The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite...The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.展开更多
The three kinds of soil formed by the weathering of the basalt in Yema village,Weining county of Guizhou province,the carbonate rock in Guiyang district and the phosphorite in the REE-bearing phosphate mining area in ...The three kinds of soil formed by the weathering of the basalt in Yema village,Weining county of Guizhou province,the carbonate rock in Guiyang district and the phosphorite in the REE-bearing phosphate mining area in Zhijin county of Guizhou province were all rich in REE.The contents of LREE in these three soil were higher than that of HREE,which was caused by the different properties of LREE and HREE complexes.Since light REE could be easily absorbed by kaolinite grains,LREE was fully enriched in the process of desorption,migration and re-absorption,which formed a typical LREE soil.The chondrite normalized distribution models of those three types of REE-enriched soil are basically similar,which belong to the right deviation type,namely,rich in light rare earth element but short of heavy rare earth element,and showing Ce negative anomalies.Eu showed intense negative anomalies in the REE in the soil formed by the weathering of the sedimentary parent rocks(such as carbonate rock and phosphorite),while no pronounced Eu anomaly was found in the REE in the soil formed by the weathering of volcanic rocks(such as basalt).It is clear that though there were intense migration and enrichment of REE during the weathering process of rocks,no obvious differentiation of REE occurred and some features of the parent rocks were retained.That is why REE is of value in analyzing the source of materials.展开更多
An REE-rich carbonatite dyke was found in Dulahala, close to the Bayan Obo superlarge REE-Nb-Fe mineral deposit in Inner Mongolia, northern China. The REE content in the dyke varies greatly, from 1% up to 20% (wt), wh...An REE-rich carbonatite dyke was found in Dulahala, close to the Bayan Obo superlarge REE-Nb-Fe mineral deposit in Inner Mongolia, northern China. The REE content in the dyke varies greatly, from 1% up to 20% (wt), which might constitute rich REE ores. Light REEs in the carbonatite are enriched and highly fractionated relative to heavy REEs and there is no Eu anomaly. The REE and trace element distribution patterns of the carbonatite are identical to those of fine-grained dolomite marble which is the host rock of the Bayan Obo REE-Nb-Fe superlarge mineral deposit. This indicates a petrogenetic linkage between the REE-rich carbonatite and the mineralizations in this region.展开更多
Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively coupl...Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively couple plasma-mass spectrometry （ICP-MS） to compare the content and distribution of 14 kinds of rare earth elements （REEs）. The method was verified by analyzing GBW07605 certified reference material. The results showed that ICP-MS is an accurate, sensitive and reliable technique for determining REEs in traditional Chinese medicine. There were big differences in contents for REEs in Flos Sophorae and Fmctus Sophorae from different areas. The contents of total REEs in Flos Sophorae samples from different areas ranged from 1.0785 to 2.2659 μg/g, while those in Fmctus Sophorae from 0.6826 to 1.0527 ktg/g. The contents of total REEs in Flos Sophorae samples from different areas were obviously higher than those in Fmctus Sophorae of the same area and there was big difference between various Flos Sophorae samples. Interestingly, the higher the content of total REEs in Flos Sophorae samples, the lower the content of total REEs in Fmctus Sophorae samples of the same area. The plots of normalized element concentration versus atomic number showed some characteristic distribution trends. The distribution trend of light REEs （La-Gd） was relatively fiat except a positive Eu anomaly, however, that was steep and discrepant for heavy REEs （Tb-Lu）. The results could provide a valuable reference for understanding the relationship between the curative mechanism, pharmacology characteristics and their geological condition for the two traditional Chinese medicines investigated.展开更多
A series of BaCe0_(3)modified with different rare earth elements(La,Y,Pr)were synthesized by coprecipitation and calcination and the effect of rare earth elements for catalytic ammonia synthesis under mild conditions ...A series of BaCe0_(3)modified with different rare earth elements(La,Y,Pr)were synthesized by coprecipitation and calcination and the effect of rare earth elements for catalytic ammonia synthesis under mild conditions was studied.The ammonia synthesis performance tests show that 2.5%Ru/BaCe_(0.9)La_(0.1)O_(3-δ)catalyst(All the percentages of Ru in this article are in mass fraction)exhibits the highest ammonia synthesis rate(34 mmol/(g·h))at 3 MPa,450℃,and no sign of deactivation after 100 h of reaction.H_(2)-TPR and XPS analyses indicate that the introduction of La increases the amount of oxygen vacancies of the catalyst,which is beneficial to increasing the electron density of Ru surface.HRTEM analysis shows that the Ru particle size is reduced greatly after La is introduced,which facilitates the catalyst generating more Bs-type sites(active sites of Ru species for N=N dissociation).CO_(2)-TPD analysis indicates that BaCe_(0.9)La_(0.1)O_(3-δ)has stronger basicity,which promotes electrons transfer from support to Ru.This work provides an effective method for design and synthesis of Ru-based multi-element composite perovskite oxide catalysts.展开更多
