Incineration of waste is increasing in the UK as landfill resources diminish. Municipal
waste incineration produces waste residues; bottom ash, fly ash and air pollution
control (APC) residues. The present research project focuses on APC residues, which
are a hazardous waste arising from cleaning of incineration flue gases. APC residues
must be pre-treated before disposal at hazardous landfill or placed in permanent
secure storage. The aim of this research project was to produce novel glass-ceramics
from optimised combinations of waste materials to provide a stabilised, safe material
of value and to provide an alternative to disposal. Pre-treatment of the APC residues
by washing was necessary to remove soluble chloride phases. Electrostatic
precipitator (EP) dust and soda-lime glass cullet were combined with the washed APC
residues as sources of glass forming oxides and borate. An optimised boratecontaining
silicate glass was produced from the wastes, from which dense, sintered
glass-ceramics and bulk glass-ceramics were successfully fabricated. A powder
sintering method was used to produce a dense sintered material from washed APC
residues, EP dust and glass cullet. It was determined that the use of commercially
available sodium borate (Neobor®) could be used to replace the waste source of
borate to produce a sintered material of equal mechanical and physical properties. The
main crystalline phases of all heat treated materials were wollastonite and gehlenite.
The resulting mechanical and physical properties of the glass-ceramics and sintered
materials indicated they would be acceptable as construction materials. The results of
the research project indicate that thermal treatment is a convenient technology for the
safe utilisation of a problematic waste (APC residues from municipal waste
incineration) in new products of potential commercial interest
