Formation mechanism of an undesirable by-product in the mild hydro-chemical process for the extraction of alumina from fly ash and its mitigation

doi:10.1016/j.hydromet.2019.04.012

	Formation mechanism of an undesirable by-product in the mild hydro-chemical process for the extraction of alumina from fly ash and its mitigation
	Ding, Jian 1; Ma, Shuhua 1; Xie, Zongli 2; Wang, Xiaohui 1; Zheng, Shili 1; Zhang, Yi 1
刊名	HYDROMETALLURGY
	2019-06-01
卷号	186 页码:292-300
关键词	Fly ash Alumina extraction Product-layer coating Hydro-chemical process
ISSN号	0304-386X
DOI	10.1016/j.hydromet.2019.04.012
英文摘要	The mild hydro-chemical process has been commercially demonstrated as an effective method to extract alumina from high alumina fly ash. This study investigated the formation mechanism of an undesirable aluminum containing by-product, hydrated sodium calcium aluminosilicate (HSCA, 1.2Na(2)O center dot 0.8CaO center dot Al2O3 center dot 2SiO(2)center dot H2O), produced during the mild hydro-chemical process and its mitigation strategy. The effects of reaction temperature, residence time and mole ratio of calcium to silicon on the alumina extraction and phase transformation of the leaching residues have been investigated, confirming the formation of HSCA phase being responsible for the decrease of alumina extraction efficiency. At the low Ca(OH)(2) addition, the HSCA phase could be easily transformed from Na8Al6Si6O24(OH)(2)(H2O)(2) combining with Ca(OH)(2). On the other hand, when the addition of Ca(OH)(2) was abundant, the existence of the NaCaHSiO4 product layer would insulate most of Ca(OH)(2) from the Na8Al6Si6O24(OH)(2)(H2O)(2) causing formation of HSCA. Based on the reaction mechanism and coating effect analysis, the mitigation strategy was also proposed. By increasing stirring speed to break the NaCaHSiO4 coating layer, HSCA phase could be completely avoided and a qualified alumina extraction efficiency of 90.84% could be achieved.
资助项目	National Natural Science Foundation of China[51774261] ; Nation 973 Project of China[2013CB632601] ; China Scholarship Council (CSC) ; Xilingol Vocational College[Y69019L088]
WOS关键词	COAL ; ACID
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000473837400035
资助机构	National Natural Science Foundation of China ; Nation 973 Project of China ; China Scholarship Council (CSC) ; Xilingol Vocational College
内容类型	期刊论文
源URL	[http://ir.ipe.ac.cn/handle/122111/30194]
专题	中国科学院过程工程研究所
通讯作者	Ma, Shuhua; Zheng, Shili
作者单位	1.Chinese Acad Sci, Inst Proc Engn, CAS Key Lab Green Proc & Engn, Natl Engn Lab Hydromet Cleaner Prod Technol, Beijing 100190, Peoples R China 2.CSIRO Mfg, Private Bag 10, Clayton, Vic 3169, Australia
推荐引用方式 GB/T 7714	Ding, Jian,Ma, Shuhua,Xie, Zongli,et al. Formation mechanism of an undesirable by-product in the mild hydro-chemical process for the extraction of alumina from fly ash and its mitigation[J]. HYDROMETALLURGY,2019,186:292-300.
APA	Ding, Jian,Ma, Shuhua,Xie, Zongli,Wang, Xiaohui,Zheng, Shili,&Zhang, Yi.(2019).Formation mechanism of an undesirable by-product in the mild hydro-chemical process for the extraction of alumina from fly ash and its mitigation.HYDROMETALLURGY,186,292-300.
MLA	Ding, Jian,et al."Formation mechanism of an undesirable by-product in the mild hydro-chemical process for the extraction of alumina from fly ash and its mitigation".HYDROMETALLURGY 186(2019):292-300.