STEP 3 OF 4

Precipitation & Recovery

The REE-rich solution from bioleaching is purified, and the metals are selectively recovered as oxalates or phosphates. Oxalic acid precipitation is the most common route; it yields high-purity REE oxalates that can be calcined to oxides.

• 🧮 Reaction: 2 REE³⁺ + 3 C₂O₄²⁻ → REE₂(C₂O₄)₃ ↓ (precipitate)
• 🔍 Selectivity: Controlling pH at about 1.5–2 keeps calcium from interfering.
• 🌡 Outcome: Around 95% of the dissolved REEs are recovered from solution, with little reagent use.