INVESTIGATION OF THE EXTRACTION OF URANIUM (Ⅳ) CHLORIDE WITH CROWN ETHERS.

In investigating the extraction capacities of U(Ⅳ) by 31 crown ethers with various substituting groups from hydrochloric acid, it is found that U(Ⅳ) is not extracted at 5.5M HC1 by dicyclohexyl-crown ethers, but distribution ratios of U(Ⅳ) increase quickly when HC1 concentration is increased to 6-8.5M HC1. The species extracted are identified as H2UC18·2DCH, DCH being dicyclohexyl-crown ethers. The extraction ability of uranium by five DCH decreases in the order: DCH-27C9>DCH-24C8>DCH-18C6>>DCH-30C10> DCH-21C7. DCH could be a useful reagent for the separation of U(Ⅵ) from U (Ⅳ).