Preparation and properties of clinker-free cement based on lithium slag and quicklime

In order to reduce the environmental harm caused by the production of traditional cement, the feasibility of preparation for clinker-free cement based on lithium slag and quicklime was investigated in this paper. Meanwhile, the effect of Na₂SO₄ on the reactivity of lithium slag was studied. The hydration degree, hydration products and microstructure of clinker-free cement paste were analyzed by FTIR, XRD, TG-DTG, NMR, and SEM, respectively. The results indicate that lithium slag itself does not have the ability to hydrate. However, the clinker-free cement paste prepared with lithium slag can harden after adding quicklime, due to the formation of hydration products C–(A)–S–H gel and AFt. Adding Na₂SO₄ can enhance the reactivity of lithium slag, and further increase the amount of hydration products. Moreover, the compressive strength of clinker-free cement paste with lithium slag and quicklime is improved (25.6 MPa at 28 d). This paper not only verifies that lithium slag and quicklime can be used to prepare the clinker-free cement, but also provides a theoretical basis for the addition of Na₂SO₄ to enhance the reactivity of lithium slag.