METHOD OF TREATING SULFUR-ALKALINE CELLULOSE PRODUCTION SOLUTIONS Russian patent published in 2000 - IPC

FIELD: paper-and-pulp industry. SUBSTANCE: invention, in particular, relates to liquid-phase oxidation of sulfide and mercaptide from condensates of sulfate cellulose production using heterogeneous carbon- containing catalyst. Sulfur-alkaline solutions are purified by way of catalytic oxidation in continuous reactor by air oxygen at elevated temperature (60-95 C) and pressure, pH 7.9-9.5 in presence of carbon cloth with 90-99% carbon, specific surface 50-1800 sq.m/g, and air permeability 100-200 cu.dm/sq.m. Consumption of air is adjusted to 2.5- 5.0 cu.dm per 1 cu.dm condensate. More specifically, starting solution utilized is condensate from vacuum-evaporation station obtained after evaporation of softwood and/or hardwood digestion lyes and containing, mg/cu.dm: sodium sulfate 3.0-530, methylmercaptan, 6.0-240, sodium thiosulfate 0.4-19.1, sodium sulfate 0.1-5.8, sodium sulfite 0.6-13.1 (all on conversion to sulfur), and methanol 140-3800. EFFECT: enhanced purification efficiency and reduced oxygen consumption. 1 tbl, 5 ex