Patents by Inventor John L. Cromwell

John L. Cromwell 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: 5620586
    Abstract: The present invention is concerned with a method for electrorefining silver in a Moebius cell whereby the anode is completely dissolved and the gold mud is removed without handling of any partially dissolved anodes. The cell is conventional except that the anodes are placed in a basket made of a thermoplastic material and surrounded by a cloth, the electrical contact between the anode and the power source takes place outside the electrolyte. The bottom of the basket is provided with apertures allowing the gold mud produced to tall into the cloth until the anode is completely dissolved.
    Type: Grant
    Filed: November 27, 1995
    Date of Patent: April 15, 1997
    Assignee: Noranda, Inc.
    Inventors: Pierre Claessens, John L. Cromwell
  • Patent number: 5378328
    Abstract: A process is provided for the recovery of bismuth from an ion exchange eluent solution consisting of at least 50% sulfuric acid maintained at a temperature of 95.degree.-100.degree. C. The process comprises the step of electrowinning bismuth from the sulfuric acid solution in an electrochemical cell at a current density up to 30 A/m.sup.2 using an insoluble anode and a cathode that is impervious to the highly corrosive environment of hot sulfuric acid, for a time interval such as to reduce the bismuth content of the solution down to about 3-5 g/L.
    Type: Grant
    Filed: August 4, 1993
    Date of Patent: January 3, 1995
    Assignee: Noranda Inc.
    Inventors: Varujan Baltazar, John L. Cromwell
  • Patent number: 5100528
    Abstract: A continuous silver refining cell comprises a tank containing an electrolyte, at least one vertical cathode disk mounted on a rotating horizontal shaft placed above the tank so that slightly less than half of the disk is immersed in the electrolyte, at least one anode basket containing impure silver anodes immersed in the electrolyte adjacent the cathode disk, and a diaphragm separating the cathode disk from the anode basket to form cathode and anode compartments. A scraper is provided for continuously removing pure silver crystals from the cathode and directing it to the side of the cell. A chain tubular conveyor may be provided for continuously or semi-continuously withdrawing a mud containing gold and other precious metals from the bottom of the cell.
    Type: Grant
    Filed: March 14, 1990
    Date of Patent: March 31, 1992
    Assignee: Noranda, Inc.
    Inventors: Pierre L. Claessens, Bernard H. Morrison, John L. Cromwell, Paul Spira
  • Patent number: 3951773
    Abstract: An auxiliary electrode for direct introduction into a static-or fluidized bed main electrode comprises a conductive base material selected from the group consisting of lead or lead alloys, and a non conductive screen material preferably made of a synthetic, organic fiber screen cloth partially embedded into the conductive base material so as to insulate the auxiliary electrode from the static-or fluidized-bed main electrode.
    Type: Grant
    Filed: May 1, 1974
    Date of Patent: April 20, 1976
    Assignee: Noranda Mines Limited
    Inventors: Pierre L. Claessens, John L. Cromwell