Processes
·
2022
·Vol. 11
·期 1
·102
·
IF 3.352
Libo Liu,Qiming Zhuo,Hongxiang Xu,Donghui Wang
The accurate determination of the coal slime filter cake pore structure has always been a problem in the field of solid–liquid separation. An innovative measurement method for the pore structure of filter cake after filtration dehydration of coal slime water, including the preparation of coal slime filter cake, the solidification of the filter cake, and the preparation and measurement of test filter cake, was established in this paper. Epoxy resin and curing agent can ensure the strength of the filter cake, and red colorant can realize the accurate separation of coal particles and pores. The most suitable perfusate consists of epoxy resin, red colorant, and curing reagent, and the optimal ratio is 12:3:5. The application of the method to the study of the effect of filtration time on the coal slime filter cake pores shows that the modified method is effective. At the initial stage of filtration, intergranular pores formed by coarse particles are the main pores. With increasing filtration time, the macropores formed by the coarse particles are mainly filled with fine particles, and the pore size of the filter cake rapidly decreases. These measuring results and rules are accurate. This method can be conveniently used to study the microstructure of filter cake, pore channel regulation, filtration dehydration mechanisms, etc.Keywords:pore structure;coal slime filter cake;solidification;filtration time
研究领域:
矿业工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Zhanshi Ni,Haobo Bi,Hao Shi,Xiang Liu,Junjian Tian,Yurou Yao,Liqun He,Kesheng Meng,Qizhao Lin
The escalating total amount of industrial solid waste is increasingly taxing the ecological environment. Co-combustion technology is seen as a potential solution to this problem. This study investigated the interaction mechanism and carbon dioxide emissions during the co-combustion process of coal slime and biomass (lignin) using a programmed heating method. The experimental results reveal that the two sub-reaction models effectively depict the combustion process of coal slime. In the co-combustion process, the comprehensive combustion and ignition performance of the mixed fuels surpasses that of coal slime, but the stability of the combustion flame is reduced. The combustion performance of the mixed fuel is primarily influenced by two common factors. The interaction between lignin and coal slime significantly changes with the variation of mixing ratio and heating rate . The main product in the combustion process of mixed fuels is carbon dioxide. Due to the competition for oxygen among volatile matter, the emission of carbon dioxide is lower than the theoretical value. When the mass percentage of lignin is 70 %, the impact on carbon dioxide is most pronounced. The experimental results of this study provide a foundation for understanding the interaction mechanism of coal slime and biomass co-combustion. The research findings also provide theoretical guidance for the safe operation of coal slime and biomass co-combustion equipment.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xuefei Zhang,Fanfei Min,Lingyun Liu,Lujun Wang,Qi Liu
Ca 2+ is an important ion in industrial wastewater such as coal slurry water. The concentration of Ca 2+ directly affects the water quality of recycled water, the physicochemical properties of particle surfaces, and the effectiveness of coal beneficiation. However, the determination of Ca 2+ in coal slurry water is influenced by other coexisting metal ions (M: K + , Na + , Mg 2+ , and Al 3+ ) in the system. The complexation color development – visible spectrophotometry (CCDVS) has been proven to be a rapid and accurate way to determine Ca 2+ . This study investigates the impact and mechanism analysis of factors such as the concentrations of coexisting ions (K + : 0–15 mg/L, Na + : 0–2000 mg/L, Mg 2+ : 0–20 mg/L, Al 3+ : 0–0.05 mg/L) and valence states (monovalent, divalent, trivalent) on the accurate determination of Ca 2+ using the CCDVS method. All ions are interested in the indicator, with the light absorption intensity order of Al 3+ (Abs = −1.783) > Mg 2+ (Abs = −1.723) > Ca 2+ (Abs = −1.248) > K + (Abs = −0.268) > Na + (Abs = −0.075) under the same ions concentration (e.g. 16 mg/L). Interestingly, the absorbance of Ca–M mixed solutions shows different trends. For example, adding Na + decreases the absorbance value of Ca 2+ , with a decrease in Abs of 0.065 when the Na + concentration is 2000 mg/L. This indicates a competitive relationship between the complexation color development reaction of Ca and Na due to the same reaction mechanism. However, for Ca–Mg mixed solutions, when the Mg 2+ concentration increases to 15 mg/L, the increase in Abs is 0.078, attributed to the stronger absorption of Mg 2+ occupying the adsorption sites of Ca 2+ . On the contrary, at industrial concentrations, the influence of K + (0–20 mg/L) and Al 3+ (0–0.05 mg/L) on Ca 2+ detection can be ignored. Complementary characterization (XRD, XPS) and DFT theoretical calculations indicate that complexation color development reaction depends on the adsorption of metal ions on the sulfonic acid sites on the indicator. Other metal cations compete with Ca 2+ for the same adsorption sites, and the reactivity of metal ions with the indicator is as follows Al 3+ > Mg 2+ > Ca 2+ > K + > Na + . Therefore, this study provides technical and theoretical support for the development of highly selective Ca 2+ detection methods, aiding in the rational control of chemical agent dosages.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Zhanglei Zhu,Wanzhong Yin,Bin Yang,Yafeng Fu,Jiwei Xue
