ToolFusion
πŸ“‹ Case Study

Rare Earth Element Recovery from Phosphate Mine Wastewater – Florida, USA

REE concentrations low (1–5 ppm), but massive flow; competing Ca/P/SOβ‚„ fouling ion exchange resins

πŸ—οΈ Project Overview

Active phosphate mining operation generating ~50 MGD wastewater rich in Y, Nd, La

🎯 Challenge

REE concentrations low (1–5 ppm), but massive flow; competing Ca/P/SOβ‚„ fouling ion exchange resins

πŸ”§ Design Approach

Pre-concentration via selective precipitation (oxalate) β†’ chelating resin (DGA-10) β†’ electrowinning

πŸ“ Design Diagram

REE Recovery from Phosphate Mine Wastewater Florida, USA | Low [REE] (1–5 ppm), High Flow, Ca/P/SOβ‚„ Fouling Wastewater (Ca²⁺, PO₄³⁻, SO₄²⁻) Oxalate Precipitation Ξ±(RE³⁺/Ca²⁺) = 4.2Γ—10⁴ DGA-10 Chelating Resin Qadj = 48 g RE/kg Electrowinning Ξ· = 76% REE Metal Product Sludge Ca-ox, P, SOβ‚„ β€’ Low REE conc.: 1–5 ppm β€’ Ca/P/SOβ‚„ fouling Pre-concentration Resin Capture Electrowinning

AI-generated project design illustration

πŸ“ Key Calculations

Oxalate Selectivity Ratio

α(RE³⁺/Ca²⁺) = K_sp(RE-ox)/K_sp(Ca-ox)
Result: 4.2Γ—10⁴
Enables >90% RE pre-concentration

Resin Capacity Adjustment

Q_adj = Qβ‚€ Γ— (1 βˆ’ f_fouling)
Result: 48 g RE/kg resin
Accounts for 22% Ca fouling in full-scale operation

Electrowinning Current Efficiency

Ξ· = (Actual RE deposited / Theoretical) Γ— 100
Result: 76%
Guides power and cell design

πŸ“Š Results

Recovered 18.3 t/year mixed REEs (Nd, Y, La); achieved 92% overall recovery; reduced disposal liability by 37%

πŸ’‘ Lessons Learned

  • β€’Oxalate pre-concentration essential for economic viability
  • β€’Resin regeneration with citric acid restored 94% capacity
  • β€’RE purity >99.95% met magnet-grade specs

βœ… Key Takeaways

  • 1Oxalate pre-concentration essential for economic viability
  • 2Resin regeneration with citric acid restored 94% capacity
  • 3RE purity >99.95% met magnet-grade specs