(1. 中南大学 冶金科学与工程学院，长沙 410017；
2. 中南大学 国家重金属污染防治工程技术研究中心，长沙 410017；
3. 江苏交通科学研究院股份有限公司，南京 210017)
摘 要: 针对芦苇浆造纸产生的浓缩黑液的特点，提出了黑液脱硅-酸析回收木质素-三维电极电解-苛化回收NaOH-出水返回生产的工艺流程。采用Ca(OH)2沉淀法去除黑液中的SiO2，黑液中硅含量由6.68 g/L降至0.12 g/L，脱硅率为98.20%；黑液脱硅后加入H2SO4去除COD并回收木质素，CODCr由220.648 g/L降至54.179 g/L左右，脱除率达到75.45%，每100 mL黑液可回收8.5 g木质素。FTIR、SEM和EDX的分析结果表明：酸析木质素结构以紫丁香基和对羟基的单体结构为主；采用三维电极反应器处理酸析液，残余CODCr为36.761 g/L，TOC的去除率达35.57%；利用苛化法回收残碱，用于制浆蒸煮工段，实现废水的零排放。苛化后的黑液中有效碱浓度为8.30 g/L，苛化度为78.60%，苛化后TOC降低了9.99%，残余CODCr浓度为33.085 g/L，可返回生产，实现了资源的综合回收与利用。
关键字: 造纸黑液；脱硅；酸析；三维电极；木质素
（1. School of Metallurgical Science and Engineering, Central South University, Changsha 410017, China;
2. National Engineering Research Center for Pollution Control of Heavy Metals,
Central South University, Changsha 410017, China;
3. Jiangsu Transportation Research Institute Co., Ltd., Nanjing 210017, China）
Abstract:A novel process was proposed to treat reed black liquor: desilication-acidification-three-dimensional electrolysis-causticization-reuse in pulp making. The precipitation method was used to remove silicon by adding Ca(OH)2. The residual concentration of silicon decreases from 6.68 g/L to 0.12 g/L and the removal rate of silicon is maintained at 98.2%. Lignin was recovered by acidulation-precipitation after the addition of sulfuric acid. The residual concentration of CODCr can be reduced from 220.648 g/L to 54.179 g/L and its removal rate is maintained at 75.45%. 8.5 g lignin was recovered from 100 mL black liquor. Based on the analysis of FTIR, EDX and SEM, it is found that the structure of lignin consists mainly of syringyl monomers and hydroxyl groups, and the lignin particles are not fibrous but granular. The reed pulp black liquor pretreated by acidification method was treated by electrolysis with a three-dimensional electrode reactor. The removal rate of TOC is maintained at 35.57% and the residual concentration of CODCr can be reduced to 36.761 g/L. Then, causticization was adopted to recovery residual alkali from the black liquor, which can be reused in the paper mill. After causticization, the concentration of effective alkali is 8.30 g/L and the causticization rate of the solution is about 78.60%, the residual concentration of CODCr in the black liquor is further reduced to 33.085 g/L and the removal rate of TOC is 9.99%.
Key words: papermaking black liquor; desilication; acidulation; three-dimensional electrode; lignin
