Synthesis and separation properties of an α-alumina …
A thin high-silica MEL membrane was synthesized on a porous α-alumina hollow fiber support by a secondary growth approach.The membrane quality was evaluated by permporometry, single-gas permeation and butane isomer separation.
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Synthesis and separation properties of an α-alumina …
Request PDF | Synthesis and separation properties of an α-alumina-supported high-silica MEL membrane | A thin high-silica MEL membrane was synthesized on a porous alpha-alumina hollow fiber ...
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Preparation of alumina nanoshell coated porous silica …
The prepared nanoAl 2 O 3 /mesoSiO 2-5 particles were well dispersed, smooth and highly spherical (Fig. 1).It is even very difficult to find the difference between bare silica and nanoAl 2 O 3 /mesoSiO 2-5 particles in the aspect of shape.This illustrated that the precipitation of alumina nanoshell on the surface of the silica sphere did not cause any aggregation, …
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Hydrous alumina/silica double-layer surface coating of …
The hydrous alumina/silica double-layer surface coating of TiO 2 pigment was prepared by precipitation method under two different conditions. High-resolution transmission electron microscopy (HRTEM), Energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrum (FTIR) as well as ζ-potential …
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Mechanical Activation of Coal Fly Ash for the Improvement of Alumina …
The pre-separation of silica and alumina in aluminosilicates is of great significance for efficiently treating alumina-/silica-bearing minerals for alumina production. In this work, the reaction ...
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Efficient separation of alumina and silica in reduction …
Alkali leaching was employed to investigate the separation of alumina and silica in roasted kaolin obtained by roasting kaolin alone in air at 1273 K for 60 min and in clinker prepared by roasting the mixed raw meal of kaolin, ferric oxide and coal powder with Fe 2 O 3 /Al 2 O 3 /C molar ratio of 1.2:2.0:1.2 in reducing atmosphere at 1373 K for 60 min. The …
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Alumina for Column Chromatography
Carbon-carbon double bonds contribute somewhat more to compound adsorption on alumina as compared to silica gel, and hence compounds with unsaturation are generally better separated on Alumina than on other polar adsorbents …
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Efficient separation of silica and alumina in simulated CFB …
The separation of alumina and silica in clinker was carried out by alkaline leaching in 160 g/L NaOH solution with solid/liquid of 5 g/50 mL at 110 °C for 180 min. Fig. 8 shows that the silica leaching ratio is about 95% and nearly unchanged when treating the clinker of RCG-800 °C and RCG-900 °C, and the corresponding A/S in the leached ...
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Thin Layer Chromatography (TLC): Principle, …
Silica gel and alumina are used in the stationary phase. The mobile phase is an organic solvent. Reversed-phase partition TLC: Plate is coated by hydrophilic silica and again coated by wax or paraffin, making it hydrophobic. ...
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Comprehensive Extraction of Silica and Alumina from High-Alumina …
Then, the efficient separation of silica and alumina from the reductively roasted product is achieved by alkaline leaching, because hercynite with spinel structure is stable in alkaline solution. The alumina in hercynite treated by pre-oxidation roasting can be efficiently extracted by Bayer digestion, and hematite in red mud can be recycled by ...
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Alumina and Silica Extraction and Byproduct Development …
With the silica gels removed for the preparation of silica fertilizers, the filtrates were added to concentrated H 2 SO 4 to precipitate alumina, as well as other impurities. The …
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Hydrothermally stable silica–alumina composite membranes …
The silica–alumina composite membranes were prepared using the previously described γ-alumina multilayer as the substrate by the deposition of a thin silica–alumina layer by the chemical vapor deposition method. ... Sol–gel derived silica membranes for separation of hydrogen at high temperature-separation performance and stability ...
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Mechanical Activation of Coal Fly Ash for the Improvement …
Efficient removal of silica is the key to alumina extraction from coal fly ash (CFA) by the Bayer process, due to the easy formation of sodium aluminosilicate hydrates during …
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Separation of aluminum and silica from coal gangue by …
Highlights. •. High-temperature direct acid leaching is highly effective for separating metal ions and silica in coal gangue. •. An increase in temperature significantly …
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Solutions for Light Hydrocarbons and Gases: PLOT …
Alumina Silica Carbon Porous polymers Porous polymers Silica Porous polymers Select Perm. Gases Select Low Sulfur Porous polymers Silica Lowox OxyPLOT 18 July 31, 2014 . ... • Poor C4 isomer separation Alumina preferred • Not sensitive to moisture • Good choice for solvents and CFCs 19 July 31, 2014 .
