Sample records for bastnaesite

  1. Interaction of reactive oily bubble in flotation of bastnaesite

    周芳; 王娄翔; 徐政和; 刘青侠; 池汝安


    To understand the flotation mechanism of bastnaesite using reactive oily bubble, the interaction between bastnaesite parti-cles and reactive oily bubbles was investigated by electro-kinetic studies, induction time measurements and small-scale flotation ex-periments. The bastnaesite flotation could be seen as a hetero-coagulation between bastnaesite particles and reactive oily bubbles which was confirmed by the zeta potential distribution and induction time measurements from pH 4.8 to pH 9.0. The small-scale flo-tation tests were consistent with the hetero-coagulation results, and showed a better flotation of reactive oily bubble than air bubble among all pH range. The interaction force between bastnaesite particles and reactive oily bubbles was evaluated by the classical DLVO theory. It indicated that the attachment could be predicted well by the DLVO theory only in a restricted pH range due to the absence of hydrophilic interaction repulsion force and chemical interaction force.

  2. Reaction process of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2


    The decomposition reactions of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2 were studied by means of TG-DTA and XRD. The results show that the process of the minerals decomposed by CaO involves two steps.The first step occurs in the temperature range of 425-540 ℃, and the main reactions are bastnaesite decomposition, i.e. REOF reacts with CaO to produce RE2O3 and CaF2, and Ce2O3 is oxidized to CeO2. During this step, CaCO3 is formed at about 500 ℃. The second step takes place in the temperature range of 610-700 ℃, and the reactions are monazite decomposition into RE2O3,Ca5F(PO4)3 and Ca3(PO4)2 by CaO and CaF2. In this process, the decomposition ability is improved because CaO from CaCO3decomposing has high chemical activity. In calcining process, the new formed Ca5F(PO4)3 restrains fluorine that can escape in form of gaseous compound. The decomposition ratio of the mixed rare earth minerals reaches 90.8% at 700 ℃.

  3. Niobium-Thorium-Strontium-Rare Earth Element Mineralogy and Preliminary Sulphur Isotope Geochemistry of the Eaglet Property, East-Central British Columbia (NTS 093A/10W)

    Hora, Z. D.; Langrová, Anna; Pivec, Edvín; Žák, Karel


    Roč. 2009, č. 1 (2010), s. 93-96. ISSN 0381-243X Institutional research plan: CEZ:AV0Z30130516 Keywords : fluorite * celestite * pyrochlore * thorite * titanbetafite * bastnaesite * sulphur isotopes * Eaglet deposit * MINFILE 093A46 Subject RIV: DD - Geochemistry

  4. 2nd conference on rare earths

    The conference heard a total of 16 papers of which 8 were incorporated in INIS, namely those dealing with the separation of rare earths from mineral raw materials (Kola apatite, bastnaesite ore), the best methods of preparing rare earth compounds for the production of polishing powders, and design of an experimental mixer-settler. (E.S.)

  5. S, C, O, H Isotope Data and Noble Gas Studies of the Maoniuping LREE Deposit, Sichuan Province, China: A Mantle Connection for Mineralization

    TIAN Shihong; DING Tiping; MAO Jingwen; LI Yanhe; YUAN Zhongxin


    The Maoniuping REE deposit, located about 22 km to the southwest of Mianning, Sichuan Province, is the second largest light REE deposit in China, subsequent to the Bayan Obo Fe-Nb-REE deposit in the Inner Mongolia Autonomous Region. Tectonically, it is located in the transitional zone between the Panxi rift and the Longmenshan-Jinpingshan orogenic zone. It is a carbonatite vein-type deposit hosted in alkaline complex rocks. The bastnaesite-barite, bastnaesite-calcite, and bastnaesitemicrocline lodes are the main three types of REE ore lodes. Among these, the first lode is distributed most extensively and its REE mineralization is the strongest. The δ34SV-CDT values of the barites in the ore of the deposit vary in a narrow range of +5.0 to +5.1‰ in the bastnaesite-calcite lode and +3.3 to +5.9‰ in the bastnaesite-barite lode, showing the isotopic characteristics of magma-derived sulfur. The δ13CV-PDB values and the δ18OV-SMOW values in the bastnaesite-calcite lode range from -3.9 to -6.9‰ and from +7.3 to +9.7 ‰, respectively, which fall into the range of "primary carbonatites", showing that carbon and oxygen in the ores of the Maoniuping deposit were derived mainly from a deep source. The δ13CV-PDB values of fluid inclusions vary from -3.0 to -5.6‰, with -3.0 to -4.0‰ in the bastnaesitecalcite lode and -3.0 to -5.6‰ in the bastnaesite-barite lode, which show characteristics of mantlederived carbon. The δDv-SMOW values of fluid inclusions range from -57 to -88‰, with -63 to -86‰ in the bastnaesite-calcite lode and -57 to -88‰ in the bastnaesite-barite lode, which show characteristics of mantle-derived hydrogen. The δ18OH2OV-SMOW values vary from +7.4 to +8.6‰ in the bastnaesitecalcite lode, and +6.7 to +7.8‰ in the bastnaesite-barite lode, almost overlapping the range of +5.5 to +9.5‰ for magmatic water. The 4He content, R/Ra ratios are (13.95 to 119.58)×10-6 (cm3/g)STP and 0.02 to 0.11, respectively, and 40Ar/36Ar is 313 ± 1 to 437

