Processes
·
2022
·Vol. 10
·期 6
·1183
·
IF 3.352
Haibing Jiang,Jiufen Liu,Huaifa Wang,Runquan Yang,Wenzhi Zhao,Duo Yang,Song Yin,Liang Shen
Foam is essential in the flotation process. However, the gas–liquid–solid three-phase froth produced in the flotation process has very strong stability and is difficult to burst spontaneously. The existence of these froths will reduce the transport capacity of the pulp and affect the working efficiency of subsequent processes, such as filtration of the flotation concentrate. In this study, a new defoaming device is designed by combining mechanical impact with depressurized defoaming and its defoaming mechanism is analyzed theoretically. In addition, the liquid level height and pulp overflow method are applied to characterize the defoaming efficiency of the new defoaming device. The effects of impeller structure, pressure drop, impeller rotation frequency, and aeration rate on defoaming efficiency were studied. The results show that when increasing the pressure drop, the defoaming increases, but it will also enhance the generation of bubbles. The efficiency of combined mechanical–vacuum defoaming technology is superior under low-pressure drop using an SC impeller. Under −1 kpa vacuum condition, it only takes 168 s to eliminate 20 cm flotation froth height with combined mechanical impact, while it takes 453 s under ambient pressure, indicating that under vacuum conditions, the mechanical-defoaming method can significantly improve the defoaming efficiency, and the two have a certain synergistic effect.Keywords:coal;flotation froth;defoaming;vacuum
研究领域:
矿业工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Sustainability
·
2025
·
IF 7.9
Xinyuan Dong,Peng Xu,Lihua Gao,Xiao Han,Junhong Zhang,Zhijun He
An environmentally friendly and low-cost co-carbonization technology has been reported as an effective route for the preparation of carbon-based synfuel for sintering processes employed in the steel industry, in which loaded CaO catalysts promote the synergistic role between sawdust (SD) and bituminous coal (BC). In this work, a series of experiments were conducted to research the effects of the co-carbonization temperature, co-carbonization holding time and addition amount of CaO on synfuel. Finally, a co-carbonization temperature of 550 °C, a co-carbonization holding time of 30 min, and the added amount of CaO at 4 wt% were reasonable preparation conditions based on the biomass/coal of 4/6. According to the above experimental parameters, the solids yield, bulk density and heat value of SD/BC synfuel were 61.07%, 403 kg m −3 and 27.82 MJ kg −1 , respectively. These results showed that adding CaO increases the order and density of synfuel microcrystals. For the surface structure, the addition of CaO could improve the content of aromatic C C and C–O, whereas the content of carbonyl C O decreased in the carbonization process, which demonstrated that the addition of CaO could improve transformation of the graphite-like structure. Additionally, SD/BC synfuel loaded with CaO exhibited a rougher surface and larger pores compared to that without CaO loading, and the number of pores decreased because the formation of CaCO 3 coated the synfuel surface. The above indicators of carbon-based synfuel obtained from this study agree with the practical requirements of sintering operations. This work reveals the mechanism of biomass/coal and CaO interaction on the preparation of carbon-based synfuel.
研究领域:
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Chenguang Yang,Jianqiang Yin,Liqin Wu,Qiuyu Zeng,Liwei Zhang
For coal and gangue, intelligent sorting processes for separation, the use of coal and gangue mineral components with different fundamental differences, and the study of different properties of minerals and coal with different scales and density regarding the gray value change law are presented. The results show that the gray value of single minerals and mixed minerals gradually decreases with the increase of their thickness and density. The greater the density of minerals, the smaller the gray value at the same thickness, and the same rule applies to different coal ranks. Via regression analysis methods, the values of the regression equation parameter a of pure minerals for graphite, quartz, kaolinite, and montmorillonite are 59.25, 65.69, 61.61, and 58.02 in the high-energy region, respectively. In the low-energy region, they are 174.95, 177.31, 186.95, and 161.81. For the regression equation parameter of mixed minerals in the form of two mixed minerals (graphite and quartz, kaolinite, or montmorillonite) and three kinds of mineral mixing (graphite–kaolinite and quartz; graphite–montmorillonite and quartz; graphite–kaolinite and montmorillonite), the gray values are 151.12, 156.00, 153.13,152.43, 152.98, and 151.98 in the high-energy region, respectively; in the low-energy region, they are 193.34, 201.34, 192.93, 191.26, 194.68, and 193.08. The phenomenon for the gray range of two kinds of single minerals locates in the range of mixed minerals that was formed from a single mineral observed after the regression equation of mixed mineral was verified by a single mineral, which agrees with the X-ray recognition pattern. In the end, as the density of coking coal, fat coal, and gas coal increases, the gray value decreases, which was in agreement with single- and mixed-mineral analyses.
