Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua,Zhijin,Guizhou

The phosphorite ores-deposits rich in rare earth elements(REE) in Zhijin, Xinhua, Guizhuo occurs in the early Cambrian Meishucun and at the bottom part of Qiongzhusi stage (the upper layer of phosphorites), belonging to Yangzi stratum section. The living creature scraps was proved existent in dolomitic-phosphorites by experiments, The REE could be extracted to provide the worthy data for the further using. Adopting the HNO3 to extract REE, through the ion exchange method, the REE recovery rate could be reached 85.44% , having certain reference value.

Enrichment characteristics and sources of the critical metal yttrium in Zhijin rare earth-containing phosphorites, Guizhou Province, China

Yttrium(Y)is a critical metallic element that is used widely in modern scientific,technological,and industrial applications.Phosphorites in the Zhijin area of Guizhou Province,China,are famous for Y enrichment,but the enrichment characteristics and sources remain unclear.Previous studies suggested that the sources of rare earth elements(REEs,La-Lu)and Y(REYs,La-Lu+Y)were related to hydrothermal deposition.However,this study presents evidence refuting that hypothesis,with major and trace elemental data collected with quadrupoleinductively coupled plasma-mass spectrometry(Q-ICPMS)analysis.These data show that Y in Zhijin REYscontaining phosphorites has a normal distribution and is particularly enriched relative to other REYs.The Y enrichment degree is different at different∑REY intervals.Specifically,the Y enrichment degree is higher at lower∑REY values and lower at higher∑REY values.The REYs-containing phosphorites show features of primary phosphorites.Both REEs and Y have good correlations with P2 O5 in the phosphorites with low REYs contents(total REYs<535 ppm),whereas at high REYs contents(total REYs>535 ppm),REEs have a good correlation with P2 O5 but Y does not.Inconsistent enrichment processes of REYs are suggestive of complex sources of Y.Thus,seafloor hydrothermal fluids were not the direct source of Y.Normal seawater mixed with terrestrial sources might have contributed to the origin of Y here.This study could lead to improvements in Y mineral resource explorations and the situation involving the global REYs supply crisis.

Rare Earths, Trace Element Characteristics of High-Mg Volcanic Rocks of Yixian Formation in Sihetun West Liaoning Province and Its Apocalypse

The high-Mg volcanic rocks of the Yixian Formation in the Sihetun area have the obvious characteristics of mantie-derived lava in rare earth, trace element characteristics with high Mg # （62 - 70） and high content of compatible elements. In the meantime, the volcanic rocks also have the obvious characteristics of Crust-source material in rare earth, trace element characteristics with high ∑ REE （ 158.78 × 10^-6 - 359.66 × 10^-6 ）, high （La/Yb） N （ 14.61 - 29.60）, high La/Nb（2.37 - 7.52） and high Ba/Nb （67.58- 205.96）, obvious positive anomaly of Pb and negative anomaly of Nb, Ta in trace element spider-gram. In Sr-Nd-Pb isotope the （^87Sr/^86Sr）i ratio is higher than 0.706 and the εNd（ t ） ratio is from - 3.4 to - 13, both reflect enriched Mantle characteristics. The characteristics above of the volcanic rocks combined with the content of Sr, Ba, Y, Yb and the ratio of Sr/Y show that the volcanic rocks have the property of the Sanukite rocks in Setouchi Japan beside subduction zone, and illuminate that the Sanukite rocks can be formed not only in island-arc near subduction zone but also in intro-plate. The analysis indicates that the high-Mg volcanic rocks in the Sihetun area result from the collective function of mantle-derived lava and crust-source materials. The result illuminates that the West Liaoning region is very special in tectonic geochemical background in Cretaceous in East China, and is an ideal region for us to further study the characteristics of magmatic activity as well as the process of Crust-Mantle interaction in Eastern China.

