Four Main Methods for the Industrial Purification of Spodumene

Due to variations in origin, the properties of spodumene ore differ significantly, and the corresponding beneficiation processes also vary. Industrially, the purification of spodumene primarily employs four mainstream processes: flotation, heavy-medium separation, magnetic separation, and combined beneficiation.

Flotation is the most fundamental and widely applied method for lithium spodumene beneficiation; virtually all lithium spodumene mines currently in operation in China utilise this process. Factors such as slime content, agitation intensity, pulp temperature, reagent ratios, collector performance and water quality all directly influence the separation efficiency. Vigorous agitation improves the surface condition of the minerals and eliminates interference from dissolved salts; an appropriate pulp temperature enhances reagent activity, thereby ensuring the required lithium spodumene separation parameters.

Heavy-medium separation relies on the density difference between spodumene and gangue to achieve separation, using a heavy liquid or heavy suspension—whose density lies between the two—as the medium. As heavy liquids are costly and often toxic, they are rarely used in industry; in production, heavy suspensions are commonly prepared using ferrosilicon or magnetite, which are more practical.

Magnetic separation is often employed as an auxiliary purification method. By exploiting differences in mineral magnetism, it removes ferromagnetic impurities from lithium concentrate to produce low-iron lithium concentrate and improve product quality. This method is generally not used in isolation but is frequently combined with flotation and heavy-medium separation to achieve efficient impurity removal.

Combined mineral processing involves the integrated operation of multiple processes and is suitable for spodumene deposits with complex ore properties and numerous associated components. Through process combinations such as ‘flotation-magnetic separation-gravity separation’ or ‘gravity separation-magnetic separation-flotation’, high-grade, low-iron lithium concentrate can be obtained, whilst effectively recovering associated valuable minerals, thereby significantly improving the comprehensive utilisation rate of lithium resources.