Silico-aluminous bottom ash valorisation in cement clinker production: Synthesis, characterization and hydration properties

•Silico-Aluminous Bottom Ash was successfully recycled in kiln feed.•Raw meals particle size was reduced with the increment of SABA addition.•Clinker main mineralogical phases weren't negatively affected by SABA presence.•All syntheses satisfied the requirements for the strength class 52.5 as per standard EN 197-1.

The utilization of Silico-Aluminous Bottom Ash (SABA), derived from bituminous coal combustion in power plants, was investigated as a raw material in the kiln feed for the production of ordinary Portland cement clinker. Three different raw meals were studied, containing natural raw materials with 0, 3 and 6 wt% of SABA. The raw mixes reactivity was assessed in terms of unreacted lime content, following sintering at 1200, 1350, 1400 and 1450 °C. Clinkers produced at 1450 °C, were characterized through means of chemical analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterized clinkers were used to produce cement specimens by co-grinding with suitable amount of gypsum. Accordingly, cement quality was evaluated by determining setting times, standard consistency, expansibility and compressive strength at 2, 7 and 28 days. XRD and TG/DTG analysis were used for the hydration study evolution after 28 days of curing. SABA presents a promising alternative in waste valorisation practice, as it can readily be used in the raw kiln feed as a partial replacement of ordinary raw materials.