磷酸活化磷尾矿制取聚合态钙镁磷肥的工艺条件研究

为减少磷尾矿对环境的损害,采用高温分子间脱水聚合的方法,对利用磷尾矿合成聚合态钙镁磷肥做了研究。将磷酸和磷尾矿按照物质的量比n（P₂O₅）∶n（CaO+MgO）]为1∶（1.2~1.8）进行混合反应,将反应的料浆在250~600 ℃下煅烧1~5 h得到干基的产品。产品检测结果表明,聚合态钙镁磷肥的聚合度为1~4,P₂O₅的聚合率在80%以上,总P₂O₅质量分数为50%~60%,CaO质量分数为17%左右,MgO质量分数为12%左右,产品结构为多孔隙的球状结构。该产品可以根据不同地区的需要灵活调整原料配比,以得到不同性质的产品。该研究已经在中试装置中进行试生产,正式生产车间目前正在中国贵州建设,目标产能为20万t/a。

Study on technological conditions of polymeric calcium magnesium phosphate fertilizer from phosphoric acid activated phosphate tailings

In order to reduce the environmental damage caused by phosphorus tailings,the synthesis of polymeric calcium magnesium phosphate fertilizer from phosphorus tailings by high temperature intermolecular dehydration polymerization was studied.Phosphoric acid and phosphorus tailings were mixed at the amount-of-substance ratio of P₂O₅ to（CaO+MgO） of 1∶（1.2~1.8）,and the slurry was calcined at 250~600 ℃ for 1~5 h to obtain dry-base products.The results showed that the degree of polymerization of polymeric calcium magnesium phosphate fertilizer was 1~4,the polymerization rate of P₂O₅ was more than 80%,the total P₂O₅ was 50%~60%（mass fraction）,the mass fraction of CaO was about 17%,the mass fraction of MgO was about 12%,and the product structure was porous spherical structure.The product can be flexibly adjusted according to the needs of different regions to obtain products of different properties.The research has been put into trial production in pilot plant,and the formal production workshop is currently being constructed in Guizhou,China,with a target capacity of 200 kt/a.