氯化焙烧粉煤灰脱除Pb、Cd的机理及其应用  

Mechanism and Application Research on Removal of Pb and Cd from Coal Fly Ash by Chlorinating Calcination

作　　者：黄齐真 石林 何柳青[1] Huang Qizhen;Shi Lin;He Liuqing(School of Environment and Energy,South China University of Technology,Guangzhou,Guangdong,China;The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters of Education,Guangzhou,Guangdong,China)

机构地区：[1]华南理工大学环境与能源学院,广东广州510006 [2]工业聚集区污染控制与生态修复教育部重点实验室,广东广州510006

出　　处：《矿产综合利用》2023年第6期187-196,共10页Multipurpose Utilization of Mineral Resources

基　　金：国家科技支撑计划项目(2015BAD05B05+2);中山市社会公益与基础研究项目(2020B2004)。

摘　　要：这是一篇冶金工程领域的论文。采用氯化钙作为氯化剂,对粉煤灰中重金属进行了脱除实验。考查了焙烧温度、焙烧时间和CaCl_(2)添加量对重金属去除率的影响。将实验结果与热力学计算结果相结合,阐明了粉煤灰氯化焙烧脱除重金属的机理,并对焙烧过程的动力学模型进行了讨论。此外,以粉煤灰为原料制备土壤调理剂,通过盆栽实验研究其肥效。研究发现,添加16%氯化钙和高温锻烧40 min后,混合物中Pb和Cd的含量分别下降了89.26%和76.88%,而余量仅为10.22 g/t和0.54 g/t。粉煤灰中含有的石英、莫来石、氧化铝、氧化钠等组分促进CaCl_(2)的分解。PbO和CdO不直接与CaCl_(2)反应,而是主要与CaCl_(2)分解生成的HCl反应生成挥发性氯化物。动力学结果表明,Pb和Cd的氯化挥分行为受界面化学反应控制,Pb氯化挥发的表观活化能为84.54 kJ/mol,Cd氯化挥发的表观活化能为44.96 kJ/mol。盆栽实验表明,制备的土壤调理剂能改善土壤环境,促进香葱对营养物质的吸收,改善香葱品质,添加CaCl_(2)能降低产品中的重金属含量,提高有效钙含量。研究提供了一种综合利用粉煤灰的方法。This is an essay in the field of metallurgical engineering.Calcium chloride was used as chlorination agent to conduct the heavy metals removal experiments for coal fly ash,investigating the effects of calcination temperature,calcination time and amount of CaCl_(2)on the removal rate of heavy metals.The results of calcination experiments and thermodynamic calculation demonstrate the mechanism of heavy metals removal in fly ash by using chlorinating volatilization method;further,the kinetic model of chlorinating process was discussed.Moreover,the coal fly ash,as raw material,was used to produce soil conditioner which was studied to discover its fertilizing effect by pot experiments.Studies found that the remaining contents of Pb and Cd in mixture were 10.22 g/t and 0.54 g/t,respectively,which meant 89.26%of Pb and 76.88%of Cd were decreased after addition of CaCl_(2)at high calcination temperature for 40 min.The mineral of mullite,quartz,alumina and disodium oxide in fly ash contributed to the decomposition of CaCl_(2).PbO and CdO mainly reacted with HCl formed by the decomposition of CaCl_(2)to form volatile chloride,meaning the oxides do not directly react with CaCl_(2).thermodynamic models fitting implied that the chlorination of Pb and Cd were controlled by the chemical reaction,and the apparent activation energy of reactions was 84.54 and 44.96 kJ/mol,respectively.Further,the pot experiments showed that the synthesized soil conditioner can improve the condition of the soil,promote nutrient absorption of chives,and improve the quality of chives.The effective calcium content of soil conditional product was increased after the reduction of heavy metals by adding CaCl_(2).This research provides a method for comprehensive utilization of fly ash.

关 键 词：冶金工程 粉煤灰 氯化焙烧 重金属去除 土壤调理剂 

分 类 号：TD95[矿业工程—选矿]