The rare earth elements(REE)content of the coal in the Erlian Basin was determined by inductively coupled plasma mass spectrometry(ICP-MS),and it turns out that the REE content from different geological age shows a si...The rare earth elements(REE)content of the coal in the Erlian Basin was determined by inductively coupled plasma mass spectrometry(ICP-MS),and it turns out that the REE content from different geological age shows a significant difference:The REE content of the coal in the Jurassic Alatanheli Group is from 152.05×10^(−6) to 1416.21×10^(−6),with an average value of 397.31×10^(−6),and the relative concentration factor shows enriched;the REE content of the coal in Early Cretaceous Baiyanhua Group is from 20.65×10^(−6) to 102.53×10^(−6),the mean value is 49.06×10^(−6),and the relative concentration factor shows normally.The REE distribution patterns samples in Jurassic and Cretaceous shows the difference:The REE pattern in Jurassic coal mainly manifests as H-type distribution,with the Y,Lu positive anomaly,it is speculated that the fluid carried REE ions into the coal-bearing basin,and the heavy REE gather in the coal due to the different chemical properties of each REE.The REE occurrence mode is presumed to be mainly organic.Flat type is the REE main distribution pattern in Cretaceous coal.The REE patterns in clastic rocks of the roof,parting and floor of coal seam are similar to the REE patterns in the coal and the most possible reason is that the REE main source is from the clastic rock.It showed that the coal of the Early Jurassic,especially of Amugulen coalfield has resource value.展开更多
The content and distribution pattern of rare earth elements(REEs)in surface sediments from the Eastern and Western Pacifi c Ocean,the Northern and Southern Atlantic Ocean,and the Southwestern Indian Ocean were explore...The content and distribution pattern of rare earth elements(REEs)in surface sediments from the Eastern and Western Pacifi c Ocean,the Northern and Southern Atlantic Ocean,and the Southwestern Indian Ocean were explored and the resources and geochemical characteristics of REEs in deep-ocean sediments from diff erent oceans were studied.The total REE abundances(ΣREE)in the diff erent oceans ranged as follows:Eastern Pacifi c,56.88–500.02μg/g;Western Pacifi c,290.68–439.94μg/g;Northern Atlantic,55.33–154.90μg/g;Southern Atlantic,40.83–69.30μg/g;and Southwestern Indian Ocean,20.24–64.76μg/g.Their corresponding LREE(La-Eu)/HREE(Gd-Lu)average values were 5.18,5.86,9.01,5.21,and 4.59,which indicated that the light REEs were all evidently enriched.δEu andδCe showed slight Eu-negative anomalies and signifi cant Ce-positive anomalies in all sediments.Although the contents of REEs in the sediments varied among the diff erent oceans,the distribution patterns of REEs were similar,and the correlation coeffi cient was greater than 0.9290.In the Eastern Pacifi c sediments,ΣREE showed a signifi cantly positive correlation with Co,Cu,Zn,Mn,Mo and a weak correlation with Fe.In the Western Pacifi c and Southern Atlantic sediments,ΣREE presented no obvious correlation and a weakly negative correlation with Co,Cu,Zn,Mn,Mo and Fe,respectively.ΣREE in the Southwestern Indian Ocean sediments positively correlated with Cu,Zn,Mn,Mo,Fe,and had a weakly negative correlation with Co.展开更多
Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able ...Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able to quantitatively monitor the temporal and spatial variation of erosion intensity, compared with traditional approaches. The applications of REETM in studying of sediment differentiation law, erosion process evolution, determination of sediment sources and sedimentation investigations, and determination of prediction parameters, were reviewed. Some application limitations were summarized.展开更多
Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on impor...Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on import as domestic production of REEs was ceased because of the environmental concerns during mining and lack of competitiveness. Nonetheless, unconventional REEs-containing resources,including produced water. acid mine drainage, and coal and coal byproducts（C＆CBs） contain significant amounts of REEs. However, the concentrations of REEs in these resources are several orders of magnitude lower than that of REEs ores. Thus, extraction of REEs from these materials is challenging. Here we report REEs extraction with environmentally friendly method that successfully concentrated REEs from312 ppm in fly ash to 99.4% in the final product. Especially, the five critically important REEs（Dy, Eu, Nd.Tb. and Y） account for up to ～63% of the total weight of all REEs in the final 99.4%-purity product. Coal fly ash is one of the major solid coal utilization byproducts, representing great potential resources for REEs extraction. Extraction of REEs from these unconventional resources could be the way to secure domestic supply of these critical materials.展开更多
