delignifiering and bleaching of cellulose pulp with an alkali oxygen hypokloritextraktion

摘要

An improved process for bleaching and delignifying cellulose pulp. The process comprises subjecting the pulp to a bleaching stage followed by washing, and thereafter extracting the bleached pulp as received from the bleaching stage in a caustic extraction stage in the presence of oxygen and hypochlorite. The preferred embodiment is a sequential treatment of the bleached pulp with oxygen and hypochlorite without a pulp washing step between chemical additions. The process is characterized by enhanced delignification with high brightness and high viscosity. The process is further characterized by extraction stage filtrates of improved environmental characteristics.