  6. Selected mineral associations in radioactive and REE occurrences in the Baie-Johan-Beetz area, Quebec

    This paper documents results of rapid chemical, spectrographic, scanning electron microscope, semiquantitative energy dispersive spectrometer, and neutron activation analyses for uranium content of minerals and host rocks for the following associations of primary and secondary minerals: 1. metasediments grading to garnetiferous feldspar pegmatites containing mafic zenoliths; 2. fergusonite-bearing pegmatite and rock-forming feldspars and micas; 3. biotite-horneblende gneiss hosting white radioactive pegmatites containing titanite, allanite and bastnaesite; 4. granite pegmatite containing associations of primary and secondary Pb, Ti, Nb, Th, U and Y minerals; 5. syenite pegmatite containing biotite, uraninite, uranothorite, zircon, apatite, allanite, xenotime, monazite, hydroxyl-bastnaesite and secondary amorphous phyllosilicates and U, Zr and REE mineral aggregates

  7. Concentration of rare earths ore from Pocos de Caldas - MG, Brazil

    The objective of this research was to concentrate, mainly by flotation, a rare-earth ore body. The valuable mineral is bastnaesite which occurs intimately associated with iron oxides and other gangue minerals, making difficult to get a concentrate of commercial grade. The use of oleic acid at a pulp temperature of -80 sup(0)C gave a concentrate of 23% rare-earth oxides at 72% overall recovery. The magnetic separation could enhance the grade of the flotation feed. (author)

  8. Partitioning properties of rare earth ores in China

    CHI Ru'an; LI Zhongjun; PENG Cui; ZHU Guocai; XU Shengming


    The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rare earth ore and the Zhushan rare earth ore are a kind of mixed ore, consisting of bastnaesite and monazite. Their rare earth partitionings are strongly enriched in light rare earths, where CeO2 is 50% and the light rare earth partitioning is totally over 95%. The Mianning rare earth ore as well as the Weishan rare earth is a kind of rare earth ore only having bastnaesite. Their rare earth partitionings are also strongly enriched in light rare earths,in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rare earth ore,there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rare earth ore, which is strongly enriched in heavy rare earths, Y2O3 is 64.83%, and the heavy and light rare earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rare earth ore, which is strongly enriched in light rare earths, CeO2 is 47.16%, and the light rare earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%,respectively, which are mainly industrial resources of the middle and the heavy rare earths.

  9. Separation chemistry and clean technique of cerium(IV):A review

    邹丹; 陈继; 李德谦


    The separation method of changeable valence RE element of cerium (Ce) was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce(IV) from RE(III), usually accompanied with fluorine (F) and phosphor (P) from bastnaesite and monazite etc. By roast or wet-air oxidation, Ce(III) of bastnaesite and monazite was oxidized into Ce(IV), and Cyanex923 and [A336][P507] have been investigated to co-extract and recover Ce(IV), F and P from H2SO4 leaching liquor, leading to favorable conditions for the subsequent separation of Th(IV) and RE(III). The interaction of Ce(IV) and F and/or P enhances the roasting, leaching and extraction of Ce(IV) due to increasing of the stability of Ce(IV), and the formation of CeF3 and CePO4 after reductive stripping will benefit the utilization of F and P. For dealing with RE ores of high-content Ce, the clean process of oxidation roasting and Ce(IV)-F separation for Sichuan bastnaesite highlights the advantages of Ce(IV) based clean technique, which firstly demonstrates the comprehensive utilization of Ce(IV), Th(IV), F and RE(III) and prevention of environmental pollution from foun-tainhead. A preliminary flowsheet of two-step oxidation and extraction of Ce(IV) for Bayan Obo mixed ores was further proposed to process the oxidation and extraction of Ce(IV) in presence of both F and P, indicating the possibility of similar effects with clean process of Sichuan bastnaesite. Ce(IV) separation chemistry and clean technique will open up new realms for light RE resources utilization, meeting“Emission Standards of Pollutants from Rare Earths Industry”promulgated by China’s Ministry of Environment Protection (MOP) in 2011.

