Patent ID: 6059925
Filing Date: 2000-05-09
Classification: D21C

Abstract:
A method of treating cellulose pulp comprising the steps of:delignifying the pulp by contacting the pulp with a first gas mixture comprising oxygen;washing the delignified pulp by contacting the pulp with a wash liquid;bleaching the washed pulp by contacting the pulp with a second gas mixture comprising ozone and oxygen;regenerating the second gas mixture from the bleaching step by contacting the second gas mixture with the wash liquid from the washing step, said regeneration of the second gas mixture converting carbon dioxide in the second gas mixture into a carbonate;delivering at least a portion of said regenerated second gas mixture in the form of the first gas mixture to the delignifying step; anddelivering at least a portion of the wash liquid from the regenerating step to the wash step.