Abstract: Boron or uranium isotopes can be chemically separated and enriched with high speed and with high separating efficiency by using weakly basic anion exchange fibers having a diameter of not more than 100 .mu., an aspect ratio of at least 5 and an exchange capacity of at least 2 meq/g-dry fiber, which are packed in a column at a specific volume of 2.0 - 20.0 ml/g-dry fiber.

Abstract: A method of simultaneously obtaining separate enriched fractions of heavier and lighter isotopes from mixtures thereof with the use of an ion exchange resin column by passing a ligand body containing this isotope mixture through the column. The isotopes, as they are passed through the column, are present in the forms of ligand-containing coordination compounds having different valence states and are followed by an eluant and form a band which travels through the column, the front and rear portions of which are respectively enriched in one of the isotopes and depleted in the other.

Abstract: A method of simultaneously obtaining separate enriched fractions of .sup.235 U and .sup.238 U from isotopic mixtures thereof with the use of an ion exchange column by passing a liquid body containing the isotopic mixture through the column. The uranium as it is passed through the column is present as a U(IV) coordination compound with a ligand at different valent states and is followed by an eluant and forms a band which travels through the column, the front and rear portions of which are respectively enriched in one of the isotopes and depleted in the other.