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

提出了多溶剂萃取、正反向同时萃取，并从理论和实验上进行了研究。提出了多溶剂结晶萃取法和逆流多级结晶萃取法，并对其进行了理论和实验研究。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。结果表明：1.结晶法多溶剂萃取法明显优于常规萃取法，使萃取相的平衡溶质浓度大大降低，最终萃取相的溶质浓度大大提高，稀溶液中的溶质在结晶中以高纯晶体的形式重新生成。实验研究了稀铜溶液中正向、反向溶剂同时萃取结晶的过程。铜离子被提取到有机相(分散胶中的Lix64N)，然后同时反萃到高浓度的硫酸中。将硫酸铜溶液浓缩至过饱和浓度，同时可回收高纯度(99.998%)的硫酸铜晶体。采用逆流多级萃取结晶法对钴与镍、铜与锰、锰与钴的高度分离进行了实验研究。在煤油中分别用PC88A(M2EHPA)、Lix64N和DP8R(D2EHPA)分别从稀钴和镍、铜和锰以及锰和钴溶液中回收抽余相中的高纯金属溶液和结晶中的高纯金属硫酸盐晶体。

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.