PARTIALLY SUBSTITUTING MgO FOR NaOH AS THE ALKALI SOURCE IN THE HIGH-CONSISTENCY RETENTION STAGE OF TRIPLOID POPLAR P-RC APMP

摘要

In the conventional P-RC APMP process sodium hydroxide is used as the alkali source. In this study, magnesium oxide was used to partially substitute for NaOH as the alkali source (substitution ratio of up to 50%) in the high-consistency retention stage of triploid poplar P-RC APMP process. The changes in pH values of the residual bleaching liquor, yields and chemical components of the refined pulp in the high-consistency retention stage of the P-RC APMP process were investigated to explore the potential advantages of MgO instead of NaOH as the alkali source. The results showed that the partial MgO substitution for NaOH resulted in a lower pH of residual bleaching liquor and a higher bleached yield than those of the NaOH-based process. In addition, the dissolution of benzene alcohol extractives, lignin, pentosans, and carbohydrates were all decreased.