废新闻纸中性碎浆过程中油墨脱离纤维的机理研究

The neutral deinking technology with advantages, such as low pollution and low running cost, is becoming the developing orientation of recycled fiber deinking. The neutral deinking is beneficial to environmental friendly production of recycled fiber pulp. The extent of ink separation from fibers in pulping controls the efficiency of the ink removal. At present, the mechanism of separation of ink particles from fibers in neutral pulping stage is not clearly and totally understood. Therefore, this proposal pays attentions to the mechanism of separation of ink particles from fibers in neutral pulping during disintegration of old newspaper(ONP) using simulative printing, simulative ink and key ink component model. The XPS, TEM, NMR etc. will be used to analyze the extent of ink separation, changes of ink characteristics, ink existence form and deinking rate. The key parameters and key characteristics which control the ink separation from fibers will be found out. The separating action of ink from fibers will be clear as well as the separating order and separating route for both outer ink and inner ink of the fibers. Therefore, the results of the investigation can explain the ink separating mechanism from fibers, which are beneficial to understand the neutral deinking mechanism. In addition, the results can help to improve the neutral deinking efficiency, boost the neutral deinking technology and provide the basis for the application of neutral deinking technology in industry, which can push the turn from alkaline deinking to neutral deinking of ONP.

中性脱墨技术具有污染轻，成本低等优势，是废纸脱墨的发展方向，对于实现废纸浆的清洁生产及固废利用具有重要意义。碎浆过程中油墨从纤维上的脱离程度是油墨去除的关键。目前，对于中性碎浆过程中油墨脱离纤维的机理仍不清晰。本项目以油墨组分模型物、模拟油墨以及油墨关键组分荧光模型物所得新闻纸印刷品为研究对象，对中性碎浆过程中油墨脱离纤维的机制和途径进行探讨。项目利用荧光测定、XPS、TEM、NMR等测定方法对油墨组分模型物及模拟油墨脱离纤维的行为、程度、速率及油墨特性变化等进行分析，得出影响油墨脱离纤维的主控因素以及关键特性，弄清油墨特性与油墨脱离纤维的关联机制，清晰纤维表层油墨和深层油墨的脱离顺序及途径，从而明确中性碎浆过程中油墨脱离纤维的机制。研究结果对于有效提高中性脱墨效率，改进中性脱墨工艺和实现工业化生产提供理论基础和依据，将有效推动废纸碱法脱墨向中性脱墨的转变进程。

该项目针对我国废新闻纸回用过程中存在的脱墨环境碱性高、油墨脱除困难、纸浆返黄严重以及脱墨废水污染负荷大等关键技术难题，进行了废新闻纸中性脱墨工艺技术及机理研究。主要进行了中性碎浆过程中油墨组分模型物及模拟油墨从纤维上脱离的主控因素分析研究、中性碎浆过程中模型物、油墨特性变化与其脱离性能的关联机制分析和中性碎浆过程中纤维表层模型物、油墨与深层模型物、油墨的脱离途径分析等方面的研究工作。研究发现，油墨中的连接料是限制油墨脱除效果的关键组分，软化或改变油墨中连接料的特性是提高油墨脱除效率的最有效途径和方法。纸张纤维上的深层油墨的脱除是整体油墨脱除的限速步骤，也是阻碍纸浆最终白度提高的关键点。在纸张印刷过程中降低油墨向纤维内部的迁移和扩散是有效提高纸浆油墨脱除效率和速度的根本方法。研究结果对于有效提高中性脱墨效率，改进中性脱墨工艺和实现工业化生产提供理论基础和依据，将有效推动废纸碱法脱墨向中性脱墨的转变进程。