Patents by Inventor Stephen Frederick Prest

Stephen Frederick Prest 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).

  • Magnetic separation of ilmenite
    Patent number: 3935094
    Abstract: Purification of ilmenite from chromite impurities by a two step magnetic separation wherein magnetically susceptible chromite is magnetically removed, followed by an oxidizing roasting of the ilmenite and a subsequent magnetic separation of ilmenite from the remaining chromite impurities to obtain an ilmenite with 1% or less chromite.
    Type: Grant
    Filed: October 10, 1974
    Date of Patent: January 27, 1976
    Assignee: Quebec Iron and Titanium Corporation - Fer et Titane du Quebec, Incorporated
    Inventors: Michel Bergeron, Stephen Frederick Prest