Patent ID: 6019870
Filing Date: 2000-02-01
Classification: D21C

Abstract:
A process for the preparation of a delignified and bleached chemical paper pulp according to which a lignocellulose pulp obtained by cooking is subjected to the following series of treatments:(a) a dignifying treatment with oxygen, followed by;(b) a treatment with a complexing or sequestering agent for transition metals, followed by washing, then followed by;(c) a treatment with hydrogen peroxide; characterized in that the treatment (b) is carried out in a medium having an alkaline pH greater or equal to 9.0 and less than or equal to 12.5, and the treatment c with hydrogen peroxide is carried out in the presence of an alkali metal silicate at a temperature t greater than 100.degree. C. and at a pressure p greater than 1.5 times the saturated vapor pressure of water at the temperature t.