Reduction effect of environmental load by waste paper recycling

本课题主要研究了废纸回收利用对提高废纸白度和环境负荷的影响。从成本与质量平衡的角度来看，废纸白度是衡量废纸回收系统能否正常运行的重要指标之一。从废水的颜色和气泡形成的角度评估了油墨去除过程的环境负荷。主要研究结果如下：1.在各种脱墨剂中，选择脂肪酸衍生物和长链醇衍生物用于报纸再生，选择长链醇衍生物用于高品质（OA）纸再生。建立了包括解离、加压、需要、破裂、再解离、浮选和洗涤等过程的变机械参数和化学参数的模型。2.浮选过程中气泡的形成和稳定性取决于药剂和充气量。油墨颗粒的尺寸取决于机械参数。3.对于报纸回收，碱处理加速了油墨颗粒的脱附。另一方面，对于OA纸张回收机械过程是更重要的，因为墨粉颗粒的热固定。4.从纸张回收的角度评估油墨去除需要详细检查各个步骤之间的能量分配，以优化总能量成本。

In this project the improvement of recycled paper whiteness and the environmental load by recycling have been studied. The whiteness of recycled paper is one of the most improtant keys to judge whether the recycling system can work, based on cost-quality balance. The environmental load was evaluated for the ink-removing process from the viewpoint of color and bubble formation of waste water. Results are summarized as follows :1.Among various ink-removing reagent, aliphatic acid derivertives and long chain alcohol derivertives are chosen for newspaper recycling, and long chain alcohol derivertives for high quality (OA) paper recycling. Model process with variable mechanical and chemical parameters was constructed including dissociation, press, needing, breaching, re-dissociation, floatation and washing.2.Formation and stability of bubble during floatation depend on both reagent and aeration rate. Size of ink-particles depends on mechanical parameters.3.For newspaper recycling desorption of ink particles is accelerated by alkali treatment. On the other hand, for OA paper recycling mechanical process is more important because of thermal fixation of toner particles.4.Evaluation of ink-removing by the viewpoint of paper recycling requires detailed examination of energy partitioning among various steps to optimize total energy cost.