The invention discloses a method for producing cotton pulp used for
cellulose triacetate by a two-step stewing technology. The method comprises the following steps of
raw material selection, cotton opening,
impurity removal, primary alkali blending, dipping, stewing, secondary alkali blending, dipping, stewing, pre-degritting, pre-pulping, concentration,
chlorine dioxide bleaching,
hydrogen peroxide bleaching, alkaline extraction,
acid treatment, after degritting, after pulping, pulp
processing, and finishing. The method has simple processes, utilizes cotton linter as a
raw material, adopts a rotary spherical digester two-step stewing technology, carries out primary stewing of impurities in cotton linter by an alkali,
hydrogen peroxide and stewing assistants having appropriate concentrations, extrudes a stewing
raffinate by steam excess pressure after heat preservation, carries out secondary heat-preservation stewing by re-feeding of certain amounts of the alkali,
hydrogen peroxide and the stewing assistants, realizes cotton pulp
dichloromethane extract content of 30 to 90PPM, has a waste water COD
discharge amount of 20250 to 25050mg / l in the whole pulping process, and reduces
sewage treatment stress.