Alkali activation of waste glass and aluminium dross for self-foaming glass ceramics production

There is a growing interest in researching eco-friendly materials and techniques for sustainable manufacturing. This study examines the production of different self-foaming glass ceramics (SFGCs) by mixing soda-lime glass (SLG) waste (particles <75 μm), secondary aluminium dross (SAD) content (2.5–10 wt%), and NaOH solution (1–3 M) at 600 rpm for 30 min, with the addition of 0.05 wt% of various surfactants. Among the tested samples, it was found that the composition containing 2.5 wt% SAD, processed at 850 °C with 3 M NaOH and 0.05 wt% of sodium dodecyl sulphate (SDS), exhibited a compressive strength of 4.1 MPa, porosity of 86 %, thermal conductivity of 0.125 W/m·K, and bulk density of 0.284 g/cm³. Overall, the SFGCs materials displayed a range of characteristics including hierarchical pore size from 0.002 to 180 μm, bulk densities from 0.284 to 0.672 g/cm³, porosities from 70 to 86 %, compressive strengths from 4.1 to 10.3 MPa, and thermal conductivities from 0.125 to 0.313 W/m·K. This study marks the first instance of producing SFGCs using SAD, SLG, and alkali activation through combined foaming techniques. The findings highlight a simple approach for sustainable SFGCs manufacturing that meets ASTM C 552, and US EPA toxicity standard, making it suitable for lightweight applications and thermal insulation.