Gehlenite and anorthite formation from fluid fly ash

Perná, Ivana; Šupová, Monika; Hanzlíček, Tomáš

doi:10.1016/j.molstruc.2017.12.084

Cited by 28 publications

(7 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, absorption bands centered at 1017 cm −1 , 975 cm −1 could be assigned to the asymmetric stretching vibrations of Si-O-Si and Si-O-Al groups of gehlenite (Ca 2 Al[AlSiO 7 ]) [63]. The absorption peaks observed in the frequency range 920-800 cm −1 and below 500 cm −1 can be attributed to AlO 4 tetrahedral and AlO 6 octahedral groups of tricalcium aluminate (3CaO Al 2 O 3 or C 3 A) [64,65]. On the other hand, the absorption maximum near 650 cm −1 could be assigned to oxidized iron carbide phases, whereas the broad absorption is around at 3450 cm −1 and the weak band at 1630 cm −1 , due to vibrations of adsorbed water molecules on KBr or the sample.…”

Section: Leaching Tests and Thermal Propertiesmentioning

confidence: 99%

Multifunctional Carbon-Based Hybrid Foams for Shape-Stabilization of Phase Change Materials, Thermal Energy Storage, and Electromagnetic Interference Shielding Functions

Gioti

Karakassides

Asimakopoulos

et al. 2022

Micro

View full text Add to dashboard Cite

Carbon-red mud foam/paraffin hybrid materials were prepared and studied for their thermal energy storage and electromagnetic interference (EMI) shielding properties. The host matrices were prepared utilizing the polymeric foam replication method, with a polyurethane sponge as a template, resin as a carbon source, and red mud as a filler. The paraffins, n-octadecane (OD) and the commercial RT18HC, were used as organic encapsulant phase change materials (PCMs) into the open pore structure of the foams. The foams’ morphological and structural study revealed a highly porous structure (bulk density, apparent porosity P > 65%), which exhibits elliptical and spherical pores, sized from 50 up to 500 μm, and cell walls composed of partially graphitized carbon and various oxide phases. The hybrid foams showed a remarkable encapsulation efficiency as shape stabilizers for paraffins: 48.8% (OD), 37.8% (RT18HC), while their melting enthalpies (ΔHm) were found to be 126.9 J/g and 115.5 J/g, respectively. The investigated hybrids showed efficient electromagnetic shielding performance in frequency range of 3.5–9.0 GHz reaching the entry-level value of ~20 dB required for commercial applications, when filled with PCMs. Their excellent thermal and EMI shielding performance places the as-prepared samples as promising candidates for use in thermal management and EMI shielding of electronic devices as well.

show abstract

Section: Leaching Tests and Thermal Propertiesmentioning

confidence: 99%

Multifunctional Carbon-Based Hybrid Foams for Shape-Stabilization of Phase Change Materials, Thermal Energy Storage, and Electromagnetic Interference Shielding Functions

Gioti

Karakassides

Asimakopoulos

et al. 2022

Micro

View full text Add to dashboard Cite

show abstract

“…This may indicate a phase transition [16]. The emerging bands at 998, 909 and 851 cm -1 indicate the apparition of a new phase, called gehlenite [17,18], resulting from the reaction between metakaolin and lime according to the following reaction [11,19]:…”

Section: Fig 2 Atr-ftir Spectra At Room Temperature (Rt) Of White Mar...mentioning

confidence: 99%

Fire Induced Microstructural Changes in Local Building Materials: Cases of White Marble and Limestone

AKRAM

2024

Mediterranean Architectural Heritage

View full text Add to dashboard Cite

Abstract. The aim of this work is to evaluate the degradation state of natural stones after their exposure to fire. These building and decorative materials, widely used in the architectural heritage, suffer irreversible damage when exposed to high temperatures. Therefore, knowledge of their residual durability is crucial in order to determine whether the post-fire building structure should be restored, reinforced or demolished. For this purpose, limestones (calcarenites) and white marbles collected from local quarries were subjected to heating-cooling cycles in a muffle furnace at various temperatures up to 1100°C. After each exposure, the selected samples were characterized at room temperature using X-ray diffraction (XRD), micro-Raman and ATR-FTIR infrared techniques. The results obtained showed that the mineralogical nature of both calcareous and marble natural stones is a key factor in their thermal stability when exposed to high temperatures. Above 570°C, natural stones undergo calcite decarbonation at different temperature ranges. Marble, which is mineralogically monophasic, underwent decomposition at 800°C, similar to calcite in its pure state. Calcarenite was decomposed at a much lower temperature of about 700 °C. This study classifies marble as more thermally stable than calcarenite.

show abstract

“…FBA mainly consists of anhydrite (CaSO 4 ), quartz (SiO 2 ), lime (CaO) and/or portlandite (Ca(OH) 2 ), and very often contains remaining non-decomposed calcite (CaCO 3 ) [12,13]. The composition of FFA is similar, complemented by roentgen-amorphous phases [14,15]. These types of ash are subdivided into two types, class C and class F, according to the content of free lime (10-35 wt.% and less than 5 wt.%, respectively), which depend on the type of coal burned [16].…”

Section: Introductionmentioning

confidence: 99%

“…• a high content of dehydrated alumina-silicates, the residue of clayed substances [22,23]; • a specific position of aluminum ions, caused by the low temperature of burning [15]; • a rather high number of compounds formed by the reaction of calcium oxide with sulfur [14]; • a content of extremely reactive free calcium oxide [24].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Phase Transformations in Fly Ash-Based Solids

et al. 2020

Self Cite

View full text Add to dashboard Cite

The presented article describes the phase transformations in solid bodies based on fluid fly ash (FFA) over eight years from the initial to the final phases. FFA has been selected as a type of industrial waste whose amount has been growing in recent years. This type of ash has self-hardening properties when watered because of the conditions of its origin. The specific temperature of fluid burning and the addition of calcium carbonate into the burning zone create a mixture of phases which are, even when solidified, ready to form new crystal phases, especially alumina-silicates, relicts of coal clay minerals. For experiments, bricks from the mixture of FFA and quartz sand were industrially produced and left outside. Subsequent mineralogical analyses of samples of various ages confirmed differences in phase compositions. It is supposed that the main role in the presented changes is played by the content of the roentgen-amorphous part of alumina-silicates because they are likely to be transformed into a stable form of feldspar. In addition to that, this article presents the hypothesis of a moving agent, which could explain the transformations in the final bodies.

show abstract

Gehlenite and anorthite formation from fluid fly ash

Cited by 28 publications

References 11 publications

Multifunctional Carbon-Based Hybrid Foams for Shape-Stabilization of Phase Change Materials, Thermal Energy Storage, and Electromagnetic Interference Shielding Functions

Multifunctional Carbon-Based Hybrid Foams for Shape-Stabilization of Phase Change Materials, Thermal Energy Storage, and Electromagnetic Interference Shielding Functions

Fire Induced Microstructural Changes in Local Building Materials: Cases of White Marble and Limestone

Phase Transformations in Fly Ash-Based Solids

Contact Info

Product

Resources

About