Patent ID: 6514380
Filing Date: 2003-02-04
Classification: D21C

Abstract:
A method of producing chemical pulp, comprising the steps of:(a) cooking comminuted cellulosic fibrous material to produce brown stock having shives; (b) washing the brown stock to produce chemical pulp at a consistency of between about 6-18%; (c) oxygen delignifying the chemical pulp at a consistency of between about 6-18%; (d) screening the pulp from step (c) to produce at least an accept fraction and a shive-containing reject fraction; steps (a)-(d) being practiced in a main fiber line; and then after step (d):(e) further treating the accept fraction, and (f) directly transporting the shive-containing reject fraction back to the main fiber line before step (c); and (f) separating gas from the pulp during the practice of step (c).