A new method for pre-enrichment of gallium and lithium based on mode of occurrence in coal gangue from Antaibao surface mine, Shanxi Province, China

Abstract

The presence of a notable concentrations of gallium (Ga) and lithium (Li) in coal gangue, an industrial solid waste, has attracted widespread attention. However, utilization of these resources remains an economic challenge. This study entailed an investigation of the potential of the pre-enrichment of Ga and Li in coal gangue so as to effectively utilize coal gangue resources. The modes of occurrence of Ga and Li in coal gangue were studied using a sequential chemical extraction procedure (SCEP), mineral phase composition, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and elemental content composition. The results indicate that the main mineral components of the coal gangue are mica, quartz, pyrite, and clay. Ga and Li are mainly associated with Al-containing minerals, such as mica and clay. Further, the main noncarrier minerals are quartz and pyrite. Ga and Al exhibit a high degree of correlation, whereas Li exhibits a predominant association with Al and Ti. Ga and Li are also negatively correlated with Fe and Sr. Moreover, sorting experiments demonstrated that the separation of Ga and Li from pre-enriched coal gangue is an effective and environmentally friendly method. This allowed for the discarding of 31.25% of the waste rock, with an Fe content of 32.69%. The concentrate products can potentially be high-quality raw materials for Ga and Li refining facilities, whereas the tailing products can serve as an effective source of iron ore raw materials.