Effects of thermal activation on the hydration performance of lithium slag-cement composite binder

In order to enhance the utilization efficiency of lithium slag (LS) in cement-based materials, calcificated and thermal activation of LS were conducted, and the activation mechanism have been analyzed. Results showed that gypsum and spodumene in LS decomposed at high temperature via calcificated and thermal activation, and spodumene as well as limestone calcination decomposed at high temperature, to generate more CS, CA and other mineral phases. Calcificated and thermal activation could enhance the activity of LS to participate in pozzolanic reaction, and generate the formation of more hydration products. After calcificated and thermal activation of LS, the hydration exothermic peak, the total amount of hydration heat, and hydration production of LS composite binder were significantly increased. The hardened matrix was more compact with less porosity. Compared with cement mortar incorporated with raw LS, the incorporation of calcificated and thermal activated LS enhanced the compressive strength of cement mortar at 3d, 7d, and 28d by 25.8%, 13.4%, and 20.5%, respectively.