Investigation of the coal fly ashes using IR spectroscopy

Comparative investigations of influence of chemical admixtures on pozzolanic and hydraulic activities of fly ash with the use of thermal analysis and infrared spectroscopy

“…The most pronounced changes in shape of IR spectrum of hydrated ash PB, compared to the result for raw fly ash, are due to the appearance of the bands of valence and deformation vibrations of water molecules, with the extreme, respectively, at 3,440 and 1,640 cm -1 , and the band at spectrum at 580-700 cm -1 are also visible. For raw fly ash in this range of wavenumbers, the bands at 678, 612, and 595 cm -1 characteristic for anhydrite [21] are observed (the main band for SO 4 2-vibration in anhydrite is not visible because it overlaps with the strong band for ash at 1,100 cm -1 ). Thus, the obtained results confirm that PB fly ash exhibits weak binding properties.…”

“…On the 3rd day of hydration, the IR spectrum resembles mixture of non-hydrated PK fly ash and Ca(OH) 2 : there is a clearly visible band at about 3,640 cm -1 corresponding to the vibration of OH -in Ca(OH) 2 [14] as well as bands at 1,420 and 875 cm -1 related to vibration of CO 3 2-in CaCO 3 which was introduced into the paste with Ca(OH) 2 . The main, intense, broad ash band with the extreme at 1,070 cm -1 , typical for vibrations of Si(Al)-O in ashes [20,21], is also visible. Very weak bands, almost invisible after 3 days of hydration, at about 3,500 and 1,660 cm -1 correspond to vibrations of water molecules.…”

Pelletization of Immobilized Amine Carbon Dioxide Sorbents with Fly Ash and Poly(vinyl chloride)

“…TheD RIFTS spectra of the FA/EI 423 -S (20/80) powder and ground FA/EI 423 -S (20/80)_PVC 62 pellet, shown in Figure 5, reveal the molecular-scale chemical interactions of the binder with the FA and sorbent. Importantly,t he spectra were collected from samples with small particle sizes and with the same IR parameters to eliminate differences in their overall background shape.T he spectra of the FA/sorbent powder and ground pellet in Figure 5a exhibit identical background shapes;t herefore,t heir IR features can be compared directly.B oth spectra show ac haracteristic broad MÀOH stretchingb and for the hydrogen-bonded MÀOH groups (M = Si or Al) of silica and FA between ñ = 3670 and 3420 cm À1 , [13,21,22] ÀNH 2 /ÀNH bandsf or immobilized EI 423 and TEPAa tñ = 3420-3100 (asymmetric/symmetric stretching doublet) and 1606 cm À1 (bending singlet), [1i, 23] and ÀCH 2 / ÀCH bands for the alkyl groups of the amines [1i] and the PVC 62 polymer binder [24] at ñ = 3000-2700 (stretching) and 1500-1400 cm À1 (bending). Thef ull spectra of PVC 62 and FA are shown in Figure S3.…”

Ultrafine grinding of fly ash with grinding aids: Impact on particle characteristics of ultrafine fly ash and properties of blended cement containing ultrafine fly ash

“…From decreases of these wave numbers of the spectral band, it can be inferred that GA can promote the lattice distortion and amorphous of fly ash in the mechanical grinding process. Additionally, the surface property of fly ash is also improved by GA through promoting the destruction of porous vitreous body and glass phase particles adhesion body [45,46].…”