Geochemical characteristics of rare earth elements in Wuhan section of the Yangtze River

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Enrichment and Release of Rare Earth Elements during Weathering of Sedimentary Rocks in Wujiang Catchments,Southwest China

Thirteen weathering profiles of sedimentary rocks such as limestone, dolomitic limestone, dolomite, sillicalite, black shale and purple sandrock from Wujiang catchments were selected for study on enrichment and release behavior of rare earth elements （REE） during weathering, and its impact on plant growth and riverine REE distribution in the catchments with methods of hierachical cluster analysis and mass balance calculation in order to set a basis for riverine material source research and agricultural production. The results show that the enrichment degree of REE in calcareous soils from the Wujiang catchments is much higher than that of limestone, yellow soil, upper continental crust （UCC）, China soil （CS） and world soil （WS）. The ability of enrichment and release of REE is partly controlled by distribution of REE in bedrocks, contents and adsorption ability of organic matters, clay minerals and Fe-oxides/hydroxides in weathering profiles. The REE released from weathering of carbonate rocks and clastic rocks can be absorbed and utilized by local plants. The results also reveal that release of REE and Fe mainly from weathering of carbonate rocks and partly from clastic rocks exerts an important control on riverine REE distribution.

EFFECTS OF RARE EARTH ELEMENTS ON THE CHARACTERISTICS OF AUTO-TEMPERING AND DECOMPOSITION OF MARTENSITE FOR A LOW CARBON Si-Mn-V STEELS

The effect of rare earth metals(REM)on the characteristics of auto-tempering and decomposition of martensite for low-carbon and low-alloy steels(20SiMn2V and 20SiMn2VRE)was investigated using TEM,dilatometer and microhardness test.Results show that both ε.and θ carbides,during auto-tempering, may precipitate from the low-carbon martensite matrix at the same time in the 20SiMn2V steel,however,the precipitation of the ε-carbides can be inhibited by the REM contained in the 20SiMn2 VRE steel,resulting in change of the type of precipitated carbides and decrease of the extent of auto-tempering.The“in-situ”ob- servations show that the decomposition of martensite is also inhibited by the REM contained in the 20SiMn2 VRE steel during low temperature tempering.

Content Characteristics of Rare Earth Elements in Stone Coal and Parting in Southern Shaanxi, China

Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation and evolution history. The content of rare earth elements in stone coal has been the focus of attention. Stone coal is widely distributed in southern Shaanxi province of China. In order to study the content and distribution of rare earth elements in stone coal, and provide a plan for the comprehensive development and utilization of stone coal, this study tested the rare earth elements content of stone coal, parting and coal ash samples, respectively, compared the content of rare earth elements in stone coal, parting, coal ash with the mean value of China coal, the mean value of world coal and the abundance value of upper crust, and discussed the features of rare earth elements content in different types of samples in southern Shaanxi province of China. The average contents of rare earth elements in the samples of stone coal, parting and coal ash were calculated, and the enrichment coefficients of the samples with the mean value of China coal, the mean value of world coal and the abundance value of upper crust were listed. The distribution rules and characteristics of the contents of rare earth elements in different types of samples in southern Shaanxi province of China were summarized.

Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption characteristics.Several characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second phase.Compressive tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous Mg-Zn-Y.The experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second phase.When the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),W-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second phase.However,the average energy absorption efficiency is independent of the Y content.In addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing temperature.The compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the struts.The deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

Rare earth elements distribution in marine sediments of Malaysia coasts

In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24–26 cm in EC4 increased to 114.1 μg/gr at 20–22 cm in EC5.The measured concentration of ...

Forms of Rare Earth Elements in Soils: Ⅱ. Differentiation of Rare Earth Elements

The present paper deals mainly with the relationships between the distribution of rare earth elements (REE) in different forms in soils and the atomic number and with the odd-even phenomenon in the distribution of ionic lanthanides in soils.The enrichment tendency of light REE relative to heavy REE in soils was pointed out on the experimental results about the proportions of Ce-group and Y-group elements in different REE forms in soils.Meanwhile,the differentiation of Tm in different soil REE forms was compared and the reasons why Tm is enriched in soils were preliminarily discussed.

