Effects of reducing environment and fusible components on carbothermal reduction-nitridation reaction of coal gangue at high temperature under N2 atmosphere

被引:4
|
作者
Ma, Zhibin [1 ,2 ]
Wen, Chaolu [1 ]
Yan, Kezhou [1 ]
Guo, Yanxia [1 ]
Cheng, Fangqin [1 ]
机构
[1] Shanxi Univ, Collaborat Innovat Ctr High Value Added Utilizat, Inst Resources & Environm Engn, State Environm Protect Key Lab Efficient Utilizat, Taiyuan 030006, Shanxi, Peoples R China
[2] Univ Western Australia, Ctr Energy M473, 35 Stirling Highway, Crawley, WA 6009, Australia
基金
中国国家自然科学基金;
关键词
Coal gangue; Coal-coke powder; CRN reaction; Fusible components; beta-SiAlON; BETA-SIALON WHISKERS; TRANSFORMATION BEHAVIOR; COMBUSTION; KAOLINITE; MECHANISM; CERAMICS; POWDER; GLASS;
D O I
10.1016/j.ceramint.2019.07.325
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
The synthesis of SiAlON materials by the carbothermal reduction-nitridation (CRN) method paves the way for utilization of coal gangue with significant economic benefits. Excessive carbon (C), which provides a high residual C content in the product, is added to the raw materials to ensure a high yield of SiAlON. The industrial solid waste of coal-coke powder is used as a reductant. In this study, the effects of the reducing environment and C content on the CRN reaction of coal gangue using corundum and graphite crucibles are investigated and a method to reduce the amount of C added to the raw materials is proposed. The process is carried out under a N-2 flow in the range of 1300-1500 degrees C with a holding time of 3 h. The effects of fusible components including CaO, Fe2O3, and MgO on the CRN reaction and micromorphology are discussed. The graphite crucible considerably promotes the conversion of mullite to beta-SiAlON and is effective for the reduction in residual C content in the product. When the graphite crucible is used, the mullite wholly transforms to beta-SiAlON and corundum, and beta-SiAlON and AlN at 1400 degrees C when the C contents in the raw materials are 11% and 18%, respectively. The content of residual C in the product is approximately 1% (or lower). The beta-SiAlON content decreases with the additions of CaO and MgO in the raw materials owing to sintering and melting. The addition of Fe2O3 promotes the formation of beta-SiAlON whiskers according to the vapor-liquid-solid mechanism. These results would be useful in parameter optimization for a cleaner production of beta-SiAlON powder using the CRN method.
引用
收藏
页码:22829 / 22840
页数:12
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