Patents by Inventor Tomiyasu Asai

Tomiyasu Asai 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).

  • Method of preparing purified silver nitrate
    Patent number: 4136157
    Abstract: A method of preparing silver nitrate of an improved purity comprising adding about 50 to about 1000 ppm of Al.sup.3+ ion to a crude silver nitrate solution resulting from dissolving metallic silver in nitric acid, adjusting the pH of the silver nitrate solution to about 5.5 to about 6.5 by adding silver oxide thereto, and then separating the precipitate formed.
    Type: Grant
    Filed: July 11, 1977
    Date of Patent: January 23, 1979
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Tomiyasu Asai, Akira Endo