Thermal stability and microstructure characterization of MgAl2O4 nanoparticles synthesized by reverse microemulsion method

Fu, Ping; Lü, Wenzhong; Lei, Wen; Ke, Wu; Xu, Yuchun; Wu, Jia‐Min

doi:10.1590/s1516-14392013005000062

Cited by 26 publications

(11 citation statements)

References 22 publications

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“…There are several processes to prepare nanocrystalline magnesium aluminate, such as sol-gel [13][14][15][16] , co-precipitation 17 , complexation 1,18 , mechanical milling 3 , mechanical-chemical process 19 , hydrothermal 20 , micro emulsion 21 , combustion method 15,[22][23][24][25][26] and fast pyrolysis 27 . However, many of those are complex, expensive, have several steps, require long time for synthesis, require high temperatures and produce nonhomogeneous and generally low surface area solids 28 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

et al. 2017

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In this paper, magnesium aluminate spinels were prepared by microwave-assisted combustion, using urea as fuel. In order to evaluate the effect of the urea excess used in the synthesis, its mass was added in a range of 1.0 to 2.5 times the stoichiometric amount required. The materials produced were characterized by TGA, FTIR, XRF, XRD, BET, SEM and TEM. The results demonstrated that magnesium aluminate spinel was formed in all solids, but the crystallinity degree and the specific surface area increased according to the amount of urea that was used in the synthesis. The use of excess fuel in the preparation was therefore advantageous, since it eliminated the need of the calcination step, at high temperatures, in order to stabilize the spinel phase and improve the crystallinity of the solid. The heat generated in the combustion process was sufficient to develop the formation of a nanocrystalline structure and produce high purity materials, with a save of 99.4% in energy.

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Section: Introductionmentioning

confidence: 99%

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

et al. 2017

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“…The formation of spinel phase at this relatively low temperature might be ascribed to the uniform distribution of Mg 2+ and Al 3+ ions during the formation of co-precipitating complexes [24,25]. In this process, the reactions could be described as follows [26].…”

Section: Effect Of Temperaturementioning

confidence: 97%

Synthesis of Magnesium Aluminate Spinel Powder from the Purified Sodium Hydroxide Leaching Solution of Black Dross

Nguyen

Lee

2019

Processes

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Synthesis of magnesium aluminate spinel (MgAl2O4) was investigated by employing ball milling and co-precipitation methods. The starting materials (aluminum hydroxides) were obtained from the purified sodium hydroxide leaching solution of black dross. The characteristics of the synthesized spinel was analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM) images. In this work, the effect of calcination temperature and time on the formation of spinel by the two methods was compared. Calcination temperature showed a great effect on the formation of spinel in both methods. The results showed that the co-precipitation method has many advantages over the ball milling method. In ball milling method, complete conversion of the starting materials to spinel was impossible even at 1500 °C, while complete conversion to spinel was accomplished at 1000 °C for 5 h by the co-precipitation method. The average size of the spinel synthesized at these optimum conditions of the co-precipitation method was about 17 nm. A process can be developed to synthesize spinel from the black dross which is regarded as hazardous materials.

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“…Magnetite bands were identified around 400 and 580 cm -1 [35], while [34]. Generally, spinels of different compositions are characterized by two main absorption peaks at about 500-550 and 690-640 cm -1 [36][37][38]. However, in this described range of wavenumbers, aluminosilicate phases like nepheline and also carnegieite show overlapping absorption bands at around 470, 700 and 1000 cm -1 [39].…”

Section: Ip From Fired Brmentioning

confidence: 99%

A Proposal for a 100 % Use of Bauxite Residue Towards Inorganic Polymer Mortar

Hertel

Blanpain

Pontikes

2016

J. Sustain. Metall.

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A new process is suggested in the present work turning bauxite residue (BR) into a ready-made mortar for the synthesis of inorganic polymers, effectively transforming the Bayer process into a zero-waste process. This was achieved by firing BR at 1100°C which supports the formation of liquid phase and results after subsequent fast cooling in a semivitreous material. Based on thermodynamic calculations, the process was subsequently improved by adding minor quantities of C and silica to BR before firing which leads to the carbothermic reduction of ferric iron into ferrous iron; the new blends demonstrated an increase in the melt formation and eventually in the content of amorphous phase after solidification. The resulting material was activated using a K-silicate solution and was cured at 60°C for 72 h. The synthesized materials were water insoluble and dense, demonstrating compressive strength exceeding 40 MPa for the silica-rich blend. These inorganic polymers can find applications in construction, such as pavement tiles or floor/roofing tiles. A possible implementation of the process to transform BR within the alumina refinery is also represented.

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Thermal stability and microstructure characterization of MgAl2O4 nanoparticles synthesized by reverse microemulsion method

Cited by 26 publications

References 22 publications

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Synthesis of Magnesium Aluminate Spinel Powder from the Purified Sodium Hydroxide Leaching Solution of Black Dross

A Proposal for a 100 % Use of Bauxite Residue Towards Inorganic Polymer Mortar

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