用磷酸铵盐从N235中反萃取铁试验研究  

Stripping of Fe(Ⅲ)From N235 With Ammonium Phosphate

作　　者：李嘉 何德文 张雪凯[3] 赵堃祺 周康根 彭长宏 陈伟[1,2] LI Jia;HE Dewen;ZHANG Xuekai;ZHAO Kunqi;ZHOU Kanggen;PENG Changhong;CHEN Wei(School of Metallurgy and Environment,Central South University,Changsha 410083,China;National Engineering Technology Center for Heavy Metal Pollution Control,Central South University,Changsha 410083,China;School of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083 [2]中南大学国家重金属污染防治工程技术中心,湖南长沙410083 [3]中南大学化学化工学院,湖南长沙410083

出　　处：《湿法冶金》2021年第4期302-309,共8页Hydrometallurgy of China

基　　金：湖南省重点研发计划项目(2018SK2023)。

摘　　要：以溶剂萃取法从赤泥酸浸液中回收铁时,铁的反萃取较为困难。基于叔胺N235反萃取相对容易和铁离子与磷酸根之间的配位能力较强的特点,提出以N235+TBP+煤油作有机相萃取铁,用磷酸铵盐溶液为反萃取剂反萃取铁。研究了反萃取剂磷酸铵盐溶液种类及浓度、反萃取温度和时间、反萃取相比对铁反萃取效果的影响。结果表明:在反萃取剂组成0.2 mol/L H3PO4+0.3 mol/L(NH4)2HPO4、温度25℃、相比Vo/Va=1/1、反萃取时间5 min条件下,Fe(Ⅲ)的单级反萃取率为95.2%;对于赤泥的实际浸出液,有机相经7次循环后,其萃取性能基本不变,所得反萃取液pH=0.02、杂质含量低,铁磷物质的量比约为0.8,可用于配制磷酸铁溶液。盐酸体系中,用N235+TBP+煤油溶液萃取Fe(Ⅲ),TBP先与N235以氢键形式组成协萃剂,再与铁配位交换实现铁的萃取,萃合物可能的组成为R3NH+…O=P(OC4H9)3·FeCl-4(o)。The stripping of Fe(Ⅲ)is difficult when recovering Fe(Ⅲ)from red mud acid leaching solution by extraction.Based on the relatively easy stripping of tertiary amine N235 and the strong coordination ability between Fe(Ⅲ)and phosphate group,N235+TBP+kerosene was used as organic phase to extract Fe(Ⅲ),and ammonium phosphate solution was used as stipping agent.The effects of phosphate species,temperature,Vo/Va and stripping time on the stripping were studied.The results show that under the conditions of 0.2 mol/L H3PO4+0.3 mol/L(NH4)2HPO4,temperature of 35℃,Vo/Va=1/1,and stripping time of 10 min,the single-stage stripping rate of Fe(Ⅲ)can reach 95.2%.The results of red mud leaching liquid circulation experiment show that the extraction performance of the organic phase is basically unchanged after 7 cycles,and the stripping solution pH is 0.02,impurity content is low and the molar ratio of Fe to P is about 0.8,which can be used to prepare ferric phosphate solution.In hydrochloric acid system,N235+TBP+kerosene is used to extract Fe(Ⅲ).First,TBP and N235 formed a synergistic agent in the form of hydrogen bond,and then exchanged Fe(Ⅲ)coordination to achieve Fe(Ⅲ)extraction.The possible composition of the extracted species is R3NH+…O=P(OC4H9)3·FeCl-4(o).

关 键 词：赤泥 酸浸液 N235 溶剂萃取 磷酸铵盐 反萃取 铁 

分 类 号：TF804.2[冶金工程—有色金属冶金]