Patent ID: 6336994
Filing Date: 2002-01-08
Classification: D21C

Abstract:
A process for producing bleached pulp comprising the steps of:cooking a cellulosic material under alkaline conditions with a cooking chemical to produce unbleached pulp; recovering a filtrate containing a used cooking chemical in a first recovery installation; washing said unbleached pulp with acid; delignifying said unbleached pulp in the presence of oxygen, whereby a filtrate is produced containing released organic material; bleaching said unbleached delignified pulp with a chlorine-free bleaching chemical; recovering a filtrate containing a used chlorine-free bleaching chemical and said filtrate containing released organic material in a second recovery installation; regenerating at least a portion of said used bleaching chemical; and supplying said regenerated bleaching chemical to at least one of said chlorine-free bleaching step or said oxygen delignification step.