Nucleation and crystal growth of glasses produced by a generic plasma arc-process

The feasibility to crystallise a glass prepared by thermal plasma vitrification of hospital wastes to produce a glass-ceramic suitable to be used as a construction material was investigated by using differential thermal analysis (DTA) and X-ray diffraction (XRD). Two crystallisation exotherms in DTA were attributed to the formation of wollastonite and a crystalline phase belonging to the melilite group (gehlenite or akermanite). DTA tests have shown that the glass is not suitable for bulk crystallisation and must be converted into a glass-ceramic by using the sintering process route through a single crystallisation step at 1000 °C for 10 min.