STUDY OF ADSORPTION OF RARE EARTH ELEMENTSBY FERRIC OXIDE GEL

A new secondary ore of rare earth was discovered in the Southwest of China. It is a kind of product of the weathered mineral. The rare earth elements (REE) in it exist probably as ionic characteristic adsorption state in manganesian and ferric oxide colloid mineral, and one bearer of REE is amorphous ferric oxide gel. It is neessary to study the binding state of rare earth elements on manganesian and ferric oxide in order to utilize comprehensively the rare earth resources and avoid latent influence on the environment resulting from the fact that highcontent rare earth elements are carried into soil by the mineral efflorescence. A simulating adsorption test of rare earth ions in weak acid media is carried out with ferric oxide gel prepared by sol-gel method. The experimental results show that the characteristics of adsorption isotherm correspond well with the Flory-Huggins equation, but deviated from the Langmuir equation. The standard molar adsorption Gibbs function, standard molar adsorption entropy and standard molar adsorption enthaply are calculated. The measurements of the point of zero charge and isoelectric point show occurrence of the characteristic adsorption. It has been proved that the OH group on the skeleton of ferric oxide gel is the innate cause of the characteristic adsorption.

Rare earth elements and yttrium in ferromanganese deposits from the South China Sea:distribution,composition and resource considerations

Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.

Rare earth elements-rich phase and enriching mechanism in sediments from CC area, the Pacific Ocean

Compared to North American shale composition (NASC), REE contents of sediments from the CC area in the Pacific Ocean are obviously high except that cerium has equal content to that of NASC. Three-valence rare earth elements were completely enriched in phosphate-phase and cerium in iron-phase. Rare earth elements in the sediments were originally derived from seawater. During lithi- genic and minerogenic processes of metalliferous nodules, three-valence rare earth elements in sediments mobilized and incorporated into sediments as authigenous biogenic-apatite, while cerium had change from Ce3+ to Ce4+ and directly precipitated from seawater and entered metalliferous nodules and caused Ce anomalies in REE pattern in sediments.

Zircon deposit and rare earth element enriched metasomatic alkaline rocks at Kyemyeongsan Formation, Chungju, Korea: Paleozoic magmatism and Zr-REE-Nb mineralization

The zircon ore deposit in metasediments and peralkaline granite of the Kyemyeongsan Formation is located in southwest of Chungju city, Korea. The deposit, closely associated with REE and Nb,is composed of metasomatic alkaline rocks and rare metal alkali granite, and was formed in late Carboniferous (340～343Ma). Zircon occurs in different paragenetic sequence: (1) earlier rare metal alkali granite, (2) later metasomatic zircon ore. The metasomatic zone contains abundant microcline, albite and quartz with minor biotite, magnetite, hornblende, allanite and zircon. The alkali granites have high silica (72.13～74.52wt.% as SiO 2), and total iron content (5.95～6.89%), and are characterized by low Al 2O 3 content (7.12～9.74%). They also show variable K 2O content (3.60～6.98%), and high ratios of K 2O/Na 2O. The REE patterns of rare metal alkali granite are similar to those of felsic volcanics from rifts, or back arc basins in, or near continental crust. Zircon ores are characterized by high iron content and low Al 2O 3, SiO 2, and K 2O content and have unusually high total REE content (0.18～2.33%). REE patterns show relatively flat to somewhat heavy REE (HREE) depleted characteristics (Ce/Yb=0.39～5.17) with large Eu negative anomaly (Eu/Eu *=0.16～0.29). Laser ablation microprobe inductively coupled plasma mass spectrometer (LAM ICP MS) analyses has been carried on zircon. The REE patterns of mineral zircons are almost the same to those of zircon ores and rare metal alkali granites, which may reflect the inability of zircons to effectively fractionated REE at formation of origin. The Sm Nd isochron age of the zircon ore and rare metal alkali granite are 330Ma, and 331Ma, respectively with ε Nd(t) being range from -2.00 to -1.84. This data suggest that the ore forming material came from the mantle. Alkali granite has suffered extensive post magmatic metasomatism of a high temperature to produce zircon ores. Geochemical characteristics show that metasomatism of alkaline fluid was probably the dominant ore forming process in Chungju district.

