Process for the chlorine-free bleaching of cellulosic materials with ozone

US5346588A · kind A · utility

Assignee

• LENZING AKTIENGESELLSCHAFT · AT

Inventors

• Herbert Sixta · Lenzing, AT
• Gerhard Gotzinger · Zistersdorf, AT
• Anton Hoglinger · Vöcklabruck, AT
• Peter Hendel · Vöcklabruck, AT
• Wilfried Ruckl · Vöcklabruck, AT
• Walter H. Peter · Vöcklabruck, AT
• Friedrich Kurz · Attnang-Puchheim, AT
• Alfred Schrittwieser · Vöcklabruck, AT
• Manfred Schneeweisz · Vöcklabruck, AT

Key dates

• Filing date: Mar 26, 1992
• Grant date: Sep 13, 1994
• Expiry date: Mar 26, 2012

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21C9/153
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

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.