Patents by Inventor Kaoru Terao

Kaoru Terao 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: 5885535
    Abstract: A process for extracting and separating silver safely and selectively from a raw material containing slightly soluble silver compounds and recovering silver from the extract in a simple manner without resorting to electrolysis or a special reducing agent, and further recovering high-purity silver, includes mixing the raw material with an organic solvent solution of an organophosphorus compound containing in the molecule sulfur in the form of S.sup.2- ions, thereby extracting silver into an organic phase simultaneously with dissolving the slightly soluble silver compounds, stripping the silver from the organic phase containing the extracted silver with an aqueous solution of alkali sulfite and forming a stripping solution, and reducing the stripping solution to separate silver therefrom.
    Type: Grant
    Filed: January 16, 1998
    Date of Patent: March 23, 1999
    Assignee: Sumitomo Metal Mining Company, Limited
    Inventors: Satoshi Asano, Kaoru Terao