Enhancing flotation removal of unburned carbon from fly ash by coal tar-based collector: Experiment and simulation
Enhancing flotation removal of unburned carbon from fly ash by coal tar-based collector: Experiment and simulation
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DOI：
10.1016/j.fuel.2022.126023
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发表时间：
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期刊：
影响因子：
7.4
通讯作者：
Kang Zheng;Wenjun Zhang;Yijiang Li;An Ping;Feng Wu;Guang-yuan Xie;W. Xia
中科院分区：
文献类型：
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作者：
Kang Zheng;Wenjun Zhang;Yijiang Li;An Ping;Feng Wu;Guang-yuan Xie;W. Xia
粉煤灰中的未燃碳（UC）是决定粉煤灰在砂浆和混凝土工业中进一步利用的重要参数。浮选是去除粉煤灰中UC的有效方法。然而，UC颗粒表面的特定物理化学性质使它们难以漂浮。采用煤焦油基（CTB）捕收剂浮选脱除粉煤灰中的UC。采用扫描电子显微镜-能谱仪（SEM-EDS）、傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）、分子动力学（MD）模拟和诱导时间测试等方法对CTB捕收剂和柴油在UC颗粒表面的吸附机理进行了表征。CTB捕收剂中的含氧官能团和芳环化合物的水平显著高于柴油中的那些。未处理的UC表面、柴油处理的UC表面和CTB捕收剂处理的UC表面上的含氧官能团含量依次降低。分子动力学模拟结果表明，芳香族化合物（二苯并呋喃和萘等）在CTB收集器强烈相互作用和吸附在深的位置与UC表面相比，烷烃（十二烷，柴油等）。烷烃作为捕收剂在粉煤灰浮选过程中是不可缺少的，并且与芳香族化合物协同作用以改善水分子在UC表面上的流动性。CTB捕收剂显著增强了UC颗粒的可浮性，从而改善了从飞灰中浮选去除UC。
The unburned carbon (UC) in fly ash is a vital parameter that governs the further utilization of fly ash in mortar and concrete industry. Flotation is an effective methodology for removing the UC from fly ash. However, the specific physicochemical properties of the UC particle surface make them difficult to float. In this study, a coal tar-based (CTB) collector was used to remove the UC from fly ash through flotation process. The adsorption mechanism of the CTB collector and diesel on the UC particle surface was characterized by scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), molecular dynamics (MD) simulation, and induction time tests. The levels of oxygen-containing functional groups and aromatic ring compounds present in the CTB collector were considerably higher than those in diesel. The oxygen-containing functional group contents on the untreated UC surface, the diesel-treated UC surface, and the CTB collector-treated UC surface decreased in that order. The MD simulation results indicated that the aromatic compounds (dibenzofuran and naphthalene, etc.) in the CTB collector interacted strongly and adsorbed at deep locations with the UC surface compared to the alkanes (dodecane, diesel, etc.). The alkanes are indispensable as the collector in the fly ash flotation process and synergize with aromatic compounds to improve the mobility of water molecules on the UC surface. The CTB collector significantly enhanced the floatability of the UC particle and hence improved the flotation removal of UC from fly ash.