Element migration and phase distribution characteristics during crystallization of rare earth phase in rare earth slag

The crystallization experiment of molten rare earth(RE)slag under different cooling rates was carried out.The characteristics of element migration and phase distribution during RE phase crystallization were studied by using different equipment.The experimental results show that there are two RE phases in the RE slag,namely(Ca,Ce,La)_(5)(SiO_(4))6F and(Ca,Ce,La,Mg)_(3)(Ti,Al,Nb)_(2)O_(7).During the cooling crystallization process of molten RE slag,Ca and P elements in the RE phase of(Ca,Ce,La)_(5)(SiO_(4))_(6)F migrate from inside to outside,and finally gather at the outer edge of the phase to form phase Ca_(3)(PO4)2.The RE phase(Ca,Ce,La)_(5)(SiO_(4))_(6)F is distributed inside the furnace-cooled slag,and the RE phase(Ca,Ce,-La,Mg)_(3)(Ti,AI,Nb)_(2)O_(7)is distributed in the surface layer of the furnace-cooled slag.And based on the phase distribution characteristics,the central hollowing method is proposed to realize the preliminary enrichment of valuable elements Ti,Nb and RE in RE slag.

REE and Trace Element Geochemistry of Yinachang Fe-Cu-REE Deposit, Yunnan Province, China

REE and other trace elements in ores, wall rocks, alkaline volcanic rocks and diabase dikes have been determined in the Yinachang Fe-Cu-REE deposit. Comparative studies of REE and trace element geochemical characteristics of these geological bodies indicate that the ores and alkaline volcanic rocks contain abundant REE and Y ({65.9}-{4633})×10+{-6}, with higher abundances of As, Mo, Nb, Co and U than those of the crust. Their chondrite-normalized patterns show a strong enrichment of LREE and a positive Eu anomaly, in contrast to those of the dolomites which are characterized by slight LREE enrichment and moderate negative Eu anomaly. The REE patterns of ores are similar to those of hydrothermal sediment cores in the East Pacific Rise, whereas the REE patterns of dolomites are similar to those of PAAS (Post-Archean Average Shale). In combination with the geological setting of the deposit, the primary ore-forming fluids might have higher REE and volatile elements, and might have been derived from mantle degassing, or the alkaline volcanic magmas. The Yinachang Fe-Cu-REE ore deposit is considered to be of volcanic exhalation-hydrothermal sedimentary origin.

Adsorption of rare earth elements on organic matter in coal

The occurrence modes of rare earth elements(lanthanide and yttrium,abbreviated as REY) in coal are impo rtant both for coal geochemistry studies and the application potential of REY as a by-product of coalbased resources.In this study,the adsorption behaviors of REY on organic matter in coal were investigated by leaching tests using REY solution and ultra-low ash coal samples.On this basis,the adsorption mechanism of REY on organic matter in coal was also studied by molecular simulation calculations.The leaching tests show that the organic matter in coal has a relatively strong adsorption capacity for REY,and that the average adsorption rate or the net adsorption amount of heavy rare earth elements(HREY:Gd,Tb,Y,Dy,Ho,Er,Tm,Yb and Lu) is always higher than that of the light rare earth elements(LREY:La,Ce,Pr,Nd,Sm and Eu).A molecular model of humic acid(HA) was constructed and the adsorption amount between REY and HA was calculated.The results show that the theoretical adsorption rate of HREY(84.88%) is higher than that of the LREY(84.00%).The analysis of the adsorption distances between REY atoms and various functional groups on HA molecules shows that the minimum adsorption distance of LREY is 0.372 nm on average,which is larger than that of HREY(0.368 nm),indicating that the adsorption capacity of the latter is stronger.In addition,a coal molecule(C_(18)H_(22)O) was also constructed to investigate the adsorption characteristics of various REY atoms on the molecule.As a result,it is found that the average binding ene rgy and bond length between the hydroxyl functional group and LREY atoms are 0.12469 Ha(Hartree,the unit of energy in the atomic unit system) and 0.1407 nm,respectively,while for HREY,0.12883 Ha and 0.1121 nm,respectively.This confirms that HREY is more stable than LREY in binding on organic matter in coal.To conclude,both leaching tests and molecular simulation calculations reveal that REY has a strong adsorption affinity for organic matter in coal,and in particular,HREY shows a stronger organic adsorption preference in coal than LREY,which is probably due to stronger chemical bonding between the former and the functional groups on the coal molecule.

