Search results for "rare earth element"
showing 10 items of 47 documents
Distribution of REEs in soil-citrus limon system(L.) Osbeck
2017
The consumers have an increasing interest about food traceability with respect to safety, quality and typicality issues. The knowledge of a chemistry relationship between the soil and the agricultural products is an important tool for the quality assessment of food. Citrus Limon is the most important fruit tree crop in the world and the detection of potential fraud could improve by using tools linking the chemistry composition of this production to its typical growing area. This study use rare earth elements (REEs) as geochemical tracers. The REEs are a set of 14 elements, from lanthanum to lutetium that can be divided in light rare earth elements (LREEs), from La to Gd and heavy rare earth…
Carbonate stromatolites from a Messinian hypersaline setting in the Caltanissetta Basin, Sicily: petrographic evidence of microbial activity and rela…
2010
Lower Messinian stromatolites of the Calcare di Base Formation at Sutera in Sicily record periods of low sea-level, strong evaporation and elevated salinity, thought to be associated with the onset of the Messinian Salinity Crisis. Overlying aragonitic limestones were precipitated in normal to slightly evaporative conditions, occasionally influenced by an influx of meteoric water. Evidence of bacterial involvement in carbonate formation is recorded in three dolomite-rich stromatolite beds in the lower portion of the section that contain low domes with irregular crinkly millimetre-scale lamination and small fenestrae. The dominant microfabrics are: (i) peloidal and clotted dolomicrite with c…
Procesos hidrotermales con enriquecimiento en REE en las carbonatitas de Fuerteventura: evidencias en minerales accesorios
2021
Carbonatitic dykes that crop out in the central western part of Fuerteventura Basal Complex (Ajuy, Punta de la Nao), were affected by the Miocene intrusive event responsible for contact metamorphism and partial melting of part of the alkaline-carbonatitic complex. Textural characteristics, monazite enriched in LREE (La, Ce, Nd) formation processes in microfractures that affect zircon crystals, show carbonatite interactions with hydrothermal fluids and partial REE remobilization. Pyrochlore is the main mineral carrier of rare earth elements (sum REE=216694 ppm), with high LREE (LaN=185816 and CeN=165209) with respect to HREE (YbN=2589 and LuN=1814) with a rather steep pattern (La/Yb)N=72 in …
Rare earth elements distribution in seawater and suspended particulate of the Central Mediterranean Sea
2004
Rare earth element (REE) content in suspended and dissolved phases from the Strait of Sicily (Central Mediterranean Sea) has been measured. Vertical profiles of several dissolved REEs along the water column reflect the 3-D oceanographic features of the studied area and identifies the different water masses present there. Shale-normalized REE distribution patterns and derived parameters calculated for the suspended particulate show different atmospheric dust-surface inputs and their interactions with seawater. Finally, combined information from [La/Yb]N, ratios, REE/La ratios and Eu anomalies measured in the suspended particulate suggest an important contribution of volcanic materials from t…
Hydrothermal processes with REE enrichment in Fuerteventura carbonatites: evidences in accessory minerals
2021
Los diques carbonatíticos que afloran en la parte centro-occidental del Complejo Basal de Fuerteventura (Ajuy, Punta de la Nao), fueron afectados por el evento intrusivo mioceno responsable del metamorfismo de contacto y fusión parcial de parte del complejo alcalino-carbonatítico. Las características texturales, los procesos de formación de monacita enriquecida en LREE (La, Ce, Nd) en microfracturas que afectan a los cristales de zircón, evidencian interacciones de las carbonatitas con fluidos hidrotermales y removilización parcial de REE. El pirocloro es el principal mineral reservorio de tierras raras (suma REE=216694 ppm), con valores elevados de LREE (LaN=185816 y CeN=165209) respecto a…
THE BIOGEOCHEMICAL BEHAVIOUR OF RARE EARTH ELEMENTS AS A CONSEQUENCE OF PROCESSES OCCURING IN THE VITIS VINIFERA L. – SOIL SYSTEM
2014
The geochemical behaviour of lanthanides and yttrium (Rare Earth Elements, REE) has been investigated mainly in geological systems as the REE exploitation in industrial and agricultural practices is progressively growing in the last years, to such an extent to become strategic materials. Extensive researches evidenced that REE capability to investigate processes occurring at the interface between different media such as the in depth investigation of REE behaviour is a matter of fact in many geochemical studies. These capabilities are a consequence of the chemical characters of REE that are exploited to investigate processes occurring during migrations of chemical elements in the soil-to-pla…
Effects of Dissolved Complexation on REE Fate During Interactions between Volcanic Ash and Coexisting Fluids
2013
AbstractThis work analyzes REE behavior during the delivery of volcanic ash into a marine system and highlights the effects induced by dissolved carbonate and humate complexes on REE release. Kinetic experiments were carried out during a 6-month period using a batch method approach. Results show that the highest degree of REE leaching occurs during the early stage. Altered phases that crystallize induce REE sorption and dissolved complexation towards surface complexation, concurrent processes that are enhanced by Y/Ho, La/Yb, and Ce/Ce* changes, whereas dissolved humates and carbonates influence the dissolution rate of ash and the dissolved REE behavior.
Recognition of water masses according to geochemical signatures in the Central Mediterranean sea: Y/Ho ratio and rare earth element behaviour
2007
This study reports the results of geochemical investigations carried out in the Strait of Sicily (Central Mediterranean Sea) during the oceanographic cruise BANSIC 2000, focusing on the area around the Pantelleria Island. We evaluate the interface processes between dissolved phase and suspended particulate matter in the water columns on the basis of Y/Ho ratio and rare earth elements and yttrium distributions that are suitable to trace the occurrence of different water layers in Central Mediterranean Area. The main source of trace elements to the sea water system was recognized in the atmospheric fallout, while different scavenging mechanisms among Y and rare earth elements occur. Cation ex…
α-Aminophosphonates, Phosphinates, and Phosphine Oxides as Extraction and Precipitation Agents for Rare Earth Metals, Thorium, and Uranium : A Review
2022
α-Aminophosphonates, -phosphinates, and -phosphine oxides are a group of organophosphorus compounds that were investigated as extraction agents for rare earth (RE) metals and actinoids for the first time in the 1960s. However, more systematic investigations of their extraction properties towards REs and actinoids were not started until the 2010s. Indeed, recent studies have shown that these α-amino-functionalized compounds can outperform the commercial organophosphorus extraction agents in RE separations. They have also proven to be very efficient extraction and precipitation agents for recovering Th and U from RE concentrates. These actinoids coexist with REs in some of the commercially im…
Developing REE parameters for soil and sediment profile analysis to identify Neolithic anthropogenic signatures at Serpis Valley (Spain)
2020
In this study, patterns of rare earth elements (REE) have been developed and applied for the first time to sediments and soils to identify anthropogenic or natural layers in profiles sampled at several Neolithic settlements in the Serpis Valley area (Alicante, Spain). Most of these sites are characterized by dark brown paleosols that are easily distinguishable from the light brown paleosols of the valley. To demonstrate whether these strata are anthropogenic or natural requires a better geochemical understanding of sediment. Soil samples were taken across six different sites; four sites are associated with archaeological findings (sites BF, LP, PB and AC8); another one is from a natural sec…