硫铁矿制酸废水处理及其回用新技术的研究

发布时间：2018-06-08 04:09

本文选题：硫酸废水 + 新技术　；参考：《湘潭大学》2015年硕士论文

【摘要】：硫铁矿制酸废水通常具有废水量多,浊度高,酸度大,有毒重金属等有害物质含量高的特点,环境危害严重。大多数国家都已放弃使用硫铁矿制酸。考虑到我国的基本国情:我国的硫铁矿资源丰富、硫磺资源匮乏、硫酸用量巨大等因素,我国仍然允许使用硫铁矿制酸。为此环保部制定新标准《硫酸工业污染物排放标准》(GB26132-2010),新标准的颁布使得硫铁矿制酸废水的处理难度增加,处理费用进一步提高。因此,对原有废水处理工艺进行改进创新已势在必行。本文在总结前人研究工作的基础之上,致力于硫铁矿制酸废水处理新技术研究,并且以株洲某硫铁矿制酸厂的制酸废水开展实验,提出了“搅拌中和—曝气氧化—沉淀分离—铁盐氧化—CO2脱钙—混凝沉淀—废水回用”联合处理的新方案.并对新技术各处理单元的各因素进行优化实验研究,包括正交试验和单因素实验,同时探讨了铁盐除砷的机理及与原有技术在物耗能耗方面进行对比实验研究等。脱氟除砷阶段,通过单因素实验得到各影响因素的最佳参数为:中和pH值为11.0;中和反应时间为20min;一次曝气反应时间为50min;二次曝气反应时间为40min;铁砷质量比为8。通过正交试验得到各影响因素的主次关系为:中和pH值一次曝气反应时间铁砷质量比二次曝气反应时间中和搅拌反应时间。通过对除砷机理的探讨,新技术中铁盐除砷主要包括砷的氧化,铁盐混凝及吸附三个方面的作用。通过对铁盐除砷吸附作用的研究,用Freundlich吸附等温方程来拟合,拟合的相关系数R2为0.94,具有较好的相关性,对K和作回归分析得出铁砷质量比对砷去除率效果的数学模型为C=(0.88+482.53)φ.。脱钙阶段,通过单因素实验得出各影响因素的最佳参数为:脱钙pH值为8.8;反应温度为50℃;搅拌时间为50min;搅拌速度为150r/min;晶种投加量为1g/L。通过正交试验得到各影响因素的主次关系为:脱钙pH晶种投加量搅拌速度反应温度搅拌时间。通过新技术处理该废水,处理后废水中氟、砷、铅的去除率分别达到90.09%、99.64%、96.26%,其残余量分别为7.95mg/L、0.28 mg/L、0.42 mg/L,其他重金属的含量也都在相关标准以下;脱钙处理后废水中钙离子浓度在饱和状态以下。通过新技术与原有技术的对比实验,新技术在物耗和能耗方面比传统技术要少,相比原有技术,新技术氧化曝气时间比原有技术缩短60min,中和药剂用量减少了2mL。
[Abstract]:Pyrite made acid wastewater is usually characterized by high amount of waste water, high turbidity, high acidity, toxic heavy metals and other harmful substances. Most countries have abandoned the use of pyrite to make acid. Considering the basic national conditions of our country, there are many factors such as rich pyrite resources, scarcity of sulphur resources and the huge amount of sulphuric acid in our country. It is still allowed to use pyrite to make acid. To this end, the Ministry of environmental protection has formulated a new standard for the emission standard of the sulphuric acid industry (GB26132-2010). The promulgation of the new standard makes the treatment difficulty of the sulfuric acid wastewater increase, and the treatment cost is further improved. Therefore, it is imperative to improve the original wastewater treatment process. On the basis of the research work, a new technology for the treatment of sulfuric acid wastewater from pyrite is studied, and a new scheme of combined treatment of "stirring neutralization - aeration oxidation - precipitation separation - iron salt oxidation - CO2 decalcification - coagulation sedimentation - wastewater reuse" is proposed. A new technology is proposed. All the factors of each unit were optimized, including the orthogonal experiment and the single factor experiment. At the same time, the mechanism of iron removal and the experimental study on the energy consumption of the original technology were also discussed. The best parameters of the influence factors were the neutralization pH value of 11, neutralization and neutralization. The reaction time is 20min, one aeration reaction time is 50min, the two aeration reaction time is 40min, the iron arsenic mass ratio is 8. through orthogonal experiment to get the main relation of the influence factors: the neutralization pH value one time aeration reaction time iron arsenic mass ratio two aeration reaction time and the stirring reaction time. Through the discussion of the arsenic removal mechanism, the new method of arsenic removal is new. In the technology, iron salt removal mainly includes three aspects: arsenic oxidation, iron salt coagulation and adsorption. Through the study of the adsorption of iron salts, the adsorption of arsenic is fitted with Freundlich adsorption isotherm equation. The correlation coefficient R2 of fitting is 0.94, and has good correlation. The number of iron arsenic mass ratio to arsenic removal efficiency is obtained by K and regression analysis. The study model is C= (0.88+482.53) Phi decalcification stage. Through single factor experiment, the best parameters are obtained: decalcification pH value is 8.8, reaction temperature is 50, stirring time is 50min, stirring speed is 150r/min, and crystal seed dosage is 1g/L. through orthogonal test, the main and secondary relation of each influence factor is decalcification pH seed mixing amount agitation The removal rate of fluorine, arsenic and lead in the waste water is 90.09%, 99.64%, 96.26%, respectively, 7.95mg/L, 0.28 mg/L, 0.42 mg/L, and the content of other heavy metals are below the relevant standards, and the concentration of calcium ions in waste water is below saturation state after decalcification treatment. Comparing the new technology with the original technology, the new technology is less than the traditional technology in the aspect of material consumption and energy consumption. Compared with the original technology, the oxidation aeration time of the new technology is shortened by 60min compared with the original technology, and the dosage of neutralization agent is reduced by 2mL.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X781.3

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