粉煤灰制备聚硅酸铝铁絮凝剂及对高浊水的处理研究.pdf

Y1526780
分类号:X1-X8
10710-06290626
岁大
硕士学位论文
粉煤灰制备聚硅酸铝铁絮凝剂及对高浊水的
处理研究
王曦
导师姓名职称
董岁明教授
申请学位级别
工学硕士学科专业名称
环境工程
论文提交日期2009年5月20日论文答辩日期2009年5月27日
学位授予单位
长安大学
答辩委员会主席
钱。会
学位论文评阅人
钱会新德武
摘要
废物资源化利用是经济可持续发展和环境生态保护的重要途径之一,本论文以
包头某火力发电厂燃烧排出的固体废弃物粉煤灰为研究对象,通过对其化学组成
成分分析可知,粉煤灰中Al2O2的含量为27,2%,Fe2O3的含量为9.32%,SiO2的
含量为57.88%,具备助溶酸浸提出这几种元素并制备聚合硅酸铝铁的条件。资料
分析表明:粉煤灰中的Feけ在酸性条件下较易溶出;而二氧化硅和氧化铝是以复
盐3 Al203 Sio2的形式存在,在一般条件下很难溶于酸或碱,需要添加助溶剂来打
开Si—AI键。首先进行了助溶和酸浸试验,研究证明,加入碳酸钠作助溶剂,可
使铝铁硅的浸出率达70%以上。并通过试验确定了使铁铝达到最高浸出率较佳的
助溶和酸浸工艺条件为:在粉煤灰中加入Na2CO3,加入量为Na2CO2/SiO2比为0.5
在高温电阻炉中焙烧1小时、焙烧温度为900℃时:再将得到的产品用4moM盐酸,
在110℃下搅拌浸取1小时,此时,铝、硅、铁的浸出率最高,原料利用率最好。
其次利用试验所获取的铝、硅、铁为原料制备了聚合硅酸铝铁絮凝剂,并对絮凝
剂制备过程中影响较大的几个因素:硅、铝和铁元素之比、絮凝剂的pH值、熟化
温度等设计了正交试验,正交试验的结果表明:Si:Al(mol:mol)为1:0.5、
Si:Fe( mol mol)为1:05、絮凝剂pH值为1.1、熟化温度60℃、熟化时间为2小时时
制备条件较佳。最后利用制备出的聚硅酸铝铁( PAFSI)絮凝剂分别对高岭土和硅
藻土悬浊液进行絮凝试验,确定了最佳的絮凝条件:当硅藻土用量为2g时,絮凝
剂用量为7.5ml,水样pH值为8时,絮团粗大,沉降速度较快,沉积物体积较小,
透光率为79.6%,絮凝效果最佳。并用制备出的 PAFSI与聚氯化铝和聚硫酸铁的絮
凝效果进行了对比,试验结果表明自制的 PAFSI的絮凝效果好于聚氯化铝和聚硫
酸铁的絮凝效果
关键词:粉煤灰、助溶剂、浸出率、酸浸工艺、聚硅酸铝铁絮凝剂、絮凝效果
Abstract
Utilization of reclamation wastes is an important means for the sustainable development
of the economy and the protection of the ecological environment In the thesis, the study of
solid excretory product, fly ash, xhausted from a thermal power plant in Baotou. By
analyzing the chemical elements, its Al O content is 27.22 percent, its Fe2 0 content is 9. 32
percent and its Sio2 content is 57.88 er cent, which avin e condition to extract those
kinds of elements and to prepare PAFSI by adopting technology of hydrotropy and
technology of acid pickling. Analysis proves that the Fe"element of fly ash is easily out in
acid environment. Aluminum oxide and silicon dioxide in double salt 3 A120 Si02 form.
Under normal operation, hey are very hard soluble in acid or alkali. In order to destroy the
chemical on the need o added co solvent ino them First, the experiment is performed
utilizing technology of hydrotropy and technology of acid pickling. This test shows that
added sodium carbonate as co solvent could make leaching yield amount to 70 percent, and
come to the conclusion that the better condition to make iron and aluminum up to the
highest leaching yield. The best conditions were as follows: the first step, added Na2c03
in o fly ash and the ratio of addition is 0.5, calcined them for 1 hour in high-temperature
electric resistance furace and the calcinations is at a emperature of 900 C. The second step.
stir and leach the product 1 hour at a temperature of 110C with 4mo /1 hydrochloric acid.
Then, using the obtained aluminum, silicon and iron as raw material prepared PAFSI,and
design an orthogonal test for the several factors during the preparation: silicon, aluminum
and iron rat, e ph of flocculants, emperature, etc. The result of orthogonal test revealing
that are better conditions of preparation, when Si: A(mol: mo)is 1 0.5, Si Fe(mol: mo1)is
1: 0.5, PH value of flocculants is1. 1, temperature is 60C, curing time is 2 hours. Last,utilizing
prepared PAFSI flocculation separately to test on kaolin and suspension, carrying out the
flocculation test de ermined the best condi ions of flocculation: whe