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New Insights into the Recovery of Strategic and Critical Metals by Solvent Extraction
Published in Bruce A. Moyer, Ion Exchange and Solvent Extraction: Volume 23, 2019
Jason B. Love, Manuel Miguirditchian, Alexandre Chagnes
Leaching metals from WEEE yields a pregnant leach solution (PLS) that generally contains a mixture of metals that require separation unless some separation process has operated at the leaching stage. Selectivity in separation is a key challenge to a hydrometallurgical metal recovery process, and a knowledge of coordination chemistry, supramolecular chemistry, and redox chemistry is important in designing a suitable system. One separation method is through precipitation and has been employed extensively in gold recovery, either carrying out separation as Au(III) or Au(I) complexes or by precipitation as Au(0) using carbonaceous- or bio-sorbents [91]. Gold deposition is also important in other fields where, for example, the size of the Au(0) nanoparticles formed in TiO2/Au materials is key to their efficacy as catalysts in a variety of chemical reactions [97].
Removal of nitrates from copper-containing aqueous acidic leach solutions by electrodialysis
Published in Mineral Processing and Extractive Metallurgy, 2021
Felipe Riveros, Nicolas guajardo, Marcelo Bravo Valenzuela, Andréa Moura Bernardes, Jane Zoppas Ferreira, Gerardo Cifuentes
Three stages are well-known for the copper hydrometallurgical extraction: leaching (and/or bioleaching), solvent-extraction (SX) and Electrowinning (EW). These processes are responsible for around 4.5 million tons of copper cathode per year (Schlesinger et al. 2011). The basic principle of the global process is to dissolve copper-containing minerals into an aqueous H2SO4 solution to produce a pregnant leach solution (PLS). The PLS is then treated via SX in order to obtain a Cu-enriched solution using an organic phase (extractant), which acts selectively with copper over other cations presents in the PLS. Finally, the Cu-enriched solution is treated in EW, where a direct current is applied and copper cathodes of high quality are obtained.