硝酸法磷酸脱氟工艺研究  

Study on defluorination of phosphoric acid by nitric acid process

作　　者：苏殊 许德华 李朝荣 杨秀山 王辛龙 张志业 Su Shu;Xu Dehua;Li Chaorong;Yang Xiushan;Wang Xinlong;Zhang Zhiye(Ministry of Education Research Center for Comprehensive Utilization and Clean Processing Engineering of Phosphorus Resources,College of Chemical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学化学工程学院,教育部磷资源综合利用与清洁加工工程研究中心,四川成都610065

出　　处：《无机盐工业》2021年第9期24-29,共6页Inorganic Chemicals Industry

基　　金：国家重点研发计划(2018YFC1900202)。

摘　　要：针对以硝酸法湿法磷酸直接制备饲料级磷酸氢钙存在磷氟比(五氧化二磷与氟的质量比)较低的问题,采用化学沉淀法,以钙盐作为脱氟剂,通过间歇实验考察了反应时间、反应温度、反应pH、酸解液中五氧化二磷和氧化钙浓度等因素对酸解液中磷沉淀率和磷氟比的影响。结果表明,反应时间和反应温度的变化对溶液的磷沉淀率和磷氟比影响不大,而降低五氧化二磷和氧化钙的浓度能够有效地提高溶液的磷氟比、降低磷沉淀率。通过对比脱氟溶液制备饲料级磷酸氢钙的收益变化可得出较优操作条件:反应温度为40℃,反应时间为20 min,酸解液中五氧化二磷质量分数为7.6%、氧化钙质量分数为3.4%,钙盐中和溶液pH为2.4。在此条件下,脱氟溶液的磷氟比达到230以上、磷损失率小于30%,可为后续饲料级磷酸氢钙的制备提供合格的原料。In view of the problem that the m(P_(2)O_(5))/m(F)of dicalcium phosphate prepared from wet process phosphoric acid by nitric acid method was quite low,the effect of reaction time,reaction temperature,reaction pH,concentration of P_(2)O_(5) and CaO in acidolysis solution on the precipitation rate of P_(2)O_(5) and m(P_(2)O_(5))/m(F)was investigated by batch experiments using chemical precipitation method with calcium salt as defluorination agent.The results showed that the change of reaction time and temperature had little effect on the precipitation rate of P_(2)O_(5) and m(P_(2)O_(5))/m(F)of the solution,but reducing the concen-tration of P_(2)O_(5) and CaO could effectively improve the m(P_(2)O_(5))/m(F)and reduce the precipitation rate of P_(2)O_(5).By comparing the benefits of defluorination solution to prepare feed grade dicalcium phosphate,giving the optimal operation conditions were as follows:reaction temperature was 40℃,reaction time was 20 min,concentration of P_(2)O_(5) and CaO was 7.6%and 3.4%,respectively,and neutralization pH was 2.4%.Under these conditions,the m(P_(2)O_(5))/m(F)was above 230,and the precipitation rate of P_(2)O_(5) was less than 30%,and it could provide qualified raw materials for subsequent preparation of feed grade dicalcium phosphate.

关 键 词：硝酸法 湿法磷酸 沉淀法 脱氟工艺 

分 类 号：TQ126.35[化学工程—无机化工]