📋 Case Study

Rare Earth Element Recovery from Acid Mine Drainage

Ultra-low REE concentrations (<10 mg/L), high Fe³⁺/Al³⁺ interference, pH-sensitive extraction

🏗️ Project Overview

Pilot-scale hydrometallurgical plant in Wales, UK

🎯 Challenge

Ultra-low REE concentrations (<10 mg/L), high Fe³⁺/Al³⁺ interference, pH-sensitive extraction

🔧 Design Approach

Two-stage solvent extraction using D2EHPA in kerosene, selective scrubbing with dilute H₂SO₄, and oxalic acid precipitation

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Distribution Ratio (D)

[REE]_org / [REE]_aq

Result: D_Y = 420 at pH 2.8

Enables >99% Y recovery in first stage

Scrubbing Efficiency

E = 1 − exp(−K_sc × V_s/V_o)

Result: 94%

Removes co-extracted Fe before stripping

📊 Results

92% total REE recovery; Fe contamination <0.05 wt% in final oxide; 89% reduction in hazardous waste volume

💡 Lessons Learned

• •pH control is non-negotiable in multicomponent SX
• •Oxalic precipitation requires strict stoichiometric dosing to avoid colloidal residues

✅ Key Takeaways

• 1pH control is non-negotiable in multicomponent SX
• 2Oxalic precipitation requires strict stoichiometric dosing to avoid colloidal residues