Kinetics of Ge(IV) Extraction Using a Microstructured Membrane Contactor
Kinetics of Ge(IV) Extraction Using a Microstructured Membrane Contactor
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DOI：
10.1002/kin.21019
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发表时间：
2016-07
影响因子：
1.5
通讯作者：
Stefan Willersinn;H. Bart
中科院分区：
文献类型：
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作者：
Stefan Willersinn;H. Bart
对于湿法冶金金属萃取，扩散传质还伴随着金属离子与萃取剂分子的化学反应，通常发生在界面处。因此，动力学要么受扩散限制，要么受化学反应限制（或在混合状态下分别受两者限制）。确定萃取动力学的传统方法常常导致误解，特别是对于快速反应，并且对界面反应的孤立观点受到限制。使用新的微接触器设置，与现有方法相比，可以用非常低的样本量进行全面的动力学分析。此外，可以量化所有个体的传质阻力，并通过开发的传质模型确定萃取制度。对化学反应部分进行了单独研究，得出了反应速率规律和动力学常数。讨论了用两种萃取剂5,8-二乙基-7-羟基十二烷-6-肟（LIX 63）和7-（4-乙基-1-甲基辛基）-8-羟基喹啉（Kelex 100）从水溶液中萃取锗（IV）的方法。结果表明，用lix63萃取物有反应限制，用Kelex 100萃取物的反应阻力与扩散阻力在同一数量级。所得结果为溶剂萃取装置的设计提供了基础动力学数据。
For hydrometallurgical metal extraction, the mass transfer by diffusion is additionally coupled with a chemical reaction of the metal ion with the extractant molecule, usually at the interface. Consequently, the kinetics is either limited by diffusion or chemical reaction (or both, respectively, in a mixed regime). Conventional methods for determining the extraction kinetics often lead to a misinterpretation, especially for fast reactions, and an isolated view of the interfacial reaction is restricted. With a new microcontactor setup, it is possible to perform a comprehensive kinetic analysis with very low sample volumes compared to established methods. Additionally, it is possible to quantify all individual mass transfer resistances and identify the extraction regime with the developed mass transfer model. The chemical reaction part is investigated isolated, to derive rate laws and kinetic constants. The methodology is discussed for the extraction of Ge(IV) from aqueous solutions with the two extractants 5,8-diethyl-7-hydroxydodecan-6-oxime (LIX 63) and 7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline (Kelex 100). It was found that the extraction with LIX 63 is reaction limited and with Kelex 100 the reaction resistance is in the same order of magnitude as the diffusion resistances. The obtained results provide fundamental kinetic data for the design of solvent extraction equipment.