Acid Penetration in sulfite cooking

Abstract

If acid penetration is incomplete, the lignin in wood dissolves out not perfectly in successive pulping . Hence by determination of the lignin dissolved out in pulping period, the degree of acid penetration can be estimated. Various effects of free sulfur dioxide, temperature and concentration of combined sulfur dioxide on the penetration of combined sulfur dioxide were investigated by determining the dissolved out lignin with colloid-titration. The penetration of combined sulfur dioxide can be acceralated by sulfonation of lignin, so that both factors free sulfur dioxide and temperature are effective on the penetration of combined sulfur dioxide