(1. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長(zhǎng)沙 410017；
2. 中南大學(xué) 國家重金屬污染防治工程技術(shù)研究中心，長(zhǎng)沙 410017；
3. 江蘇交通科學(xué)研究院股份有限公司，南京 210017)
摘 要: 針對(duì)蘆葦漿造紙產(chǎn)生的濃縮黑液的特點(diǎn)，提出了黑液脫硅-酸析回收木質(zhì)素-三維電極電解-苛化回收NaOH-出水返回生產(chǎn)的工藝流程。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，脫硅率為98.20%；黑液脫硅后加入H2SO4去除COD并回收木質(zhì)素，CODCr由220.648 g/L降至54.179 g/L左右，脫除率達(dá)到75.45%，每100 mL黑液可回收8.5 g木質(zhì)素。FTIR、SEM和EDX的分析結(jié)果表明：酸析木質(zhì)素結(jié)構(gòu)以紫丁香基和對(duì)羥基的單體結(jié)構(gòu)為主；采用三維電極反應(yīng)器處理酸析液，殘余CODCr為36.761 g/L，TOC的去除率達(dá)35.57%；利用苛化法回收殘堿，用于制漿蒸煮工段，實(shí)現(xiàn)廢水的零排放。苛化后的黑液中有效堿濃度為8.30 g/L，苛化度為78.60%，苛化后TOC降低了9.99%，殘余CODCr濃度為33.085 g/L，可返回生產(chǎn)，實(shí)現(xiàn)了資源的綜合回收與利用。
關(guān)鍵字: 造紙黑液；脫硅；酸析；三維電極；木質(zhì)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
