磷石膏的综合利用对保护环境、促进企业可持续健康发展具有重要意义,但是磷石膏中的磷、氟、二氧化硅等杂质影响其利用。针对云南磷石膏中二氧化硅含量高的问题,采用正浮选工艺开展了磷石膏提质降杂的实验研究。通过单因素条件实验获得了合适的工艺参数：浮选温度为15 ℃、矿浆pH为2、十二胺用量为300 g/t。在此条件下,进行了“一粗二精”的正浮选开路流程实验,获得了二水石膏（CaSO₄·2H₂O）质量分数为97.5%、二氧化硅质量分数为1.17%的精矿,所得精矿达到了GB/T 23456—2018《磷石膏》一级品指标的要求;二水石膏回收率为98.58%、二氧化硅去除率为92.23%。通过正浮选不仅成功实现了二水石膏和二氧化硅的有效分离,而且磷石膏中的水溶磷和水溶氟也得到了有效去除,从而提高了磷石膏的品质。

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.