Phase evolution and properties of glass ceramic foams prepared by bottom ash, fly ash and pickling sludge

Municipal solid waste incineration products of bottom ash (BA), fly ash (FA), and pickling sludge (PS), causing severe environmental pollution, were transformed into glass ceramic foams with the aid of CaCO₃ as a pore-foaming agent during sintering. The effect of the BA/FA mass ratio on the phase composition, pore morphology, pore size distribution, physical properties, and glass structure was investigated, with results showing that with the increase in the BA/FA ratio, the content of the glass phase, Si–O–Si, and Q³Si units decrease gradually. The glass transmission temperature of the mixture was also reduced. When combined, the glass viscosity decreases, causing bubble coalescence and uneven pore distribution. Glass ceramic foams with uniform spherical pores are fabricated. When the content of BA, FA, and PS are 35wt%, 45wt%, and 20wt%, respectively, contributing to high performance glass ceramic foams with a bulk density of 1.76 g/cm³, porosity of 56.01%, and compressive strength exceeding 16.23 MPa. This versatile and low-cost approach provides new insight into synergistically recycling solid wastes.