Synergistic development of one-part alkali-activated cements using spent bleaching earth and mine tailings with a waste-derived activator

Menacho-Rodriguez L.A.; Solis J.L.; Morales M.A.; Pérez-Villarejo L.; Eliche-Quesada D. · Open Ceramics (2026) · DOI: 10.1016/j.oceram.2026.101054

Resumen

This study investigated sustainable one-part alkali-activated cements (AAC) using spent oil bleaching earth (BE) and Cobriza mine tailings (MT) as precursors, activated by a novel circular reagent from spent diatomaceous earth and NaOH. Eight formulations (30–100 wt% BE) were characterized using XRD, FTIR, 57Fe Mössbauer spectroscopy, SEM-EDS, TGA, and isothermal calorimetry. MT addition promoted a hybrid (N,C)-A-F-S-H gel via partial Fe3+ incorporation into tetrahedral matrix sites and significant physical densification. The 30BE-70MT formulation achieved the highest 28-day compressive strength (48.0 MPa), meeting EN 998–2 (M20) and ASTM C270 (Type M) structural masonry standards. While most heavy metals were successfully immobilized within EU inert waste criteria (2003/33/EC), high-MT mixtures exhibited significant arsenic leaching due to arsenian sulfide dissolution under alkaline conditions. Future work must focus on targeted chemical stabilization strategies to immobilize arsenic prior to unconfined structural applications.

Instituciones: Universidad Nacional de Ingeniería