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摘要：制浆造纸是我国重要的一种国民经济产业，而黑液是造纸厂所排放的主要污染物。目前国内外的废液治理技术在木浆纸厂应用的都已经有相对较成熟。然而，对于原料为草类的厂家，由于产生的黑液热值低、硅和灰份含量较高，碱回收运行起来比较困难，大大增加了治理难度。35438
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本论文以制浆造纸黑液为原料，对黑液废水处理增设了木质素提取及碳酸根离子转化成碳酸钙的过程，并对其进行了实验与研究，实现废物资源再利用的循环经济。采用酸析法制备木质素，通过酸化，过滤，洗涤，烘干等方法提取木质素。通过不断尝试寻找出木质素沉淀效果最佳的酸性条件。当pH值=3的时候，木质素沉淀可达90%。另外根据国家标准要求，工业废水的排放pH需要大于7。用廉价的CaO将酸性的木质素滤液调至碱性，再通入富含CO2的烟道气结晶出CaCO3。最后应用吸附沉降等物理方法处理废水，以达到国家要求的排放标准。
毕业论文关键词：造纸黒液；木质素；酸性；碳酸钙；排放
The study of black liquid of papermaking treatment
Abstract: Pulping papermaking is an important industry of national economy in China, however, black liquor is the main pollutant emitted by paper mill. At present , the liquid-waste treatment technology applications have been relatively mature in the pulp mill at home and abroad. But due to the low calorific value of black liquor, high silicon and ash content and difficult operation of alkali recovery, greatly increased the difficulty of governance on manufacturers which with grass as material.
We took the pulping black liquor of papermaking as raw material, It achieved circular economy of reusing waste resources and was experimented and researched, for addition of the process of lignin extraction and carbonate ions converted into calcium carbonate in black liquor liquid-waste treatment. The preparation of lignin was used acid precipitation. Extracted lignin by acidification, filtration, washing, drying and other methods. By constantly trying to find the best acid conditions of the lignin precipitation effect. Lignin precipitation can reach 90% when PH=3. According to the national standard, the pH of discharging industrial wastewater need to be more than 7. The lignin filtrate was modulated from acidic to alkaline by the cheap CaO, and then added CO2 to crystallized CaCO3. Finally, the treatment of liquid-waste by physical methods such as adsorption sedimentation.
Key words: the black liquor of papermaking; lignin; acidic; calcium; carbonate discharge
目 录
1 绪论 1
1.1 开题依据 1
1.2 造纸黒液 1
1.2.1 造纸黒液性状 1
1.2.2 造纸黑液的危害 1
1.2.3 造纸黑液处理现状 2
1.3木质素的提取方法 2
1.3.1 碱析法 3
1.3.2 酸析法 4
1.3.3 絮凝沉淀法 4
1.3.4 超滤法 4
1.4碳酸钙的提取方法 4
1.4.1 Ca(OH)2—H2O—CO2反应系统 5
1.4.2 Ca2+—R—CO32-反应系统 6
1.4.3 3Ca2+-H2O-CO32-反应系统 6
1.5 废水处理 7
1.5.1 废水排放标准 7
1.5.2 废水指标 8
1.5.3 废水处理方法 9
1.6课题的来源、研究意义及内容 10
1.6.1 课题的来源 10
1.6.2 课题的研究意义 10
1.6.3 课题的研究内容 11
2 实验部分 12
2.1 实验原料与仪器设备 12
2.1.1 实验原料 12