Abstract: Provided herein are methods recovering rare earth elements (REEs) from a solution containing one or more REEs. These methods can comprise contacting an aqueous solution comprising one or more rare earth elements (REEs) with a solid sequestration media (e.g., a stabilized flue gas desulfurization (sFGD) material, or a sludge by-product from a water treatment process) to provide a REE-containing solid feedstock; and contacting the solid feedstock with an extraction solution to generate a rare earth element (REE) solution.