Patents by Inventor Wenche Elisabeth Hermansson

Wenche Elisabeth Hermansson 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 acid bleaching of lignocellulose-containing pulp with a magnesium compound
    Patent number: 6398908
    Abstract: A process for delignification and bleaching of chemically digested lignocellulose-containing pulp. In a first embodiment, the pulp is acid treated at a pH of between about 1 and about 6, whereupon a water-soluble compound containing an alkaline earth metal is added at a pH of between about 1 and about 7 before the pulp is treated with a chlorine-free bleaching agent. In a second embodiment, the acid and alkaline earth metal treatments are carried out in a single step. The chlorine-free bleaching agent includes peroxide compounds, ozone, oxygen and sodium dithionite in an optional sequence or mixture. After the treatment according to the invention, the pulp may be finally bleached to the desired brightness, suitably with a chlorine-free bleaching agent, such as ozone, to completely avoid formation and discharge of AOX.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: June 4, 2002
    Assignee: Eka Nobel AB
    Inventors: Wenche Elisabeth Hermansson, Lennart Andersson, Magnus Linsten, Jiri Basta, Lillemor Holtinger