Recovery of Rare-Earth Elements from Brazilian Ion-Adsorption Clay: A Preliminary Study
Abstract
Ion-adsorption clays (IAC) are alumino-silicate ores, considered an essential source of heavy rare-earth elements (REE). With the increasing discovery and exploitation of IAC deposits, the present work sought to evaluate different methods of solubilization of REE through the use of different concentrations of inorganic acids (H2SO4, HCl, and HNO3), as well as different concentrations of ammonium sulfate and lactic acid. According to the results, the sulfuric acid solution favored the solubilization of both La3+ and Sm3+ elements. The solubilization of REE in the presence of ammonium sulfate showed no significant differences as a function of the leaching time but favored the solubilization of Y3+ and Tb3+. More efficient solubilization of Sm3+ was observed with the addition of lactic acid at a concentration of 30 g L-1, leading to 90% (4.5 ppm) of Sm3+ extraction. The solubilization of La3+ was favored by the contact time, with higher Sm3+ extraction yields in 14 days of leaching.

-
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
-
Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
-
Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).