化工进展 ›› 2021, Vol. 40 ›› Issue (6): 3058-3071.doi: 10.16085/j.issn.1000-6613.2020-1384

• 化工过程与装备 • 上一篇    下一篇

循环流化床粉煤灰理化特性及元素溶出行为研究进展

马志斌(), 张学里, 郭彦霞, 程芳琴()   

  1. 山西大学资源与环境工程研究所,国家环境保护煤炭废弃物资源化高效利用技术重点实验室,山西低附加值 煤基资源高值利用协同创新中心,山西 太原 030006
  • 收稿日期:2020-07-20 修回日期:2021-01-12 出版日期:2021-06-06 发布日期:2021-06-22
  • 通讯作者: 程芳琴 E-mail:mazhibin@sxu.edu.cn;cfangqin@sxu.edu.cn
  • 作者简介:马志斌(1987—),男,副教授,硕士生导师,研究方向为工业固废资源化利用。E-mail:mazhibin@sxu.edu.cn
  • 基金资助:
    国家重点研发计划(2017YFB0603101);NSFC-山西煤基低碳联合基金(U1610254);山西省研究生教育创新项目(2020SY009)

Research progress on characteristics and element dissolution behaviors of circulating gluidized bed-derived fly ash

MA Zhibin(), ZHANG Xueli, GUO Yanxia, CHENG Fangqin()   

  1. Institute of Resources and Environmental Engineering of Shanxi University, State Environmental Protection Key Laboratory on Efficient Resource-utilization Techniques of Coal Waste, Collaborative Innovation Center of High Value-added Utilization of Coal-relate Waste, Taiyuan 030006, Shanxi, China
  • Received:2020-07-20 Revised:2021-01-12 Online:2021-06-06 Published:2021-06-22
  • Contact: CHENG Fangqin E-mail:mazhibin@sxu.edu.cn;cfangqin@sxu.edu.cn

摘要:

综合论述了循环流化床(CFB)粉煤灰粒度、微观形貌、化学及物相组成、化学结构等理化特性,并与煤粉炉(PC)粉煤灰进行对比分析,突出了CFB灰在理化特性方面的独特性。其次,总结了CFB灰在酸碱体系中主要元素溶出行为及浓度、液固比、反应时间和温度等因素对溶出行为的影响。结果表明,CFB灰中铝硅聚合度低于PC灰,物相以无定形硅铝酸盐为主,晶体矿物质质量分数之和仅为灰质量的20%~30%。同等条件下CFB灰中铝在酸溶液的溶出活性高于PC灰,使得CFB灰在有价元素提取方面更具优势。然而,随着铝在酸溶液中的溶出,硅逐渐累积并附着在颗粒表面,阻碍了铝的进一步溶出。因此,综合考虑CFB灰有价元素温和提取及酸浸渣利用可大幅提高技术经济性。在碱性体系中CFB灰主要溶出元素为硅和铝,目前对CFB灰无定形硅铝酸盐中硅铝在碱性体系溶出行为缺乏深入的认识,加强该方面研究可提高对CFB灰碱激发过程胶凝机理的认识,从而促进CFB灰制备胶凝材料方面的发展。

关键词: 循环流化床粉煤灰, 理化特性, 酸溶, 碱溶, 元素溶出

Abstract:

The physical and chemical characteristics of circulating fluidized bed-derived fly ash, such as particle size distribution, micromorphology, chemical composition, phase composition, and chemical structure, were summarized in this review. Characteristics of CFB-derived fly ash and pulverized coal (PC) boiler-derived fly ash were discussed, and the uniqueness of CFB-derived ash was highlighted. The dissolution behaviors of valuable elements in CFB-derived ash via acid and alkali leaching and the effect of key factors on them were also discussed. The results show that the polymerization degree of silicon and aluminum in CFB-derived ash is lower than that in PC-derived ash. The contents of crystalline minerals in CFB-derived ash are only 20%—30%, and the others are amorphous aluminosilicates. Under the same conditions, the dissolution activities of valuable elements in CFB-derived ash during acid leaching are higher than those in PC-derived ash, which makes CFB-derived ash more advantageous in the extraction of valuable elements. However, the accumulation of residual Si on the particle surface hinders the further dissolution of Al in acid solution. Therefore, a comprehensive consideration of the mild extraction of valuable elements in the CFB-derived ash and the utilization of acid leaching residues can greatly improve technical and economic efficiency. Si and Al are the main dissolved elements in the alkali solutions. At present, there is still a lack of in-depth understanding of the dissolution behavior of Si and Al from CFB-derived ash in alkaline systems. The strengthening in this area can improve the understanding of the gelation mechanism during the alkali activation process, and thereby promoting the development of preparation of cementing materials using CFB-derived fly ash.

Key words: circulating fluidized bed-derived fly ash, characteristics, acid leaching, alkali leaching, element dissolution

中图分类号: 

  • TQ536.4