Slime contamination is an urgent problem that should be solved in coal flotation. The adverse effects of slime contamination, by which low-ash clean coal is covered by high-ash fine slime and hence cannot be separated through the direct flotation process, have been recognized for the past decades. In this investigation, to reduce slime contamination, the reverse-and-direct flotation process was proposed. Flotation results indicated that, based on the similar ash content, the concentrate yield increased by 7.36% using the reserve-and-direct flotation process compared with the two-steps direct flotation process. XPS (X-ray Photoelectron Spectroscopy) and SEM (Scanning Electron Microscopy) results verified that the reduction of fine clay minerals coating on the surface of clean coal was achieved and hence the flotation performance was improved with the reverse-and direct flotation process. Therefore, it can be arrived that the reverse-and-direct flotation process is a potential and effective separation method to upgrade the flotation performance of fine coking coal.
研究领域:
矿物加工工程
·
煤炭浮选技术
✓ 已验证
产品关联
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2016
·Vol. 42
·期 10
·7345-7358
·
IF 1.833
Wang Ruikun,Zhao Zhenghui,Liu Jianzhong,Lv Yukun,Ye Xuemin
Municipal wastewater sludge (hereafter, sludge) is economically recycled by mixing with coal to prepare slurry fuels, called coal sludge slurry (CSS). However, raw sludge needs to be pretreated before being prepared as CSS because of its high viscosity. Alkali and ultrasonication pretreatment can effectively disrupt the sludge flocs and improve slurrying performance. The alkali pretreatment method takes a long time but has a low cost, whereas the ultrasonication pretreatment method needs a high energy input but takes a short time. This study combined these two methods with complementary advantages to reduce the sludge pretreatment time and ultrasonication energy demand to improve the slurrying performance for sludge. Results showed that, compared with only alkali and only ultrasonication, the combined alkali and ultrasonication pretreatment method had stronger effects on reducing slurry viscosity. The characteristic viscosity η
c of CSS prepared by raw sludge was 1663.60 mPa s. It was reduced to 1033.44 and 1472.10 mPa s, respectively, after the sludge was only pretreated by NaOH and Ca(OH) 2 at a dosage of 10 % dry sludge (DS) for 2 h, while it was reduced to 1205.43 mPa s after the sludge was only pretreated by ultrasonication of 30 kJ/g DS. After combined pretreatment, η
c of CSS was reduced to 774.98 mPa s (NaOH of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS) and 1083.24 mPa s (Ca(OH) 2 of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS), respectively. Apparently, the combined method can effectively decrease the alkali dosage or the ultrasonication energy input.
研究领域:
环境科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2024
·Vol. 19
·期 4
·e3074
·
IF 1.4
Fangqin Lu,Lingyun Liu,Chuilei Kong,Hongyu Zhao
Addressing the issue of processing fine kaolinite and quartz particles in coal slime, this study utilized molecular simulation and Density Functional Theory (DFT) to investigate the chelate adsorption characteristics of sodium dodecyl sulfate (SDS) on kaolinite surfaces. As a major clay mineral component in coal slime, kaolinite reduces coal's calorific value but holds potential for industrial and agricultural applications. The research identified distinct interactions between SDS and the tetrahedral Si O layer and octahedral Al O layer of kaolinite, in contrast to quartz, which contains only the tetrahedral Si O layer. This difference is crucial for the effective separation of kaolinite from quartz. The study focused on analyzing SDS adsorption on the (001) and (00-1) planes of kaolinite. The findings revealed strong adsorption of SDS on kaolinite surfaces, especially on the (001) plane, evidenced by significant charge transfer indicating efficient chelation. This effect results from the interaction of SDS's electron-donating atoms (such as S and O) with the metal atoms on the surface of kaolinite. Adsorption strength was quantified through adsorption energy calculations, showing a stronger interaction on the (001) surface. Experimental validations, including single mineral flotation experiments and infrared spectroscopic analysis, further corroborated the simulation outcomes. These tests demonstrated improved flotation recovery of kaolinite in the presence of SDS and with reduced particle size. Infrared analysis revealed that SDS selectively and strongly adsorbs on kaolinite surfaces, as indicated by diminished hydroxyl group stretching vibrations in the FTIR spectrum and changes in absorption peaks related to inorganic vibrations and sulfonic acid groups. The study demonstrates that SDS can selectively and effectively adsorb onto kaolinite surfaces, particularly on the (001) plane, facilitating the efficient extraction of fine kaolinite from coal slime. This research holds significant potential for enhancing the utilization of resources from coal slime in the coal industry, offering both economic and environmental benefits.
