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Wyświetlanie 1-8 z 8
Tytuł:
Mass transfer process of leaching weathered crust elution-deposited rare earth ore with magnesium salts
Autorzy:
Chen, Z.
Zhang, Z.
He, Z.
Chi, R.
Powiązania:
https://bibliotekanauki.pl/articles/110343.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mass transfer
magnesium salts
theory plate
weathered crust elution-deposited rare earth ore
Opis:
In order to optimize the leaching process of weathered crust elution-deposited rare earth ore with magnesium salts, the influence of different flow rate, concentration of magnesium ions, initial pH of magnesium salts solution and experimental temperature on the mass transfer process of rare earth and aluminum was investigated in the case of using magnesium salts as leaching agent. The relationship between the flow rate μ and the HETP (Height Equivalent of Theoretical Plate) is in accordance with the Van Deemter equation when magnesium salts were used as leaching agent. The optimum condition for rare earth and aluminum were 0.4 cm3/min of flow rate and 0.2 mol/dm3 of magnesium ion concentration of magnesium sulfate, magnesium chloride and magnesium nitrate respectively. Under this condition the mass transfer efficiency of rare earth and aluminum with three kinds of magnesium salts follow the order of Mg(NO3)2>Mg(Cl)2>MgSO4. High temperature contributes to improving the mass transfer efficiency of rare earth and aluminum. Magnesium nitrate as the leaching agent can get the highest leaching mass transfer efficiency of rare earth and magnesium sulfate as the leaching agent can make the impurity leaching and mass transfer efficiency of Al is the lowest.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 1004-1013
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogical and chemical characteristics of the lead-zinc tailing and contaminated soil from the mine tailing pond in Hunan Province (China)
Autorzy:
Li, C.
Zeng, L.
Fu, J.
Chen, J.
He, J.
He, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110442.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mineralogical characteristics
chemical fractionation
remediation
Opis:
The mineralogical and chemical characteristics of heavy metals in tailings and soils is an imperative for potential ecological risk assessment of metals to environment and heavy metals pollution prevention and control. The lead-zinc tailing and contaminated soil in and near the tailing pond were sampeled from a mine tailing pond in Hunan province (China), in which the chemical composition, phase composition and thermal behavior of tailing and soil were investigated. Furthermore, the petrography of lead-zinc tailing and chemical fractionations of Pb and Zn in the contaminated soil were studied in details. The mineral phases of lead-zinc tailing were galena, pyrite, chalcopyrite, sphalerite, quartz and fluorite, as distinguished by the reflected light microscopy and further proofed by the scanning electron microscope-energy dispersive spectrometer under the back scattered electron mode. Chemical fractionations were carried out by the European Community Bureau of Reference (BCR) sequential extraction procedure for Pb and Zn in the soil and the mild acido-soluble (F1), reducible (F2), oxidizable (F3), and residual (F4) fractions were 5.90, 75.24, 4.90 and 13.96% for Pb, and 47.74, 34.06, 9.59 and 8.61% for Zn, respectively. Subsequently, the individual contamination factor (ICF) of Pb and Zn were calculated as 6.16 and 10.61, respectively. The DTPA-available content of Pb and Zn in the contaminated soil were 39.9 and 170.7 mg·kg-1, respectively. The study provided a base for selecting remediation strategies in the studied area.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1133-1147
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving separation efficiency of 6-1 mm coal by introducing vibration energy to dense medium gas-solid fluidized bed
Autorzy:
He, J.
Zhao, Y.
Luo, Z.
Zhao, J.
Duan, C.
He, Y.
Powiązania:
https://bibliotekanauki.pl/articles/110018.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vibration energy
dense medium gas-solid fluidized bed
fluidization quality
density uniformity
separation efficiency
Opis:
Effects of the vibration energy on the fluidization quality and separation performance of dense medium gas-solid fluidized bed were investigated experimentally. The magnetite powder with a wide size range of 0.3-0.074 mm was utilized as the basic medium solids. 6-1 mm fine coal sample from Yongcheng (China) was used to perform the separation experiments. The results indicate that the vibration amplitude A and superficial gas velocity U are greatly significant to the fluidization stability and the density distribution uniformity. Comparing with the bed without vibration, the optimal SP and Sρ values of 0.034 kPa and 0.018 g/cm3 are acquired in vibration bed with the operating factors of A = 1 mm, U = 1.8Umf, f = 15 Hz and Hs = 150 mm. The coal ash content was reduced from 27.84% to 9.50% at a separating density of 1.68 g/cm3 with a probable error E value of 0.505. The separation efficiency of 6-1mm fine coal is effectively improved by introducing vibration energy to dense medium gas-solid fluidized bed. The technology provides a novel approach to achieve high-efficiency separation of 6-1 mm fine coal in the arid and water-shortage areas.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 95-108
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dry beneficiation and cleaning of chinese high-ash coarse coal utilizing a dense-medium gas-solid fluidized bed separator
Autorzy:
He, J.
Tan, M.
Zhu, R.
Luo, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110808.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal cleaning
dense-medium fluidized bed
density distribution
segregation
separation performance
Opis:
Dry dense-medium fluidized bed separation provides a new alternative approach for coal beneficiation and cleaning. An indicator of segregation degree Sash was proposed to evaluate the stratified performance of coal samples by bed density. Fluidization stability of the bed was greatly enhanced by mixing a certain amount (21.53%) of fine magnetite powder (< 0.15 mm) into the fluidized media, which indicated a uniform density distribution as well as slight fluctuations in bed. It was found that the favorable density-segregation performance of 3–13 mm coarse coal occurred with a static bed height of 80 mm and a superficial gas velocity of 11.84 cm/s. The optimal segregation degree values of 0.67, 0.74 and 0.76 were obtained for 3–6, 6–10 and 10–13 mm coal samples, respectively. Low-ash clean coal with yields of 50.79, 56.83 and 61.24% were effectively acquired by the dry separation for various coal size fractions, respectively. Probable error values of 0.07, 0.055 and 0.05 g/cm3 were achieved, indicating good separation performance.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 662-675
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanisms for the improved flotation of inherently hydrophobic graphite in electrolyte solution
Autorzy:
Lai, Q.
