The process of separating and purifying rare earth elements is selectively carried out by utilizing different distribution ratios of certain components in the aqueous phase in the organic phase. It is one of the important methods for the separation and purification of rare earth elements. The continuous organic phase formed by the extractant and the organic solvent is in sufficient contact with the aqueous phase containing the separated rare earth element without being mutually miscible (ie, sufficiently mixed and clarified), thereby achieving unequal concentration of the rare earth component in the two phases. The distribution achieves the purpose of separation and purification of rare earth elements. The solvent extraction process of rare earth elements includes the selection of extraction system, the selection of extractor and extraction method, the determination of extraction separation process conditions and the implementation of extraction and stripping processes, and the post-treatment of various solutions after separation (see solvent extraction). There are single-stage and cascade-level extraction methods. In order to obtain high-purity products, cascade extraction is usually adopted. Cascade extraction has different forms such as cross-flow, co-flow, countercurrent, fractionation and reflux. Since the 1970s, the extraction and separation of rare earths has been dominated by fractional distillation, supplemented by other processes. The determination of the extractant, extraction system and process conditions is mainly based on the separation factor β A/B of the separated A and B components (or two elements): Where D A is the distribution ratio of the A component in two phases; D B is the distribution ratio of the B component in the two phases, C A (0), C A (a) is the A component in the equilibrium organic phase and water The concentration of the phase, C B (0), C B (a) is the concentration of the B component in the equilibrium organic phase and the aqueous phase. The size of β A/B indicates the difference between the separation effect of the two components A and B. The larger the β A/B value, the better the separation effect, that is, the higher the selectivity of the extractant. If D A = D B and β A/B =1, it indicates that the two components A and B cannot be separated by the extraction system, and the size of β is related to the atomic number of the rare earth element and the extraction system. The application of new extractants and advances in extraction theory and process research have strongly promoted the development of rare earth separation and purification technologies. Solvent extraction technology has become the main means of separation and purification of rare earth elements. It has been used to separate and purify each rare earth element from raw materials of various rare earth components. The cascade extraction theory provides the theoretical basis for the optimal design of the extraction process and has been widely used in the separation and production of rare earths. Well Drilling Equipment,Track Drilling Rig,Portable Well Drilling Machine,Water Well Drilling Equipment Taian Longye Import And Export Trade Co.,ltd , https://www.drillingrigfactory.com