研究领域:
矿物加工工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Chunquan Li,Xinlin Wang,Kefu Ma,Jiayu Liu,Fang Yuan,Qizhou Wang,Zhiming Sun
Coal slime-based peroxymonosulfate (PMS) catalytic materials were synthesized utilizing coal slime (CS) as raw material under the N 2 atmosphere in this study. Raw and calcined coal slime were systematically characterized concerning morphologies, pore structures , chemical bonds, phase constituents, and defect density . Results show that after being calcinated with FeCl 2 ∙4H 2 O at 750 °C, the specific surface area increased by nearly 21.0 times higher than that of CS. The addition of FeCl 2 ∙4H 2 O has certain effect on the chemical bonds of calcined coal slime, i.e. the Fe elements can be fixed by the silicon aluminum skeleton with sekaninaite (Fe 2 Al 4 Si 5 O 18 ) and aluminum iron silicon (Al 0.5 Fe 3 Si 0.5 , above 650 °C) generation, and the I D /I G values increase to 2.96 for CS-FeCl 2 -750. In addition, the degradation percentage of phenol by using CS-FeCl 2 can achieve 100% in 25 min under optimized conditions. Furthermore, 1 O 2 plays a major role in phenol degradation, followed by • OH and SO 4 •− in the CS-FeCl 2 /PMS system from the quenching experiments and electron paramagnetic resonance results. Overall, the novel CS-FeCl 2 material displays good application prospects in the field of effluent treatment , with efficient utilization of carbonaceous and silicon aluminum skeleton in coal slime.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Zhe Yang,Yinfei Liao,Hourui Ren,Xiaodong Hao,Xingwei Song,Zechen Liu
Waste motor oil (WMO) is a hazardous oil pollutant in the automobile industry and low-rank coal slime (LRCS) is a solid waste produced during coal preparation. This paper introduces a comprehensive utilization scheme for these two waste resources through froth flotation . Fourier Transform Infrared Spectroscopy (FTIR) measurement showed that WMO contains hydrocarbons and their oxides (alkane, aromatic derives, ester or carboxylic acid). When acting as a collector for the flotation of LRCS, WMO resulted in a cleaned coal yield of 77.29% and an ash content of 8.97% at the dosage of 5 kg/t, which was a significant improvement over the traditional collector, diesel oil. A novel co-treatment scheme for WMO and LRCS was proposed and discussed. The co-treatment scheme can bring high quality products for the coal preparation plant and give an alternative of disposing the WMO. The traditional WMO disposal methods like WMO regeneration may produce secondary pollution while the co-treatment scheme has little and controllable environmental impact. What’s more, the scheme has better economic benefit than LRCS flotation using diesel oil or the WMO traditional disposal method.
