Characterization of 鈥淐hailings鈥? A Char Created from Coal Tailings

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• 作者：Priscilla Tremain ; Jafar Zanganeh ; Lyndal Hugo ; Shane Curry ; Behdad Moghtaderi
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：December 18, 2014
• 年：2014
• 卷：28
• 期：12
• 页码：7609-7615
• 全文大小：429K
• ISSN：1520-5029

文摘

Coal tailings are a waste product of the coal mining process and consist primarily of gangue mineral matter and fine coal particles. In this study, coal tailings sourced from two Australian coal mines (Mine A and Mine B) were subjected to a slow pyrolysis process at temperatures of 400鈥?00 掳C to create char hereafter known as 鈥渃hailings鈥? Chailings were originally conceptualized based on the concept of biochar and are a novel waste management strategy for coal tailings. Several methods were used to characterize chailings and quantify the effect of different pyrolysis conditions. X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques identified the primary mineral constituents as silica (i.e., quartz) and aluminosilicates (i.e., kaolinite or illite). Clear morphologic changes were observed via optical and scanning electron microscopy (SEM) for increasing pyrolysis temperature, with evidence of swelling and devolatilization apparent at high temperatures (>600 掳C). Proximate analyses indicated near complete devolatilization was apparent at 800 掳C for both mines, with thermogravimetric analysis (TGA) revealing that peak devolatilization occurred at 455 掳C for Mine A and 467 掳C for Mine B. A substantial increase in surface area with increasing pyrolysis temperature was observed for Mine A chailings from 2.7 m²/g at 400 掳C to 75.3 m²/g at 800 掳C, because of the presence of microporosity, while Mine B chailings decreased from 2.4 m²/g at 400 掳C to 1.2 m²/g at 800 掳C, which was attributed to macroporosity and aggregation of particles. Properties of high-temperature (>600 掳C) chailings, namely, surface area, porosity, and pH offer promise for future investigations regarding the application of chailings to soil.