Lenzing Aktiengesellschaft

Manfred Schneeweisz

Herbert Sixta

Walter Peter

Friedrich Kurz

Peter Hendel

Alfred Schrittwieser

Anton Hoglinger

Gerhard Gotzinger

Wilfried Ruckl

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.

Process for the chlorine-free bleaching of cellulosic materials with

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Vocklabruck, Austria

Manfred Schneeweisz