Recovery of rare earth elements from phosphogypsum waste in resin-in-leach process by eluting with biodegradable complexing agents

Phosphogypsum waste is a potential, secondary rare earth element (REE) source that available in very large volumes. Extraction and purification of REE from this complex was studied using resin-in-leach (RIL) followed by batch elution. Multiple consecutive RIL cycles with Purolite S940 resin dilute H2SO4 solution were performed for an industrial phosphogypsum waste. loading (max. 0.92 equiv./kg) purity over calcium (70%) increased up to seven cycles. the impurities separated treating loaded packed bed column two-step elution procedure. Calcium efficiently removed 0.06 M HCl. Alkaline solutions biodegradable chelating agents N,N–dicarboxymethyl glutamic acid (GLDA), methylglycinediacetic (MGDA), oxalic acid, citric iminodiacetate second step. MGDA GLDA both suitable candidates effective resin. A free, high fraction (up 99.01%) obtained MGDA. The most likely REE:MGDA stoichiometry found be 1:1 method continuous variation.