紫穗槐碱法纸浆的漂白性能研究

紫穗槐烧碱—蒽醌浆的实验室漂白的研究表明,其白度可达到生产一般书写纸和有光纸的要求。采用常规次氯酸盐单段或次氯酸盐两段漂白,白度能达到66—70°。研究中发现,碱法紫穗槐浆的硬度对漂白的影响最大,当硬度为高锰酸钾值14～16时,其漂率相当于麦草浆的漂率。研究中还发现,选用HA—P(次氯酸盐/酸处理—过氧化氢)法漂白时,也能获得较好的白度。     

Synergism of enzymes in chemical pulp bleaching from an industrial point of view: A critical review

Enzymes are biological catalysts and are very specific, catalyzing either a single chemical reaction or a limited number of closely related reactions. For example, xylanases are enzymes that catalyze the cleavage of polymeric xylan and thereby break down this hemicellulose. The first xylanase enzyme preparations used in the bleaching process of chemical pulp also contained cellulase, which catalyzes the hydrolysis of cellulose. This obviously had an adverse effect on pulp yield and quality. Unfortunately, this setback gave enzyme-assisted pulp bleaching a negative reputation. At a later stage, enzyme producers managed to engineer enzyme production strains that generated cellulase-free xylanase preparations. However, due to the initial negative experiences with the earlier enzyme mixtures, only a limited number of companies in the pulp industry have seriously considered using these so-called second-generation enzymes in their bleach plants. It is apparent that these improved enzyme preparations would bring about significant benefits in terms of chemical cost savings and effluent quality. In addition to xylanase-aided bleaching, it is possible to improve the effectivity further by adding other enzymes, such as lipase and esterase, to create an enzyme cocktail. This may be particularly beneficial in the bleaching of hardwood pulp, such as white birch, which often encounters complex and troublesome problems with wood extractives. By adding different types of enzymes at more than one position in the fiberline, even further improvements are possible. The main objective of this review is to discuss the advantages of incorporating modern enzyme preparations in the bleaching of chemical pulp.     

二氧化氯的生产和应用评述

详细评述了 2 0世纪二氧化氯的主要生产工艺和制备方法及二氧化氯作为漂白剂、消毒杀菌剂、水处理剂等在多种行业中的应用 ,分析展望了 2 1世纪二氧化氯的生产和应用前景 ,认为应在我国大力发展二氧化氯的生产并促进其应用。     

碱法麦草浆木聚糖酶处理后木质素及碳水化合物的变化

采用UV光谱、凝胶色谱、X—射线衍射及扫描电镜等技术对碱法麦草浆的酶解浆和酶解液进行分析,探讨了木聚糖酶对碱法麦草浆处理后浆中木质素和碳水化合物的变化情况。研究认为,木聚糖酶对碱法麦草浆漂白作用主要是因为木聚糖酶降解了浆中部分木聚糖和残余木质素中的LCC结构,从而使后序漂白中漂液更易渗透,木质素的溶出更多、更易。     

商品漂水的稳定性及其研究

对影响商品漂水的稳定性的原因进行了理论分析。对影响因素进行了初步的探讨，提出了提高商品漂水稳定性的方法：降低浓度，过滤，改善储存环境，提高粘度。     

以废白土制备洗涤膏

植物油脱色用过的活性白土是含油的废白土 ,本文探索了一种充分利用废白土的方法。以强碱与废白土含的油按化学计量比进行皂化反应可得一种洗涤膏。这种洗涤膏主要适用机械工人洗手 ,也可用以清洗瓷砖等硬表面。通过对比试验 ,表明该洗涤膏在这两类应用场合中的洗涤效果良好     

高档色织斜纹织物的设计与生产

设计并生产了高档色织斜纹织物.从松筒、装纱、入染前处理、入染、入染后处理、烘干等方面介绍了筒子染色工序;整浆联合工序要严格控制上浆率,从烘房温度、车速等方面控制回潮率;合理设计开口时间、上机张力、车速、后梁高低与前后位置、主辅喷嘴气压与启闭时间等织造工艺.通过采取以上技术措施,生产的产品织造效率达到了92.1％,经向台...     

显微观测技术在漂粉精生产中的应用

显微观测技术可以有效地监测漂粉精生产的氯化反应进程,准确确定反应终点,从而获得较高的产率和产品质量,显微观测技术还可以用于石料活性的鉴定,简单,准确。     

高岭土的化学除铁增白方法研究进展

简述了高岭土的化学除铁增白方法的基本原理,综述了高岭土化学除铁增白法的研究进展,并指出了化学法的发展方向及需要进一步解决的问题.化学法能够根据需要选择合适的化学试剂将高岭土中的杂质溶解除去,除铁效果好,能够得到优质、高白度值的高岭土.针对目前我国高岭土资源储量丰富、品位不高的情况,适宜选用化学法对其进行除铁增白,提高其综合性能及应用价值.同时,仍需对化学法的作用机理进行更深一步的研究,以期解决过程中尚存在的一些问题.     

TCF BLEACHED PULPS FROM MISCANTHUS SINENSIS BY THE IMPREGNATION RAPID STEAM PULPING (IRSP) PROCESS

ABSTRACT

The production of bleached cellulose pulps from elephant grass (Miscanthus sinensis) via a two-stage soda pulping process and a TCF bleaching sequence is evaluated in this work. The impregnation rapid steam pulping process (IRSP) involves impregnating of the lignocellulosic material with the pulping liquor, withdrawing the excess liquor and rapidly steaming the impregnated material at 180–200°C for a short time. In this paper the process variables and their effect on the kappa number, yield and viscosity of the unbleached pulps are discussed. Bleaching by an ozone-based TCF sequence was tested, and the papermaking properties of the bleached pulp were determined. A kappa number of 19 was obtained by impregnating at an alkali charge of 30 + 0.1% anthraquinone carboxylic acid (AQCA) and pulping at 180°C for only 15 min. Kappa was reduced to 16 by extending pulping time to 26 min. The alkali consumption during impregnation and pulping was 10.2 g NaOH/100 g of dry Miscanthus. Screened pulp yield, viscosity and brightness for this pulp were 54.6%, 913 mL/g and 37.3%, respectively. After bleaching, the pulp had an ISO brightness of 87.4% and a viscosity of 700 mL/g. Refining in a PFI mill provided optimal strength properties of the bleached pulp at 4500 revolutions (71°SR): breaking length 7.2 km, tensile index 72 N m/g, and burst index 4.3 kN/g. Tear index was 7.9 mN m²/g at this degree of refining.