Enhancement of lithium extraction from coal gangue based on deep dissociation of coal components and acid leaching

The extraction of lithium resources from coal measures is an important guarantee for alleviating the shortage of strategic metal resources. However, the lattice substitution characteristics of lithium in carrier minerals and its extremely fine intercalation and entrainment behavior are the challenges that constrain the extraction efficiency of lithium from coal series. This study focuses on improving the separation efficiency between lithium containing minerals and other minerals, and enhancing the release behavior of lithium elements in the liquid phase. Firstly, the feasibility of extracting lithium from carrier minerals is confirmed based on the occurrence state and the process mineralogy characterized by BPMA and TOF-SIMS. Subsequently, the selective grinding behavior achieved the optimal effect under 15 minutes, and therefore the carrier minerals of Li including chlorite, kaolinite, and halloysite delivers the best dispersion effect with other minerals. Thus, the pre-enrichment of enriched lithium carrier minerals has been achieved based on screening process. Further, the leaching efficiency of Li reached 97.43% under the conditions of 1 mol/L hydrochloric acid, 15 g/L pulp density, 70 °C, and 20 min. The leaching kinetics studies indicated that the decrease in apparent energy validates the impact of grinding on metal leaching, aligning with the rate-controlling step of a chemical reaction. The proposed process outlined in this study achieves the coordinated control of size and components in coal gangue, resulting in effective selective enrichment of lithium, thanks to its low energy consumption and environmentally friendly nature.