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

摘要

As an alkali source, sodium hydroxide (NaOH) is used in the conventional preconditioning followed by refiner chemical treatment alkaline peroxide mechanical pulping (P-RC APMP) process. In this study, NaOH was partially substituted by magnesium oxide (MgO) as the alkali source (substitution percentage of up to 50%) in the high-consistency retention stage of triploid poplar P-RC APMP process. The pH values of the bleaching liquor, yields and chemical components of the refined pulp were investigated to explore the potential advantages of MgO instead of NaOH as the alkali source. The results showed that partially substituting MgO for NaOH resulted in a lower pH of bleaching liquor and a higher bleached pulp yield than those of the NaOHbased process. In addition, the dissolution of benzene alcohol extractives, lignin, pentosans, and carbohydrates all decreased.