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The supply of technologically important rare earth elements (REE) is a concern in Europe, hence the recovery of REE from alternative sources has recently become widely investigated. One of the problems is the lack of cost-effective technologies for REE recovery from leaching solutions. The present work investigated the potential for recovering REE and Th from leaching solutions by co-precipitation with Pb phosphates. A set of four experiments were conducted using analytical reagent grade chemicals to analyze the effects of Pb and different pH on the efficiency of REE and Th removal from aqueous solutions. After selecting the best conditions, two additional experiments were performed using solutions obtained from leaching REE-rich apatite mine waste. The precipitates resulting from the experiments as well as the solutions before and after precipitation were analyzed. It was found that the formation of a crystalline mixture of REE- and Th- enriched pyromorphite, Pb 5 (PO 4) 3 Cl, and Pb-phosphates, about which little has been known so far, was responsible for complete (>99%) removal of REE and Th from aqueous solutions at pH 4 and 6. At lower pH, the removal is incomplete except for Sc and Th, which probably form a distinct phases. Besides that, no fractionation of LREE and HREE was observed. The experiments included the study of solutions resulting from the leaching of REE-rich apatite waste, which may contribute to the development of new technologies for REE recovery from wastes. • For the first time REE and Th were recovered by co-precipitation with Pb phosphates. • Complete removal results from precipitation of Pb-phosphates rich in REE and Th. • The process is instantaneous and proceeds at ambient temperature at pH = 4 and 6. • Perspective use in beneficiation by leaching of minerals (e.g., apatite) or waste. • This novel approach contributes to the development of circular economy. [ABSTRACT FROM AUTHOR]

This account summarizes recent work by us and others on the development of ligands for the separation of actinides from lanthanides contained in nuclear waste streams in the context of a future European strategy for nuclear waste management. The current status of actinide/lanthanide separations worldwide is briefly discussed, and the synthesis, development, and testing of different classes of heterocyclic soft N- and S-donor ligands in Europe over the last 20 years is presented. This work has led to the current benchmark ligand that displays many of the desirable qualities for industrial use. The improvement of radiolytic stability through ligand design is also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The criteria for the evaluation of the REE composition of phosphorites and sedimentary rocks have been determined. These data are required to reconstruct depositional environments. Literature data on the geochemistry of some phosphorite deposits of Eurasia are considered. The REE patterns of Mesozoic phosphorites of the East European Platform are studied. On the basis of REE contents, the ratios of lanthanides and fields on the La–(Nd + Sm)–(Y + Dy), La–(Ce + Nd + Sm)–(Y + Dy), and LREE–MREE–(HREE×10) diagrams have been determined as indicators of climate and the depth and facies conditions of sedimentation. [Copyright &y& Elsevier]

Salt marshes act as natural deposits of different metals (e.g. heavy-metals), while halophyte plants are known to retain and accumulate them in the different tissues. Scarce data exists on accumulation, partition and fractionation of YREE in these plants. To study the relationship between halophyte plants and YREE, contents of these metals were determined by ICP-MS in sediment, and in the different plants organs, from Rosário's salt marsh, in Tagus estuary (SW Europe). Results show significant differences (p < 0.001) in YREE contents between sediments. In non-colonised sediment Y was lower (5.0-18 mg·kg -1 ) compared to the Sarcocornia fruticosa and Spartina maritima sediment cores (19-26 and 20-26 mg·kg -1 , respectively). The same was observed for ΣREE, with lower values in non-colonised sediment (32-138 mg·kg -1 ), while colonised ones presented higher contents (146-174 and 151-190 mg·kg -1 , for S. fruticosa and S. maritima, respectively). These significant differences (p < 0.05) are explained by the sediments' nature. Yttrium and ΣREE Al-normalised ratios in non-colonised sediment ranged from 1.5 to 2.3 and 11 to 13, respectively. The colonised sediments revealed significant higher ratios (particularly for ΣREE/Al ratios; p < 0.001), varying from Y/Al: 1.8-2.3 and ΣREE: 13-16 for S. fruticosa, and Y/Al: 1.4-2.3 and ΣREE: 12-18, for S. maritima. Results suggest that these plants may promote YREE enrichment in the sediments. No differences in fractionation patterns among sediments and in both species roots were found, but fractionation was different from those in the sediment, with similar middle-REE (MREE) enrichment and no light-REE (LREE) and heavy-REE (HREE) fractionation. No evidence of YREE transfer to aboveground organs was observed. Different fractionation patterns in stems and leaves were registered, with clear enrichment of LREE relative to HREE and an increase in the MREE enrichment. Therefore, these plants showed low ability to accumulate and translocate YREE but may promote its enrichment in the sediments., (Copyright © 2018 Elsevier B.V. All rights reserved.)