Patents by Inventor Daniel Arthur Burnham

Daniel Arthur Burnham 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 recovering high purity tungsten compositions from wolframite ores
    Patent number: 4092400
    Abstract: A process for recovering tungsten values in the form of ammonium paratungstate from tungsten ores and ore concentrates, particularly wolframite ores and ore concentrates, incorporating a plurality of steps for necessary removal of impurities and formation of the product ammonium paratungstate. The steps of the process include grinding, caustic leaching, filtrations, chemical treatment including acidification particularly for the removal of silica impurities, further filtration, solvent extraction of the tungsten values, stripping of the tungsten values from the solvent solution in the form of ammonium paratungstate, and recovery of the ammonium paratungstate product. The caustic leaching step may be carried out in the substantial absence of oxygen.
    Type: Grant
    Filed: April 11, 1977
    Date of Patent: May 30, 1978
    Assignee: Engelhard Minerals & Chemicals Corp.
    Inventors: Vladimir Zbranek, Zdenka Zbranek, Daniel Arthur Burnham