Effect of slag composition on the crystallization of synthetic CaO–SiO2–Al2O3–MgO slags: Part I—Crystallization behavior

Esfahani, Shaghayegh; Barati, Mansoor

doi:10.1016/j.jnoncrysol.2015.12.011

Cited by 46 publications

(19 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One issue of this technique is that it is highly susceptible to heterogeneous nucleation due to the contact of the liquid with the DTA pan; By cooling the liquid at different rates and carrying out a microscopic or X‐ray diffraction (XRD) analysis to determine if the sample is crystallized. The cooling process can be made by the “thermocouple method”, where the material remains in direct contact with a thermocouple, which gives a high accuracy in the temperature determination; in thermal analysis equipment; or in the crucible where the material was melted. However, the thermocouple and the crucible material frequently induce heterogeneous nucleation, which affects the method's reproducibility.…”

Section: Governing Equationsmentioning

confidence: 99%

“…The R c can be determined by cooling the liquid at different speeds, and then measuring the critical cooling rate to form only a small arbitrary crystallized fraction on the cooling path. These methods, however, are highly affected by the surface in contact with the supercooled liquid during the cooling, and the R c determined by different authors can differ by orders of magnitude . One can also determine the crystal nucleation and growth rates as a function of temperature, and then construct time‐temperature‐transformation (TTT), or continuous cooling transformation (CCT) curves from which R c can be calculated.…”

Section: Introductionmentioning

confidence: 99%

“…These methods, however, are highly affected by the surface in contact with the supercooled liquid during the cooling, and the R c determined by different authors can differ by orders of magnitude. [20][21][22][23][24][25] One can also determine the crystal nucleation and growth rates as a function of temperature, and then construct time-temperature-transformation (TTT), or continuous cooling transformation (CCT) curves 26,27 from which R c can be calculated. The drawback is that constructing these curves is very time consuming.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Viscosity and liquidus‐based predictor of glass‐forming ability of oxide glasses

et al. 2019

View full text Add to dashboard Cite

Glass‐forming ability (GFA) is a measure of the easiness to vitrify a given substance. Theoretically, it is possible to make a glass from any liquid provided it is quenched from its liquidus temperature with a cooling rate above a critical value Rc to avoid crystallization. However, measuring GFA is a laborious and time‐consuming task. Moreover, predicting the GFA of substances that have never been vitrified is of greater interest. Here, we propose and evaluate a new parameter that can predict the glass forming ability of oxide mixtures. We derived a mother parameter, GFA = 1/Rc ∝ [U(Tmax) × TL]−1, where U(Tmax) is the maximum crystal growth rate, and TL is the liquidus temperature, which strongly correlates with the experimental critical cooling rates of oxide glass‐formers. A simplified version derived from the mother parameter—which does not need (scarce) crystal growth rate data and only relies on viscosity η and TL, GFA ∝ [η(TL)/TL2]—also correlates well with the Rc of several oxide compositions. This new GFA parameter, dubbed Jezica, works when heterogeneous nucleation prevails. It corroborates the widespread concept that substances having high viscosity at TL, and a low TL can be easily vitrified, and provides a powerful tool for the quest and design of novel glasses.

show abstract

Section: Governing Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Viscosity and liquidus‐based predictor of glass‐forming ability of oxide glasses

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Based on the principle of the apparatus of Ordway [33] and Welch [34], SHTT/DHTT method was developed by Kashiwaya et al [28,29] for the in situ observation of crystallization in mould slag under isothermal (SHTT) or near-service (DHTT) conditions. The original set-up, which was only slightly modified in some cases, has been used by several research groups for mould flux characterization [35][36][37][38][39][40][41][42][43][44][45][46]. The devices include the experimental unit, the hot thermocouple drivers and a video capture system.…”

Section: Experimental Set-up Of Shtt/dhttmentioning

confidence: 99%

High-temperature investigation of mould slag crystallization by single and double hot thermocouple techniques

Kölbl

Marschall

Harmuth

2019

J. Iron Steel Res. Int.

View full text Add to dashboard Cite

Methods for the characterization of mould slag crystallization with special emphasis on the single/double hot thermocouple technique (SHTT/DHTT) are reviewed. In the continuous casting process of steels, horizontal heat transfer is mainly influenced by the crystallization behaviour of the mould flux film. Here, both precipitation of crystals out of a liquid phase and devitrification of the glassy film in contact with the mould are of main interest. Therefore, various investigation methods are implemented to characterize different slag properties related to crystallization: a viscometer for determining the break temperature, differential thermal analysis (DTA), confocal scanning laser microscopy, and the water-cooled copper finger test. For near-service conditions, DHTT reveals the most detailed information, including not only the crystallization or devitrification temperature but also the morphology as well as the crystallization velocity. Due to improvements in the device and the representation of the results, a comparison of different samples is possible. Nevertheless, the application field of SHTT/DHTT is restricted to slag systems with low contents of evaporating components. Furthermore, the time required for data analysis is significantly longer than that required for other methods, e.g. DTA. Therefore, the application of DHTT is mainly advisable for mould slag research and development, whereas DTA can also be used for incoming inspections. Keywords Single hot thermocouple technique Á Double hot thermocouple technique Á Mould slag Á Near-service condition Á In situ investigation Á Crystallization

show abstract

“…Slag crystallization investigations have been performed by several authors in the recent years [8][9][10]. As the crystallization phenomenon is barely understood, experimental investigations on crystallization kinetics and products are favored in science.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Sample Homogeneity, Crucible Material, and Oxygen Partial Pressure on the Crystallization of Fe-Rich Oxidic Slag in CLSM Experiments

Schupsky

Guo

Blanpain

et al. 2020

J. Sustain. Metall.

View full text Add to dashboard Cite

Crystallization tendency and the state of oxidic slags are important influencing factors for slag viscosity and therefore slag tapping. During the gasification process slag is constantly produced and flows down the gasifier walls until it is intercepted and stored for further treatment or a possible valorisation. The kinds of fuel used for gasification lead to different kinds of slag composition likewise. Slag viscosity is strongly influenced by the composition of the slag and the temperature. However, the process of crystallization represents another major influencing factor. Slag crystallization is also affected by several parameters, whose effects need to be considered in experimental studies. This study investigated the impact of the sample state, the chosen crucible material, and the oxygen partial pressure on the crystallization of a Fe-rich oxidic slag in the confocal laser scanning microscope (CLSM) experiment. Using sample powder may lead to heterogeneous nucleation and crystallization during heating due to heterogeneous melting of the compounds. The selection of crucible material is crucial to prevent alloy formation of Fe-species with Pt-crucibles under reducing atmosphere. Finally, the partial pressure of oxygen influences the crystallization tendency as well as the morphology of the crystallized phases. These parameters impede the reproducibility of results as well as the comparison with results deriving from other experiments like sample quenching. This contribution provides an enhanced understanding of the stated parameter effects on the experimental investigation of oxidic slags using the CLSM setup and yields advice to prevent experimental influence on the results.

show abstract

Effect of slag composition on the crystallization of synthetic CaO–SiO2–Al2O3–MgO slags: Part I—Crystallization behavior

Cited by 46 publications

References 9 publications

Viscosity and liquidus‐based predictor of glass‐forming ability of oxide glasses

Viscosity and liquidus‐based predictor of glass‐forming ability of oxide glasses

High-temperature investigation of mould slag crystallization by single and double hot thermocouple techniques

The Impact of Sample Homogeneity, Crucible Material, and Oxygen Partial Pressure on the Crystallization of Fe-Rich Oxidic Slag in CLSM Experiments

Contact Info

Product

Resources

About