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:
Sep. 13, 1994
Filed:
Mar. 26, 1992
Herbert Sixta, Vocklabruck, AT;
Gerhard Gotzinger, Fistersdorf, AT;
Anton Hoglinger, Timelkam, AT;
Peter Hendel, Vocklabruck, AT;
Wilfried Ruckl, Vocklabruck, AT;
Walter Peter, Vocklabruck, AT;
Friedrich Kurz, Attnang-Puchheim, AT;
Alfred Schrittwieser, Vocklabruck, AT;
Manfred Schneeweisz, Vocklabruck, AT;
Lenzing Aktiengesellschaft, Lenzing, AT;
Abstract
A process for the chlorine-free bleaching of pulps in an aqueous suspension which comprises forming the suspension with a consistency of 3 to 20 mass percent; introducing into the suspension an ozone-containing gas having an ozone content of 20 to 300 g/m.sup.3 in an amount corresponding to at most 2 mass percent ozone calculated on dry pulp of the suspension during vigorous agitation of the suspension to form a reaction mixture; maintaining a pressure of the ozone-containing gas at a pressure of 1 to 15 bar during introduction into the suspension; and controlling reaction conditions during contact of the ozone-containing gas with the suspension to maintain a reaction temperature of 15.degree. to 80.degree. and a pH value of 1 to 8.