研究领域:
矿业工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 43
·期 4
·839-846
·
IF 2.516
Guo Yu,Xing Fan,Xue-Ming Dong,Rui-Yu Wang,Yun-Peng Zhao,Hong-Cun Bai,Tian-Sheng Zhao,Qing-Jie Guo,Xian-Yong Wei
Dayan lignite was subjected to thermal dissolution sequentially with cyclohexane, acetone, and methanol. Each thermal dissolution extract was subjected to further separation/enrichment using column chromatography, which was sequentially eluted with petroleum ether, a mixture of ethyl acetate and petroleum ether (vol:vol = 1:1), and ethyl acetate. The three thermal dissolution extracts and nine enrichment subfractions were characterized by an Orbitrap mass spectrometry equipped with an atmospheric pressure chemical ionization ion source. The mass spectrometry data were also statistically analyzed by principal component analysis, which can reduce the dimensionality of data and classify multiple samples according to principal components. Identified compounds in the extracts and subfractions are classified into eight classes according to the heteroatom distribution. Hydrocarbon class is mainly presented in the petroleum ether fraction, and oxygen class, nitrogen class, and oxygen-nitrogen class are distributed in both petroleum ether/ethyl acetate and ethyl acetate subfractions. The combination of different analytical methods enhances the understanding of coal at the molecular level and provides important data for downstream refining processes.
研究领域:
化学
·
能源科学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Hai-Xu Zou,Xiang Bai,Xing Fan,Min-Hua Wang,Yang-Yang Xu,Feng-Yun Ma,Xian-Yong Wei,Peter N. Kuznetsov
Three biomass (rice straw, rice husk and wheat straw) and three coal samples (lignite, subbituminous coal and bituminous coal) were extracted via a thermal dissolution (TD) process, and the TD extracts were treated by catalytic hydrogenation to obtain reaction products. To reveal the similarity in molecular information among the samples and elucidate their chemical reactivity, four machine learning algorithms were applied to analyze the Fourier transform infrared spectra of both TD extracts and catalytic hydrogenation products. Functional groups were used as variables and the difference in peak area can be treated as the basis for sample classification. Aromatic C H, C O C, aliphatic CH 2 or CH 3 and aromatic C O or C C bonds were the main characteristic variables in principal component analysis algorithm to classify biomass- and coal-derivated samples. These samples were also grouped into four clusters by hierarchical clustering analysis algorithm according to the similarity and difference in the distribution of functional groups. For artificial neural network algorithm, aliphatic C H and OH bonds are the most important variables to classify these samples into four groups, and aromatic C H, OH, and C O C groups are the main variables contributed to the classification trees in random forest algorithm. Machine learning algorithms will provide methodological guidance for the data mining of the spectra of complex organic systems.
研究领域:
化学工程
·
数据科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Shuai Chen,Wei Zhou,Yani Ding,Guangbo Zhao,Jihui Gao
Understanding the evolution of carbon structure in coal-assisted water electrolysis for hydrogen production (CAWE) is essential for seeking strategies to improve the rate of CAWE and getting more insight into the potential significance of CAWE. In this work, 13C nuclear magnetic resonance (NMR) is used to make out the evolution of carbon structure in CAWE. First, the electrolysis characteristics of three different-rank coals are revealed using electrochemical methods. Then, before and after electrolysis, the evolution of carbon structure is analyzed. The results show that CAWE is a process of reducing carbon and increasing oxygen, and the accumulation of oxygen-containing groups is mainly owing to the increase of oxygen aliphatic carbons and oxygen aromatic carbons. After CAWE, the aromatic cluster size decreases and increases for low-rank coals and high-rank coals, respectively.
