汽蒸-冷碱法制备溶解浆的研究

Preparation of Dissolving Pulp by Steaming -Cold Alkali Treatment of Bleached Softwood Kraft Pulp

关键词:  漂白硫酸盐针叶木浆  汽蒸  冷碱处理  溶解浆

Key Words:bleached softwood kraft pulp  steaming  cold alkali treatment  dissolving pulp

摘要:研究并开发了汽蒸与冷碱处理相结合（汽蒸-冷碱法）将漂白硫酸盐针叶木浆升级至溶解浆的技术。探讨了汽蒸处理过程中，汽蒸压力、维压时间、浆浓对汽蒸浆的黏度、抗碱性（R10）、得率以及废液pH值的影响；考察了冷碱处理过程中，碱浓、温度、处理时间对溶解浆的黏度、抗碱性（R10）、多戊糖含量及得率的影响。结果表明，汽蒸压力是影响汽蒸处理效果最重要的因素，维压时间次之，浆浓最小；碱浓是影响冷碱处理效果最重要的因素，温度次之，处理时间最小。汽蒸处理的适宜工艺条件为：浆浓40%，汽蒸压力0.6 MPa，维压时间25 min；冷碱处理的适宜工艺条件为：浆浓20%，碱浓12.5%，温度20～40℃，处理时间1 h。在此条件下制备得到的溶解浆各项性能为：黏度398 mL/g，抗碱性（R10）92.2%，多戊糖含量3.87%，白度86.1%，达到了QB/T 4898—2015中针叶木溶解浆优等品的质量指标。

Abstract:Combination of steaming and cold alkali treatments （steaming-cold alkali treatment method） as a process for upgrading bleached softwood kraft pulp to dissolving pulp was studied and developed. During the steaming process， the effect of different steaming pressure， time under pressure and pulp consistency on the viscosity， alkali resistance （R10）， the yield of steamed pulp and pH value of waste liquor was discussed. During the cold alkali treatment process， the effect of alkali concentration， temperature， and treatment time on the viscosity， alkali resistance （R10）， pentosan content and the yield of the dissolving pulp was studied. The results indicated that steaming pressure was the key factor affecting the steaming result， then followed the time under pressure and the pulp consistency was the least important. On the other hand， NaOH concentration was the most important factor affecting the effect of cold alkali treatment， followed by temperature， and the influence of treatment time was minimal. Finally， the optimum conditions of steaming were as follows: the pulp consistency of 40%， the steaming pressure of 0.6 MPa， the time under pressure of 25 min. The optimum conditions of cold alkali treatment were as follows: the NaOH concentration of 12.5%， the temperature of 20～40℃， the treatment time of 1 h and the pulp consistency of 20%. The resulting pulp with high reactivity， the viscosity of 398 mL/g， the alkali resistance （R10）of 92.2%， the pentosan content of 3.87%， the brightness of 86.1%（ISO）.