In coming years, global lithium production is expected to increase as the result of widespread electric vehicle adoption. To meet the expected increase in demand, lithium must be sourced from both brine and hard-rock deposits. Heavy liquid separation (HLS) and dense media separation (DMS) tests were conducted on the pegmatites from Hidden Lake, NWT, Canada to demonstrate the potential role of this technology in the concentration of spodumene (LiAlSi₂O₆) from hard-rock sources. A continuously operated DMS circuit test, conducted on +840 µm material, produced a concentrate grading 6.11% Li₂O with ~50% lithium recovery. The circuit rejected 50% of the original mass to tailings, with only 8% lithium losses. Sensitivity analysis showed that minor changes (+/−0.05) in the DMS-specific gravity cut point resulted in significant changes to the mass rejected and to the concentrate grade produced; this may limit the feasibility and operability of the downstream grinding and flotation circuits. The results demonstrate the potential for DMS in the concentration of spodumene from the Hidden Lake pegmatites, and by extension, the potential for DMS in the concentration of spodumene from other hard-rock occurrences.

Lepidolite flotation testwork was performed on 21 variability samples from the EMILI deposit in Allier, France, with head assays ranging from 0.49 to 1.38% Li2O and an average K80 of 236 mm. After desliming, flotation was performed with an amine collector which was able to produce lepidolite concentrates grading >4.2% Li₂O with over 74.6% Lithium recovery from 13 samples - often without cleaner flotation. The lower grade lepidolite concentrates (<4.2% Li2O) were a result of unwanted recovery of other mica-type gangue minerals, as well as low feed grades below the 0.8% Li₂O cut-off grade already excluded from the mine plan.

Spodumene is the primary Lithium mineral, however, other minerals like lepidolite, petalite, zinnwaldite, and Li-clays are gaining importance. Different processing approaches are needed to address different challenges. Dense Media Separation (DMS) can concentrate spodumene and petalite, but recoveries are often limited by grain size. Froth flotation is widely used to concentrate spodumene and is the main lepidolite beneficiation method, where spodumene is floated with anionic fatty acids and lepidolite with cationic amine collectors. Zinnwaldite, a high-iron lepidolite mineral, can utilize magnetic separation and to some extent, flotation, whereas and Li-clays (e.g., hectorite and illite) are primarily concentrated through size classification.