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

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