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Wyświetlanie 1-5 z 5
Tytuł:
Understanding the difficult selective separation characteristics of high-ash fine coal
Autorzy:
Yang, Zili
Liu, Min
Chang, Guohui
Xia, Yangchao
Li, Ming
Xing, Yaowen
Gui, Xiahui
Powiązania:
https://bibliotekanauki.pl/articles/1845210.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-ash fine coal
flotation
rod grinding
floatability
slime coating
Opis:
As the supply of high-quality coals decreases and mechanical coal mining becomes more widespread, the high selective recovery of high-ash fine coal has become a prominent problem in the flotation process. Herein, we discuss the main reasons why the selective separation of high-ash fine coal is difficult. The analysis of high-ash fine coal properties shows that coarse particles (0.25-0.5 mm) account for 22.53% of the total size fraction and that 57.90% of the coal is moderate- or high-density (+1.4 g/cm3) intergrowth. Grinding experiments show that the traditional rod mill has little impact on the liberation of the intergrowth. Instead, its main function is to adjust the particle size composition to ensure that the particle sizes of high-ash fine coal are within the particle size range suitable for flotation. The flotation results show that a clean coal yield of 30.42%, with a 12.46% ash content, is obtained with the optimal flotation parameters through the roughing and cleaning flotation process. However, the flotation results also show that in the separation of high-ash fine coal, it is difficult to obtain clean coal with a high yield and low ash content at the same time. This is mainly due to the similar floatability of moderate-density and low-density coal particles, which allows a large number of moderate-density coal particles to be recovered, and a significant slime coating of clay on the coal’s surface that is generated during the flotation process. The results of this work provide valuable guidance for high-ash fine coal industrial flotation applications.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 874-883
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of calcium and magnesium cations in the interactions between kaolinite and chalcopyrite in seawater
Autorzy:
Uribe, L.
Gutierrez, L.
Laskowski, J. S.
Castro, S.
Powiązania:
https://bibliotekanauki.pl/articles/109955.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
froth flotation
chalcopyrite
chalcopyrite flotation
clay minerals
kaolinite
seawater
slime coating
Opis:
A number of flotation plants around the world have increased the use of seawater due to limited sources of fresh water. The aim of this research work is to study the role that Mg2+ and Ca2+ ions play in the interactions between kaolinite and chalcopyrite in seawater. In order to achieve this objective, the effect of kaolinite on flotation of chalcopyrite is studied over the pH range from 8 to 11, when flotation is carried out in seawater and in a 0.01M NaCl solution. The influence of calcium, magnesium, sodium, and potassium ions on the extent of depression by kaolinite is evaluated. The micro-flotation results indicate that chalcopyrite is depressed by kaolinite in both 0.01 NaCl solution and seawater. In the 0.01 NaCl solution, the depressing effect of kaolinite decreases as the pH increases from 8 to 11. However, the results obtained using seawater show that the depressing effect of kaolinite is similar to what is observed in a 0.01 NaCl solution only at pH values below 9, but above this pH kaolinite significantly affects the recovery of chalcopyrite. The results from experiments with using solutions containing individual cations show that the depressing action of kaolinite in the presence of Mg2+ and Ca2+ is more obvious at pH values of 9 and 10, respectively, which correlates with the pH values at which the first hydroxy-complexes of these divalent cations start forming. This seems to indicate that depressing effect of kaolinite on chalcopyrite in seawater may be related to formation of hydrolyzed species of calcium and magnesium. These species can induce heterocoagulation between kaolinite and chalcopyrite. The trends observed in the micro-flotation experiments are in good agreement with the results of the induction time measurements and slime coating tests.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 737-749
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of montmorillonite hydration and delamination on coal flotation
Autorzy:
Zhang, Lucheng
Zhang, Mingqing
Liu, Qi
Song, Shuoshuo
Tian, Yu
Barvora, Joshua Bosco
Powiązania:
https://bibliotekanauki.pl/articles/2175432.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal flotation
montmorillonite
hydration
delamination
slime coating
Opis:
In this study, the influence of montmorillonite (MT) hydration and delamination on coal flotation was investigated through flotation tests using coal-MT mixtures. MT particles were subjected to hydration at different time intervals. The Fuerstenau upgrading curve was plotted to evaluate the change in overall flotation selectivity. The zeta potential and particle size distribution were used to characterize the delamination behavior of MT in deionized water at natural pH level. Atomic force microscopy (AFM) (colloidal probe) was used to analyze the interaction force between coal and MT particles. It was found that smaller particles (individual silicate layers or thin packets of layers) with higher zeta potentials appeared gradually, and their volume proportion increased with increasing hydration time. AFM results showed that a monotonous repulsive force was detected consistently throughout the separation distance between coal and these emerging smaller MT particles. The decrease of these MT coating on coal surface was responsible for the higher flotation recovery and better selectivity. A jump-into-contact phenomenon was observed in coal and MT interaction when MT hydrated incompletely. It showed that heterocoagulation between coal and MT occurred and MT coating on the coal surface was responsible for the depression of flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 153085
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of colloidal montmorillonite particles on froth flotation of graphite, galena and fluorite
Autorzy:
Chen, T.
Zhao, Y.
Li, H.
Song, S.
Powiązania:
https://bibliotekanauki.pl/articles/110589.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
montmorillonite
graphite
galena
fluorite
slime coating
entrainment
Opis:
The effect of colloidal montmorillonite (MMT) on froth flotation of graphite, galena and fluorite was investigated in this work. The results showed that the presence of sufficient amount of colloidal MMT particles in the mineral slurry would be detrimental of flotation by reducing the recovery of minerals. This observation was attributed to slime coating of MMT on the coarse valuable mineral particles and entrainment of MMT particles in the froth product together with water in the triangle froth zones. The former would reduce the recovery of the valuable minerals because of hydrophilic MMT coating. The latter would decrease the concentrate grade. The degree of slime coating depended on slurry pH, while the degree of entrainment was closely related to water recovery. It was also found that slime coating was a dominant factor in mineral flotation in acidic pH regions in the presence of colloidal MMT particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 699-713
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of swelling clay dispersion type on fine coal flotation
Autorzy:
Zhang, Mingqing
Yu, Wei
Cao, Yijun
Xu, Haiyu
Powiązania:
https://bibliotekanauki.pl/articles/110246.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fine coal flotation
swelling clay
controlled dispersion
CaCl2
slime coating
Opis:
The influence of bentonite dispersion on fine coal flotation was examined to better understand the role of swelling clay in the process of flotation. It was found that the coal flotation recovery was lower with uncontrolled dispersion of bentonite than with controlled dispersion. The detrimental effect was attributed to the increase in slime coating. In the uncontrolled dispersion, the dispersed bentonite platelets formed an extensive card-house structure. The three-dimensional networks increased the slurry viscosity, and caused significant coating of the coal particles, thereby inhibiting particle mobility and bubble-particle attachment. In the controlled dispersion, the bentonite mineral appeared as separate particles with low aspect ratios. The coal particles were partially coated, and the slurry viscosity was lower, resulting in higher flotation recovery. The findings in this study suggested that a practical solution to mitigate the negative impact of swelling clay on flotation would be to maintain high electrolyte levels in the wash water to inhibit clay swelling and dispersion.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 380-388
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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