METHOD OF PRODUCTION OF SULFATE PULP FOR CHEMICAL PROCESSING Russian patent published in 2013 - IPC D21C3/02 

FIELD: textiles, paper.

SUBSTANCE: method comprises processing of wood chips in two stages with aqueous alkaline media prepared by mixing black and white liquors and containing 15-30 g/dm³ of active alkali in units of Na₂O for the first stage and 55-70 g/dm³ for the second stage. Processing at the first stage is carried out with the temperature rise to 125-155°C for 30 minutes and exposure for impregnation, hydrolysis and pulping at the final temperature for 60 minutes. The output of the waste media at this stage is carried out by its displacement with the aqueous medium for the second stage. The second stage is carried out with the temperature rise to 140°C for 40 minutes, exposure for impregnation and pulping at this temperature for 40 minutes, the temperature rise to 170°C for 40 minutes, exposure for pulping at 170°C for 90 min.

EFFECT: possibility is provided to obtain from larch wood the pulp for chemical processing or sanitary and hygienic purposes with values acceptable for these purposes for Kappa pulp, viscosity and content of α-cellulose, increase in pulp yield, increase in utilisation rate of heat and chemicals of waste alkaline media.

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