Patents by Inventor Robert Lefrancois

Robert Lefrancois 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).

  • Process for preparing pure sodium bichromate
    Patent number: 3933972
    Abstract: Processes for preparing vanadium- and chlorine-free sodium bichromate which comprises concentration of a sodium chromate liquor so as to cause formation of crystals of neutral sodium chromate tetrahydrate, separation of these crystals from their mother liquor, treatment thereof with sulfuric acid, concentration of the acid solution obtained, and after separation of insoluble sodium sulfate so formed, crystallization of sodium bichromate.
    Type: Grant
    Filed: February 11, 1974
    Date of Patent: January 20, 1976
    Assignee: Products Chimiques Ugine Kuhlmann
    Inventors: Robert Bauwens, Robert Lefrancois, Michel Gabriel