Removal of sodium (Na2O) from alumina extracted coal fly ash by a mild hydrothermal process

被引：15

作者：

Li, Huiquan ^{[1
]}

Hui, Junbo ^{[1
,2
]}

Wang, Chenye ^{[1
]}

Bao, Weijun ^{[1
]}

Sun, Zhenhua ^{[1
]}

机构：

[1] Chinese Acad Sci, Key Lab Green Proc & Engn, Inst Proc Engn, Natl Engn Lab Hydromet Cleaner Prod Technol, Beijing 100190, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

来源：

HYDROMETALLURGY | 2015年 / 153卷

关键词：

Coal fly ash; NaCaHSiO4; Sodium removal; Hydrothermal process; C-S-H; ALKALI;

D O I：

10.1016/j.hydromet.2015.02.001

中图分类号：

TF [冶金工业];

学科分类号：

0806 ;

摘要：

Sodium was removed from alumina-extracted coal fly ash (CFA) by using diluted NaOH solution. The effects of reaction temperature, reaction time, and NaOH concentration on sodium removal were studied. Result shows that the sodium (Na2O) content of the alumina-extracted CFA was decreased from 20 wt.% to 0.6 wt.% under optimal conditions: temperature of 185 degrees C, NaOH concentration of 50 g/L, residence time of 2 h, and liquid-to-solid ratio of 40 for water washing. The possible mechanism of sodium removal was also investigated using Fourier transform infrared spectroscopy, X-ray diffraction analysis, and nuclear magnetic resonance spectroscopy. The results indicated that NaCaHSiO4 in the residue was decomposed by NaOH to form NaSiO3 and Ca(OH)(2), and then converted into tobermorite [Ca5Si6O16(OH)(2)center dot nH(2)O] and NaOH. The sodium obtained through the reaction in the residue was mainly combined with the silanol group and then washed with water. (C) 2015 Elsevier B.V. All rights reserved.

引用

页码：1 / 5

页数：5

共 21 条

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