  10. 2004 China Rare Earth Review


    production1. Rare Earth MineralsIn 2004, output of rare earth minerals kept on increasing,approached 98,300 tons including Baotou ore 46,600 tons,Sichuan ore 21,700 tons and ion adsorption rare earth ore30,000 tons (calculated by REO, following the same),increasing 6.84% over previous year (Table 1).Table 1 Constitution of Chinese Rare Earth Mineralsin 2004 (REO, ton)OutputTotalMixed RE Ore46,600Ion AdsorptionRE Ore30,000Bastnaesite21,70198,3102. Rare Earth Smelted and Separated ProductsProduction of rare e...

  11. Fluid—Melt and Fluid Inclusions in Mianning REE Deposit,Sichuan Southwest Cina

    牛贺才; 林茂青; 等


    Abundant fluid-melt inclusions are found in the aegirine-augite-barite pegmatite and carbonatite veins in the Mianning REE deposit,Sichuan,They were trapped in early stage fluorite and quartz from a salt-melt system at temperatures higher than 5000℃,Meanwhile,fluid inclusions are also present in alrge amounts in bastnaesite.Homogenized between 150 and 270℃,these inclusions are thought to be representative of the physico-chemical conditions of REE mineralization.These results show that the Mianning REE deposit is of typical hydrothermal origin developed from a salt-melt system.

  12. Concept of separation technology for rare earth elements

    The initial raw material for the designed separation of rare earth elements were flotation concetrates of bastnaesite ore from the Vietnamese Socialist Republic or phosphate concentrates produced during the manufacture of NPK fertilizer from the Kola apatite. A unified hydrometallurgical method shown in the figure was suggested for the reprocessing of the said concentrates. Liquid concentrate with a low content of Ce, without Th and with minimum content of fluorides enters the extraction separation: Di-2-ethylhexylphosphoric acid is used as the extraction agent. (E.S.). 1 fig

  13. Elucidating the formation of terra fuscas using Sr–Nd–Pb isotopes and rare earth elements

    Highlights: • Geochemical evidences on stabile phase confirm Bajocian marl as terra fusca parent material. • Precipitation/Dissolution of secondary carbonates controls geochemistry of labile phases. • This terra fusca sequence record at least four geological and environmental events. - Abstract: Carbonate weathering mantles, like terra fusca, are common in Europe but their formation and evolution is still badly understood. We propose to combine geological, mineralogical and pedological knowledge with trace element and isotope data of a weathering mantle as a novel approach to understand the evolution of terra fuscas. Sr–Nd–Pb isotopes and rare earth element (REE) contents were analyzed in a cambisol developing on a typical terra fusca on top of a condensed Bajocian limestone-marl succession from the eastern side of the Paris Basin. The isotope data, REE distribution patterns and mass balance calculations suggest that the cambisol mirrors the trace element enrichments present in this carbonate lithology, which are exceptionally high compared to global average carbonate. The deeper soil horizons are strongly enriched not only in REE (ΣREE: 2640 ppm) but also in redox-sensitive elements such as Fe (44 wt.%), V (1000 ppm), Cr (700 ppm), Zn (550 ppm), As (260 ppm), Co (45 ppm) and Cd (2.4 ppm). The trace element distribution patterns of the carbonate bedrock are similar to those of the soil suggesting their close genetic relationships. Sr–Nd–Pb isotope data allow to identify four principal components in the soil: a silicate-rich pool close to the surface, a leachable REE enriched pool at the bottom of the soil profile, the limestone on which the weathering profile developed and an anthropogenic, atmosphere-derived component detected in the soil leachates of the uppermost soil horizon. The leachable phases are mainly secondary carbonate-bearing REE phases such as bastnaesite ((X) Ca(CO3)2F) (for X: Ce, La and Nd). The isotope data and trace element

  14. Geochemical characterization of niobium (Nb) bearing granites in and around Kanigiri, Prakasham district, A.P.: implications for RMRE mineral exploration

    A number of granite bodies of Mesoproterozoic age occur intermittently over a stretch of about 300 km from Vinukonda (Guntur district) in the north to Sri Kalahasthi (Chittoor district) in the south, proximal to the eastern margin of the Cuddapah basin. Notable among them are the Vinukonda granite, Darsi granite, Podili granite, Kanigiri granite and Anumalakonda granite. Columbite-tantalite, fergusonite, bastnaesite, samarskite, allanite, monazite and thorite are the rare metal and rare earth bearing minerals in the Kanigiri pluton. Based on the geochemical analysis of sixty (60) granite samples by Wavelength Dispersive X-ray Fluorescence Spectrometry (WDXRFS), the samples were grouped into Nb rich and Nb poor varieties. The present study attempts geochemical characterization of Nb-rich and normal granitoids (Nb poor) in and around Kanigiri, Prakasham dist, A.P.

