摘要
二次铝灰中含有氟化物、氮化物、碳化物等有毒有害成分,对其安全处置具有重要的环境意义。本研究结合钙盐沉淀法,提出了以工业固废脱硫石膏固化二次铝灰中氟离子的技术思路,并结合偏高岭土的高火山灰活性,进一步改善了脱硫石膏-二次铝灰组成的气硬性胶凝体系的耐水性能。试验对比研究了不同脱硫石膏/二次铝灰、脱硫石膏/偏高岭土/二次铝灰比例所组成的复合胶凝体系中氟离子的溶出特性及耐水性能。利用XRD、SEM及热力学参数分析了脱硫石膏、偏高岭土对二次铝灰中氟离子的固化机理。研究结果表明:脱硫石膏可以与二次铝灰中的可溶性氟离子生成氟化钙,对氟离子具有良好的固化效果,但脱硫石膏-二次铝灰组成的固化体系的耐水性较差;以适量偏高岭土替代脱硫石膏形成的脱硫石膏-偏高岭土-二次铝灰复合体系对二次铝灰中氟离子的固化效果无不良影响,且可显著改善复合固化体系的耐水性。此研究结果为二次铝灰的安全处置及资源化应用提供了理论指导。
The secondary aluminum dross(SAD)contains toxic substances,such as fluoride,nitride,carbide and so on.It has important environmental significance for the safe disposition of SAD.In this study,fluoride ions in SAD were solidified with flue gas desulfurization gypsum(FGDG)by calcium salt precipitation method.Then,metakaolin(MK)was added to improve the water resistance of FGDG-SAD cementitious system.The fluorine ions dissolution performance and water resistance of FGDG-SAD and FGDG-MK-SAD were studied by using different proportions.The solidification mechanism of fluoride ion in SAD was analyzed by XRD,SEM and thermodynamic parameters.The results show that FGDG can reacted with soluble fluoride ions in SAD to form calcium fluoride,which has a good solidification effect on fluoride ions.However,FGDG-SAD cementitious system has poor water resistance.The water resistance of FGDG-SAD cementitious system can be significantly improved by replacing FGDG with an appropriate amount of MK,and has no adverse effect on the fluoride ion solidification.The research results provide theoretical guidance for the safe disposal and resource utilization of SAD.
作者
宋学锋
杨尔康
SONG Xuefeng;YANG Erkang(School of Materials Science and Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2023年第7期92-97,共6页
Materials Reports
基金
陕西省科技厅资助项目(2018SF-367)。
关键词
二次铝灰
脱硫石膏
偏高岭土
氟离子浸出
耐水性
secondary aluminum dross
desulfurization gypsum
metakaolin
fluoride ion leaching
resistance to water