研究领域:
能源与资源工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Yafeng Fu,Hongliang Li,Hao Mei,Zeyu Feng,Ruxia Chen,Jianbo Li,Yongmei Wang,Wenbiao Fu
In coal preparation plants, the tailing coal slime filter cake contains large amounts of super fine particles. It can be hypothesized that the large quantity of organically contaminated water may be purified by a capable filtration process. Meanwhile, the treatment process would be an adsorbent recycling free process, with a roasting process followed in the industry. In this study, methyl blue (MB) was selected as the target organic contaminant, and its removal by filtration was investigated. Meanwhile, the adsorption capacity of MB on Tween-80-modified filter cake was discussed and the spatial structure of the filter was analyzed by micro-CT. With an increasing Tween-80 concentration, the adsorption efficiency of the MB initially increased and reached the maximum adsorption value when the Tween-80 concentration was 60 mg/L, and there was no negative effect on solid-liquid separation. The micro-CT test results indicate that after the modification of Tween-80, the spatial structure of the filter cake was greatly improved, resulting in a relatively stronger adsorption capacity and a higher filtration efficiency. These findings of this study are of great significance for reducing the pollution of water resources and improving the filtration efficiency in the coal washing plant.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Zili Yang,Yangchao Xia,Yanzhen Fu,Qinshan Liu,Ming Li,Xiahui Gui
Effective inhibition of clay minerals remains a challenge in the flotation separation of fine coal with high ash content. The quest for efficient, environmentally friendly, and cost-effective depressants to improve the flotation efficiency of fine coal-slime has become a focus of current research. Humic acid (HA), a macromolecular organic compound widely present in nature, is known for its non-toxic, low-cost, and biodegradable properties. In this study, the potential selective depressant HA was utilized to enhance the recovery of low-ash clean coal in the coal-kaolinite system. Adsorption and inhibition mechanisms were explored through contact angle measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) methods. Flotation tests demonstrated that HA, at varying dosages, significantly increased combustible matter recovery while reducing ash recovery compared to conventional flotation. Optimal conditions, with an HA dosage of 750 g/t, resulted in a combustible matter recovery of 40.56 % and an ash content of 17.77 % in the clean coal. Contact angle measurements confirmed that high-dosage HA significantly reduces the coal surface hydrophobicity, resulting in a rapid decline in the recovery of combustible matter. It did not significantly alter the contact angle of kaolinite, however, across the entire range of HA dosages. Furthermore, XPS studies revealed that the reduction in hydrophobicity on the coal surface after HA adsorption is mainly attributed to the coverage of surface carbon–carbon/carbon-hydrogen groups (C–C/C–H) and the increased presence of carbonyl groups (C = O). Additionally, the study found that HA predominantly adsorbs on the Si-OH groups of kaolinite. Finally, AFM results showed that the primary mechanism underlying the altered heterocoagulation behavior between coal and kaolinite is HA’s effect on their interaction forces. The optimal flotation results achieved at the HA dosage of 750 g/t are primarily attributed to the consistent presence of repulsive forces during the approach process and weak adhesion forces during the retraction process between coal and kaolinite, thus reducing kaolinite coating on the coal surface. These findings provide a promising direction for utilizing HA to enhance flotation deashing of high-ash coal-slime.
研究领域:
矿物加工工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Zhanshi Ni,Zhihui Song,Haobo Bi,Chunlong Jiang,Hao Sun,Zhicong Qiu,Liqun He,Qizhao Lin
Facing the severe environmental and energy crisis, how to use solid waste cleanly and efficiently is imminent. In this study, coal slime and cellulose are used for co-combustion experiments. Coal slime and cellulose are tested at mass ratios of 10:0, 9:1, 7:3, 5:5, 3:7, 1:9, and 0:10. When 10 % cellulose is added to the coal slime, the ignition temperature decreases by 169.3 °C, and the ignition characteristic index increased by 2.9 times. The addition of cellulose makes the comprehensive combustion performance of the sample increase exponentially. By analyzing the dominant reaction in the co-combustion process of coal slime and cellulose, the variance contribution rates of the first principal component and the second principal component are 67.84 and 29.18 %, respectively. Co-combustion of coal slime and cellulose enhances the release and combustion of early volatiles. In addition, the evolution law of gaseous products and the temperature dependence of gaseous products in the co-combustion process of coal slime and cellulose are analyzed by fourier transform infrared spectroscopy and two-dimensional correlation spectroscopy, respectively. This study provides a theoretical basis for the large-scale application of co-combustion of coal slime and biomass.
研究领域:
能源与环境科学
·
燃烧化学
✓ 已验证
DOI
高影响因子
International Journal of Coal Preparation and Utilization
·
2024
·
IF 2
Xing Li,Hongzheng Zhu,Xiaojian Wang,Wenliang Zhu
Using the high-speed motion acquisition system, we studied the settling process of the coal flocs under different addition interval time. The gray value and zeta potential of supernatant generally increased as the interval time increased, proving the effect of interval time on coal slime sedimentation. Furthermore, the interval time 25 s presented the smallest floc amount. The floc size and zeta potential were measured via the inverted fluorescence microscope and the micro electrophoresis, respectively. The interval time 25 s presented the fastest settling velocity. The floc amount in supernatant roughly decreased as the zeta potential increased. The settling velocity decreased with the settling time. The results can provide valuable insight into the development of technology for coal slime sedimentation.
研究领域:
矿物加工工程
·
环境科学与工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）