Infrared and Raman Spectroscopy of Mullite Ceramics Synthesized from Fly Ash and Kaolin

Abstract

Infrared spectroscopy and Raman spectroscopy were used to characterize mullite ceramics prepared from fly ash and kaolin by annealing at 1000 °C, 1100 °C, 1200 °C, and 1300 °C. IR spectroscopy confirmed the presence of SiO4 tetrahedra and AlO6 octahedra in samples. The presence of mullite has been confirmed at all temperatures. The presence of quartz has been confirmed up to a temperature of 1100 °C, and the presence of an amorphous form of SiO2 has been confirmed at temperatures of 1200 °C and 1300 °C. The transformation of quartz into the amorphous form of SiO2 at temperatures above 1100 °C is assumed. Transformation was performed on the percentage intensity decrease of the bending vibration of Si-O-Si (at about 450 cm−1) and Al-O-Si (at about 550 cm−1). Raman spectroscopy confirmed the presence of mullite at different stages of structural ordering (a well-ordered structure at a temperature of 1100 °C and a disordered structure at a temperature of 1300 °C).

Enhancement of Cashew (Anacardium occidentale L.) Seedlings Growth in Semiarid Regions Using a Superabsorbent Hydrogel Composite

“…The bands at 1115, 1032, and 1012 cm –1 refer to the Si–O–Si stretching in SiO 4 tetrahedra, while the band at 918 cm –1 is due to the Al–O deformation in AlO 6 octahedra . Bands observed at 789 and 749 cm –1 indicate the presence of low substitution and crystalline kaolinite. , Finally, bands in the range of 540–420 cm –1 are assigned to the Al–O–Si and Si–O–Si bending …”

Preparation of γ-phase pigment Red 170 through hydrothermal treatment and kaolin coating modification

“…In the spectrum of kaolin, the absorption peaks at 753 and 789 cm −1 corresponded to the Si-Si stretching vibrations, and the peaks at 1006 and 1114 cm −1 belonged to the Si-O stretching vibrations. 32 In the spectrum of kaolin-modied pigment, the above four peaks disappeared, suggesting kaolin was coated on pigment Red 170, and the characteristic absorption peaks of kaolin were covered.…”

Thermal Behavior of Ceramic Bodies Based on Fly Ash and Smectites

“…In the case of the NAU-H sample, the transformation to cristobalite also took place, but it is not so unambiguous. Other spectral bands found in the spectra MMT-H and BEI-H at about 1164, 907, 721, 554 cm −1 and 460 cm −1 were assigned to the high-temperature mullite phase based on literature sources [46][47][48].…”