为了解二异丁基甲酮(DIBK)和二(2-乙基己基)磷酸(P204,HA)组成的混合萃取剂萃取锆和铪的化学行为,分别采用斜率法和饱和容量法研究DIBK-P204体系在HSCN介质中萃取锆和铪的性能及机理。结果表明:DIBK-P204体系萃取分离锆和铪时优先萃取铪,具有正协萃能力,萃取反应为加合反应机理;萃合物中Zr4+( Hf4+)、P204、DIBK的摩尔比为1:2:1,其萃合物组成分别为Zr(SCN)3?HA 2?DIBK和Hf(SCN)3?HA 2?DIBK;采用红外光谱分析负载有机相,推测萃合物可能存在的结构。因此,DIBK和P204混合使用可以改善HSCN介质下锆和铪的萃取分离效果。
To master the chemical behavior of the extraction of hafnium and zirconium in the mixture of diisobutyl ketone (DIBK) and P204, the characteristics and mechanism about the extraction of zirconium and hafnium by DIBK-P204 system in thiocyanic acid (HSCN) medium were studied through the methods of slope coefficient and saturated volumetric. The results show that hafnium is extracted preferentially by DIBK-P204 system, the synergistic extractive effects are found, and the extraction reactions follow the mechanism of the addition reactions. The composition of extracted complex is determined as n(Zr4+(Hf4+)):n(P204):n(DIBK)=1:2:1 and the extracted complexes are identified as Zr(SCN) 3?HA 2?DIBK and Hf(SCN) 3?HA 2?DIBK, and the possible synergistic extraction complex structures are suggested through infrared spectrum analysis of the loaded organic phase. The extraction and separation effect of zirconium and hafnium can be improved with synergistic mixture of DIBK and P204.