This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major ...This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major phase of CeO2 and minor phases of La2O3,Pr2O3,and Nd2O3 using a process devised by the authors.The suggested approach consisted of five processes：the synthesis of NaR E（SO4）2·xH2O from rare earth oxides in Na2SO4-H2SO4-H2 O solutions（Process 1）,the conversion of NaR E（SO4）2·xH2O into RE（OH）3 using NaO H（Process 2）,and the oxidation of Ce（OH）3 into Ce（OH）4 using air with O2 injection（Process 3）,followed by Processes 4 and 5 for separation of REEs by acid leaching using HCl and H2SO4,respectively.To confirm the high yield of NaR E（SO4）2·xH2O in Process 1,experiments were carried out under various Na2SO4 concentrations（0.4–2.5 mol/L）,sulfuric acid concentrations（6–14 mol/L）,and reaction temperatures（95–125 oC）.In addition,the effect of the pH value on the separation of Ce（OH）4 in HCl-H2 O solutions with Ce（OH）4,La-,Pr-,and Nd（OH）3 in Process 4 was also investigated.On the basis of above results,the possibility of effective separation of REEs from REPPWs could be confirmed.展开更多
For a better understanding the adsorption of rare earth elements(REEs) on minerals and its controlling factors, adsorption experiments were performed with kaolin in a matrix of various concentration of anion (Cl-, ClO...For a better understanding the adsorption of rare earth elements(REEs) on minerals and its controlling factors, adsorption experiments were performed with kaolin in a matrix of various concentration of anion (Cl-, ClO4-, SO42-) in the pH 6.5. The adsorption of REEs onto the kaolin increase with increasing anion concentration, especially in the presence of SO42-, which is ascribe to the Na+ mass effect and anion complexation. furthermore, the heavy REEs are more adsorbed onto kaolin in presence of higher concentration of anion, especially for Cl-and SO42-, presumably due to the difference of anion complexation with light REE and heavy REEs.展开更多
This study focuses on the trace and rare earth elements(REE)geochemistry of the Nkporo and Ekenkpon Shales of the Calabar Flank.The main aim is to infer their depositional environment and the degree of their metal enr...This study focuses on the trace and rare earth elements(REE)geochemistry of the Nkporo and Ekenkpon Shales of the Calabar Flank.The main aim is to infer their depositional environment and the degree of their metal enrichment.The shale samples were analyzed using inductively coupled plasma mass spectrometry.The results indicated that the mean concentrations of K,Na,and Fe in Nkporo and Ekenkpon Shales are 1.45,0.4,and 4.17 wt%,and 1.11,0.44,and 5.42 wt%;respectively.The Nkporo Shale is enriched with the following trace elements;P>Mn>Sr>Ba>Zn>Ce>Rb>Zr>V>Cr>Ni and depleted in the following trace elements;Ta>Ge>Sb>Bi>Cd>Ag>Te>In>Hg.While the Ekenkpon Shale is enriched with the following trace elements;P>Mn>Ba>Sr>V>Ce>Zr>Rb>Cr>Zn>Ni and depleted in;Sb>Ge>Bi>Ag>Ce>Te>In>Hg.The concentration of redox-sensitive elements such as V,Ni,Mo,U,Cu,Cr,Re,Cd,Sb,Ti,Mn,and their ratio V/Mo and U/Mo in the black and grey shale samples show different patterns.The REE obtained from the Nkporo and Ekenkpon Shales were PAAS normalized.The Nkporo Shale showed a slightly flat light rare-earth element(LREE),middle rare-earth element(MREE),and heavy rare earth element(HREE)pattern enrichment.Ce/Ce*ranges from 0.95 to 1.09 in Nkporo Shale and 0.67 to 1.40 in Ekenkpon Shale.The Ekenkpon Shale showed a slight LREE,MREE enrichment,and depleted HREE patterns.The Mn contents and U/Mo ratio in Nkporo and Ekenkpon Shales suggests a poor oxygen transitional environment.The V/Mo and V/(V+Ni)ratios indicated that the Nkporo shales were deposited in an anoxic to suboxic conditions and Ekenkpon shales were also deposited under an anoxic to suboxic conditions.The V/Ni ratio indicated that the organic matter in the Nkporo shale is terrigenous while that of the Ekenkpon shales are both terrigenous and marine in origin.展开更多
A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower...A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochemical behavior differences between Y and Ho.展开更多
The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,micr...The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.展开更多
The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncer...The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.展开更多
In the last five decades,Rare Earth Elements(REE)are mostly produced from carbonatite complexes and alkaline magmatic environments.In this respect,pyroclastic flows produced by the potassic-alkaline Gölcük v...In the last five decades,Rare Earth Elements(REE)are mostly produced from carbonatite complexes and alkaline magmatic environments.In this respect,pyroclastic flows produced by the potassic-alkaline Gölcük volcanism in the Isparta(SW,Turkey)angle stand out as an important target area where REE enrichments can be observed.This study focuses on the REE potential,geochemical and mineralogical characteristics of REE-bearing minerals as well as formation modeling of unconsolidated pyroclastic flows in Darıdere-Direkli-Yakaören(DDY)deposits in Turkey.REE-bearing minerals of DDY deposits which contain abundant trachytic-trachyandesitic rock fragments were determined as fluorapatite,britholite,and chevkinite by using XRD and SEM–EDX analyses.According to the geochemical analysis,the vast majority of RREE(up to 996 ppm)content is LREE such as La,Ce and Nd.Darıdere is the most REE enriched region followed by Yakaören and Direkli regions in terms of LREE(574.9 ppm),relative to MREE(38.5 ppm)and HREE(5.28 ppm)contents.These results are also on par with subduction-related Italian extrusive carbonatites such as Polino,Cupaello and San Venenzo.The DDY deposits can also be comparable with intraplate extrusive REE deposits in terms of LREE enrichments,however,HREE,Nb,Th and Zr values are generally lower.The RREE concentrations tend to rise with the increasing contents of alkaline elements(Na and K),HFSE(such as Nb and U),as well as LILE(Ba,Sr and Rb)and are negatively affected by sedimentary carbonate involvement.The economic value of the DDY deposits can gain importance due to the increasing global demand for LREE’s.