Resources and process

Spodumene (LiAlSi₂O₆) is the most established hard-rock lithium source. Beneficiation yields a 5.5–6.5% Li₂O concentrate, which is calcined at 1000–1100 °C for the α→β transformation and then leached by the sulfuric acid or alkaline route to produce lithium carbonate or hydroxide.

1. 01
   Mining & crushingOpen-pit mining, crushed to liberation size
2. 02
   Dense medium / flotationUpgraded to 5.5–6.5% Li₂O
3. 03
   Calcinationα→β phase change raises reactivity
4. 04
   Acid / alkaline leachingSulfuric acid or alkaline pressure leach gives lithium sulfate solution
5. 05
   Purification & crystallisationImpurity removal, carbonation or causticisation to battery-grade salt

Salt-lake brine is evaporated and concentrated, stripped of magnesium and boron, and then precipitated to lithium carbonate. The magnesium-to-lithium ratio is the decisive process variable: low ratios suit precipitation, while high ratios rely on adsorption, membrane and solvent-extraction methods.

1. 01
   Brine extractionWells or channels feed the evaporation ponds
2. 02
   Evaporation & concentrationSolar evaporation raises Li⁺ concentration
3. 03
   Magnesium and boron removalLime, resin or extraction lowers impurities
4. 04
   Adsorption / membraneSelective lithium recovery for high Mg:Li brine
5. 05
   Lithium precipitationSodium carbonate precipitation yields lithium carbonate

Lepidolite carries lithium together with potassium, rubidium, caesium and fluorine, making integrated recovery attractive. The typical flowsheet is sulfate roasting followed by water leaching, or pressure leaching and purification, producing lithium carbonate while recovering potash, rubidium and caesium salts and fluoride.

1. 01
   Flotation upgradingConcentrate grading 3.5–4.5% Li₂O
2. 02
   Sulfate roastingK₂SO₄/Na₂SO₄ system converts the lithium
3. 03
   Water leachingLithium enters solution; K, Rb and Cs are recovered stepwise
4. 04
   PurificationFluoride, aluminium and silicon removal
5. 05
   Lithium precipitationSodium carbonate precipitation yields lithium carbonate

End-of-life batteries are discharged, dismantled and shredded to black mass, then leached hydrometallurgically (sulfuric, hydrochloric or organic acid) to bring lithium, nickel, cobalt and manganese into solution. Extraction, purification and precipitation then yield battery-grade lithium carbonate or precursor.

1. 01
   Testing & dischargeSOH assessment followed by safe discharge
2. 02
   Dismantling & shreddingCasing, copper and aluminium, and separator are separated
3. 03
   SortingBlack mass is separated from graphite and metal-rich fractions
4. 04
   Hydrometallurgical leachingAcid leach with reductant brings metals into solution
5. 05
   Purification & lithium precipitationExtraction and resin polishing, then sodium carbonate precipitation