麦草纸浆漂白工艺方法的优化

Bleaching Process Optimization of Wheat Straw Pulp

以烧碱-蒽醌(NaOH-AQ)麦草浆为原料,基于三段漂流程,分别将氯、二氧化氯、氧和过氧化氢等漂白试剂用于各段漂白,通过漂白后纸浆性质的比较以确定各段适宜的漂白方法。实验结果表明:一段漂白分别采用氯、氧和二氧化氯3种漂白剂进行比较,二氧化氯漂白(D1)不仅能有效地脱出木素,而且使浆料保持较高的黏度,在漂白过程中具有较好的选择性;二段采用的几种碱处理方法中,氧-过氧化氢强化(EOP)碱处理的浆料具有较高的黏度和最高的白度;经过D1EOP两段漂白的浆料再经过第三段D2漂白,在较低二氧化氯用量的条件下,可将麦草浆漂白至84.0%ISO的白度,漂后浆料具有较高的成纸强度。通过漂白实验效果的综合比较,以二氧化氯为主要的漂白试剂,采用D1EOPD2三段工艺过程比较适合麦草浆的漂白。

Using Soda-AQ wheat straw pulp as raw stock, based on three stage bleaching process, chlorine, chlorine dioxide, oxygen and hydrogen peroxide etc were used as chemicals separately in each bleaching stage. The bleaching process was optimized by comparing the bleaching effects of different chemicals. The results showed that chlorine dioxide has the high selectivity in first bleaching, it can oxide lignin efficiently but hurt cellulose very slightly, so the brightness, viscosity are higher than the pulp bleached by oxygen or chlorine; the pulp treated by Eov has the best brightness and better viscosity than other alkali extraction; at last the pulp treated by DIEop was bleached by D2 as third stage, the finished stock has stronger strength and its brightness is 84.0% ISO. Through of comprehensive comparison of bleaching experiment abvoe, it is concluded that the better bleaching sequence is to use chlorine dioxide as bleaching chemical in the first stage of multistage bleaching system, and D1EovD2 is the best way to bleach wheat straw pulp.