Recycling of lithium slag extracted from lithium mica by preparing white Portland cement

In recent years, lithium slag (LS) has increased sharply with the development of lithium industry, which has caused serious environmental problems. However, the utilization of this industrial waste residue has been a difficult topic in lithium industry. In this paper, the effects of LS on mineral crystal type, ionic solid solution, decomposition temperature of CaCO₃ and strength of white Portland cement clinker were studied by XRD, FT-IR, DSC, SEM-EDS and other means. The results show that LS can stabilize the M1 crystal of C₃S, improve the crystallinity of C₃A, and reduce the content of ACn. The LS content of 5 wt% can reduce the decomposition temperature of CaCO₃ about 10 °C, but increase the low eutectic temperature of materials. Na elements tended to be dissolved in the intermediate phase, while Al3+ dissolved in calcium silicate may replace Ca²⁺ or Si⁴⁺. Sintering white Portland cement clinker with appropriate content of LS can effectively reduce the content of f-CaO and greatly improve the early compressive strength of clinker. Therefore, LS within 5 wt% can be used as high quality raw material of white cement, which can recycle LS.