Patents by Inventor Nathan O. Spears

Nathan O. Spears 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: 5288728
    Abstract: Silver is recovered from a mixture of seasoned photoprocessing solutions by contacting the solutions with a mercapto-s-triazine or water-soluble salt thereof, the mercapto-s-triazine having the formula ##STR1## wherein: R is hydrogen, --NH.sub.4, --OH, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, phenyl, cyclohexyl, oxazinyl, phenoxy, --NR'.sub.2 or SR";whereinR' is hydrogen, alkyl having 1 to 8 carbon atoms, phenyl, cyclohexyl, naphthyl or benzyl;and whereinR" is alkyl having 1 to 8 carbon atoms, phenyl, cyclohexyl, naphthyl or benzyl;m is an integer from 1 to 3; andn is 0 or an integer from 1 to 2.Using these compounds, silver ion complexes with the compound of formula I and the complex can be allowed to settle and separated from the solutions to decrease silver ion concentration in the solutions. The mixture of solutions includes a seasoned stabilizer solution and other seasoned solutions, including bleach, bleach-fix, and developer.
    Type: Grant
    Filed: September 17, 1992
    Date of Patent: February 22, 1994
    Assignee: Eastman Kodak Company
    Inventors: Nathan O. Spears, Ernest R. Anderson, Elizabeth A. Murphy