Effect of metallurgical dust on NO emissions during coal combustion process

• Published in: Journal of iron and steel research, international international, 2018, Vol.25 (1), p.19-27
• Main Authors: Gao, Zhi-fang, Long, Hong-ming, Chun, Tie-jun, Wu, Zhao-jin, Yu, Zheng-wei
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Engineering; Machines; Manufacturing; Materials Engineering; Materials Science; Metallic Materials; Original Paper; Physical Chemistry; Processes
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1007/s42243-017-0007-x

NO emissions from coal combustion are receiving significant attention in recent years. As a solid waste generated from metallurgical industry, metallurgical dust (MD) contains a large amount of metal oxides, such as Fe 2 O 3 , CaO, SiO 2 and Al 2 O 3 , as well as other rare metal oxides. The influence of MD on the NO emissions and the mechanism of the coal combustion systems were analyzed. The results show that the peak values of NO emission decrease with the increase in MD mass percent, and the curve of NO emission can be divided into two stages including rapid generation (400−600 °C) and slow release (800−900 °C). The reduction of NO is significantly affected by temperature, volatile components, O 2 and CO. CO has a significant catalytic action which can deoxidize NO to N 2 . The results obtained by X-ray diffraction and scanning electron microscopy indicate that multiple components in MD, such as Fe 9 TiO 15 , Fe 2 O 3 and TiO 2 , can react with NO to produce TiN. Besides, the alkali metals in MD, such as Na, K and Ca, may catalyze NO precursor to inhibit NO emission. These results indicate that MD is cheap and highly efficient in controlling NO emissions during coal combustion processes.