Abstract: The subject matter described herein includes a method of separating a mixture of trivalent rare-earth elements, based on their reduction potential, and solubility in a divalent state. The method includes adding the mixture of trivalent rare-earth elements to a tetraborate salt with deionized water to form a salt mixture, grinding the salt mixture with boric acid to form a solid mixture, wetting the solid mixture with water to form a paste, heating the paste to form a resultant product, dissolving the resultant product, thereby creating a residual solid in aqueous solution, wherein the residual solid includes a second mixture of trivalent rare-earth elements, and the aqueous solution includes a substantially singular element of a divalent rare-earth element in an aqueous state, and removing the residual solid, thereby separating the divalent rare-earth element from the mixture of trivalent rare-earth elements.

Abstract: The subject matter described herein includes a method of separating a mixture of trivalent rare-earth elements, based on their reduction potential, and solubility in a divalent state. The method includes adding the mixture of trivalent rare-earth elements to a tetraborate salt with deionized water to form a salt mixture, grinding the salt mixture with boric acid to form a solid mixture, wetting the solid mixture with water to form a paste, heating the paste to form a resultant product, dissolving the resultant product, thereby creating a residual solid in aqueous solution, wherein the residual solid includes a second mixture of trivalent rare-earth elements, and the aqueous solution includes a substantially singular element of a divalent rare-earth element in an aqueous state, and removing the residual solid, thereby separating the divalent rare-earth element from the mixture of trivalent rare-earth elements.