P204/4PC协萃体系在酸性硫酸盐溶液中选择性萃取镍的机理研究

Mechanism Study on Selective Extraction of Nickel from Acidic Sulfate Solution by Using the Synergistic Solvent Extraction System of P204 and 4PC

采用斜率法、恒摩尔法、饱和容量法研究从酸性硫酸盐溶液中用P204和4PC协同萃取镍的机理,并测定协萃反应的热力学平衡常数,得到协萃反应的焓变和熵变。结果表明,P204/4PC协同萃取镍的反应呈正协同效应,镍萃合物的结构为NiA2L2,且协萃过程为吸热反应,焓变和熵变分别为29.52J/mol和-6.53kJ/(mol·K)。采用P204与4PC协萃体系可显著提高酸性硫酸盐溶液介质中镍的选择性萃取效果。

The mechanism of synergistic solvent extraction of nickel by P204 and 4PC from acidic sulfate solution was studied with slope method,constant molecale method and saturation extraction method,respectively. The thermodynamic equilibrium constant of the synergistic reaction was determined,and its enthalpy and entropy changes were also obtained.The results show that the combination of P204 with 4PC has a positive synergistic effect for nickel extraction,and the extracted complex is identified as NiA2L2.The synergistic solvent extraction is an endothermic reaction with enthalpy change of 29.52J/mol and entropy change of-6.53kJ/(mol·K).The synergistic solvent extraction system of P204and 4PC can obviously promote the selective extraction of nickel from acidic sulfate solution.