共查询到20条相似文献,搜索用时 31 毫秒
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Zili Yang Dongyue Wang Xia Yangchao 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(4):420-426
Beneficiation of clean coal from flotation tailings with a high intergrown ash content is gaining popularity in China. It not only improves the utilization rate of coal resources but also reduces environmental pollution. In this paper, a novel gravity–flotation process is proposed to concentrate low-ash fine coal and includes the disposal of tailings via gravity, grinding liberation, and froth flotation. The experimental results show that the clean coal had an ash content of 12.33% and the yield from the flotation tailings was 32.24% with an ash content of 46.39%, which has economic value in the current market. 相似文献
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Effect of different grinding conditions on the dissociation and flotation of difficult-to-float coal
G. Cheng J. T. Liu X. H. Gui Z. B. Hu Y. T. Wang 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(8):1103-1109
The recovery of clean coal can be improved through grinding. In this study, grinding and flotation experiments were conducted on difficult-to-float coal. Results show that the particle size obtained from ball milling is finer than that obtained from rod milling. However, the particle size distribution obtained from rod milling is more evenly distributed than that obtained from ball milling. The contact styles of steel rod and steel ball are “line contact” and “point contact,” respectively. Results from the flotation experiments are consistent with those from the orthogonal experiments. 相似文献
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Chenwei Li Lunan Dong 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(3):373-379
In this paper, clean coal was recovered from tailings by flotation with the aid of ultrasonic irradiation. Flotation test, coal surface scanning and collector adsorption measurement were carried out. The results show that ultrasonic alleviated slime coating and decreased collector adsorption on coal surfaces. Meanwhile, the combustible recovery increased while the recovery of ash-formed minerals decreased. Particles with different size and density fractions have different flotation behaviors, which were also analyzed by measuring size fraction distribution and density fraction distribution of clean coal. This practice saved coal resources and benefitted environment. 相似文献
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Weining Xie Yaqun He Hong Li Yu Zhang Xiangnan Zhu 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(4):446-452
Raw coal was ground in a Hardgrove mill, and mineral liberation from coal was investigated by float-sink test and electron probe microanalyzer (EPMA). Based on EPMA, associated conditions of mineral were determined. Analyses of energy-size reduction show that energy efficiency decreases with time. For +0.074 mm progenies, yields of particles in ?1.5 g.cm?3 decrease with the increase of size and time, and products in +1.8 g.cm?3 show the opposite trend. EPMA of 0.25–0.125 mm, 1.5–1.8 g.cm?3 products ground for 10 min indicates that only part of minerals are liberated. For ?0.074 mm products, the yield of particles in ?1.5 g.cm?3 decreases by 23.36% in last several minutes, but ash content of +1.8 g.cm?3 also decreases by 13.18%. Since breakage of raw coal in last 9 min does not reduce particle size obviously, and liberation degree cannot be improved dramatically, closed grinding of 10 min in Hardgrove mill is proper to balance the size reduction and mineral liberation. 相似文献
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Xiangnan Zhu Qixiao Sun 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(18):2741-2748
The influence of microwave pretreatment on the heating response, moisture content, surface morphology, grindability, and liberation of coal were investigated. The results show that microwave irradiation has a weak effect on the chemical composition, but can reduce moisture content significantly. Intuitionistic evidence was discovered that microwave energy can induce micron cracks on the interface among different minerals. The results of grinding tests show that microwave pretreatment can remarkably promote the fine grinding of coal. Density analysis shows that the liberation degree of grinding products increases with the microwave pretreatment time due to the auxiliary grinding and selective heating effect of microwave radiation. 相似文献
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众所周知,影响风扇磨煤机的性能参数主要有:煤质特性,风扇磨的结构特笥和运动特性,传统的风扇磨的选型往往是根据煤的可磨度,煤粉细度和原煤水份等系数来确定风扇磨的性能参数,实践证明,该选型方法是不完善的,其通用性较差,采用煤种的试磨方法是风扇磨选型和制粉系统设计较为可靠的方法,本文介绍了根据流动和几何相似原理建立起的S02.300型风扇磨试验系统,通过对扎赉诺尔和零林河褐煤的试验验证,把试磨的有关参数移值到大型风扇磨的选型设计中去,为设计院根据煤种合理选择风扇磨及其制粉系统设计提供依据。 相似文献
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基于 40· 5 3型双进双出磨煤机实际工况条件 ,对双进双出磨煤机内流场进行了数值模拟。通过分析磨煤机入口风速和磨煤机填充率对内部流场的影响规律 ,获得了一些有利于磨煤机的研磨、干燥、气力选粉和输粉过程的相关条件。图 5表 2参 7 相似文献
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对双进双出磨煤机进行了冷态模型试验研究,得到了滚筒式磨煤机中气固两相流场的运行特性,进一步弄清了不同流场运行方式对磨煤机干燥、研磨和气力输送过程的影响。所得结果对双进双出磨煤机的设计和控制具有指导作用。 相似文献
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Mengdi Xu Ming Li Wei Jin Yijun Cao 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(20):2394-2399
Oxidized coal is difficult-to-float using conventional diesel as the collector due to the abundant oxygen-containing groups on coal surface. In this study, a short-chain cationic amine, n-octylamine, was added into diesel in 1:4 ratio for enhancing oxidized coal flotation. X-ray photoelectron spectroscopy (XPS) was used to identify the interaction mechanism between diesel-n-octylamine mixture (DO) and oxidized coal. The results showed that the flotation yield using 500 g/t DO mixture was much higher than that of using 2000 g/t diesel under a similar ash content of clean coal. The addition of n-octylamine was proven to be an effective way to lower the oily collector consumption in oxidized coal flotation. XPS showed that electrostatic bonding between n-octylamine and negative-charged hydrophilic sites on oxidized coal surface was responsible for the enhancement of flotation recovery using DO as the collector. 相似文献
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Wanzhong Yin Bin Yang Yafeng Fu Jin Yao 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(5):636-644
