Patents by Inventor Paul Kawulka

Paul Kawulka 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: 4004991
    Abstract: Direct pressure leaching of zinc and iron containing mineral sulphides in dilute H.sub.2 SO.sub.4 is carried out in a two-stage countercurrent process in which finely divided sulphides are leached in a first leaching stage with solution from the second leaching stage to produce a first stage leach solution containing a high zinc concentration and low iron and H.sub.2 SO.sub.4 concentrations. The first stage solution, after suitable purification treatment, may be treated for zinc recovery by conventional electrowinning. The residue from the first stage leach is pressure leached with return electrolyte from the electrowinning operation with the leach end solution being passed to the first stage leach as already stated. The acid and sulphides concentrations in each of the first and second leaching stage is controlled such that (1) sufficient acid and sulphides enter the leaching circuit to ensure that the final leach solution exiting from the first leaching stage will contain sufficient dissolved zinc, e.g.
    Type: Grant
    Filed: December 12, 1975
    Date of Patent: January 25, 1977
    Assignee: Sherritt Gordon Mines Limited
    Inventors: Herbert Veltman, Geoffrey James Julien Mould, Paul Kawulka