Crystallization kinetics of glass–ceramics prepared from high-carbon ferrochromium slag

Bai, Zhitao; Qiu, Guibo; Yue, Changsheng; Guo, Min; Zhang, Mei

doi:10.1016/j.ceramint.2016.09.102

Cited by 36 publications

(10 citation statements)

References 37 publications

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“…These curves comply with the principle of non‐isothermal process, that is, the temperature of the maximum of the exothermic peak increases with the increase of the heating rate, which allows the study of the kinetic mechanism by DTA. Thus, T p increases from 827°C to 877°C when the heating rate increases from 10°C min −1 to 50°C min −1 ; this result is in good agreement with that reported in other studies 21,46,47 . According to Bai et al., 46 the increase in temperature with heating rate is related to the fact that heat transfer becomes more difficult as the heating rate increases.…”

Section: Resultssupporting

confidence: 91%

“…These curves comply with the principle of non-isothermal process, that is, the temperature of the maximum of the exothermic peak increases with the increase of the heating rate, which allows the study C min −1 ; this result is in good agreement with that reported in other studies. 21,46,47 According to Bai et al, 46 the increase in temperature with heating rate is related to the fact that heat transfer becomes more difficult as the heating rate increases. Accordingly, much more energy will be required for nucleation and crystallization processes to occur.…”

Section: Resultsmentioning

confidence: 99%

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Kinetic study of the transformation of sodalite to nepheline

2022

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The kinetics and mechanism of the development of nepheline (NaAlSiO4) through thermal transformation of sodalite (Na4Al3Si3O12Cl) was studied by means of differential thermal analysis at different heating rates (10°C min−1 to 50°C min−1) to control the evolution of the crystallization fraction. The conversion of sodalite (cubic crystal) to pure nepheline (hexagonal crystal) took place in the 800°C–900°C interval. The activation energy for nepheline crystallization from sodalite was determined by isothermal and non‐isothermal methods. The ratio t0.75/t0.25, together with the Avrami exponent (n) and the numerical factor of the dimensionality of crystal growth (m) parameters indicated that dominant crystallization mechanism in nepheline development is bulk crystallization mechanism controlled by interface reaction.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Kinetic study of the transformation of sodalite to nepheline

2022

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“…At the same time, glass-ceramics possess strong mechanical strength, excellent thermochemical stability, and outstanding corrosion resistance . Waste-derived glass-ceramics (WDGC) are generally prepared via a two-step process involving (i) vitrification of solid residues to homogeneous amorphous slags by melting (>1400 °C) and quenching, and (ii) controlled crystallization of the amorphous slags to compact and environmentally stable glass-ceramics by sintering (800–1100 °C). − However, the main drawback of this method is the high treatment cost caused by high melting temperatures. Bingham et al demonstrated that vitrification of toxic wastes was not economically feasible on any substantial scale.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and Prediction of Cr and Zn Immobilization from Industrial Residues by Glass-Ceramics

et al. 2021

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Controllable preparation of a waste-derived glass-ceramics provides a promising and environmentally safe strategy for industrial residue recycling by immobilizing hazardous heavy metals in its amorphous-crystal multiphase structure. A modified two-step method was developed for treatment of Zn- and Cr-containing wastes to enhance the economic feasibility and reduce the risk of heavy metal evaporation. ZnO and Cr2O3 with various Zn or Cr contents (1, 5, and 10 wt %) were added after vitrifying the CaO(25 wt %)-Al2O3(20 wt %)-SiO2(55 wt %) system, followed by crystallization at 1000 and 1100 °C, respectively. Various qualitative and quantitative characterizations including TG-DSC, XRD, Rietveld refinement analysis of XRD patterns, XPS, and HRTEM were performed to demonstrate the immobilization mechanism of Zn and Cr species. Meanwhile, an artificial neural network (ANN) model was trained and optimized for simulation and prediction of heavy metal immobilization in glass-ceramics. The results demonstrated that the predicted results obtained from the well-trained ANN model fitted well with the experimental results. Both Zn and Cr were immobilized in glass-ceramics efficiently with immobilization efficiencies of 86.5–97.6% for Zn and 99.3–99.9% for Cr. Zn preferred to be immobilized in glass-ceramics by chemical stabilization. Around 50 wt % of Zn was incorporated in Ca2ZnSi2O7 crystals, while the rest was present in the glass matrix as dissolved Zn2+ ions. However, the most dominant immobilization mechanism of Cr was physical encapsulation, with 82 wt % of Cr embedded in the glass matrix of glass-ceramics as Cr2O3 crystals. The sensitive analysis suggests that the heavy metal content played the most important role, while crystallization temperature contributed the least for heavy metal immobilization. Among various inherent natures of heavy metals, the atomic radius was the most critical in determining immobilization efficiency of heavy metals. The results provide a comprehensive guidance for the preparation of heavy-metal-incorporated glass-ceramics and further enhancement of heavy metal immobilization effects.

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“…13,14 Research works that focused on the optimum heat treatment schedule, nucleation agent, and physical properties of glass ceramics have revealed some critical information about slag glass ceramics, and provided theoretical instruction for future studies on BF slag glass ceramics. [14][15][16][17] However, the industrial manufacture of glass ceramics related to molten blast furnace slag is confronted with many problems, and one of the most important reasons is that the understanding and control of structure and properties of melts are not thoroughly studied. For glass ceramics from BF slag, preparation of glass melt prior to heat treatment is always one of the most critical and necessary procedures.…”

Section: Introductionmentioning

confidence: 99%

Structure, viscosity, and crystallization of glass melt from molten blast furnace slag

Zhang

Xiao

et al. 2020

Int J of Appl Glass Sci

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Molten blast furnace slag (BF slag) was modified using liquid‐liquid mixing method for glass ceramics preparation, and the structure and viscosity of glass melt after modification were investigated. The BF slag proportion increased from 52.72 wt. % to 67.05 wt. %, and CaO/(SiO2 + Al2O3) also varied from 0.33 to 0.47. The structure of BF slag melt after modification was investigated using 29Si and 27Al MAS NMR spectra. With increasing CaO/(SiO2 + Al2O3), the amount of Q1 remarkably increased while that of Q2 decreased significantly. Specifically, when CaO/(SiO2 + Al2O3) was more than 0.38, Q3 disappeared in glass melt. The viscosity of glass melt with CaO/(SiO2 + Al2O3) of 0.47 exhibited a steep change at 1169°C, which was mainly caused by the sufficient crystallization of gehlenite confirmed by DTA cooling analysis, XRD, and FE‐SEM‐EDS analysis.

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Crystallization kinetics of glass–ceramics prepared from high-carbon ferrochromium slag

Cited by 36 publications

References 37 publications

Kinetic study of the transformation of sodalite to nepheline

Kinetic study of the transformation of sodalite to nepheline

Mechanism and Prediction of Cr and Zn Immobilization from Industrial Residues by Glass-Ceramics

Structure, viscosity, and crystallization of glass melt from molten blast furnace slag

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