An extension of Free's extraction isotherm for the solvent extraction of cations using acidic extractants

Q1 Earth and Planetary Sciences

International Journal of Mineral Processing Pub Date : 2017-10-10 DOI:10.1016/j.minpro.2017.08.005

V. Agarwal, M.S. Safarzadeh, J. Galvin

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引用次数: 1

Abstract

A simple theoretical model has been developed for the solvent extraction of cations with different oxidation states varying from +1 to +4 using acidic extractants. The basic assumption behind this theoretical model is that the cationic species (Mⁿ⁺) will exist in ionic form and not form any complexes in the aqueous phase. A direct relationship between the concentration of metal ions in the aqueous phase and that in the organic phase was developed for trivalent and tetravalent cationic species. Using this model, the distribution isotherms were plotted for a given set of conditions. The effect of pH and equilibrium constant on the distribution isotherms were represented in three-dimensional form for trivalent and tetravalent cationic species. Consistent with expectations, the results suggest that with increasing pH and an increasing equilibrium constant one finds an enhancement of the extraction of cationic species for a given set of conditions. The calculations were performed in the pH range of 1 through 3 because for higher pH values, the pH shift accompanying the extraction is significant and thereby affects the mass balance equations. A comparison of the distribution isotherms shows that the total metal ion concentration to extractant concentration ratio determines the distribution behavior of metal ions with different valency. At low total metal ion concentration to extractant concentration ratio, the distribution coefficient was higher for higher oxidation state cations under similar experimental conditions, and this trend started to reverse when the total metal ion concentration to extractant concentration ratio was increased.

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用酸性萃取剂溶剂萃取阳离子的自由萃取等温线的扩展

建立了用酸性萃取剂萃取+1 ~ +4不同氧化态阳离子的简单理论模型。该理论模型背后的基本假设是，阳离子(Mn+)将以离子形式存在，而不会在水相中形成任何配合物。在三价和四价阳离子中发现了水相中金属离子浓度与有机相中金属离子浓度之间的直接关系。利用该模型，绘制了给定条件下的分布等温线。pH和平衡常数对三价和四价阳离子种类分布等温线的影响以三维形式表示。与预期一致，结果表明，随着pH值的增加和平衡常数的增加，人们发现在给定的一组条件下阳离子物种的提取增强。计算是在1到3的pH范围内进行的，因为对于较高的pH值，pH值随萃取而变化是显著的，从而影响质量平衡方程。分布等温线的比较表明，总金属离子浓度与萃取剂浓度比决定了不同价态金属离子的分布行为。当总金属离子浓度与萃取剂浓度比较低时，相同实验条件下，氧化态阳离子越高，分配系数越高，随着总金属离子浓度与萃取剂浓度比的增加，这一趋势开始逆转。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Mineral Processing 工程技术-工程：化工

CiteScore

3.02

自引率

0.00%

发文量

审稿时长

11.1 months

期刊介绍： International Journal of Mineral Processing has been discontinued as of the end of 2017, due to the merger with Minerals Engineering. The International Journal of Mineral Processing covers aspects of the processing of mineral resources such as: Metallic and non-metallic ores, coals, and secondary resources. Topics dealt with include: Geometallurgy, comminution, sizing, classification (in air and water), gravity concentration, flotation, electric and magnetic separation, thickening, filtering, drying, and (bio)hydrometallurgy (when applied to low-grade raw materials), control and automation, waste treatment and disposal. In addition to research papers, the journal publishes review articles, technical notes, and letters to the editor..