosphogypsum was carried out by using direct flotation process.Through the single factor condition test,the suitable process conditions were as following: the flotation temperature was 15 ℃,pH of pulp was 2.0,dodecylamine was as the collector with a dosage of 300 g/t.By adopting the opencircuit flotation flowsheet of one-stage roughing and two-stage cleaning,a concentrate product containing 97.50% of CaSO₄·2H₂O and 1.17% of SiO₂ was obtained,and it reached the first grade requirements of the national standard GB/T 23456—2018 pho-sphogypsum.The recovery of CaSO₄·2H₂O and removal of SiO₂ were 98.58% and 92.23% respectively.The effective separation of CaSO₄·2H₂O and SiO₂ was successfully achieved by direct flotation.Simultaneously,the water-soluble phosphorus and the water-soluble fluorine in phosphogypsum were also effectively removed.Thus the quality of phosphogypsum was improved.