Systematic review of sulfate roasting for Lithium extraction from Lepidolite: From fundamental mechanisms to industrial application

This review comprehensively examines the extraction of lithium from lepidolite via the sulfate roasting method. As demand for lithium, particularly for lithium-ion batteries, continues to grow, the exploitation of lithium-bearing minerals like lepidolite has become increasingly important. The sulfate roasting process, involving mixing, roasting, water leaching, purification, and precipitation, is highlighted as a promising industrial method due to its high lithium recovery efficiency and relatively low environmental impact compared to alternatives like acid digestion or chlorination roasting. Notably, the process allows for the effective management of toxic by-products such as fluorine (via fixation) and thallium (via targeted removal), which is crucial for sustainable operation. The review details the critical factors affecting lithium yield, such as the particle size of lepidolite, the type and ratio of sulfates (e.g., Na₂SO₄, K₂SO₄, CaSO₄, FeSO₄), roasting temperature and duration, and leaching conditions, and discusses the underlying mechanisms, primarily ion exchange and mineral decomposition. Furthermore, it addresses the potential for co-extraction of valuable by-products like rubidium and cesium and identifies future research directions, including reducing energy consumption and optimizing additives for improved efficiency and sustainability. • The Li extraction mechanism attributed to ion exchange and mineral decomposition. • Roasting temperature, time, and, gas flowability have impacts on the recovery of Li. • Reducing energy consumption and co-extraction of Rb and Cs needs to be explored.