<p>The application of lithium slag (derived from the production of lithium carbonate using spodumene) to high belite sulfoaluminate cement clinker (HBSAC) has not been previously reported. A mainly composed of HBSAC includes 2CaO·SiO₂ (C₂S), 3CaO·3Al₂O₃·CaSO₄ (C₄A₃$) and a small amount of 4CaO·Al₂O₃·Fe₂O₃ (C₄AF). The Gibbs free energy (<i>ΔG</i>) of CaO-Al₂O₃-SiO₂-Fe₂O₃-SO₃ multicomponent reaction system involved in the calcination process of HBSAC clinker was calculated. The suitable preparation process of HBSAC clinker by lithium slag was also investigated. The results show that all components of lithium slag can be used as raw materials for the preparation of HBSAC clinker. The <i>ΔG</i> results suggest that the calcination temperature for the simultaneous formation of C₂S, C₄A₃$ and C₄AF should be higher than 1200 °C, with sufficient CaO and SO₃ content. In the preparation process of HBSAC clinker by lithium slag, the contents of CaCO₃ and CaSO₄·2H₂O are 1.07 and 4 times than those of their theoretical design contents (Excessive CaCO₃ and CaSO₄·2H₂O are less likely to produce impurity phases) with the roast temperature 1250 °C for 1 h. The phase compositions of the prepared clinker fall within the ranges of HBSAC clinker. Additionally, the content of free calcium oxide of the clinker is less than 0.2%, which meets the requirements of the sulphoaluminate cement clinker (GB/T 37125-2018). This work provides a foundation for the high-value resource development and utilization of lithium slag.</p> Graphical Abstract <p></p>