Upcycling Waste Glass into Ceramic Tiles: Eco‐Design for a Circular Manufacturing Route

ABSTRACT Ceramic tile manufacturing faces increasing pressure to cut energy use and reliance on virgin raw materials. Here, soda‐lime waste glass was evaluated as a partial replacement for feldspar flux in tile bodies under industrially relevant processing. Five formulations containing 0–20 wt.% waste glass were produced via wet milling, granulation, two‐stage uniaxial pressing, and fast firing in an industrial roller kiln (peak 1177°C; total 53 min). Thermal behavior, phase evolution, microstructure, and properties were assessed by DTA/TG, XRD, SEM/EDS, and standardized tests. Waste glass promoted earlier liquid‐phase formation, increased vitrification, and lowered porosity under fast‐firing conditions. The optimal composition was 15 wt.% glass, leading to the best densification balance with low water absorption (2.83%), reduced open porosity (4.97%), controlled linear shrinkage (7.99%), and high flexural strength (∼61 MPa). XRD showed decreasing crystallinity with increasing glass and albite formation, attributed to sodium diffusion from the glassy phase, consistent with the denser microstructure. This study demonstrates waste‐glass fluxing in an industrial fast‐firing roller kiln, defines a practical composition‐property window at fixed firing temperature, and connects thermal, phase, microstructural, and performance changes. Soda‐lime waste glass is therefore a scalable flux for energy‐efficient, circular‐economy ceramic tile production.