In this study, the influence of particle shape and surface roughness on the flotation behavior of +0.25–0.5 mm low-ash coking coal particles was investigated. The low-ash coking coal particles with different particle shape and surface roughness obtained through grinding or crushing were measured, calculated, and analyzed using an optical microscope associated with Image J software. The flotation kinetics tests were conducted in a 0.75 L XFD flotation cell with the presence of frother and in the absence of collector in order to investigate the natural floatability of the low-ash coking coal particles. The flotation kinetics constant of low-ash coking coal particles was calculated through the first-order rate equation. The experimental results illustrated that the flotation kinetics constant increased with increasing the aspect ratio and roughness, while the particle owning high roundness and circularity value led to smaller flotation kinetics constant. Finally, the quantitative contributions of particle shape and roughness of low-ash coking coal particles on flotation performance were established. 相似文献
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Yangchao Xia Rui Zhang Zili Yang Yaowen Xing 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(15):1838-1846
Shale oil (SO) was adopted as flotation collector to recover clean low-rank coal. Gas chromatography-mass spectrometry, flotation, X-ray photoelectron spectroscopy and contact angle measurements were performed to identify the chemical constituents and flotation performance of SO, and the surface properties of low-rank coal. The results indicated that the long-chain hydrocarbon and high viscosity of SO may lead to the higher combustible matter recovery and lower ash content of clean coal. The adsorption of SO significantly enhanced the carbon-bearing content and decreased the C?O content, which was favorable to enhance the hydrophobicity, and thus improve the flotability of low-rank coal. 相似文献
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为了提高煤炭的使用率,降低燃烧产生的烟尘对环境的污染,需要通过选煤进行洁净处理。叙述了选煤中如何通过浮选指标来预测快灰数据的方法。 相似文献
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Wencheng Xia 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(13):1938-1943
Biodiesel is a renewable and clean energy which is being developed day by day. However, oil and coal reserves are decreasing due to an increase in energy demand for the development of social economy. Additionally, fine coal is usually beneficiated by flotation using diesel or kerosene as collectors, which may be a waste of energy. Therefore, using biodiesel as a collector for coal flotation has its potential value. In this investigation, biodiesel was used as a collector for coal flotation. Three bituminous coal samples with different coal ranks were selected, that is, gas coal, coking coal, and lean coal. FTIR results showed that biodiesel contained much more abundant unsaturated fatty acids than diesel. Flotation results showed that the flotation performances of three coal samples using biodiesel as collector were similar to that using diesel as collector. Even better, the concentrate yields of three coal samples using biodiesel as collector were a little higher than that using diesel as collector, while their concentrate ash contents were similar. Throughout this paper, it was proved that biodiesel could have a potential application in coal flotation. 相似文献
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You Zhou Guosheng Li Xiangnan Zhu 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(10):1209-1215
The separation of particles by flotation is achieved based on the difference in their surface properties. The controlling step for successful flotation is bubble–particle attachment. The time required for attachment of a particle to an air bubble is defined as the attachment time. Given that attachment times cannot be measured in flotation cells due to the presence of a large number of bubbles and particles which are in motion, the only possibility is to calculate attachment times using the fundamental flotation model. The focus of this paper is to determine the attachment times of low-rank coal in the presence of air bubbles and oily bubbles. The flotation recovery, the rate constant and the attachment efficiency for the oily bubble–coal flotation system were found to be higher than those for the air bubble–coal flotation system. The difference between the flotation rate constants for the air bubble–coal flotation system and that for the oily bubble–coal flotation system was small. However, when considering the difference between the attachment efficiency results, the opposite was true. The relationship between the attachment efficiencies and the attachment times was found to be an exponential decay. The similar trend was also observed for the curve showing the relationship between the flotation rate constants and the attachment times. This work shows the importance of determination of attachment times in coal flotation research. 相似文献
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Meijun Wang Chunhui Fu Kechang Xie 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(3):347-353
Two Chinese coals were selected to investigate the effects of flotation on the release behavior of sulfur and nitrogen during pyrolysis. The results show that the removal rate of minerals and sulfur-containing compounds from raw coal by flotation are closely related to coal properties. The significant alterations of sulfur and nitrogen forms on coal surface are mainly presented in the decrease of sulfidic-S, thiophenic-S, and pyridinic-N, the increase of sulfones-S and quaternary-N after flotation. The release of sulfur- and nitrogen-containing gases during pyrolysis of raw and clean coals has evident differences, which are mainly caused by the change of the relative proportions of different sulfur and nitrogen forms in the process of flotation. 相似文献
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《Energy Policy》2015
Energy consumption in China is currently dominated by coal, a major source of air pollution and carbon emissions. The utilization of clean coal technologies is a likely strategic choice for China at present, however, although there have been many successes in clean coal technologies worldwide, they are not widely used in China. This paper examines the challenges that China faces in the implementation of such clean coal technologies, where the analysis shows that those drivers that have a negative bearing on the utilization of clean coal in China are mainly non-technical factors such as the low legal liability of atmospheric pollution related to coal use, and the lack of laws and mandatory regulations for clean coal use in China. Policies for the development of clean coal technologies are in their early stages in China, and the lack of laws and detailed implementation requirements for clean coal require resolution in order to accelerate China's clean coal developments. Currently, environmental pollution has gained widespread attention from the wider Chinese populace and taking advantage of this opportunity provides a space in which to regain the initiative to raise people’s awareness of clean coal products, and improve enterprises’ enthusiasm for clean coal. 相似文献