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Enhancement of the gas separation properties of polyurethane membranes
ATR-FTIR spectra were used for characterizing the structure of the pure alumina, PUs, and hybrids. The results are shown in Fig. 1, Fig. 2.The absence of the NCO peak at 2270 cm −1 indicates completion of the reaction. N–H stretching of urethanes and C O peaks appears at around 3300 cm −1 and 1670–1730 cm −1, respectively.The signals of the urethane ether, …
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Hydrothermally stable silica–alumina composite membranes …
Composite membranes prepared by sol–gel methods composed of silica with other inorganic oxides such as alumina (Al 2 O 3), titania (TiO 2) and zirconia (ZrO 2) have been reported to improve the stability of silica membranes for use under humid atmospheres at high temperature.Fotou et al. [20] introduced these oxides and MgO into the membranes by doping …
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Mineral phase transformation in coal gangue by high …
The addition of CaSO4 and CaO remarkably decreased the separation efficiency of alumina and silica in metakaolinite, which could be attributed to the formation of Si-bearing minerals: (1) Fayalite ...
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Hydrothermally stable silica–alumina composite
DOI: 10.1016/J.MEMSCI.2007.10.025 Corpus ID: 94429279; Hydrothermally stable silica–alumina composite membranes for hydrogen separation @article{Gu2008HydrothermallySS, title={Hydrothermally stable silica–alumina composite membranes for hydrogen separation}, author={Yunfeng Gu and Pelin Hacarlioglu and Shigeo …
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(PDF) Chemical Processing of Bauxite: Alumina and Silica …
such as hydrated alumina and silica minerals, the Chapter covers the impact of other constituents, suc h as titania, iron compounds, organics, and other impurities. The use of lime in the Bayer ...
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Efficient separation of silica and alumina in simulated CFB …
After magnetic separation, the alumina content, silica content, and the mass ratio of alumina/silica in the non-magnetic part of the separation product was 80.36 wt%, 6.49 wt%, and 12.38 ...
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Engineering silica membranes for separation performance, …
Membrane technology has emerged as a leading separation process because of its high energy efficiency, easiness in scale-up and operation, and absence of chemical wastes [1, 2].For example, membranes have been practiced to desalinate salty water, remove CO 2 from natural gas (CO 2 /CH 4 separation), produce N 2 from the air (O 2 /N 2 separation), and …
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Complete Extraction of Amorphous …
Ma et al. showed that by using dual treatment of CFA by acid and alkali, the silica extraction degree reaches only 70%. Leaching of silica from the surface of the CFA particles allows for destruction of the Si-O-Al bonds. The …
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Separation of alumina and silica from metakaolinite by …
Separation of alumina and silica from metakaolinite by reduction roasting−alkaline leaching process: Effect of CaSO4 and CaO @article{Wang2022SeparationOA, title={Separation of alumina and silica from metakaolinite by reduction roasting−alkaline leaching process: Effect of CaSO4 and CaO}, author={Hongyang Wang and Xiao-xue Zhang and Siyuan ...
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Adsorption Chromatography: Definition, Principle, …
Adsorption Another name for chromatography is adsorption separation. The mixture of gas or liquid splits into its parts after passing over the adsorbent bed, which adsorbs various chemicals at varying speeds. ... The adsorbent, which is usually carbon, alumina, or silica, can bind and hold molecules to its surface by weak non-ionic interactions ...
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Synthesis and separation properties of an α-alumina …
A thin high-silica MEL membrane was synthesized on a porous α-alumina hollow fiber support by a secondary growth approach. The membrane quality was evaluated by permporometry, single-gas permeation and butane isomer separation.
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Removal of Silica and Alumina as Impurities from Low …
This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53. ...
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Review Silica-alumina catalytic materials: A critical review
The applications of silica-aluminas in industrial catalytic processes are briefly reviewed. The literature data on the surface chemistry and structural chemistry of silica …
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High-Selectivity, High-Flux Silica Membranes for Gas Separation
Coherent and strong porous α-Al 2 O 3 membrane supports were made from granulated alumina powder ().The supports were uniaxially pressed at 10 5 kPa to shape the disk, followed by isostatic pressing at 4000 kPa to achieve a higher and more uniform "green" density. They were then sintered at 1250°C to a final porosity of 40% with an average Ø = 160 …
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