Liao, Y.
Liu, Z.
He, Y.
Zhao, Y.
Powiązania:
https://bibliotekanauki.pl/articles/110761.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
graphite
low-grade
electrolyte
Opis:
It is well documented that unavoidable ions in a pulp such as Mg2+, Ca2+, and K+ have a significant effect on the interaction for particles, especially for flotation of metallic sulfide minerals and clay minerals. In this study, the effect of electrolytes on the flotation of inherently hydrophobic mineral-graphite was studied. It was found that the zeta potential showed a dramatic decrease, and the reagent adsorption capacity of mineral enhanced in the present of electrolytes. The possible mechanism responsible for improved recovery was investigated by electrokinetic, surface tension and ions adsorption tests. It is likely that the hydrophobic force is stronger than the electrostatic force due to the reduced potential of graphite. This might be in favor of the formation of hydrophobic oil film leading to an increase in the graphite floatability. The experiments provided a new spectacle to study inherently hydrophobic mineral processing with electrolyte solution.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 944-954
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation of wolframite from quartz using N-oleoyl sarcosine acid as collector
Autorzy:
Xian-Ping, L.
Feng, B.
Xianwen, Z.
Li-Yying, L.
Zheng-He, X.
Powiązania:
https://bibliotekanauki.pl/articles/109444.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
N-oleoyl sarcosine acid
wolframite
quartz
Opis:
In this study the collecting power of N-oleoyl sarcosine acid towards wolframite and quartz was studied using flotation. The adsorption mechanism was also discussed based on the results from adsorption experiments, zeta potential measurements and infrared spectroscopy study. The flotation results showed that N-oleoyl sarcosine acid showed a good collecting power towards wolframite, and the optimal flotation pH = 7 was obtained. However, the collecting power of N-oleoyl sarcosine acid towards quartz was weak. Therefore, the flotation separation of wolframite from quartz can be performed using N-oleoyl sarcosine acid as a collector. The adsorption tests and electrokinetic studies showed that N-oleoyl sarcosine acid adsorbed only on the wolframite surface. Additionally, the results from the infrared spectroscopy study confirmed that N-oleoyl sarcosine acid is adsorbed on the wolframite surface, and the metal complex (ferriccarboxylate) maybe the major adsorbed species.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 34-41
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of polyacrylic acid on the surface properties of calcite and fluorite aiming at their selective flotation
Autorzy:
Zhang, C.
Gao, Z.
Hu, Y.
Sun, W.
Tang, H.
Yin, Z.
He, J.
Guan, Q.
Zhu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/110577.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcite
fluorite
selective flotation
polyacrylic acid
Opis:
In this study, the polyacrylic acid (PAA) was studied as a selective depressant for calcite in the selective flotation of fluorite and calcite, and the implications of this process for the separation of fluorite ore were studied using micro-flotation tests, and the results were analyzed with Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The flotation tests indicated that the preferential adsorption of PAA onto calcite rather than sodium oleate (NaOl) could selectively depress the flotation of calcite, allowing its separation from fluorite at pH 7. The zeta potential of calcite became more negative with the addition of PAA rather than with NaOl. However, the characteristic features of PAA adsorption were not observed for fluorite, suggesting that NaOl preferentially adsorbed on the surface of fluorite, or that PAA could be replaced by NaOl on the fluorite surface. FT-IR and XPS analysis were utilized to obtain a better understanding of the mechanism by which PAA was more strongly adsorbed on the calcite surface than NaOl. This was revealed to occur through chemical bonding between the carboxyl group of PAA and the hydroxyl groups of the Ca species on the calcite surface, modifying the structure of the adsorbed layer. A possible adsorption mechanism, along with a postulated adsorption mode for the surface interaction between PAA and calcite, is proposed.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 868-877
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of energy-size reduction to the control of circulating load in vertical spindle pulverizer
Autorzy:
Li, H.
He, Y.
Zhang, Y.
Ge, Z.
Xie, W.
Wang, S.
Li, K.
Powiązania:
https://bibliotekanauki.pl/articles/110803.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
circulating load control
response of energy-size reduction
mixture grinding
energy efficiency
Opis:
In the vertical spindle pulverizer (VSP), the large circulation ratio and high ash and sulfur contents in circulating load would result in intensive energy consumption and low grinding efficiency. Although the control of circulating load would help increase the energy efficiency, no quantitative study has been conducted due to the high temperature and pressure in the closed VSP. In this study, response of energy-size reduction to the control of circulating load was studied by the experimental simulation method. Coal mixtures with fine/coarse ratio of 11:1, 8:1 and 6:1 were ground by a lab-scale roller mill. Energy-size reductions of the coarse coal were compared to evaluate the influence of circulating load control. Results showed that the product with the coarse coal increased by 30% when the specific breakage energy was 1.0 kWht–1 as the circulation ratio decreased from 11 to 6. Meanwhile, a breakage characteristic index of the coarse coal was two times higher due to the cushioning effect of fines. Besides, decrease of circulation ratio led to increase of the breakage rate of coarse coal, and the energy saving improved by 57%. With the same energy input of 2.0 kWht-1, the yield of –0.09 mm pulverized fuel (PF) increased from 22 to 43%. Therefore, controlling the circulating load is an effective method to improve the breakage rate of coarse coal and energy efficiency for PF generation.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 793-801
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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