Pilot Scale Testing of Lignite Adsorption Capability and the Benefits for the Recovery of Rare Earth Elements from Dilute Leach Solutions

Naturally occurring organic materials containing humic acids show a strong affinity towards rare earth elements (REE) and other critical elements. Leaching experiments on lignite coal waste produced from construction sand production revealed that the contained REEs were associated with matter. Furthermore, adsorption studies was capable of extracting model solution increased REE content by more than 100%. As such, this study aimed to utilize adsorb pregnant leach solutions acid mine drainage sources having low concentrations subsequently material produce relatively high amounts REEs, which benefits performance economic viability downstream separation purification processes. An integrated flowsheet developed based concept tested at pilot scale. The leachate (PLS) generated heap pad 2000 tons Baker seam coarse refuse. scale circuit comprised aluminum precipitation, using lignite, earth-critical metal (RE-CM) precipitation stages in succession. results indicated stage removed over 88% 99% Al Fe, respectively. 457 ppm 1065 whole mass basis. heavy (HREE) feedstock approximately 250%, raised percentage HREE distribution 19 absolute points. In addition such as Mn, Ni, Zn also improved 75%, 37%, Bench-scale tests increasing solids concentration PLS mix 1% 20% weight enhanced efficiency 32.0% 99.5%, new proposed provides significantly higher can be fed directly solvent extraction and/or oxalic and, thereby, enhancing process economics.