  15. Discovery of Cu-Zn, Cu-Sn intermetallic minerals and its significance for genesis of the Mianning-Dechang REE Metallogenic Belt, Sichuan Province, China

    XIE Yuling; HOU Zengqian; XU Jiuhua; YUAN Zhongxin; BAI Ge; LI Xiaoyu


    Mianning-Dechang Himalayan REE Metallogenetic Belt in Sichuan Province lies along the western margin of the Yangtze Craton. We have conducted detailed mineralogical studies on ore minerals collected from Maoniuping and Dalucao, the two largest deposits in the belt. With optical microscope, SEM/EDS, and EPMA, three rare intermetallic minerals, i.e., zinccopperite (Cu2Zn), Sn- bearing native copper, and Cu-bearing jupiter were found to occur in the main ore along with barite, fluorite, apatite, sulfide and bastnaesite. Since the conditions under which zinccopperite and Sn- bearing native copper formed are quite unique, finding of these minerals, for the first time in domestic REE deposits, has significant implications for the genesis of the ore deposits in which they occur. In comparison with Cu-Zn intermetallic minerals in other occurrences, we propose that the formation of this REE metallogenetic belt is associated with fast upwelling of the Himalayan magma from deep source.

  16. Mineralized lateritic profile in Sn, Zr, Th, Nb, Y and ETR (Serra do Madeira - Pitinga - AM): mineralogical characteristics and geochemical evolution

    The Pitinga region is located in the north 250 km far from Manaus, in the Amazonas State, Brazil. The Serra do Madeira is the local name of one hill located in the Madeira granite with important primary and supergenic mineralizations of Sn (cassiterite), Zr (zircon), Th (thorite), Nb (columbite and pyroclore), Y and REE (xenotime). The Serra do Madeira was constituted by a lateritic profile with 20 m of thickness where were identified seven horizons: parent rock, saprolite, clayey, bauxitic, concretionary, coluvion and latosol. The lateritization promoted the chemistry instability of the parent-rock forming a clayey material where Al2O3, Fe2O3, Sn, Th and Nb were enriched as kaolinite, gibbsite, hematite, goethite, cassiterite, zircon, thorite and columbite; SiO2, FeO, CaO, Na2O, K2O, F, Pb, Rb, and U were leached as quartz, K-feldspar, plagioclase, riebeckite/arfvedsonite, biotite, and iron sulfides; Y, P and ETR were enriched and leached correlated to xenotime, bastnaesite, fluorcerite and probably churchite and ytriofluorite

  17. Investigation and analysis to the content of natural radionuclides at rate-earth ore and solid waste in China through the first nationwide pollution source survey

    China has launched the First Nationwide Pollution Source Survey (FNPSS) during 2006-2009. Ministry Environmental Protection (MEP) sponsored the campaign of measuring the natural radionuclide contents. And the Ministry Environmental Protection (MEP) organized the measurements of natural radionuclide contents of in the factories and mines associated with rare-earth, niobium/tantalum, zircon, tin, lead/zinc, copper, iron, phosphate, coal, aluminum and vanadium. This paper analyzes mainly the data on the contents of U, 232Th and 226Ra in the rare-earth ore and solid waste produced by the rare-earth industry in China, as one of a series of papers on naturally occurring radioactive materials (NORM) s investigation. It is concluded that the average of the U, 232Th and 226Ra for the monazite sand of rare-earth ore is 16911, 49683, and 20072 Bq/kg, respectively. The average of U, 232Th and 226Ra in bastnaesite is 42, 701 and 91 Bq/kg, respectively. The average of U, 232Th and 226Ra in the ionic type rare-earth ore is 3918.6, 2315 and 1221 Bq/kg, respectively. (authors)

  18. Decomposition Reaction of Mixed Rare Earth Concentrate and Roasted with CaO and NaCl

    Wu Wenyuan; Hu Guangyong; Sun Shuchen; Chen Xudong; Tu Ganfeng


    The reaction of the mixed rare earth concentrate including monazite ( REPO4 ) and bastnaesite ( REFCO3 )decomposed by CaO and NaCl additives at the temperature range from 100 to 1000 ℃ was studied by means of XRD and TG-DTA.The results show that when CaO and NaCl are not added, only REFCO3 can be decomposed at the temperature of 377 ~ 450 ℃.The decomposition products include REOF, RE2O3 and CeO2.However, REFCO3 can not be decomposed.When CaO is added, the decomposition reactions occur at the temperature range from 660 to 750 ℃.CaO has three decomposition functions: ( 1 ) REPO4 can be decomposed by CaO and the decomposition products include RE2O3 and Ca3 (PO4)2; (2) CaO can decompose REOF, and the decomposition products are RE2O3 and CaF2; (3)CaO can decompose REPO4 with CaF2, and the decomposition products are RE2 O3, Ca5 F( PO4 )3.The decomposition ratio of the mixed rare earth concentrate increased obviously, when CaO and NaC1 were added.NaC1 can supply the liquid for the reaction, improve the mass transfer process and accelerate the reaction.At the same time, NaC1 participated in the reaction that REPO4 was decomposed by CaO.