Effect of Low Concentration of Yttrium on Physiological Characteristics of Cucumber (Cucumis Sativus L.)

There is no doubt that rare earth elements stand an important position among the essential elements of plant growth and it is long time since they are first used as plant growth promoters. Given their effects on microstructure, most reports are focused on the toxicology rather than promotion. Using cucumis sativus L. (Jin Chun No.5) as experiment material, we try to find out the nutritional effects of low Y3+ concentrations on cucumber seedlings′ leaves. The present paper suggests that the rare earth elements act as micronutrients at low concentrations while they give rise to toxicity at high concentration. Benefits defeat toxicity with concentration ranging from 5 to 25 μmol·L-1. Through careful study, at the Y(NO3)3 concentration of 10 μmol·L-1 the content of chlorophyll as well as the activities of SOD, Cu-Zn SOD and the POD are the highest. It indicates 10 μmol·L-1 is the optimum concentration of yttrium for promoting the cucumber growth.

Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China

Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing,southwestern China.The mineralogy,degree of enrichment,distribution patterns,modes of occurrence,and sediment origin of REY were investigated.Compared with the average of world coals,the concentration of REY in the K1a coals were normal,dominated by light REY(LREY),with less medium and heavy REY(MREY,HREY).The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples,deduced from the mixed enrichment type of REY,mainly including M-H-type,and a few L-M type and H-type.In addition,the combination of anomalies of Ce,Eu,Gd,and Al_(2)O_(3)/TiO_(2) parameters,the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence,and the samples were affected by seawater intrusion during early peat accumulation.Although the minerals primarily consist of kaolinite,illite,pyrite,and small amounts of quartz,calcite and anatase,REY are correlated with ash yield,SiO2,and Al_(2)O_(3),revealing that the REY mainly occur in aluminosilicate minerals,especially kaolinite and illite.Meanwhile,REY positively relate to P_(2)O_(5) and Zr,which may exist in phosphate-containing minerals or zircon.Furthermore,most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY.With the exception of central Guizhou,southwestern Chongqing,and the junction of western Guizhou and northeastern Yunnan,the REY content in coals from southwestern China are high,and its by-products are suitable as potential REY sources.

火电厂燃煤产物中关键微量元素富集特征研究

煤系共伴生战略性关键元素可在燃煤产物中富集,研究燃煤产物中关键元素的富集特点可为元素的预富集和提取利用提供依据。以我国东西部不同火电厂燃煤产物为例,采用波长色散荧光光谱仪(AxiosmAX)、电感耦合等离子体质谱仪(iCAP-Qc)测试了燃煤产物中常量元素和关键微量元素的含量,分析了燃煤产物中关键微量元素分布富集的一般性规律。结果表明:①粉煤灰中主要常量元素为Si、Al、Fe,三者氧化物占比达87.79%;微量元素中稀土元素、锂、镓、铀、锗的含量分别为456.95μg/g、163.58μg/g、49.07μg/g、8.67μg/g、4.59μg/g,除铀、锗外均高于世界煤灰平均值。②常量元素中P趋向富集于细灰中,Fe、Ca更易富集于粗灰中;稀土元素分布模式保持一致,且在细灰中的含量高于粗灰,锂、镓、铀、锗均在细粒燃煤产物中更为富集,分异系数分别为1.17、2.45、1.53、2.14。③数理统计分析表明,煤中稀土元素与无机矿物相关,且富集于燃煤产物的非磁性组分中;锂主要与黏土矿物有关,燃烧后主要以LiAlO2的形式存在;镓、铀赋存形式不单一,与黏土矿物有一定的关系;锗与无机相相关性弱,表明其主要与有机质结合。