展开更多
The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China...The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China, were investigated. All samples were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The chondrite-normalized distribution patterns of mudstone samples are uniform. All samples belong to the light rare earth element （LREE）-rich type and are enriched in LREEs relative to heavy rare earth elements （HREEs）. The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period. The results indicate that REE patterns are not controlled by materials from the seawater or land plants. The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly. So, the sources of REEs are controlled by terrigenous material, and the Mount Emei basalt is the predominant source of terrigenous material. Thus, transgression-regression is another control factor of REEs enrichment.展开更多
Emission from burning coals is one of the major sources of the airborne particles in China.We carried out a study on the rare earth elements(REEs)in the inhalable particulate matter(PM10)emitted from burning coals and...Emission from burning coals is one of the major sources of the airborne particles in China.We carried out a study on the rare earth elements(REEs)in the inhalable particulate matter(PM10)emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system.Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes.The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquetteburning PM10.In addition,the contents of the light rare earth elements(LREEs)are higher than those of the heavy rare earth elements(HREEs)in the PM10 emitted from burning the coals and briquettes,demonstrating that the REEs in both the coal-burning and briquetteburning PM10 are dominated by LREEs.The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals.A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes,being lower than 2,are lower than those in the particles from gasoline-powered vehicle emission.展开更多
Aquifer Storage and Recovery (ASR) was a pilot project for solving flood and drought problem in the northern part of Chao Phraya River basin, Thailand. This part of Thailand always faces flooding in rainy season and d...Aquifer Storage and Recovery (ASR) was a pilot project for solving flood and drought problem in the northern part of Chao Phraya River basin, Thailand. This part of Thailand always faces flooding in rainy season and drought during dry season every year. The overexploitation of groundwater during dry season leads to continuously decline of water level in this area. In this project, the excessive surface water during rainy season was stored by injection of this treated surface water through recharge wells into the underground aquifers. This would serve to raise the water level, which can be extracted for use during the dry season. To assess the efficiency of the ASR process some tracers are required. The aim of this study is to prove the suitability of natural tracers to follow up the artificial recharge process;emphasis will be placed on Strontium (Sr) isotopic composition. The results showed that the change in <sup>87</sup>Sr/<sup>86</sup>Sr ratios could be observed during an artificial recharge due to the different isotopic fingerprint of surface water and groundwater. However, the flow direction of the injected water cannot be clearly interpreted because of the limited number of monitoring wells, small distance between each monitoring well and the short duration of injection.展开更多
Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tong...Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shan- grao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phos- phorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10^-6 and P205 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE con- tents and low P205 contents, with the lowest total REE content of 53.19× 10^-6, and the lowest P205 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous ele- ment. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies （Slu） in reducing condition due to relatively closed sedimentary environ- ment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies （DRa） in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P205 sediments and REE were low. At a shallow water ramp facies （including shoals and tidal flats） （SRa）, with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be tbrmed with abundant REE minerals, and finally turned into high REE beating phosphorous deposits.展开更多
文摘The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.
