Stability optimisation of CaO-doped partially stabilised zirconia by microwave sintering

Zhang, Mingyuan; Gao, Lei; Kang, Juanxue; Pu, Juan; Peng, Jinhui; Omran, Mamdouh; Chen, Guo

doi:10.1016/j.ceramint.2019.08.024

Cited by 21 publications

(14 citation statements)

References 19 publications

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“…Nonetheless, the deposition of one oxide on another oxide is interesting to understand. In general, ZrO 2 can be partially stabilized when doped with CaO [36,41,42]. In addition, when ZrO 2 can be partially stabilized for any doped agent, the crystalline structures can undergo changes because the ZrO 2 has an ability to embed foreign cations in their network [11,43].…”

Section: Introductionmentioning

confidence: 99%

The Effect of the ZrO2 Loading in SiO2@ZrO2-CaO Catalysts for Transesterification Reaction

et al. 2020

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The effect of the ZrO2 loading was studied on spherical SiO2@ZrO2-CaO structures synthetized by a simple route that combines the Stöber and sol-gel methods. The texture of these materials was determined using SBET by N2 adsorption, where the increment in SiO2 spheres’ surface areas was reached with the incorporation of ZrO2. Combined the characterization techniques of using different alcoholic dissolutions of zirconium (VI) butoxide 0.04 M, 0.06 M, and 0.08 M, we obtained SiO2@ZrO2 materials with 5.7, 20.2, and 25.2 wt % of Zr. Transmission electron microscopy (TEM) analysis also uncovered the shape and reproducibility of the SiO2 spheres. The presence of Zr and Ca in the core–shell was also determined by TEM. X-ray diffraction (XRD) profiles showed that the c-ZrO2 phase changed in to m-ZrO2 by incorporating calcium, which was confirmed by Raman spectroscopy. The purity of the SiO2 spheres, as well as the presence of Zr and Ca in the core–shell, was assessed by the Fourier transform infrared (FTIR) method. CO2 temperature programmed desorption (TPD-CO2) measurements confirmed the increment in the amount of the basic sites and strength of these basic sites due to calcium incorporation. The catalyst reuse in FAME production from canola oil transesterification allowed confirmation that these calcium core@shell catalysts turn out to be actives and stables for this reaction.

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Section: Introductionmentioning

confidence: 99%

The Effect of the ZrO2 Loading in SiO2@ZrO2-CaO Catalysts for Transesterification Reaction

et al. 2020

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“…( 1), it can be concluded that there must occur the phase transition of fused zirconia, with the reversible martensitic transformation occurring in zirconia material with temperature change. The conversion of tetragonal phase (t-ZrO 2 ) to monoclinic phase (m-ZrO 2 ) occurs at 1000 °C with a corresponding reverse phase transition occurring at 1170 °C [25,26], and the roasting temperatures in the work were controlled at the regimes of 1000 °C to 1450 °C; therefore, it can be speculated that at the chosen temperature regime, the conversion of cubic phase (c-ZrO 2 ) to tetragonal phase (t-ZrO 2 ) and the conversion of tetragonal phase (t-ZrO 2 ) to monoclinic phase (m-ZrO 2 ) occurred, causing that the cubic phase (c-ZrO 2 ) was partially converted into monoclinic phase (m-ZrO 2 ), further rendering the decrease of stability properties. Additionally, the stability rate was 100% at 950 °C, indicating that there was no monoclinic phase zirconia (m-ZrO 2 ) produced, which was ascribed to that the temperature at 950 °C was lower than the conversion temperature of tetragonal phase (t-ZrO 2 ) to monoclinic phase (m-ZrO 2 ) at 1000 °C.…”

Section: Effect Of Roasting Temperature On Stability Ratementioning

confidence: 99%

One-step preparation of CaO-doped partially stabilized zirconia from fused zirconia

Chen

Peng

et al. 2020

Ceramics International

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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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Stability optimisation of CaO-doped partially stabilised zirconia by microwave sintering

Cited by 21 publications

References 19 publications

The Effect of the ZrO2 Loading in SiO2@ZrO2-CaO Catalysts for Transesterification Reaction

The Effect of the ZrO2 Loading in SiO2@ZrO2-CaO Catalysts for Transesterification Reaction

One-step preparation of CaO-doped partially stabilized zirconia from fused zirconia

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

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