A kinetic study on the aluminothermic reduction of ZrO2

Flores, Alfredo; Juárez, R.; Torres, J.; Ayala, Z.; Ochoa, Rocio

doi:10.1016/j.matpr.2018.10.414

Cited by 4 publications

(5 citation statements)

References 4 publications

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“…We conducted 27 experiments, where the effects of temperature, percentage of magnesium in the alloy, and agitation speed in the molten bath were investigated. The operational parameters and their values were selected from preliminary works [8][9][10][11][12], where the kinetics of the aluminothermic reactions have been studied, not only for attaining reliable reaction efficiencies, but also to avoid metal losses during treatment. Initially, a factorial design was proposed to reduce the experimental errors.…”

Section: Methodsmentioning

confidence: 99%

“…• 1123 K = −970.09 kJ (9) In turn, Al 2 O 3 and MgO react according to Equation (4) to form the so-called spinel, MgAl 2 O 4 .…”

Section: Thermodynamic Consideration For the Al-nio-mg Systemmentioning

confidence: 99%

“…In general, it can be observed from these graphs that the aluminothermic reduction reaction was not completed for any value of the parameters studied (i.e., temperature, initial magnesium concentration, or agitation speed), owing to the diffusive nature of the reaction, as it will be explained later. 2Mg + O = 2MgO, ∆° = −970.09 kJ (9) In turn, Al2O3 and MgO react according to Equation (4) to form the so-called spinel, MgAl2O4. All of the reaction products described by the reactions given by Equations (1), (2), (4), (5), or (7)-(9) were found in the slags obtained from the NiO reduction process studied in this work.…”

Section: Kinetic Measurementsmentioning

confidence: 99%

“…Currently, an aluminothermic reduction is used for the preparation of aluminum master alloys, such as Al-Sr-Mg, Al-Ce-Mg, Al-Zn, Al-Mn, Al-Zr, Al-Mg-Fe-Cr, Al-Li, and so on. [6][7][8][9][10][11][12][13][14][15]. Nowadays, aluminothermic reduction is the most common practice used in the production of both kinds of products, pure metals or alloys [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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A Kinetic Study on the Preparation of AlNi Alloys by Aluminothermic Reduction of NiO Powders

Beltran¹,

Valdés²,

Torres³

et al. 2018

Metals

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In this work, the experimental results obtained during the preparation of Al-Ni and Al-Ni-Mg alloys using the aluminothermic reduction of NiO by submerged powder injection, assisted with mechanical agitation are presented and discussed. The analyzed variables were melt temperature, agitation speed, and initial magnesium concentration in the molten alloy. For some of the experiments performed, it was found that the Ni concentration increased from 0 to about 3 wt-% after 90 min of treatment at constant temperature and constant agitation speed. In order to determine the values of the kinetic parameters of interest, such as the activation energy and the rate constants, the values of the results obtained were fitted to the kinetic formulae available. Moreover, the kinetics of the reaction were found to be governed by the diffusion of Al and Mg to the NiO boundary layer, where MgAl2O4 or Al2O3 were formed as the main reaction products. Finally, from a thermodynamic study of the system, the main reactions that took place are explained.

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Section: Methodsmentioning

confidence: 99%

“…• 1123 K = −970.09 kJ (9) In turn, Al 2 O 3 and MgO react according to Equation (4) to form the so-called spinel, MgAl 2 O 4 .…”

Section: Thermodynamic Consideration For the Al-nio-mg Systemmentioning

confidence: 99%

Section: Kinetic Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Kinetic Study on the Preparation of AlNi Alloys by Aluminothermic Reduction of NiO Powders

Beltran¹,

Valdés²,

Torres³

et al. 2018

Metals

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“…If the kinetics are accelerated up to 5% by weight, additional magnesium must be added to the molten alloy, which is consumed by the aluminothermic reduction reactions. This magnesium (Mg) loss is associated with increasing the effectiveness of the chemical reduction reaction, as well as improving the wettability of particles of Mn oxides by the molten alloys [19,20]. In particular, kinetic information about the aluminothermic reduction rate by which MnO can be reduced is essential for the development of new sustainable products and processes that apply the recycling of both aluminum and alkaline batteries [16,17].…”

Section: Introductionmentioning

confidence: 99%

A Kinetic Study on the Preparation of Al-Mn Alloys by Aluminothermic Reduction of Mn3O4 and MnO Powders

Salas Avilés,

Flores Valdés,

Torres Torres

et al. 2023

Metals

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The study of aluminothermic reduction in manganese compounds is a complex challenge in preparing Al-Mn alloys. The primary objective of this study was to ascertain the activation energy values for the aluminothermic reduction of MnO and Mn3O4 oxides derived from alkaline batteries. The study melted aluminum found in beverage cans and utilized the technique of powder addition with mechanical agitation. The kinetics of the reaction were studied under the effects of temperature (750, 800, and 850 °C), degree of agitation (200, 250, and 300 rpm), and the initial concentration of magnesium in molten aluminum (1, 2, 3, and 4% by weight). Kinetic measurements for Mn3O4 particles suggest a reaction mechanism that occurs in stages, where manganese undergoes oxidation states [Mn+3] to [Mn+2] until it reaches the oxidation state Mn0, which allows it to dissolve in the molten aluminum, forming alloys with up to 1.5 wt.% of Mn. Therefore, the kinetic of the aluminothermic reduction of MnO is described by the geometric contraction model, while the mechanism of Mn3O4 reduction occurs in two stages: geometric contraction, followed by an additional stage involving the diffusion of chemical species to the boundary layer. In addition, this stage can be considered a competition between the formation of MnO and the chemical reaction itself.

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Electrochemical behavior of Zr(IV) and co-reduction synthesis of Al-Zr alloys in KF-AlF3-Al2O3-ZrO2 molten salt

Chen¹,

Yang²,

Zhang³

et al. 2023

Electrochimica Acta

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A kinetic study on the aluminothermic reduction of ZrO2

Cited by 4 publications

References 4 publications

A Kinetic Study on the Preparation of AlNi Alloys by Aluminothermic Reduction of NiO Powders

A Kinetic Study on the Preparation of AlNi Alloys by Aluminothermic Reduction of NiO Powders

A Kinetic Study on the Preparation of Al-Mn Alloys by Aluminothermic Reduction of Mn3O4 and MnO Powders

Electrochemical behavior of Zr(IV) and co-reduction synthesis of Al-Zr alloys in KF-AlF3-Al2O3-ZrO2 molten salt

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