基金Project is supported by the Young Scientists Project of Natural Science Foundation of Guizhou University (Grant No. 2009070)Technology Education Talents of Guizhou Province (Grant No. 2009105)
文摘The three kinds of soil formed by the weathering of the basalt in Yema village,Weining county of Guizhou province,the carbonate rock in Guiyang district and the phosphorite in the REE-bearing phosphate mining area in Zhijin county of Guizhou province were all rich in REE.The contents of LREE in these three soil were higher than that of HREE,which was caused by the different properties of LREE and HREE complexes.Since light REE could be easily absorbed by kaolinite grains,LREE was fully enriched in the process of desorption,migration and re-absorption,which formed a typical LREE soil.The chondrite normalized distribution models of those three types of REE-enriched soil are basically similar,which belong to the right deviation type,namely,rich in light rare earth element but short of heavy rare earth element,and showing Ce negative anomalies.Eu showed intense negative anomalies in the REE in the soil formed by the weathering of the sedimentary parent rocks(such as carbonate rock and phosphorite),while no pronounced Eu anomaly was found in the REE in the soil formed by the weathering of volcanic rocks(such as basalt).It is clear that though there were intense migration and enrichment of REE during the weathering process of rocks,no obvious differentiation of REE occurred and some features of the parent rocks were retained.That is why REE is of value in analyzing the source of materials.
基金supported by the National Natural Science Foundation of China(grant No.49872032)for YXMthe Ministry of Science and Technology of China(grant No.G1999043204)for ZYF
文摘An REE-rich carbonatite dyke was found in Dulahala, close to the Bayan Obo superlarge REE-Nb-Fe mineral deposit in Inner Mongolia, northern China. The REE content in the dyke varies greatly, from 1% up to 20% (wt), which might constitute rich REE ores. Light REEs in the carbonatite are enriched and highly fractionated relative to heavy REEs and there is no Eu anomaly. The REE and trace element distribution patterns of the carbonatite are identical to those of fine-grained dolomite marble which is the host rock of the Bayan Obo REE-Nb-Fe superlarge mineral deposit. This indicates a petrogenetic linkage between the REE-rich carbonatite and the mineralizations in this region.
基金Project supported by the Scientific Project of the Dezhou Government (2006067)the Science Fundation of Shandong Province (Q2008B08)the Key Technologies R&D Programme of Shandong Province (2010GSF10615)
文摘Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively couple plasma-mass spectrometry （ICP-MS） to compare the content and distribution of 14 kinds of rare earth elements （REEs）. The method was verified by analyzing GBW07605 certified reference material. The results showed that ICP-MS is an accurate, sensitive and reliable technique for determining REEs in traditional Chinese medicine. There were big differences in contents for REEs in Flos Sophorae and Fmctus Sophorae from different areas. The contents of total REEs in Flos Sophorae samples from different areas ranged from 1.0785 to 2.2659 μg/g, while those in Fmctus Sophorae from 0.6826 to 1.0527 ktg/g. The contents of total REEs in Flos Sophorae samples from different areas were obviously higher than those in Fmctus Sophorae of the same area and there was big difference between various Flos Sophorae samples. Interestingly, the higher the content of total REEs in Flos Sophorae samples, the lower the content of total REEs in Fmctus Sophorae samples of the same area. The plots of normalized element concentration versus atomic number showed some characteristic distribution trends. The distribution trend of light REEs （La-Gd） was relatively fiat except a positive Eu anomaly, however, that was steep and discrepant for heavy REEs （Tb-Lu）. The results could provide a valuable reference for understanding the relationship between the curative mechanism, pharmacology characteristics and their geological condition for the two traditional Chinese medicines investigated.
基金Project supported by the National Natural Science Foundation of China(21671147)Natural Science Foundation of Shanxi Province(201901D211117)Coal Bed Methane Joint Foundation of Shanxi Province(2016012004).
文摘A series of BaCe0_(3)modified with different rare earth elements(La,Y,Pr)were synthesized by coprecipitation and calcination and the effect of rare earth elements for catalytic ammonia synthesis under mild conditions was studied.The ammonia synthesis performance tests show that 2.5%Ru/BaCe_(0.9)La_(0.1)O_(3-δ)catalyst(All the percentages of Ru in this article are in mass fraction)exhibits the highest ammonia synthesis rate(34 mmol/(g·h))at 3 MPa,450℃,and no sign of deactivation after 100 h of reaction.H_(2)-TPR and XPS analyses indicate that the introduction of La increases the amount of oxygen vacancies of the catalyst,which is beneficial to increasing the electron density of Ru surface.HRTEM analysis shows that the Ru particle size is reduced greatly after La is introduced,which facilitates the catalyst generating more Bs-type sites(active sites of Ru species for N=N dissociation).CO_(2)-TPD analysis indicates that BaCe_(0.9)La_(0.1)O_(3-δ)has stronger basicity,which promotes electrons transfer from support to Ru.This work provides an effective method for design and synthesis of Ru-based multi-element composite perovskite oxide catalysts.
