School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001, PR China.
School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001, PR China.
Waste Manag. 2021 Dec;136:283-294. doi: 10.1016/j.wasman.2021.10.024. Epub 2021 Oct 29.
The high carbon content (20-60%) in coal gasification fine ash (CGFA) makes CGFA unable to be directly used in the building materials and ceramic industries, and can only be dissipated in landfills, which brings serious environmental safety problems. This paper uses physical (flotation method) and chemical (multi-stage pickling method) methods to treat CGFA, analyze the separated carbon, and evaluate its application. The carbon content of the filter cake ash (FCA) residual carbon recovered by the flotation method is slightly increased, and the carbon ash separation effect for the water-containing CGFA is poor. The carbon content of dry ash (DA) recovered carbon in acid treatment increased from 16.33% to 89.97%. The specific surface area of the acid-washed recovered carbon is 6-34 times that of the original sample, and the specific surface area of dry ash-HCl/HF/HCl (DA-CFC) is as high as 425.31 m/g, and its pore structure network is more developed than before deashing. After pickling treatment, the microcrystalline structure changes, the carbon skeleton becomes looser, the degree of crosslinking decreases, and the reaction activity increases. The relative content of CC in the acid-washed recovered carbon increased by 6.4-46.3%, and the relative content of functional group CH bonds increased by 48.5-89.5%. Compared with the activation energy of the original sample, the activation energy E of the sample after flotation and acid treatment is reduced, and the reaction activity is enhanced. Flotation and pickling methods can improve the grade of fuel, and multi-stage pickling methods to obtain high specific surface area carbon can be used as a precursor for the preparation of activated carbon. Carbon-ash separation of DA by flotation method can be applied to fuel combustion, fine chemical industry, and road filling. However, for FCA, it is necessary to use a pickling scheme for carbon-ash separation to realize resource utilization and harmlessness.
煤气化细灰（CGFA）的高碳含量（20-60%）使其无法直接用于建材和陶瓷行业，只能在垃圾填埋场中消耗，这带来了严重的环境安全问题。本文采用物理（浮选法）和化学（多级酸洗法）方法对 CGFA 进行处理，分析分离出的碳，并评估其应用。浮选法回收的过滤饼灰（FCA）残余碳的含碳量略有增加，对含水 CGFA 的碳灰分离效果较差。酸处理回收的干灰（DA）中碳的含量从 16.33%增加到 89.97%。酸洗回收碳的比表面积是原始样品的 6-34 倍，酸洗-干灰-HCl/HF/HCl（DA-CFC）的比表面积高达 425.31 m/g，其孔结构网络比脱灰前更为发达。酸洗处理后，微晶结构发生变化，碳骨架变得更加疏松，交联程度降低，反应活性增加。酸洗回收碳中 CC 的相对含量增加了 6.4-46.3%，CH 键官能团的相对含量增加了 48.5-89.5%。与原始样品的活化能相比，浮选和酸处理后的样品的活化能 E 降低，反应活性增强。浮选和酸洗方法可以提高燃料的等级，多级酸洗方法获得高比表面积的碳可以作为制备活性炭的前体。浮选法对 DA 的碳灰分离可应用于燃料燃烧、精细化工和道路填充。然而，对于 FCA，需要采用酸洗方案进行碳灰分离，以实现资源利用和无害化。
