烧碱行业无机化工废渣污染特征与污染风险控制研究

发布时间：2018-05-20 10:15

本文选题：盐泥 + 废隔膜　；参考：《北京化工大学》2015年硕士论文

【摘要】：我国拥有全球最大的烧碱生产能力和消费量,生产烧碱系统中产生盐泥、废隔膜、废硫酸等无机化工废渣,这些废渣难以处理,长年累月堆积如山,严重地困扰着我国烧碱行业的发展。本研究通过现场调查、采样分析研究和烧碱废渣的污染风险评价,米探究烧碱行业废渣的产生特性和污染特征,并提出废渣相应的风险控制措施。经过企业调研得到,在隔膜法制烧碱工艺中产生盐泥、废隔膜、废硫酸和芒硝四种废渣,生产每吨烧碱产品时原料原盐的消耗量为1462.5kg,四种废渣的产生量分别为盐泥62.5kg、废隔膜0.13kg、废硫酸26.1 kg、芒硝25.5 kg。在离子膜法制烧碱工艺中产生盐泥、废硫酸和芒硝三种废渣,生产每吨烧碱产品时原料原盐的消耗量为1462.5 kg,三科废渣的产生量分别为盐泥93.3kg、废硫酸26.1kg、芒硝25.5 kg。由实验分析结果得,盐泥中主要含有CaCO3、NaCl、SiO2等,各组分相对含量约为CaCO340%～97%,NaCl 3%～16%,SiO27%～10%,采用钡法脱硝技术产生的盐泥中还含30%左右的BaSO4。其中铬、锌、钡、汞、铜、镉、铅等重金属的含量与《+壤环境质量标准》相比基本无超标现象,盐泥的pH介于11～12之间,上述重金属的浸出毒性与危废鉴别标准相比无超标情况,盐泥不具备腐蚀性和浸出毒性的危废特性。对废隔膜样品分析发现其中存在石棉成分,土要类型为温石棉,是一种危废。废硫酸的浓度为75%左右,其中基本不含重金属杂质,但氯含量在0.04%左右。芒硝废渣主要组成物质是占比70%的Na2SO4,其次为NaCl,其中主要重金属的含量与《土壤环境质量标准》相比基本无超标现象。盐泥废渣中的重金属通过逸散和浸出会对环境和人体健康造成危害,通过选取RBCA模型对其进行风险表征,可得盐泥堆存处理过程的风险是可接受的。盐泥用于制建材砖、制脱硫剂等再利用的方式尚在试验中,存在诸多难题,在企业中难以推广,目前烧碱企业主要采用就近填埋堆存的处理方法。盐泥控制方面首先应从减量化着手削减它的产生量,同时加大研发它的再利用技术并积极推广相关的示范工程建设。隔膜废渣中含有危废石棉,目前以水泥固化进行深度填埋为主,随着我国隔膜法烧碱产能装置的陆续淘汰,隔膜废渣届时可以通过集中处理的办法被一次性彻底解决。烧碱工业产生的废硫酸中基本不存在杂质,它的回收再利用是必然选择,浓缩技术以及循环利用等工艺能够有效地解决废硫酸不好处理的难题,值得推广。废硫酸按危废管理带来很多难度,在烧碱企业和管理部门的努力下,废硫酸的综合利用率会得到提高,有望作为烧碱工业中的副产品进行管理。
[Abstract]:China has the largest caustic soda production capacity and consumption in the world, producing salt sludge, waste diaphragm, waste sulfuric acid and other inorganic chemical waste slag in the production of caustic soda system. The development of caustic soda industry in China is seriously perplexed. Through field investigation, sampling analysis and pollution risk evaluation of caustic soda waste residue, the characteristics of production and pollution of caustic soda industry waste slag were investigated, and the corresponding risk control measures were put forward. Through enterprise investigation, four kinds of waste slag, salt sludge, waste membrane, waste sulfuric acid and mirabilite, were produced in the process of producing caustic soda by diaphragm process. The consumption of raw salt per ton of caustic soda was 1462.5 kg, the production of four kinds of waste residue was 62.5 kg of salt sludge, 0.13 kg of waste membrane, 26.1 kg of sulfuric acid and 25.5 kg of glauber nitrate. Salt sludge was produced in ionic membrane caustic soda process. The consumption of raw salt per ton of caustic soda was 1462.5 kg. The production of waste residue was 93. 3 kg of salt sludge, 26. 1 kg of waste sulfuric acid and 25. 5 kg of mirabilite. The results of experimental analysis show that the salt mud mainly contains CaCO3 + NaCl-SiO2, and the relative content of each component is about CaCO340T ~ (97) C ~ (97) C ~ (3 +) NaCl ~ (3 +) ~ (16) and Sio _ (27). The salt mud produced by barium denitrification also contains about 30% of BaSO _ 4. The contents of chromium, zinc, barium, mercury, copper, cadmium, lead and other heavy metals were basically no more than the soil environmental quality standard, the pH of salt mud was between 11 ~ 12, and the leaching toxicity of the above heavy metals was no more than that of hazardous waste. Salt sludge does not possess the characteristics of corrosion and leaching toxicity. The analysis of waste membrane samples found that there is asbestos in it, and chrysotile is a kind of dangerous waste. The concentration of waste sulfuric acid is about 75%, in which there is almost no heavy metal impurity, but the chlorine content is about 0.04%. The main component of the waste residue is 70% Na _ 2SO _ 4, followed by NaCl.The content of the main heavy metals is almost no more than that of "soil Environmental quality Standard". Heavy metals in salt sludge waste residue can cause harm to environment and human health by dispersing and leaching. The risk of salt sludge storage can be obtained by selecting RBCA model to characterize the risk. The reusing methods of salt mud used in making building materials brick and desulfurizing agent are still in the test, and there are many problems which are difficult to be popularized in enterprises. At present, the caustic soda enterprises mainly adopt the treatment method of nearby landfill and storage. In the aspect of salt sludge control, the production of salt sludge should be reduced first, and the reuse technology should be developed and the related demonstration project should be popularized at the same time. There is dangerous asbestos in the membrane waste. At present, cement solidification is the main method of deep landfill. With the elimination of the membrane caustic soda production units in our country, the membrane waste can be solved once and for all by centralized treatment. There is no impurity in the waste sulfuric acid produced by caustic soda industry. The recovery and reuse of the waste sulfuric acid is an inevitable choice. The technology of concentration and recycling can effectively solve the difficult problem of poor treatment of waste sulfuric acid, and it is worth popularizing. It is difficult to manage the waste sulfuric acid according to the dangerous waste. With the efforts of caustic soda enterprises and management departments, the comprehensive utilization rate of waste sulfuric acid will be improved, which is expected to be managed as a by-product of caustic soda industry.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X781.2

【参考文献】