湿法磷酸脱氟渣中磷和氟的浸取回收  

Recovery of phosphorus and fluorine in defluorination sludge from wet-process phosphoric acid by leaching

作　　者：张程[1] 钟文婧 纪利俊[1] 陈葵[1] 朱家文[1] ZHANG Cheng;ZHONG Wen-jing;JI Li-jun;CHEN Kui;ZHU Jia-wen(School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化工学院

出　　处：《化学工程》2019年第8期1-5,21,共6页Chemical Engineering(China)

摘　　要：脱氟渣是湿法磷酸在脱氟过程中产生的废渣,其中含有价值的磷、氟。为回收脱氟渣的磷,研究了浸取法分离脱氟渣中磷、氟的工艺。分别以水、碳酸钠溶液作为浸取剂,考察了不同的浸取时间、pH值、温度、液固比及2级浸取条件下,脱氟渣中P2O5、F的浸出率和浸出液的磷氟比(P2O5/F)。结果表明:在水浸取体系,适宜的条件是浸取时间为30min、液固比为2∶1、温度为30℃,P2O5和F的浸出率分别为92.38%、11.56%,浸出液的P2O5/F为9.54;在碱浸取体系,适宜的条件是浸取时间为30min,液固比为3∶1、pH值为3.8、温度为25℃,P2O5和F的浸出率分别为75.68%、1.49%,P2O5/F为61.36;二级浸取能减少浸取剂的用量,并有效地降低F的浸出率。将水浸出液浓缩能有效地提高P2O5/F,可以得到饲料级MCP生产所需的磷酸。Defluorination sludge is the waste generated from the defluorination process of wet-process phosphoric acid;it contains valuable phosphorus and fluorine resources.In order to recycle the phosphorus resources,separation process of phosphorus and fluorine in defluorination sludge by leaching method was studied.The leaching ratio of P2O5 and F in defluorination sludge and the phosphor-fluorine ratio(P2O5/F)of the leaching solution were investigated under different leaching time,pH,temperature and liquid-solid ratio choosing water and sodium carbonate solution as the leaching agents respectively.The results showed that the optimal conditions were as follows:leaching time is 30 min,liquid-solid ratio is 2∶1,temperature is 30℃,the leaching ratio of P2O5 and F are 92.38%and 11.56%respectively,and the P2O5/F of leaching solution is 9.54.For the alkali system,the optimal conditions were determined at leaching time of 30 min,liquid-solid ratio of 3∶1,pH of 3.8,temperature of 25℃,the leaching ratio of P2O5 and F are 75.68%and 1.49%respectively,and the P2O5/F of the leaching solution is 61.36.The two-stage leaching can reduce the amount of leaching agents and the leaching ratio of F.The P2O5/F can be effectively increased by condensing water leaching solution to get the phosphoric acid that required for the feed-grade calcium dihydrogen phosphate(MCP).

关 键 词：湿法磷酸 脱氟渣 浸取 磷氟比 

分 类 号：TQ126.35[化学工程—无机化工]