Assessment of lithium slag as a supplementary siliceous material in autoclaved aerated concrete: Physical properties and hydration characteristics

How to realize the resource utilization of by-product lithium slag has become an urgent problem with the rise of lithium batteries. This study investigates the feasibility of using lithium slag as a supplementary siliceous material for the preparation of autoclaved aerated concrete. The effect of replacement method and substitution level on the physical properties of lithium slag based autoclaved aerated concrete were evaluated. In addition, the matching relationship between hydration products and physical properties was investigated by utilizing multiple microscopic tests. The results showed that the incorporation of lithium slag contributed to the enhancement of system reactivity at the chemical level. In contrast to quartz sand, lithium slag introduced reactive Al2O3 to the system, leading to the generation of Al-substituted tobermorite and katoite. The suitable level of substitution promoted the generation of hydration products. The composition of the elements and the morphology of hydration products were made closer to the desirable state, which contributed to strength development. Considering the comprehensive impact of lithium slag incorporation on physical properties and microstructures, specimens prepared utilizing lithium slag with a substitution rate of 50 %-75 % by the material quality control method possessed better application prospects.