  19. Setting and genesis of uranium mineralization at Rexspar

    Preto, V.A.


    The Rexspar uranium deposit is located approximately 5 kilometers south of Birch Island, B.C. Three separate zones of commercial-grade uranium mineralization mineable by open pit have been outlined. Uranium and fluorite-celestite mineralization occur in a trachytic member of alkali-feldspar porphyry, lithic tuff, tuff breccia and pyritic schist conformably interlayered with a succession of strongly deformed greenschists and fragmental rocks that are, in large part at least, of volcanic origin. The age of these strata is not precisely known, but they are considered as part of the possibly Mississippian Eagle Bay Formation. Commercial-grade uranium mineralization is always associated with fluorphlogopite-pyrite replacement of the trachytic unit and is contiguous to, but separate from, a zone of ore-grade fluorite mineralization. In all zones, ore occurs in lenses of variable thickness and lateral extent, which lie parallel to the schistosity of the trachytic rocks and surrounding greenschists. The principal radioactive minerals at Rexspar have been identified by other workers as uraninite, uranothorite, bastnaesite, torbernite and metatorbernite. Considerable amounts of thorium oxide and widespread rare earths have been reported from all three radioactive zones. The geology of the deposit suggests that the trachytic rocks represent a highly differentiated intrusive-extrusive system in which fluorphlogopite, pyrite, fluorite and uranium-bearing minerals were deposited late in the evolution of the system by deuteric, volatile-rich fluids. The considerable amounts of thorium and widespread rare earths associated with the uranium tend to support the thesis that this element is of primary origin rather than secondary.

  20. Petrology and textural evolution of granites associated with tin and rare-metals mineralization at the Pitinga mine, Amazonas, Brazil

    Lenharo, Sara Lais Rahal; Pollard, Peter J.; Born, Helmut


    The Água Boa and Madeira igneous complexes at the Pitinga mine were emplaced into acid volcanic rocks of the Paleoproterozoic Iricoumé Group, and host major tin, rare-metal (Zr, Nb, Ta, Y, REE) and cryolite mineralization. The igneous complexes are elongate NE-SW and each is composed of three major facies that, in order of emplacement, include porphyritic and equigranular rapakivi granite and biotite granite in both igneous complexes, followed by topaz granite in the Água Boa igneous complex (ABIC) and albite granite in the Madeira igneous complex (MIC). Rapakivi, porphyritic and granophyric textures observed in the granites are interpreted to reflect multiple stages of crystallization at different pressures (depths). Decompression during ascent shifted the magmas into the plagioclase stability field, causing partial resorption of quartz, with subsequent growth at lower pressure. Fluid saturation and separation probably occurred after final emplacement at shallow levels. Temperature and pressure estimates based on phase relations and zircon concentrations range from a maximum of 930 °C and 5 kbar for the rapakivi granites to below 650 °C and 1 kbar for the peralkaline albite granite. This suggests initial crystallization of early intrusive phases at around 15 km depth, with final emplacement of more volatile-rich crystal-mush at a depth of 0.5-1 km. Accessory minerals, including zircon, thorite, monazite, columbite-tantalite, cassiterite, bastnaesite and xenotime are present in almost all facies of the Água Boa and Madeira igneous complexes, attesting to the highly evolved character of the magmas. The presence of magnetite and/or primary cassiterite indicate crystallization under oxidizing conditions above the NNO buffer. The evolutionary sequence and Nd isotope characteristics ( TDM=2.2-2.4 Ga) of the Pitinga granites are similar to those of other Proterozoic rapakivi granites. However, petrographic, geochemical and Nd isotopic data ( ɛNd initial=-2.1 to +0

  1. Hydrothermal Concentration of Zr, Y + HREE in the Lake Zone of the Thor Lake Rare Metal Deposit, Northwest Territories

    Sheard, E. R.; Heiligmann, M.; Williams-Jones, A. E.