基金This study was supported by the project of the China Geological Survey(DD20160187)the Science and Technology Special Project of the China National Administration of Coal Geology(ZMKJ-2019-J02).
文摘The rare earth elements(REE)content of the coal in the Erlian Basin was determined by inductively coupled plasma mass spectrometry(ICP-MS),and it turns out that the REE content from different geological age shows a significant difference:The REE content of the coal in the Jurassic Alatanheli Group is from 152.05×10^(−6) to 1416.21×10^(−6),with an average value of 397.31×10^(−6),and the relative concentration factor shows enriched;the REE content of the coal in Early Cretaceous Baiyanhua Group is from 20.65×10^(−6) to 102.53×10^(−6),the mean value is 49.06×10^(−6),and the relative concentration factor shows normally.The REE distribution patterns samples in Jurassic and Cretaceous shows the difference:The REE pattern in Jurassic coal mainly manifests as H-type distribution,with the Y,Lu positive anomaly,it is speculated that the fluid carried REE ions into the coal-bearing basin,and the heavy REE gather in the coal due to the different chemical properties of each REE.The REE occurrence mode is presumed to be mainly organic.Flat type is the REE main distribution pattern in Cretaceous coal.The REE patterns in clastic rocks of the roof,parting and floor of coal seam are similar to the REE patterns in the coal and the most possible reason is that the REE main source is from the clastic rock.It showed that the coal of the Early Jurassic,especially of Amugulen coalfield has resource value.
基金Supported by the Basic Scientifi c Fund for National Public Research Institutes of China(No.2020Q10)and the China Ocean Mineral Resources R&D Association(Nos.DY135-E2-1-07,DY135-E2-4)。
文摘The content and distribution pattern of rare earth elements(REEs)in surface sediments from the Eastern and Western Pacifi c Ocean,the Northern and Southern Atlantic Ocean,and the Southwestern Indian Ocean were explored and the resources and geochemical characteristics of REEs in deep-ocean sediments from diff erent oceans were studied.The total REE abundances(ΣREE)in the diff erent oceans ranged as follows:Eastern Pacifi c,56.88–500.02μg/g;Western Pacifi c,290.68–439.94μg/g;Northern Atlantic,55.33–154.90μg/g;Southern Atlantic,40.83–69.30μg/g;and Southwestern Indian Ocean,20.24–64.76μg/g.Their corresponding LREE(La-Eu)/HREE(Gd-Lu)average values were 5.18,5.86,9.01,5.21,and 4.59,which indicated that the light REEs were all evidently enriched.δEu andδCe showed slight Eu-negative anomalies and signifi cant Ce-positive anomalies in all sediments.Although the contents of REEs in the sediments varied among the diff erent oceans,the distribution patterns of REEs were similar,and the correlation coeffi cient was greater than 0.9290.In the Eastern Pacifi c sediments,ΣREE showed a signifi cantly positive correlation with Co,Cu,Zn,Mn,Mo and a weak correlation with Fe.In the Western Pacifi c and Southern Atlantic sediments,ΣREE presented no obvious correlation and a weakly negative correlation with Co,Cu,Zn,Mn,Mo and Fe,respectively.ΣREE in the Southwestern Indian Ocean sediments positively correlated with Cu,Zn,Mn,Mo,Fe,and had a weakly negative correlation with Co.
基金supported by the National Key Technology R&D Program of China(2006BAC10B020,2008BAD98B08)
文摘Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able to quantitatively monitor the temporal and spatial variation of erosion intensity, compared with traditional approaches. The applications of REETM in studying of sediment differentiation law, erosion process evolution, determination of sediment sources and sedimentation investigations, and determination of prediction parameters, were reviewed. Some application limitations were summarized.
基金Project supported by the Department of Energy through"Rare Earth Elements From Coal and Coal By-Products"program(DE-FE00027069)
文摘Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on import as domestic production of REEs was ceased because of the environmental concerns during mining and lack of competitiveness. Nonetheless, unconventional REEs-containing resources,including produced water. acid mine drainage, and coal and coal byproducts（C＆CBs） contain significant amounts of REEs. However, the concentrations of REEs in these resources are several orders of magnitude lower than that of REEs ores. Thus, extraction of REEs from these materials is challenging. Here we report REEs extraction with environmentally friendly method that successfully concentrated REEs from312 ppm in fly ash to 99.4% in the final product. Especially, the five critically important REEs（Dy, Eu, Nd.Tb. and Y） account for up to ～63% of the total weight of all REEs in the final 99.4%-purity product. Coal fly ash is one of the major solid coal utilization byproducts, representing great potential resources for REEs extraction. Extraction of REEs from these unconventional resources could be the way to secure domestic supply of these critical materials.
