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:
Oct. 11, 1977
Filed:
Apr. 26, 1976
Bengt Goran Hultman, Domsjoverken, SW;
Sture Erik Noreus, Husum, SW;
Mo och Domsjo Aktiebolag, Ornskoldsvik, SW;
Abstract
A cyclic process is provided for utilizing sodium values in sulfate cellulose pulping, in which sodium losses normally are less than sodium additions to the process, thus tending to build up a sodium surplus, and which includes the steps of pulping cellulosic material with a pulping liquor comprising sodium hydroxide and sodium sulfide, separating spent pulping black liquor, evaporating and combusting the black liquor to recover sodium values as sodium sulfide and sodium carbonate, dissolving the sulfide and sodium carbonate in water to form green liquor, causticizing the green liquor with calcium hydroxide to form white liquor, and recycling white liquor to form pulping liquor, the improvement comprising maintaining sodium balance at least in part by removing sodium values as white liquor, oxidizing the white liquor with air at an elevated temperature, and utilizing the oxidized white liquor as a source of alkali in another cellulose pulp treatment process.