    The Thor Lake rare-metal (Zr, Y, REE, Nb, Ta, Be, Ga) deposit in Northwest Territories contains Canada's largest resource of Zr, Y and HREE and is one of the largest resources of these elements on the planet. Much of the mineralization was clearly concentrated by hydrothermal processes, providing compelling evidence for Zr mobility. Geologically, the deposit is situated at the southern edge of the Slave Province of the Canadian Shield, within the 2150 Ma alkaline to peralkaline Blachford Lake complex consisting of an early suite of gabbro, quartz syenite and granite, which was intruded by the Grace Lake granite and, in turn, by the Thor Lake syenite [1]. A layered alkaline intrusion dominated by nepheline syenite occurs below the Thor Lake syenite and is thought to represent the youngest phase of the complex. This intrusion comprises numerous sub- horizontal layers of sodalite syenite, alkali syenite and lujavrite. Evidence of cumulate and adcumulus textures, cyclic magmatic differentiation and rhythmic layering of mafic and felsic units on scales ranging from tens of centimetres to several metres indicate a complex history of pulsed injection of magma and magmatic differentiation. The upper part of the layered intrusion and the overlying Thor Lake syenite contain the bulk of the rare metal mineralization, with Zr hosted primarily by zircon, Nb primarily by ferrocolumbite and fergusonite, and Y + HREE by fergusonite and zircon. The LREE are hosted by monazite, allanite, bastnaesite and synchisite/parisite. The precursor rocks to the ore were pervasively altered by Fe- and K-rich hydrothermal fluids, which replaced much of the primary mineralogy by magnetite, biotite and K-feldspar and redistributed/concentrated the rare metals including Zr (as secondary zircon). This alteration was overprinted locally by intense sodic alteration. In other rare-metal-rich alkaline complexes such as Strange Lake, Ilimaussaq and Lovozero, the Zr, Nb, Y + REE mineralization has been

  2. Radiological safety in extraction of rare earths in India: regulatory control

    The term 'rare earths' refers to a group of f-block elements in the periodic table including those with atomic numbers 57 (Lanthanum) to 71 (Lutetium), as well as the transition metals Yttrium (39) and Scandium (21). Economically extractable concentrations of rare earths are found in minerals such as monazite, bastnaesite, cerites, xenotime etc. Of these, monazite forms the main source for rare earths in India, which along with other heavy minerals is found abundantly in the coastal beach sands. However, in addition to rare earths, monazite also contains 0.35% U3O8 and 8-9% ThO2. Hence, extraction of rare earths involves chemical separation of the rare earths from thorium and uranium which are radioactive. The processing and extraction of rare earths from monazite therefore invariably results in occupational radiation exposure to the workers involved in these operations. In addition, in the process of removal of radioactivity from rare earths, radioactive solid waste gets generated which has 228Ra concentration in the range 2000-5000 Bq/g. Unregulated disposal of such high active waste would not only result in contamination of the soil but the radionuclides would eventually enter the food chain and lead to internal exposure of the general public. Therefore such facilities involved in recovery of rare earths from monazite attract the provisions of radiological safety regulations. Atomic Energy Regulatory Board of India has been enforcing the provisions of The Atomic Energy (Radiation Protection) Rules, 2004 and The Atomic Energy (Safe Disposal of Radioactive Waste) Rules, 1987 in these facilities. This paper shall discuss the associated radiological hazard involved in recovery of rare earths from monazite. It shall also highlight the regulatory requirements for controlling the occupational exposure of workers during design stage such as requirements on lay out of the building, ventilation, containment of radioactivity, etc and also the during operational phase such

  3. Energy status and R and D activities on ADS in Turkey

    Although there have been three attempts in Turkey to built a NPP, in 1965, 1974, and 1980, there is no nuclear power plants in operation, under construction nor decommissioned. According to the current long term energy planning studies in Turkey, nuclear electricity will begin to contribute national electricity production in 2020 with a capacity of 2 GWe. The nuclear policy of the country includes research and development activities in the application of nuclear energy sectors. Research and development activities in the nuclear field in Turkey are performed by The Turkish Atomic Energy Authority (TAEK), The Mineral Exploration and Research Directorate and related departments of some universities in Turkey. After the postponement of the third Akkuyu NPP Project, the Government stated that the intention to use and to participate in the development of innovative nuclear technologies. In this context, Turkey has been participating in the International Project on Innovative Nuclear Reactor Technologies and Fuel Cycles (INPRO), Technical Working Group on Gas Cooled Reactors coordinated by the IAEA. Co-operation with international/national groups on theoretical and experimental projects concerning innovative technologies would lead to an increase of staff capabilities and experience on nuclear technology in Turkey. A national project, named, 'Separation and purification of rare earth minerals and thorium from bastnaesite complex ore of Eskisehir-Sivirihisar region has been started in 2003 in order to determine the feasibility of 380,000 ton low grade (∼0.21%) thorium and some rare earth minerals at the vicinity of Eskisehir-Sivirihisar. After the production of CeO2 was succeeded in March 2004, simultaneously, thorium has been extracted from the samples with 99% efficiency as byproduct where thorium is considered to be economical. In view of the suitability of ADS design for the thorium utilization, an intention exists to participate to relevant ADS activities

