选择性萃取分离酸溶液中钪的试验与热力学研究

Experiment and Mechanism of Selective Extraction and Separation of Scandium from Acid Solution

采用P507选择性萃取分离赤泥酸浸液中的钪。研究了溶液pH值、P507用量、A/O和萃取时间对钪萃取率和分离效果的影响,同时分析了此体系中钪萃取热力学及钪和铁的萃取分离动力学特征。结果表明:当溶液pH值为0.6,P507用量为8%,A/O为15和震荡时间为6 min时,钪萃取率可达99%。铁离子是影响钪萃取和分离的主要杂质离子,随着震荡时间从2 min提高至10 min,D_(Sc)可由48提高到1650,而D_(Fe)仅提高至3.1,此时钪和铁均未达到平衡。当反应时间为6 min时,钪对铁的分离系数最大,β_(Sc/Fe)可达到776,此体系中钪的萃取焓变为20.46 kJ·mol(-1)。

Selective extraction and separation of scandium of acid leaching solution from red mud with P507 was put forward. The parameters of solution pH, P507 amount, AZO and extraction time on extraction rate of scandium and separation effect were investigated. The extraction thermodynamics of scandium and the kinetics properties of scandium and iron were analyzed. The results showed that the extraction of scandium could reach 99% under the condition sof solution pH value of 0.6, P507 amount of 8% , A/O of 15 and extraction time of 6 rain. The main impurity ion of influence scandium extraction and separation was iron ion. The Dsc was increased from 48 to 1650 with increasing extraction time from 2 to 10 min, where the DFe was only increased to 3.1. The extraction of scandium and iron were not balanced and the separation factor of scandium on iron was the largest at extraction time of 6 min. Theβ（Sc/Fe） could reach 776, where the enthalpy of scandium extraction was 20.46 kJ·mol^-1 in the system.