Patents Assigned to Osakeyhtio A. Ahlstrom
  • Alkaline sulfite pulping process with sodium aluminate and anthraquinone
    Patent number: 4384921
    Abstract: An alkaline sulfite pulping process in which the lignocellulosic material is cooked in a solution containing sodium sulfite is provided. Sodium aluminate is used as a buffering agent. As a result of this, the stability of the pH of the cook and the properties of the pulp are improved. The amount of sodium aluminate as NaOH is from 2% to 8% based on the dry weight of the chips. The pulping process is carried out with the addition of a small dosage of anthraquinone, to produce chemically defibered pulps.
    Type: Grant
    Filed: May 4, 1981
    Date of Patent: May 24, 1983
    Assignee: Osakeyhtio A. Ahlstrom
    Inventors: Soile H. Pihlajamaki, Nils-Erik Virkola