The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 01, 1984
Filed:
Dec. 16, 1982
Hans O Samuelson, Gothenburg, SE;
Mo och Domsjo Aktiebolag, Ornskoldsvik, SE;
Abstract
A process for delignifying bleaching cellulose pulp in three stages, an activating stage, and first and second alkaline stages, NO and/or NO.sub.2 and O.sub.2, and optionally HNO.sub.3, being supplied to the water-containing pulp in the activating stage; in the first alkaline stage, alkali being supplied as carbonate, primarily HCO.sub.3.sup.-, with oxygen gas having a partial pressure, on average, of from 0 to 0.2 MPa, the lignin content of the pulp being lowered in this stage so that the Kappa number of the pulp after the stage is from 10 to 60% of the Kappa number of the pulp entering the activating stage; in the second alkaline stage, alkali being supplied as carbonate, primarily CO.sub.3.sup.=, with oxygen gas at a partial pressure, on average, of from 0.1 to 3 MPa.