Patents by Inventor Kaj-Henrik Lindroos

Kaj-Henrik Lindroos 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).

  • Method for regenerating pickling acids
    Patent number: 4526650
    Abstract: The residual acid mixture containing metals which has been produced in the steel pickling process is regenerated to become new HF/HNO.sub.3 pickling acid by applying H.sub.2 SO.sub.4 addition and evaporation. The metal sulphate salt produced in evaporation is converted into scarcely soluble iron jarosite Na[Fe.sub.3 (SO.sub.4).sub.2 (OH).sub.6 ] and chrome and nickel hydroxide, the last mentioned metal hydroxide being obtained as a separately utilizable precipitate.The metal sulphate salt is separated from 60% H.sub.2 SO.sub.4 solution, wherein the main part of the salt is also crystallized. For promoting the crystallization, part of the salt is crystallized in a side line where 80% H.sub.2 SO.sub.4 concentration is used. The acid slurry produced is carried back to the crystallizing stage in the main line.
    Type: Grant
    Filed: January 23, 1984
    Date of Patent: July 2, 1985
    Assignee: Outokumpu Oy
    Inventors: Seppo I. Blomquist, Markku T. Saarela, Hannu J. Pouru, Bror G. Nyman, Kaj-Henrik Lindroos, Timo T. Koivunen, Sigmund P. Fugleberg