METHOD OF PREPARING BISULFITE MAGNESIUM-BASED COOKING LIQUOR FOR CELLULOSE PRODUCTION Russian patent published in 2000 - IPC

FIELD: paper-and-pulp industry. SUBSTANCE: invention can be applied in production of cellulose from fibrous intermediate products involving magnesium base-containing bisulfite cooking solutions. In particular, sulfur dioxide interacts with magnesia material (lump brucite with fractions 50 to 600 mm) at pH 1.5-2.5 until content of bound sulfur dioxide 40-45% is attained, while exhaust gas is removed. Resultant solution is further treated to pH 3.0-5.0, final level of sulfur dioxide 4-6%, and portion of bound sulfur dioxide 47-55%. Interaction of sulfur dioxide with lump brucite is conducted to excess sulfur dioxide content superior to final sulfur dioxide level by 0.5-1.5%, while brucite is consumed completely. After that treatment of solution is conducted by way of blowing away excess of total sulfur dioxide with steam or air in amounts providing desired final level of sulfur dioxide. EFFECT: increased technological effectiveness of process. 1 tbl