硝磷酸脱氟过程中氟离子及金属离子的反应机理研究  

Study on the reaction mechanism of fluorine and metal ions in the defluorination process of nitro-phosphoric acid

作　　者：苏殊 许德华 杨秀山 严正娟 张志业 王辛龙 SU Shu;XU De-hua;YANG Xiu-shan;YAN Zheng-juan;ZHANG Zhi-ye;WANG Xin-long(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：《应用化工》2022年第2期302-306,共5页Applied Chemical Industry

基　　金：国家重点研发计划(2018YFC1900202)。

摘　　要：硝酸法磷酸脱氟制备饲料级磷酸氢钙拓宽了硝酸法磷酸的产品范围,但是目前对脱氟过程中氟离子及金属离子的反应机理还缺乏认识。对含不同金属离子和氟离子组成的模拟硝磷酸溶液进行中和沉淀分析。结果表明,溶液中游离氟和其它离子(SiF_(6)^(2-))解离生成的F^(-)与Ca^(2+)结合生成CaF_(2)沉淀;金属离子Al^(3+)、Fe^(3+)、Mg^(2+)和Ca^(2+)等与磷酸根结合生成AlPO_(4)、Fe_(5)(PO_(4))_(4)(OH)_(3)·2H_(2)O、MgHPO_(4)·0.78H_(2)O和CaHPO_(4)·2H_(2)O等磷酸盐沉淀,在此过程中生成的磷酸氢钙在不同溶液中有不同形貌。The preparation of feed grade dicalcium phosphate from defluorinated wet process phosphoric acid by nitric acid process widens the product range,but the reaction mechanism of fluoride and metal ions in defluorination process is still lack of understanding.The precipitates generated from neutralizing simulated nitro-phosphoric acid solution containing different metal and fluorine ions are characterized.The results show that the free fluorine ion and that formed by dissociating other ions(SiF_(6)^(2-))combine with Ca^(2+)to form CaF_(2)precipitate;the metal ions of Al^(3+),Fe^(3+),Mg^(2+)and Ca^(2+)combine with phosphate to form AlPO_(4),Fe_(5)(PO_(4))_(4)(OH)_(3)·2H_(2)O,MgHPO_(4)·0.78 H_(2)O and CaHPO_(4)·2H_(2)O.The results show that the morphology of calcium hydrogen phosphate crystals is different in different solutions.

关 键 词：硝酸法 湿法磷酸 脱氟机理 金属离子 

分 类 号：TQ124.3[化学工程—无机化工]