Patents by Inventor Yukari Ishii

Yukari Ishii has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5258167
    Abstract: An extractant for extracting rare earth metal ions comprises, for instance, di-(3-methylcyclohexyl)phosphoric acid, di-1-ethylpentylphosphoric acid, docosyl-(2 isopropyl-5-methylcyclohexyl) phosphoric acid, 2-ethylhexyl-2-methylcyclohexylphosphoric acid and/or 2-hexyloctyl-cyclohexylphosphoric acid or a combination of, for instance, dicyclohexylphosphoric acid and di-(2-heptylundecyl) phosphoric acid. A method for extracting rare earth metals comprises the step of bringing an acidic aqueous solution containing ions of rare earth metals into contact with an extraction medium containing an extractant exemplified above to transfer the rare earth metal ions to the extraction medium. The extractant not only exhibits high extractability for rare earth metal ions but also facilitates the back extraction of the rare earth metal ions therefrom.
    Type: Grant
    Filed: May 31, 1991
    Date of Patent: November 2, 1993
    Assignee: Lion Corporation
    Inventors: Toshio Takahashi, Hiroaki Nishizawa, Yukari Ishii