研究领域:
能源科学
·
材料化学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 17
·50496-50508
·
IF 5.8
Wu Xijun,Dong Ying,Zhao Jian,Liu Jing,Zhang Yaning
This study investigated the spatial distribution, pollution source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the Kuye River, which is a typical river in the mining area of China, 16 priority PAHs were quantitatively detected at 59 sampling sites by high-performance liquid chromatography-diode array detector-fluorescence detector. The results showed that the ∑PAHs concentrations in the Kuye River were in the range of 50.06–278.16 ng/L. The PAHs monomer concentrations were in the range 0–121.22 ng/L, of which chrysene had the highest average concentration (36.58 ng/L), followed by benzo[a]anthracene and phenanthrene. In addition, the 4-ring PAHs showed the highest relative abundance in the 59 samples, ranging from 38.59 to 70.85%. Moreover, the highest concentrations of PAHs were mainly observed in coal mining, industrial, and densely populated areas. On the other hand, according to the diagnostic ratios and positive matrix factorization (PMF) analysis, it can be concluded that coking/petroleum sources, coal combustion, vehicle emission, and fuel-wood combustion contributed to the PAHs concentrations in the Kuye River by 37.91%, 36.31%, 13.93%, and 11.85%, respectively. In addition, the results of the ecological risk assessment indicated that benzo[a]anthracene had a high ecological risk. Among the 59 sampling sites, only 12 belong to low ecological risk areas, and others were at medium to high ecological risks. The current study provides data support and a theoretical basis to effectively manage pollution sources and ecological environment treatment in mining areas.
研究领域:
环境科学
·
生态学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Lei Wu,Guansheng Qi,Wei Lu,Zhenglong He,Jialiang Li,Jinliang Li,Min He
In the process of coal mining, coal spontaneous combustion in the gob area poses serious threats to the safety of mine production. Besides, coal combustion also produces a large amount of greenhouse gas CO 2 , which triggers a series of ecological environment problems. In order to solve these two problems, the idea of mineralizing CO 2 with the alkaline industrial waste calcium carbide slag and then sending the foams to the gob area for coal spontaneous combustion prevention was proposed in this study. First, the effects of calcium carbide slag foaming under the action of different types of foaming agents, including sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), polyoxyethylene fatty alcohol sodium sulfate (AES), and octyl decyl glucoside (APG0810), were tested and analyzed. Furthermore, the effects of water glass (WG), sodium alginate (SA), polyvinyl alcohol 1799 (PVA), cement, and silica micro-powder on the foam stability were analyzed by investigating the stability coefficient and drainage volume of calcium carbide slag foam. On this basis, the configuration scheme of calcium carbide slag foam with high efficiency and good stability was determined. The experimental results on CO 2 mineralization and coal spontaneous combustion inhibition reveal that the prepared calcium carbide slag foam can rapidly absorb CO 2 . Moreover, after calcium carbide slag foam treatment, the spontaneous combustion tendency of the coal sample is significantly reduced.
研究领域:
矿业工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2023
·
IF 7.5
Heyu Li,Zhe Sun,Shaochen Shang,Yan Cao
The development of cost-effective and reactive oxygen carriers and the fast and complete conversion of solid fuels are two critical issues in the solid fuel chemical looping technology. Red mud, a solid waste from the alumina industry, was found to be an economic oxygen carrier candidate simultaneously realizing the use of solid wastes and the CO 2 abatement after comparing with other two different iron-based materials (pure Fe 2 O 3 and hematite). This study validated red mud as an excellent oxygen carrier to achieve the almost complete conversion of char in solid fuels (SFs) (99.4%) and meanwhile the hydrogen production with high-purity (97% H 2 purity) and higher H 2 yield (around 500 mL/g), in the optimized pyrolysis procedure of solid fuels with proper gasification agent and rationalized reaction temperatures (1000 °C) and residence time (10mins). Characterizations of red mud using SEM-EDS and XRD revealed that the unique microscopic crystalline structures of both Fe 2 O 3 and Ca 2 Al 2 SiO 7 particles nested on Na 4 Al 2 Si 2 O 9 molten substrate, implying that the existence of Na-containing component of the red mud OC likely accounts for its higher reactivity and stability in multiple redox cycles.
