The controlled preparation and stability mechanism of partially stabilized zirconia by microwave intensification

Li, Kangqiang; Jiang, Qi; Chen, Jin; Peng, Jinhui; Li, Xinpei; Koppala, Sivasankar; Omran, Mamdouh; Guo, Cheng

doi:10.1016/j.ceramint.2019.11.251

Cited by 25 publications

(15 citation statements)

References 42 publications

(46 reference statements)

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“…The temperature reached a higher value in the same time period, which denoted that the greater the microwave power, the faster the material heating rate will be. Under certain conditions, increasing the microwave output power means the enhancement in the electric field intensity [46][47][48]. As the electric field intensity (E) increases, the microwave can penetrate into the roasting material better and evenly, increasing the microwave penetration of zinc-containing residues and promoting the absorption of microwave power, further to make the material heat up quickly Therefore, appropriately increasing the microwave power can shorten the heating time and increase the apparent average heating rate of zinc-containing residues.…”

Section: Analysis Of Microwave Heating Characteristicsmentioning

confidence: 99%

Investigations on the Thermodynamics Characteristics, Thermal and Dielectric Properties of Calcium-Activated Zinc-Containing Metallurgical Residues

Zheng

Gao

et al. 2022

Materials

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An activate pretreatment of zinc-containing metallurgical residues were proposed by adding CaO and introducing microwave heating approach into the CaO activation pretreatment process to realize the conversion of refractory ore phases into pre-treated ore phase. Thermodynamic characteristics analysis indicated that adding CaO can realize the conversion of refractory ore phases, with the same effect as the carbon additives. Thermal conductivity properties analysis denoted that the thermal conductivity properties of ZnS and ZnFe2O4 were relatively poor. Meanwhile, the thermal conductivity properties of the residues sample added with 25% CaO were significantly superior to the residues added with other CaO contents, with the maximum specific heat value of 1.348 J/g·K at 350 °C. Dielectric properties analysis highlighted that adding CaO with the dielectric constant properties significantly higher than that of other substances can enhance the microwave absorption capacity of zinc-containing residues. The decrease in dielectric loss and loss tangent value with the increase of temperature and the residues having large microwave penetration depth guaranteed to obtain better uniformity of microwave heating. Furthermore, adding 25% CaO promoted the microwave penetration depth of the residues sample increased in the range of 300–500 °C. This work can lay a theoretical research foundation for solving the key difficulty for efficient Zn recovery from complex zinc-containing metallurgical residues.

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Section: Analysis Of Microwave Heating Characteristicsmentioning

confidence: 99%

Investigations on the Thermodynamics Characteristics, Thermal and Dielectric Properties of Calcium-Activated Zinc-Containing Metallurgical Residues

Zheng

Gao

et al. 2022

Materials

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“…However, the process temperature and time of this conventional treatment both need to be reduced to decrease energy cost. In contrast to conventional heating, microwave heating endows the distinctive advantages of shorter time and lower process temperature, selective heating, and controllable operation [27][28][29][30][31][32][33][34]. Due to the difference of microwave absorption of various useful minerals and gangue minerals, different heating efficiencies will appear during microwave heating.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Leaching of Zinc from Zinc-Containing Metallurgical Residues via Microwave Calcium Activation Pretreatment

Zheng

Gao

et al. 2021

Metals

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Given the shortage of zinc resource, the low utilisation efficiency of secondary zinc resource, and the crucial problem that the synchronous dissolution of zinc from different mineral phases, an activation pretreatment method merged with calcium activation and microwave heating approach was proposed to enhance the zinc leaching from complex encapsulated zinc-containing metallurgical residues (ZMR). Results indicated that under the optimal pretreatment conditions, including microwave activation temperature of 400 °C, CaO addition of 25% and activation time of 20 min, the zinc leaching rate reached 91.67%, which was 3.9% higher than that by conventional roasting pretreatment. Meanwhile, microwave heating presents excellent treatment effects, manifested by the zinc leaching rates, all exceeding that of conventional roasting under the same conditions, while the process temperature is decreased by 200 °C. In addition, XRD and SEM-EDS analysis denoted that microwave calcification pretreatment can effectively promote the transformation of the refractory zinc minerals like Zn2SiO4 and ZnFe2O4 into the easily leachable zinc oxides. The distinctive selective heating characteristics of microwave heating strengthened the dissociation of mineral inclusion, and the generated cracks increased the interfacial reaction area and further enhancing the leaching reaction of zinc from ZMR.

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“…However, as well as rapid heating and improvement in the flow of gases, there are other inherent advantages of this route using the heating promoted by microwave energy when compared to traditional processes. Such advantages are found in the great environmental benefits, among which the reduction of CO 2 during the heating process of the particles 7,8 , since the carbonaceous material inherent to the production of pig iron becomes necessary mainly as a chemical factor and no longer energetic.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Carbothermic Reduction of Iron Ore-Coke Composite Mixtures by Microwave Heating

et al. 2021

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In recent decades, microwave energy has been successfully experimented for mining and metallurgy processes and is considered a promising new method for ironmaking. In this context, in the present work, self-reducing mixtures composed of fines of iron ore and coke were prepared, intending to evaluate the degree of reduction of iron ore using microwave energy, applying different contents of coke, levels of power, and reaction times. For this, the degree of reduction was assessed as a function of these variables. Additionally, the reduction kinetics was investigated using chemical and diffusional models, and the microstructure of the samples was evaluated using scanning electron microscopy (SEM). The highest degree of reduction obtained after the experiments was greater than 60% and a statistical investigation showed that the reaction time is the factor with the greatest influence on these results, followed by microwave power and coke content. The investigation of the reaction kinetics showed that the process is chemically controlled, depending on the gasification steps governed by the Boudouard reaction. The images obtained by SEM led to the conclusion that the temperature inside the sample reached 1200°C. Pig iron was found both in the form of whiskers and in the form of metallic droplets.

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The controlled preparation and stability mechanism of partially stabilized zirconia by microwave intensification

Cited by 25 publications

References 42 publications

Investigations on the Thermodynamics Characteristics, Thermal and Dielectric Properties of Calcium-Activated Zinc-Containing Metallurgical Residues

Investigations on the Thermodynamics Characteristics, Thermal and Dielectric Properties of Calcium-Activated Zinc-Containing Metallurgical Residues

Enhanced Leaching of Zinc from Zinc-Containing Metallurgical Residues via Microwave Calcium Activation Pretreatment

Analysis of the Carbothermic Reduction of Iron Ore-Coke Composite Mixtures by Microwave Heating

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