MgO部分替代NaOH对杨木CTMP过氧化氢漂白的影响

Effect of Partially Substituting MgO for NaOH on the Properties of DCS and Pulp in the Peroxide Bleaching of Poplar CTMP

关键词:  MgO  碱性过氧化氢漂白  漂白浓度  溶解及胶体物质  浆料性能

Key Words:magnesium oxide  alkaline peroxide bleaching  bleaching consistency  DCS  pulp properties

摘要:采用MgO部分替代NaOH作为碱源对杨木CTMP进行碱性过氧化氢漂白。分析了在不同的漂白浓度和镁碱替代比例下,DCS水样及漂后浆料的性能。结果表明，随着MgO替代NaOH比例的增加,DCS水样的pH值、电导率、固含量和阳离子需求量均逐渐下降，浊度先增大后减小；当漂白浆浓增加,DCS水样的电导率、固含量、阳离子需求量和浊度均增加；随着漂白浆浓的增加,漂后浆料的松厚度、不透明度和光散射系数均下降,抗张强度和白度上升,其中两组条件下(30%的漂白浆浓和MgO替代比例为25%,及10%的漂白浆浓和无MgO替代)浆料的强度性能接近,而浆料的松厚度和不透明度略微增加。

Abstract:Alkaline peroxide bleaching of poplar chemi-thermomechanical pulp (CTMP) was conducted by partially magnesium oxide (MgO) for substituting sodium hydroxide (NaOH). The properties of the dissolved and colloidal substances (DCS) and the pulp under different bleaching consistencies and substitution percentages of MgO were analyzed. The results showed that the pH, conductivity, solid content and cationic demand (CD) of the DCS water samples decreased obviously with the increase of substitution percentages of MgO, while the turbidity increased firstly and then decreased. The conductivity, solid content and CD of the DCS water samples increased with the increase of bleaching consistency within the range of 10%～30%. The pulp strength and brightness were higher at higher bleaching consistency, but the bulk, opacity and light-scattering coefficient of the resultant pulp decreased. Meanwhile, at two different conditions (30% bleaching consistency with 25% substitution percentage of MgO, and 10% bleaching consistency without using MgO), the strength properties of the resultant pulps were much similar, while the bulk and opacity increased significantly.