Rare Earth Elements And Yttrium Distribution Research Articles

Geochemistry of Late Permian coals from the Yueliangtian coal deposit, Guizhou: Evidence of sediment source and evaluation on critical elements

The enrichment of rare, scattered, rare earth, and noble elements, such as Li, Ga, Ge, rare earth elements and yttrium (REY), platinum group elements (PGE), Au, and Ag, have been discovered in the Late Permian coals from southwestern China. With the gradual depletion of traditional ore deposits, the geochemistry and resource utilization of critical metals in coals have received considerable attention. The geochemistry of associated elements in the Late Permian coals from the No. 10 coal profile of the Yueliangtian (YLT) underground mine, Liupanshui coalfield in Guizhou, were investigated to reveal the sediment source of inorganic components, as well as utilization prospects and controlling factors of critical metals. Silver and Pb were slightly enriched in the Yueliangtian coals, while Be, Rb, Sr, Mo, Cs, Ba, Tl, Bi, and U were significantly lower than that of world hard coals. The concentrations of total REY and individual elements in the Yueliangtian coals were similar to those of world hard coals. The minerals kaolinite, pyrite, calcite, and quartz predominated in coals, with trace amounts of anatase, gypsum, and apatite. High anatase proportion was identified in the floor and roof rock samples. Based on the Al2O3/TiO2 and Zr/TiO2 versus Nb/Y ratios, elemental assemblages, REY distribution, and paleogeography, the sediment source of mineral matter in the Yueliangtian coals dominated by felsic-intermediate rocks that from a distal volcanic arc or orogens was inferred. The terrigenous debris in the roof and floor rocks primarily originated from the high-Ti basalt of the Emeishan Large Igneous Province (ELIP). The relatively low elemental concentrations in these coals were primarily determined by their sediment sources. Although most critical metals in this coal were not enriched, the concentration of REY in coal ash was high enough to be considered as a potential resource for REY recovery given the extremely low ash yields of this coal.

Cycling of calcite and hydrous metal oxides and chemical changes of major element and REE chemistry in monomictic hardwater lake: Impact on sedimentation

The variation of major and rare earth elements and yttrium (REY) in the monomictic hardwater Lake Tiberias during the wet and dry seasons of the hydrological year was studied in two profiles. The average volume and Cl concentration of the known and unknown saline inflows of 1.6×107m3 and 1.2×109mol are derived by closing both balances. This brine corresponds to a mixture of 83% of groundwater from Cretaceous aquifers and 17% of very saline deep brine. Taking cycling of calcite in the hypolimnion into account, the settling rate of authigenic calcite is estimated to be 3.3molm−2a−1.In the stratified lake of the dry season dissolved inorganic carbon increases by 490μM at the thermo-/chemocline due to microbial reduction of SO42−, NO3−, chemical reduction of Fe(III) and MnO2 colloids, and cycling of calcite in the hypolimnion. REY distribution in the stratified water column is dominantly controlled by coprecipitation with calcite, hydrous ferric oxides and MnO2 in the epilimnion and cycling of these compounds in the hypolimnion. The positive Ce anomaly in the hypolimnetic water is produced by cycling of MnO2. The simulation of the increase of REY in the hypolimnion reveals that hydrous ferric and manganese oxides only play a negligible role except Ce. Only about 10% of REY from cycled matter enhance REY in solution. Most of the released REY are adsorbed by particular matter and thus settling on the floor of the lake.Different from Na, U, SO42− and SiO2, the other elements, in particular REY, increase in the mixed water column from the top to the lower third and mostly decrease thereafter toward the bottom in the mixed lake during the wet season. The behavior of REY is caused by some cycling of calcite and pH-dependent re-equilibration of REY bound to hydrous ferric and manganese oxides adsorbed by particular matter.

Anomaly and geochemistry of rare earth elements and yttrium in the late Permian coal from the Moxinpo mine, Chongqing, southwestern China

AbstractThe rare earth elements and yttrium (REY) of the K2 coal from the Moxinpo mine, Chongqing, were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results show that REY are enriched in the K2 coal, with the average content up to 462 μg/g, much higher than average values of most coals in the world. The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum. The fractionation of individual light-REY is higher than that of the heavy-REY. The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion. Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer (SEM-EDX). The REY distributions through the coal seam, SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter. The K2 coal is a potential rare-metal resource due to its high REY contents, and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.