毕业论文模板.docxVIP

毕 业 论 文题 目 从粉煤灰中提取二氧化硅的工艺研究英文题目 research the technology extracting silica from fly ash学生姓名： 刘欢 申请学位门类：学士学位学 号： 201120100209专 业： 化学工程与工艺学 院： 化学生物与材料科学学院指导老师： 邹丽霞 职称：教授二 0 一 五 年 六月 5 日从粉煤灰中提取二氧化硅的工艺研究刘欢research the technology extracting silica from fly ashLiuHuan2014年5月10号摘要本文介绍了从江西某地发电厂产生的粉煤灰中提取二氧化硅（白炭黑）的几种方法：气相法，溶胶一凝胶法，沉淀法。比较了他们的优缺点之后,本论文采用的是沉淀法提取二氧化硅的方法。将粉煤灰和溶度30%-50%的氢氧化钠溶液按1.5:1—3.0:1,的比例混合加热至90℃—140℃，反应20min—90min，冷却，过滤。再用4%的氢氧化钠对滤渣进行洗涤，过滤，提取滤液。将两次过滤过滤所得的滤液进行蒸发浓缩，结晶。然后通入二氧化碳，使溶液PH值达到7.0。得到二氧化硅沉淀，然后进行过滤，清洗，烘干，干燥，得到二氧化硅含量最高94%的二氧化硅固体。通过实验研究发现，当氢氧化钠溶度为40%，液固比为2.5:1，反应时间为60min，反应温度为110℃，溶液PH为7.0的条件时，二氧化硅的产率最高。沉淀法提取二氧化硅具有实验器材和材料要求少，操作简单，实验时间短，二氧化硅含量比较高的优点。对于粉煤灰的处理和利用有很好的前景，还能够实现对粉煤灰的回收利用，同时也减少了粉煤灰对环境的污染。实现了资源的合理利用，具有良好的社会效益和良好的济价值！关键词：粉煤灰 、二氧化硅 、沉淀法 、提取ABSTRACTThis article describes several methods of fly ash from power plants in Jiangxi toextract silica (silica) are: gas, sol-gel method, precipitation method. After comparing their strengths and weaknesses, this paper is a method used to extract precipitated silica. The fly ash and solubility of 30% -50% of the sodium hydroxide solution of 1.5: 1-3.0: 1, the ratio of mixed and heated to 90 ℃ -140 ℃, the reaction 20min-90min, cooledandfiltered. 4% sodium hydroxide and then the filter residue was washed, filtered, and the filtrate was extracted. The two filters filtering the resulting filtrate was concentrated by evaporation, crystallization. Then with carbon dioxide, the solution PH value of 7.0. Silica precipitate, followed by filtration, washing, drying, and dried, to give a silica content of up to 94 percent silica solids. Experimental study found that when the solubility of 40% sodium hydroxide liquid to solid ratio of 2.5: 1, reaction time was 60min, the reaction temperature was 110 ℃, the solution for the condition PH 7.0, silica highest yield. Extraction precipitated silica has a small laboratory equipment and material requirements, simple operation, test time is short, the advanta