  4. Thorium partitioning in Greek industrial bauxite investigated by synchrotron radiation and laser-ablation techniques

    Gamaletsos, P. [Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 15784 Zographou (Greece); Godelitsas, A., E-mail: [Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 15784 Zographou (Greece); Mertzimekis, T.J. [Department of Physics, University of Athens, Panepistimioupolis, 15771 Zographou (Greece); Goettlicher, J.; Steininger, R. [Karlsruhe Institute of Technology, Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Xanthos, S. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Berndt, J.; Klemme, S. [Institut fuer Mineralogie, Corrensstrasse 24, Universitaet Muenster, 48149 Muenster (Germany); Kuzmin, A. [Institute of Solid State Physics, University of Latvia, Kengaraga st. 8, 1063 Riga (Latvia); Bardossy, G. [Hungarian Academy of Sciences, H-1051 Budapest (Hungary)


    Typical red-brown (Fe-rich) and high-quality white-grey (Fe-depleted) bauxite samples from active mines of the Parnassos-Ghiona area, central Greece, were investigated. According to XRF and ICP-MS analyses their actinide content, and particularly of Th, is relatively increased. Fe-depleted samples contain up to 62.75 ppm Th corresponding to 220 Bq/kg due to {sup 228}Ac ({sup 232}Th-series), whereas Fe-rich samples are less Th-radioactive (up to 58.25 ppm Th, 180 Bq/kg due to {sup 228}Ac). Powder-XRD patterns showed that Th-enriched (Fe-depleted) bauxite consists mostly of diaspore (AlOOH polymorph), anatase and rutile (TiO{sub 2} polymorphs). SEM-EDS indicated the presence of Ti-Fe-containing phases (e.g. ilmenite, FeTiO{sub 3}), chromite (Cr-spinel) and besides LREE-minerals (mostly bastnaesite/parisite-group) and zircon (ZrSiO{sub 4}) hosting a part of the bulk Th. The presence of Th in diaspore and in Ti-containing phases (not detected by SEM-EDS as in the case of REE-minerals and zircon) was investigated, into distinct pisoliths of Fe-depleted bauxite, using {mu}-XRF and {mu}-XAFS in the SUL-X beamline of the ANKA Synchrotron facility (KIT, Germany). XAFS spectra of Th salts and Th-containing reference materials were obtained as well. Accordingly it was revealed, for the first time in the literature, that Ti-phases, and particularly anatase, host significant amounts of Th. This novel conclusion was complementary supported by LA-ICP-MS analyses indicated an average of 73 ppm Th in anatase grains together with abundant Nb (3356 ppm), Ta (247 ppm) and U (33 ppm). The Th L{sub III}-edge XAFS spectra as compared to reference materials, give also evidence that Th{sup 4+} may not replace Ti{sup 4+} in distorted [TiO{sub 6}] fundamental octahedral units of anatase and ilmenite lattice (CN = 6). The occupation of either extraframework sites of higher coordination (CN = 6.9 or even CN = 7.4), according to EXAFS signals evaluation, or of defected/vacant (**) sites is more

  5. Proximal and distal styles of pegmatite-related metasomatic emerald mineralization at Ianapera, southern Madagascar

    Andrianjakavah, Prosper Rakotovao; Salvi, Stefano; Béziat, Didier; Rakotondrazafy, Michel; Giuliani, Gaston


    The Ianapera emerald deposit is located in the Neoproterozoic Vohibory Block of southern Madagascar. The local geology consists of intercalated migmatitic gneissic units and calcareous metasedimentary rocks, containing boudinaged metamorphosed mafic/ultramafic lenses, all intruded by pegmatite veins. These units occur near the hinge of the tightly folded Ianapera antiform, within a few kilometers of the Ampanihy shear zone. Emerald mineralization is hosted by metasomatic phlogopite veins, and bodies developed within the mafic/ultramafic rocks. Based on field and textural relationships, we distinguish proximal and distal styles of mineralization. Proximal mineralization occurs at the contact of pegmatite veins with mafic/ultramafic units; in the distal style, pegmatites are not observed. Three types of emeralds could be distinguished, mainly on the basis of color and mineral zoning. Some of these emeralds have the most Al-depleted and Cr-rich composition ever recorded. Another characteristic feature to the Ianapera deposit and, to our knowledge, yet unreported, is the association of some emeralds with scapolite in metasomatised mafic rocks. Mineral inclusions are common in most emeralds and include phlogopite, carbonates, barite, K-feldspar, quartz, pyrite, zircon, monazite, bastnaesite, phenakite, plus Fe and Cr oxides. However, feldspar and rare earth element-bearing minerals occur predominantly in proximal emeralds, which also have a more incompatible trace-element signature than distal emeralds. We propose a model related to syn- to post-tectonic magmatic-hydrothermal activity. Pegmatitic bodies intruded units of the Ianapera antiform probably during tectonic relaxation. Exsolution of fluids rich in halogens and incompatible elements from the cooling pegmatites caused hydrothermal metasomatism of Cr-bearing mafic/ultramafic rocks in direct contact with the pegmatites. Local fracturing favored fluid infiltration, permitting the formation of distal mineralization

