Development of High-degree Separation Technique with Multiple-Solvent Extraction and its Practical Application

提出了多溶剂萃取、同时正、反溶剂萃取的方法，并进行了理论和实验研究。提出了多溶剂结晶萃取法和逆流多级溶剂结晶萃取法，并对其进行了理论和实验研究。本研究结果总结如下：1。提出了有结晶和无结晶多溶剂萃取的平衡计算方法。多溶剂结晶萃取法比传统的萃取法有明显的优越性，表明它在萃余相中使平衡溶质浓度低得多，在最终萃取相中使溶质浓度高得多，并且使稀溶液中的溶质在结晶器中回收为高纯度的晶体。实验研究了在稀铜溶液中同时进行正、反溶剂萃取的结晶过程。铜离子被萃取到有机相（Lix64N分散溶胶）中，然后同时被剥离到高浓度硫酸中。将硫酸铜溶液浓缩至过饱和浓度，可同时回收高纯度（99.998%）的硫酸铜晶体。实验研究了逆流多级溶剂萃取结晶法对钴镍、铜锰、锰钴的高度分离，用PC88A（M2EHPA）分别从稀释的钴镍、铜锰和锰钴溶液中回收萃余相中的高纯金属溶液和结晶过程中的高纯金属硫酸盐晶体。煤油中的Lix64N和DP8R（D2EHPA）。

The multiple-solvent extraction,simultaneous forward-,backward- solvent extraction has been proposed and studied theoretically and experimentally. Both the multiple-solvent extraction with crystallization and the countercurrent multistage solvent extraction with crystallization were proposed and studied theoretically and exprimentally. Results obtained from this study are summarized as follows;1. Equilibrium calculation method is proposed for the multiple-solvent extraction with and without crystallization. The multiple-solvent extraction with crystallization process is much superior to the conventional extraction processes, indicating that it makes a much lower equilibrium solute concentration in the raffinate phase, a much higher solute concentration in the final extraction phase and it makes a solute in a dilute solution recovered as high purity crystal in the crystallizer.2. The simultaneous forward-, backward-solvent extraction with crystallization was studied experimentally in case of a dilute copper solution. The copper ions are extracted into an organic phase (Lix64N in dispersol), then simultaneously stripped into a high concentrated sulfuric acid. The copper sulfate solution is concentrated upto supersaturation concentration, then simultaniously the high purity(99.998%) copper sulfate crystal can be recovered.3. The high degree separation of cobalt from nickel, copper from manganese, manganese from cobalt with the countercurrent multistage solvent extraction with crystallization are studied experimentally, both the high purity metal solution in the raffinate phase and the high purity metal sulfate crystals in the crystallization can be recovered respectively from a dilute cobalt and nickel-, copper and manganese- and manganese and cobaltsolution by respectively PC88A(M2EHPA), Lix64N and DP8R(D2EHPA) in kerosen.