文摘This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major phase of CeO2 and minor phases of La2O3,Pr2O3,and Nd2O3 using a process devised by the authors.The suggested approach consisted of five processes：the synthesis of NaR E（SO4）2·xH2O from rare earth oxides in Na2SO4-H2SO4-H2 O solutions（Process 1）,the conversion of NaR E（SO4）2·xH2O into RE（OH）3 using NaO H（Process 2）,and the oxidation of Ce（OH）3 into Ce（OH）4 using air with O2 injection（Process 3）,followed by Processes 4 and 5 for separation of REEs by acid leaching using HCl and H2SO4,respectively.To confirm the high yield of NaR E（SO4）2·xH2O in Process 1,experiments were carried out under various Na2SO4 concentrations（0.4–2.5 mol/L）,sulfuric acid concentrations（6–14 mol/L）,and reaction temperatures（95–125 oC）.In addition,the effect of the pH value on the separation of Ce（OH）4 in HCl-H2 O solutions with Ce（OH）4,La-,Pr-,and Nd（OH）3 in Process 4 was also investigated.On the basis of above results,the possibility of effective separation of REEs from REPPWs could be confirmed.
基金Project supported by the Peking Education Council (km200611417014)Peking Excellent Person with Ability SpecialFoundation (20042D0502210)the Programof Peking Strengthening Education for Person with Ability
文摘For a better understanding the adsorption of rare earth elements(REEs) on minerals and its controlling factors, adsorption experiments were performed with kaolin in a matrix of various concentration of anion (Cl-, ClO4-, SO42-) in the pH 6.5. The adsorption of REEs onto the kaolin increase with increasing anion concentration, especially in the presence of SO42-, which is ascribe to the Na+ mass effect and anion complexation. furthermore, the heavy REEs are more adsorbed onto kaolin in presence of higher concentration of anion, especially for Cl-and SO42-, presumably due to the difference of anion complexation with light REE and heavy REEs.
文摘This study focuses on the trace and rare earth elements(REE)geochemistry of the Nkporo and Ekenkpon Shales of the Calabar Flank.The main aim is to infer their depositional environment and the degree of their metal enrichment.The shale samples were analyzed using inductively coupled plasma mass spectrometry.The results indicated that the mean concentrations of K,Na,and Fe in Nkporo and Ekenkpon Shales are 1.45,0.4,and 4.17 wt%,and 1.11,0.44,and 5.42 wt%;respectively.The Nkporo Shale is enriched with the following trace elements;P>Mn>Sr>Ba>Zn>Ce>Rb>Zr>V>Cr>Ni and depleted in the following trace elements;Ta>Ge>Sb>Bi>Cd>Ag>Te>In>Hg.While the Ekenkpon Shale is enriched with the following trace elements;P>Mn>Ba>Sr>V>Ce>Zr>Rb>Cr>Zn>Ni and depleted in;Sb>Ge>Bi>Ag>Ce>Te>In>Hg.The concentration of redox-sensitive elements such as V,Ni,Mo,U,Cu,Cr,Re,Cd,Sb,Ti,Mn,and their ratio V/Mo and U/Mo in the black and grey shale samples show different patterns.The REE obtained from the Nkporo and Ekenkpon Shales were PAAS normalized.The Nkporo Shale showed a slightly flat light rare-earth element(LREE),middle rare-earth element(MREE),and heavy rare earth element(HREE)pattern enrichment.Ce/Ce*ranges from 0.95 to 1.09 in Nkporo Shale and 0.67 to 1.40 in Ekenkpon Shale.The Ekenkpon Shale showed a slight LREE,MREE enrichment,and depleted HREE patterns.The Mn contents and U/Mo ratio in Nkporo and Ekenkpon Shales suggests a poor oxygen transitional environment.The V/Mo and V/(V+Ni)ratios indicated that the Nkporo shales were deposited in an anoxic to suboxic conditions and Ekenkpon shales were also deposited under an anoxic to suboxic conditions.The V/Ni ratio indicated that the organic matter in the Nkporo shale is terrigenous while that of the Ekenkpon shales are both terrigenous and marine in origin.
基金Supported by the National Natural Science Foundation of China(No.41376050)
文摘A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochemical behavior differences between Y and Ho.
基金BAP project FBA-2021-4691 for their financial support。
文摘The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.
基金Under the auspices of National Key Technology Research and Development Program(No.2012BAB03B01)National Natural Science Foundation of China(No.41273015,51278172,51478167)
文摘The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.
