Influence of Lithium Slag on the Performance of Fly Ash–Based Autoclaved Aerated Concrete

Abstract To improve the resource utilization of lithium slag (LS) with high gypsum content, this study systematically investigated its feasibility as a substitute for fly ash (FA) in autoclaved aerated concrete (AAC). The effects of LS content, aluminum powder dosage, and alkalinity on the viscosity, foaming behavior, pH value, compressive strength, bulk density, and microstructure of AAC were examined. The results indicated that the incorporation of LS promoted the formation of ettringite, inhibited foaming, and consequently increased both the bulk density and compressive strength of AAC. Specifically, a mixture containing 35% LS, with Na 2 CO 3 and aluminum powder as the foaming agent, achieved a bulk density of 538 kg / m 3 and a compressive strength of 2.5 MPa. These findings demonstrate a viable pathway for the resource utilization of LS in building materials.