Patents by Inventor Stig E. Hultholm

Stig E. Hultholm 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 the production of an iron-free chronium (III) compound
    Patent number: 4393029
    Abstract: An iron-free chromium(III) compound is precipitated at an elevated temperature and pressure from an acidic aqueous solution which contains iron and chromium. In order to prevent coprecipitation of iron, an additive is added to the precipitation stage in an amount sufficient to provide in the precipitation conditions at least 2 g/l of bivalent chromium in the solution.
    Type: Grant
    Filed: July 22, 1981
    Date of Patent: July 12, 1983
    Assignee: Outokumpu Oy
    Inventors: Seppo O. Heimala, Stig E. Hultholm, Frans H. Tuovinen