Mo Och Domsjo Aktiebolag

Hans Olof Samuelson

Leif Ake Smedman

Erik Olof Hagglund

Kent Ivar Sondell

Kjell Evert Abrahamsson

Allan Geoffrey Jamieson

A process is provided for the delignification of lignocellulosic material wherein the lignocellulosic material, prior to the delignification, is treated with water or an aqueous solution to remove compounds which catalyze the degradation of carbohydrates and then the delignification is carried out with oxygen and alkali in the presence of a manganese compound to improve the selectivity of the delignification and increase the rate of delignification.

Oxygen-alkali delignification of lignocellulosic material in the

Process for improving the selectivity of delignification of lignocellulosic material in the presence of oxygen gas and alkali by maintaining a carbon monoxide content in the gas phase within the range from about 1% to about 12% by volume. The carbon monoxide concentration is maintained by withdrawing carbon monoxide and oxygen gas from the delignification, and separating and recycling withdrawn oxygen gas.

Process for the delignification of lignocellulosic material by

A process is provided for delignifying and bleaching cellulose pulp, which comprises carrying out the delignification and bleaching with oxygen and alkali in the presence of sodium bicarbonate, while removing carbon dioxide from the gas phase as required to maintain a carbon dioxide partial pressure within the range from about 0.001 to about 3 bars, thereby improving the selectivity of the delignification and bleaching.

Process for delignifying and bleaching cellulose pulp

A process is provided for producing cellulose pulp of high brightness, which comprises pulping lignocellulosic material such as wood with oxygen under superatmospheric pressure in two stages, in the first at a pH within the range from about 6 to about 9, and in the second at a more alkaline pH of at least about 10.

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Goteborg, Sweden

Hans Olof Samuelson