Lenzing Aktiengesellschaft

University of Maine System

Herbert Sixta

Andrea Borgards

Roland Möslinger

Andrea Promberger

Adriaan Van Heiningen

Herwig Schottenberger

Gabriele Schild

Walter Peter

Friedrich Kurz

Peter Van Walsum

Gerhard Gotzinger

Manfred Schneeweisz

Alfred Schrittwieser

Peter Hendel

Anton Hoglinger

Byung-Hwan Um

Wilfried Ruckl

Roland Moeslinger

Andrea Proberger

Carmen Froschauer

Hedda K Weber

The invention relates to a process for producing a dissolving pulp from a cellulosic starting material using the kraft process, comprising the step of cooking the starting material with a cooking liquor. The process according to the invention characterized in that the starting material is exposed to a steam treatment prior to cooking and that the pulp obtained by cooking is subjected to cold caustic extraction (CCE) in the course of further processing.

Process for producing a pulp

In a process for recovering acetic acid from a wood extract, an aqueous wood extract is provided that contains acetic acid and dissolved hemicellulose containing uronic acid. A water insoluble solvent containing an extractant for the acetic acid is also provided. In a preferred embodiment, the solvent is undecane and the extractant is trioctylphosphine oxide. The wood extract is contacted with the solvent and extractant in order to extract the acetic acid from the wood extract. The acetic acid is then recovered from the solvent and extractant.

Recovery of acetic acid from wood extracts

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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Lenzing, Austria

Herbert Sixta