Glass‐Ceramic Tiles Prepared by Pressing and Sintering DC Plasma‐Vitrified Air Pollution Control Residues

Abstract

Air pollution control (APC) residues produced from cleaning gas emissions at energy from waste (EfW) plants processing municipal solid waste are a problematic hazardous waste. In this research they have been treated using DC plasma technology and this produces an inert glass. Glass‐ceramic tiles were prepared by powder pressing and sintering fritted APC residue‐derived glass. Tile samples prepared with high levels of plasma treated APC residue glass had comparable physical properties to commercially available ceramics such as porcelain and monoporosa, with high bulk density (2.4 g/cm3), low water absorption (<6%) and high flexural strength (∼60 MPa).

Application of an Industrial Waste Glass in “Glass-Ceramic Stoneware”

“…10,11 Compared with the conventional nucleation/growth process, adopted for most glass-ceramics, also from waste glasses (Russian ''Slagsitalls,'' dating back to the 1960s, constitute a quite familiar example), 11,12 sinter-crystallization leads to dense and highly crystalline materials with much shorter and more economic thermal treatments. [13][14][15] A previous paper 16 reported the feasibility of sintered gehlenite-based glass-ceramics from Europlasma's glass, from pressed fine powders (o40 mm), without binders, underlining the advantages of a very fast processing consisting of direct insertion of samples at 10501C, with a holding time of 1 h. Similar gehlenite-based glassceramics have been recently prepared by Rani Devaraj et al 9 by adopting slower treatments and coarser powders (o250 mm), added with a small amount of bentonite.…”

“…In particular, the introduction of soda‐lime glass as secondary glass allowed the tuning of the balance between crystallization and densification and led to products exhibiting remarkable mechanical properties (e.g., bending strength exceeding 100 MPa), although sintered at low temperature (900–950°C instead of 1150–1200°C, for porcelain stoneware standard formulations). Also presented is the effect of the application of high heating rates (e.g., 40°C/min), not discussed previously, important for the possible industrialization (it is well known that industrial furnaces operate with a heating rate far >10°C/min, applied in many papers) 9,13,18,21 …”

“…This glass was obtained from municipal solid waste (MSW) incinerator fly ashes by the application of thermal plasma melting, one of the most promising technologies for the treatment of hazardous waste (e.g., due to flexibility, efficiency in destroying organic compounds, lack of waste products, and compactness of plants). [5][6][7][8][9] With regard to valorization, it must be underlined that waste glasses, in the form of frits, may be easily converted into glass-ceramics, owing to a sinter-crystallization mechanism. 10,11 Compared with the conventional nucleation/growth process, adopted for most glass-ceramics, also from waste glasses (Russian ''Slagsitalls,'' dating back to the 1960s, constitute a quite familiar example), 11,12 sinter-crystallization leads to dense and highly crystalline materials with much shorter and more economic thermal treatments.…”

“…Also presented is the effect of the application of high heating rates (e.g., 401C/min), not discussed previously, important for the possible industrialization (it is well known that industrial furnaces operate with a heating rate far 4101C/min, applied in many papers). 9,13,18,21 Experimental Procedure…”

“…The fast vitrification is useful also for improving the sealing of hazardous pollutants, as long treatments at high temperature, favorable to the volatilization of some oxides, are avoided. The rapid cooling of the glass melt, by lamination through cooled metallic rollers, is actually adopted by Europlasma (Bordeaux, France), 4 for the glass used in the present investigation, named “Plasmalit.” This glass was obtained from municipal solid waste (MSW) incinerator fly ashes by the application of thermal plasma melting, one of the most promising technologies for the treatment of hazardous waste (e.g., due to flexibility, efficiency in destroying organic compounds, lack of waste products, and compactness of plants) 5–9 . With regard to valorization, it must be underlined that waste glasses, in the form of frits, may be easily converted into glass–ceramics, owing to a sinter‐crystallization mechanism 10,11 .…”