镁碱取代钠碱的杨木P-RC APMP高浓停留段工艺参数优化

Optimizing the Process Parameters in High-Consistency Retention Stage of Triploid Poplar P-RC APMP by Partially Substituting MgO for NaOH

关键词:  三倍体毛白杨  P-RC APMP  高浓停留段  MgO

Key Words:triploid poplar  P-RC APMP  high-consistency retention stage  MgO

摘要:以三倍体毛白杨为原料进行P-RC APMP制浆，探讨高浓停留段工艺参数（NaOH用量、H₂O₂用量和反应时间）对浆张性能的影响，在主要考虑浆张的白度和松厚度的情况下，对高浓停留段工艺参数进行优化；然后在优化的工艺条件下，研究不同的MgO取代NaOH比例对浆张性能的影响。结果表明，优化后高浓停留段的工艺条件为NaOH用量3.5%、H₂O₂用量3.5%、时间90 min。在优化的工艺条件下，随着MgO取代NaOH比例的增加(0~60%)，浆张抗张强度、撕裂度下降，浆张白度、不透明度、光散射系数、松厚度均增大；当MgO取代NaOH比例为40%时，浆张白度提高2.4个百分点，松厚度和光散射系数分别提高11.9%和12.4%，而浆张抗张指数和撕裂指数分别下降23.9%和22.4%。

Abstract:The effects of bleaching time, NaOH and H2O2 dosages in high-consistency retention stage of triploid poplar P-RC APMP on the pulp physical and optical properties were investigated. The three parametes were optimized mainly based on the brightness and the bulk of the handsheets. Under the optimized process conditions, the influences of various substitution percentages of MgO for NaOH on physical and optical properties of the pulp were studied. The results showed that the optimized parameters were 90 min of bleaching time, 3.5% NaOH and 3.5% H2O2. Under the optimized process conditions, with the increase of the substitution percentage of MgO for NaOH in the high-consistency retention stage (from 0% to 60%), the optical properties of the handsheets were improved, but the physical strength properties were decreased. As the MgO substitution percentage was 40%, the resultant P-RC APMP pulp could have a 2.4 ISO units brightness gain, a higher bulk and light-scattering coefficient, while the tensile index and the tear index were decreased by 23.9% and 22.4%, respectively, compared to those without any MgO substitution.