  6. Rare earth minerals and resources in the world

    Kanazawa, Yasuo [Human Resource Department, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)]. E-mail:; Kamitani, Masaharu [Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567 (Japan)


    About 200 rare earth (RE) minerals are distributed in a wide variety of mineral classes, such as halides, carbonates, oxides, phosphates, silicates, etc. Due to the large ionic radii and trivalent oxidation state, RE ions in the minerals have large coordination numbers (c.n.) 6-10 by anions (O, F, OH). Light rare earth elements (LREEs) tend to occupy the larger sites of 8-10 c.n. and concentrate in carbonates and phosphates. On the other hand, heavy rare earth elements (HREEs) and Y occupy 6-8 c.n. sites and are abundant in oxides and a part of phosphates. Only a few mineral species, such as bastnaesite (Ce,La)(CO{sub 3})F, monazite (Ce,La)PO{sub 4}, xenotime YPO{sub 4}, and RE-bearing clay have been recovered for commercial production. Bayan Obo, China is the biggest RE deposit in the world. One of probable hypotheses for ore geneses is that the deposit might be formed by hydrothermal replacement of carbonate rocks of sedimentary origin. The hydrothermal fluid may be derived from an alkaline-carbonatite intrusive series. Following Bayan Obo, more than 550 carbonatite/alkaline complex rocks constitute the majority of the world RE resources. The distribution is restricted to interior and marginal regions of continents, especially Precambrian cratons and shields, or related to large-scale rift structures. Main concentrated areas of the complexes are East African rift zones, northern Scandinavia-Kola peninsula, eastern Canada and southern Brazil. Representative sedimentary deposits of REE are placer- and conglomerate-types. The major potential countries are Australia, India, Brazil, and Malaysia. Weathered residual deposits have been formed under tropical and sub-tropical climates. Bauxite and laterite nickel deposit are the representative. Ion adsorption clay without radioactive elements is known in southern China. Weathering processes concentrate REE in a particular clay mineral-layer in the weathered crusts whose source were originally REE-rich rocks like granite

  7. Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

    Hissler, Christophe; Stille, Peter


    suggesting their close genetic relationships. Sr-Nd-Pb isotope data allow to identify four principal components in the soil: a silicate-rich pool at close to the surface, a leachable REE enriched pool at the bottom of the soil profile, the limestone facies on which the weathering profile developed and an anthropogenic, atmosphere-derived component detected in the soil leachates of the uppermost soil horizon. The leachable phases are mainly secondary carbonate-bearing REE phases such as bastnaesite. The isotope data and trace element distribution patterns indicate that at least four geological and environmental events impacted the chemical and isotopical compositions of the soil system since the Cretaceous.

  8. Chemical and ceramic methods toward safe storage of actinides using monazite. 1998 annual progress report

    'The use of ceramic monazite, (La,Ce)PO4, for sequestering actinides, especially plutonium, and some other radioactive waste elements (rare earths e.g.) and thus isolating them from the environment has been championed by Lynn Boatner of ORNL. It may be used alone or, as it is compatible with many other minerals in nature, can be used in composite combinations. Natural monazite, which almost invariably contains Th and U, is often formed in hydrothermal pegmatites and is extremely water resistant--examples are known where the mineral has been washed out of rocks (becoming a placer mineral as on the beach sands of India, Australia, Brazil etc.) then reincorporated into new rocks with new crystal overgrowths and then washed out again--being 2.5--3 billion years old. During this demanding water treatment it has retained Th and U. Where very low levels of water attack have been seen (in more siliceous waters), the Th is tied up as new ThSiO4 and remains immobile. Lest it be thought that rare-earths are rare or expensive, this is not so. In fact, the less common lanthanides such as gadolinium, samarium, europium, and terbium, are necessarily extracted and much used by, e.g., the electronics industry, leaving La and Ce as not-sufficiently-used by-products. The recent development of large scale use of Nd in Nd-B-Fe magnets has further exaggerated this. Large deposits of the parent mineral bastnaesite are present in the USA and in China. (Mineral monazite itself is not preferred due to its thorium content.) In the last 5 years it has become apparent show that monazite (more specifically La-monazite) is an unrecognized/becoming-interesting ceramic material. PuPO4 itself has the monazite structure; the PO4 3-unit strongly stabilizes actinides and rare earths in their trivalent state. Monazite melts without decomposition (in a closed system) at 2,074 C and, being compatible with common ceramic oxides such as alumina, mullite, zirconia and YAG, is useful in oxidatively stable