METHOD FOR PRODUCING OF CELLULOSE Russian patent published in 2004 - IPC

FIELD: pulp-and-paper industry, in particular, production of paper from wood of coniferous trees.

SUBSTANCE: method involves cooking cellulose-containing raw material based on coniferous wood by sulfite cooking solution with pH value of 1.65-2.00, total content of SO₂ of 8.5-9.5 wt% in said solution and temperature of 143-146⁰C; washing resultant mass and treating with mixture of potassium fluoride, hydrogen peroxide and oxalic acid, said components being used in predetermined ratio; performing cooking process with the use of sulfite cooking solution based on sodium, magnesium and mixed sodium and magnesium base at NaO₂ and MgO ratio of 1:1 and treating washed mass at temperature of 75-85⁰C. Consumption of mixture of potassium fluoride, hydrogen peroxide and oxalic acid is 0.8-1.2% by weight of perfectly dry fiber and mass concentration of 6-8%. Cellulose produced by said method is readily whitened by means of ecologically clean reactants.

EFFECT: provision for obtaining of soft cellulose exhibiting high mechanical strength and increased ecology control in the process of manufacture of cellulose.

3 cl, 1 tbl, 5 ex