研究领域:
能源科学
·
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Fei Wang,Xueming Dong,Xing Fan,Yun-Peng Zhao,Guo-Sheng Li,Chu-Fan Wang,Xian-Yong Wei,Feng-Yun Ma,Mei Zhong
In-source collision activated dissociation (ISCAD) is an effective method to obtain molecular structure of coal and biomass and provide basic knowledge for coal/biomass conversion. Twenty two coal/biomass-based model compounds and one coal extract were studied via ISCAD to understand the relationship between collision energy and molecular structure and the application of ISCAD in the characterization of coal. Model compounds showed different fragmentation patterns with the increase of collision energy and the detailed fragmentation pathways in context of collision energies were proposed. According to the ISCAD results of coal extract, the weighted mean molecular weight (MW) and weighted mean double-bond equivalent (DBE) values of ionized coal molecules decreased over collision energy of 80 eV. The decrease of weighted mean MW and DBE were mainly caused by the cleavage of alkyl chains, bridged bonds, and minor cracking of small aromatic cores from precursor ions upon fragmentation. Therefore, the optimal ISCAD collision energy for the investigation of aromatic core structures of the coal extract should be around 80 eV.
研究领域:
化学
·
能源科学
·
分析化学
✓ 已验证
DOI
高影响因子
TALANTA
·
2023
·
IF 6.1
Xiao Tian,Lei Zhao
Concentrations of trace elements in coal and coal combustion products are commonly analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) due to large number of elements detected and the relatively the low detection limits of this technique. Like other geological samples, complete dissolution of coal and coal combustion products is also essential for accurate ICP-MS results. In this study, Sr and Ba in coal and coal combustion products (fly and bottom ashes) from two coal-combustion power plants from North China analyzed by XRF and ICP-MS were comparatively studied. The concentrations of Sr and Ba analyzed by ICP-MS, when a mixture of acids (2 ml HF + 5 ml HNO 3 for each 50 mg coal sample and 5 ml HF + 2 ml HNO 3 for each 50 mg ash sample) was used for microwave-assisted digestion, do not fit well with the their relative XRF results. This is most probably due to the formation of the fluorides during microwave digestion, and this assumption is supported by the presence of various fluoride compounds, NaMgAl(F, OH) 6 ·H 2 O, NH 4 MgAlF 6 , AlF 3 , and K 2 SiF 6 , in the residues of all the coal and ash samples in our sequential extraction experiment. Cations of Sr and Ba were probably trapped into the divalent cation sites of the fluorides. Concentrations of Sr and Ba analyzed by ICP-MS using increased HF and HF/HNO 3 ratio (7 ml HF and 2 ml HNO 3 for each 50 mg coal/ash sample) are in better agreement with the XRF results. Our results indicate that excess amount of HF probably has led to the suppression of these elements due to fluoride precipitation. The results indicate that the modified digestion method is capable of achieving complete digestion of coal samples and results in a reliable analysis of Sr and Ba concentrations in coal samples and most fly ashes by ICP-MS. However, the formation of insoluble fluorides is probably not completely suppressed for some bottom ash samples, which can result in underestimation of Sr and Ba concentrations. Nevertheless, XRF analysis can serve as a reliable cross-check method to assist in the evaluation of the accuracy of ICP-MS results.
研究领域:
环境科学
·
分析化学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Chao Han,Shibin Nie,Zegong Liu,Song Liu,Hong Zhang,Jiayi Li,Haoran Zhang,Zihan Wang
In order to address the environmentally friendly issue of fire prevention and extinguishing materials in coal mines, A new biomass sodium alginate gel foam (SC-GF) was prepared by using sodium alginate (SA), calcium L-lactate (CL), alkyl glycoside (APG) and tea saponin (TS). The effect of different concentrations of CL on the properties of SC-GF was analyzed by studying the gelation time, foaming volume and half-life of the SC-GF. The results show that the gelation time of SC-GF is successfully controlled by using the weak electrolyte CL as the cross-linking agent. When SA: CL: APG: TS = 4 : 1 : 2 : 1, the gelation time of SC-GF is 10 min with half-life of 16 days. Furthermore, A metal coordination bond favorable to the stability of SC-GF is formed by the carboxylate ion of α-L-gulonic acid in SA and Ca 2+ ionized by CL. SC-GF exhibits excellent fire prevention and extinguishing properties. The CO concentration of the coal sample treated with SC-GF decreases from 7556.8 to 34.92 ppm in the process of oxidation at room temperature for 48 h. The temperature-programmed oxidation test shows that SC-GF can delay the accelerated oxidation temperature from 120 to 160 °C, and the CO inhibition rate is as high as 60.5 % at 200 °C. The fire extinguishing test indicates that SC-GF can significantly reduce the temperature of the coal sample and extinguish the coal fire quickly. The study is useful to develop efficient and environmentally friendly coal mine fire prevention and extinguishing materials.
研究领域:
矿业工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）