Structural change of chrysotile caused by isothermal annealing and glassification was examined by 57Fe-Mössbauer spectroscopy, X-ray diffractometry (XRD), X-ray fluorescence analysis (XRF), differential thermal analysis (DTA) and scanning electron micrography (SEM). From 57Fe-Mössbauer spectra, it proved that FeII in the pristine chrysotile was oxidized to FeIII when annealed at 1,000°C. By contrast, FeIII was reduced into FeII when annealed at 1,300°C under in ambient atmosphere. Both forsterite (Mg 2SiO4) and fayalite ((Fe, Mg)2SiO4) were precipitated when the chrysotile was annealed at higher than 1,000°C. Homogeneous glass samples were obtained by melting asbestos with waste-glass powder, Na2CO3 and K2CO3 at 1,300°C for 15 min. A constant isomer shift value of 0.23 ±0.01 mm s∈-∈1 and an increase in the quadrupole splitting value from 0.70 ±0.02 to 1.01 ±0.02 mm s∈-∈1 were observed in the glassified chrysotile.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics
- Condensed Matter Physics
- Physical and Theoretical Chemistry