Glass ceramic foams from coal ash and waste glass: production and characterisation

Abstract

Lightweight glass ceramic foams have been produced from a mixture of silicate wastes, namely 20 wt-% coal pond ash and 80 wt-% bottle glass cullet. A powder sintering route with the incorporation of 2 wt-%SiC as foaming agent was used. The pore morphology achieved under different sintering conditions was investigated in detail using X-ray microtomography. The apparent density of the foams ranged from 0 . 2 to 0 . 4 g cm 23 , and the porosity ranged from 70 to 90%. Other variables, such as pore wall thickness, pore size and roundness, all behaved consistently with sintering temperature. The optimum sintering temperature was found to be in the range 1000-1050uC, at which porosity was about 75% and was the most uniform. Foams produced under this condition exhibit satisfactory compressive strength of about 1 . 5 MPa and show relatively high thermal shock resistance, with compressive strength gradually decreasing as quenching temperature increases.

Glass-ceramics: Their production from wastes—A Review

“…In the case of recycling oil shale ash [184], the best mixture (80wt% oil shale ash, 16wt% soda ash, and 4wt% sand) was foamed at 900ºC for 10 minutes, and a porosity of about 85% was achieved. The pore sizes were similar to the study on CRT glasses [182] Gorokhovsky [183] that excessive limestone as the foaming agent (>5wt%) is detrimental to the mechanical properties of the foamed glass-ceramic.…”

“…The authors [184] have also recently produced foamed glass-ceramics from a mixture of coal pond ash and waste bottle glass cullet that incorporated less than 5wt% of fine SiC powder (5-25μm) as foaming agent. A short single-stage sintering/crystallisation treatment, that also promoted the reaction of SiC with oxygen, thus generating CO 2 as pore forming gas, was employed.…”

Foam glass processing using a polishing glass powder residue

“…The glass bottles in Japan were reported 1.98 million tons in 1998 and 74% of the container glass production was used as waste glass [3]. The cullet is estimated to reach about 0.5 million ton per year in UK [18]. Only 0.21 million ton of 0.67-0.77 million ton of waste flat glass generated every year in UK are recycled, while the rest is used as landfill [19].…”

Production and Characterization of Porous Ceramics From Coal Fly Ash and Clay

“…The similarity in the chemical composition of the fl y ash and clay make the fl y ash a possible substitute for clay consumption. By using different materials as pore creators there are many procedures that are usually employed to make porous ceramics products (Wu, Boccaccini, Lee, Kershaw and Rawlings, 2006;Bossert et al, 2004;Mangutova, Fidancevska, Milosevski and Bossert, 2004). Wang et al (2008) reported for developing lightweight aggregate from fl y ash and dry sewage sludge.…”