基金supported by the CAYDAG(1001)from the Scientific and Technological Research Council of Turkey(TUBITAK)。
文摘In the last five decades,Rare Earth Elements(REE)are mostly produced from carbonatite complexes and alkaline magmatic environments.In this respect,pyroclastic flows produced by the potassic-alkaline Gölcük volcanism in the Isparta(SW,Turkey)angle stand out as an important target area where REE enrichments can be observed.This study focuses on the REE potential,geochemical and mineralogical characteristics of REE-bearing minerals as well as formation modeling of unconsolidated pyroclastic flows in Darıdere-Direkli-Yakaören(DDY)deposits in Turkey.REE-bearing minerals of DDY deposits which contain abundant trachytic-trachyandesitic rock fragments were determined as fluorapatite,britholite,and chevkinite by using XRD and SEM–EDX analyses.According to the geochemical analysis,the vast majority of RREE(up to 996 ppm)content is LREE such as La,Ce and Nd.Darıdere is the most REE enriched region followed by Yakaören and Direkli regions in terms of LREE(574.9 ppm),relative to MREE(38.5 ppm)and HREE(5.28 ppm)contents.These results are also on par with subduction-related Italian extrusive carbonatites such as Polino,Cupaello and San Venenzo.The DDY deposits can also be comparable with intraplate extrusive REE deposits in terms of LREE enrichments,however,HREE,Nb,Th and Zr values are generally lower.The RREE concentrations tend to rise with the increasing contents of alkaline elements(Na and K),HFSE(such as Nb and U),as well as LILE(Ba,Sr and Rb)and are negatively affected by sedimentary carbonate involvement.The economic value of the DDY deposits can gain importance due to the increasing global demand for LREE’s.
基金Project(40839910) supported by the National Natural Science Foundation of China
文摘The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China, were investigated. All samples were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The chondrite-normalized distribution patterns of mudstone samples are uniform. All samples belong to the light rare earth element （LREE）-rich type and are enriched in LREEs relative to heavy rare earth elements （HREEs）. The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period. The results indicate that REE patterns are not controlled by materials from the seawater or land plants. The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly. So, the sources of REEs are controlled by terrigenous material, and the Mount Emei basalt is the predominant source of terrigenous material. Thus, transgression-regression is another control factor of REEs enrichment.
基金supported by the Projects of International Cooperation and Exchanges NSFC(No.41571130031)the National Basic Research Program of China(No.2013CB228503)the Yueqi Scholar Fund of China University of Mining and Technology(Beijing)。
文摘Emission from burning coals is one of the major sources of the airborne particles in China.We carried out a study on the rare earth elements(REEs)in the inhalable particulate matter(PM10)emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system.Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes.The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquetteburning PM10.In addition,the contents of the light rare earth elements(LREEs)are higher than those of the heavy rare earth elements(HREEs)in the PM10 emitted from burning the coals and briquettes,demonstrating that the REEs in both the coal-burning and briquetteburning PM10 are dominated by LREEs.The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals.A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes,being lower than 2,are lower than those in the particles from gasoline-powered vehicle emission.
文摘Aquifer Storage and Recovery (ASR) was a pilot project for solving flood and drought problem in the northern part of Chao Phraya River basin, Thailand. This part of Thailand always faces flooding in rainy season and drought during dry season every year. The overexploitation of groundwater during dry season leads to continuously decline of water level in this area. In this project, the excessive surface water during rainy season was stored by injection of this treated surface water through recharge wells into the underground aquifers. This would serve to raise the water level, which can be extracted for use during the dry season. To assess the efficiency of the ASR process some tracers are required. The aim of this study is to prove the suitability of natural tracers to follow up the artificial recharge process;emphasis will be placed on Strontium (Sr) isotopic composition. The results showed that the change in <sup>87</sup>Sr/<sup>86</sup>Sr ratios could be observed during an artificial recharge due to the different isotopic fingerprint of surface water and groundwater. However, the flow direction of the injected water cannot be clearly interpreted because of the limited number of monitoring wells, small distance between each monitoring well and the short duration of injection.
基金Project supported by National Natural Science Foundation of China(50164001)the State Programs of Science and Technology Development funded by The Ministry of Science and Technology of China(2007BAB08B03)+3 种基金the Outstanding Scientific and Technological Talents Fund of Guizhou Province(2009008)the Graduates Innovation Fund of Guizhou University(2010009)the Youth Fund of Guizhou University(2009070)the Youth Fund of College of Resources and Environmental Engineering,Guizhou University(ZHY0901)
文摘Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shan- grao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phos- phorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10^-6 and P205 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE con- tents and low P205 contents, with the lowest total REE content of 53.19× 10^-6, and the lowest P205 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous ele- ment. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies （Slu） in reducing condition due to relatively closed sedimentary environ- ment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies （DRa） in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P205 sediments and REE were low. At a shallow water ramp facies （including shoals and tidal flats） （SRa）, with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be tbrmed with abundant REE minerals, and finally turned into high REE beating phosphorous deposits.
