Sample records for bastnaesite

  1. Interaction of reactive oily bubble in flotation of bastnaesite

    Institute of Scientific and Technical Information of China (English)

    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. Thermodynamic Mechanism Analysis of Calcification Roasting Process of Bastnaesite Concentrates (United States)

    Cen, Peng; Wu, Wenyuan; Bian, Xue


    A novel calcification roasting decomposition method for bastnaesite concentrates has been proposed previously. In this work, the thermodynamic mechanism was investigated via simultaneous measurements of thermogravimetry and differential thermal analyses, combined with X-ray diffraction analyses. Rare earth oxides and calcium fluorides were generated after bastnaesite and calcium hydroxide broke down, respectively. The generation and decomposition of calcium carbonate occurred at the same time. Considering the difficulties in obtaining pure substances, theoretical calculations were applied to determine the standard enthalpy of formation (Δf H 298), Gibbs free energies of formation (Δf G 298), and heat capacities at constant pressure (C p) of some rare earth minerals (CeFCO3 and CeOF). Based on these results, the standard Gibbs energy of reaction at different temperatures (Δr G T) was ascertained, and the major reactions were verified to be thermodynamically reasonable.

  3. Study on leaching rare earths from bastnaesite treated by calcification transition

    Institute of Scientific and Technical Information of China (English)

    黄宇坤; 张廷安; 豆志河; 刘江; 唐方方


    Extracting rare earths from bastnaesite concentrate treated by calcification transition was studied through the single factor test and XRD patterns of bastnaesite after calcification and slags after leaching in HCl solution. And the effects of the main calcified parameters such as temperature, liquid/solid and calcified time on transition performance of bastnaesite were investigated. It was found that under the optimal conditions of calcification temperature of 250 ºC, liquid/solid of 20 mL/g, calcification time of 180 min, the highest leaching rate of rare earth were obtained, with the leaching ratio of rare earths 83.70%and Ce 77.01%, La 90.55%, Nd 92.03%, respectively;loss rates of fluorine with different calcification conditions were always less than 1%and XRD patterns of cal-cification slags and leaching slags showed that fluorine existed in the form of CaF2.

  4. Study on thorium recovery from bastnaesite treatment process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongqi; XU Yang; HUANG Xiaowei; LONG Zhiqi; CUI Dali; HU Feng


    Thorium (Th) stripping behavior from HEH/EHP (2-(ethylhexyl) phosphoric acid mono-2-ethylhexyl ester) with H2SO4,HCl and HNO3 were investigaated.The results indicated that H2SO4 was the most effective stripping reagent compared with HCl and HNO3.Selecting H2SO4 as the stripping reagent,the effect of phase ratio,acidity,H2SO4 amount,HEH/EHP concentration and Th loading in HEH/EHP on Th stripping were systematically investigated.As a result,the optimum stripping conditions of Th(Ⅳ) were obtained as the concentration of H2SO4 solution was 3.50 mol/L,phase ratio was 4∶1.Low HEH/EHP concentration was benefit for Th stripping.Based on the results,pilot test for new Bastnaesite treatment process was carried out and the recovery of Ce,F and Th were more than 99%,98% and 95% separately.

  5. Separation of Rare Earth Elements (Sm, Eu, Gd) in Bastnaesite by Displacement Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Se Mann; Lee, Jin Young; Han, Choon [Kwangwoon University, Seoul (Korea); Kim, Sung Don; Yoon, Ho Sung; Kim, Joon Soo [Korea Institute of Geology Mining and Materials, Taejon (Korea)


    Rare earth elements (Sm, Eu, Gd) in bastnaesite were separated by displacement chromatography. Experiments were conducted to investigate elution characteristics and effects of retaining ions on separations of those elements. During separation processes, ions were exchanged in loading and separation columns packed with the cation-exchange resin (DOWEX 50WX8-200). Various retaining ions such as Cu{sup 2+}, Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Fe{sup 3+} and Al{sup 3+} were employed in the separation column. When the EDTA solution was used as an eluent, acidity and concentrations were regulated. Also, rare earth elements(RE) in bastnaesite ore were ionized by hydrochloric acid prior to separations. According to experimental results, Gd, Eu and Sm were eluated by turns and the order was in accord with that of stability constants for chelating complex with EDTA. During the eluation of RE, the acidity of eluate was lowered (pH 5-6) because retaining ions formed chelating complex with EDTA and hydrogen ion was formed as a result. The highest separation efficiency ({alpha}{sub Gd}{sup Sm} = 0.9388) was obtained when Al{sup 3+} was employed as a retaining ion. On the other hand, the lowest ({alpha}{sub Gd}{sup Sm} = 0.3876) was when Fe{sup 3+} was employed as a retaining ion. Another series of experiments were conducted to investigate effects of RE{sub 1}-EDTA eluent on the separation of RE. For experiments, Cu{sup 2+}, in the separation column was exchanged with retaining ion. Then, pure RE{sub 1}(Sm, Eu) was mixed with EDTA to form RE{sub 1}-EDTA solution(O.015 M) which was fed to the column as an eluent. Results showed that the separation efficiency improved because the eluation of RE{sub 1} in RE{sub 1}-EDTA solution was retarded compared to other RE. That is, the separation efficiency({alpha}{sub Gd}{sup Sm}) increased to 1.1612 and 1.4545 when SM-EDTA and EU-EDTA solution were used respectively. When EDTA solution was only used as an eluent, {alpha}{sub Gd}{sup Sm

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

    Institute of Scientific and Technical Information of China (English)


    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 ℃.

  7. On the Origin of Bastnaesite-(La,Nd,Y in the Nissi (Patitira Bauxite Laterite Deposit, Lokris, Greece

    Directory of Open Access Journals (Sweden)

    Sofia Kalatha


    Full Text Available A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al–Ni–silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y(CO3F member of the bastnaesite-group associated with Al–Ni–silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

  8. 白云鄂博氟碳铈矿-独居石混合精矿中非稀土元素的氯化反应%Carbochlorination of Non- rare Earth Elements in Baiyunebo Mixed Bastnaesite- monazite Concentrate

    Institute of Scientific and Technical Information of China (English)

    张丽清; 赵玲燕; 周华锋; 于秀兰


    The isothermal carbochlorination reaction of non-rare earth element in Baiyunebo mixed bastnaesite-mon azite concentrate and the change of its physical states in this process were investigated. When the temperature is 500t ,the non-rare earth elements of Ca,Ba and Mg in Baiyunebo mixed bastnaesite-monazite were carbochlorinat ed completely using carbon as reductant,chlorine as chlorination agent,SiCl4 as defluoration agent. Their carbon chloration products were dissolved in water with the carbonchloration products of rare-earth. TiCl4 mainly exit in the insoluble residues, less than 1 % of which was vaporized in the carbochlorination process and deposited in the recep tors around 450^. FeCl3 was deposited in the receptors at 300t to 150T!. POC13 was deposited in the receptors below 150t. The separation of Fe, P Th from other substances and the separation of a little substance which was not carbonchlorated from carbonchloration products can be realized by dissolved the carbonchloration products in water.%研究了白云鄂博氟碳铈矿-独居石混合精矿中非稀土元素的等温碳热氯化反应以及反应过程中物理状态的变化.当反应温度低至500℃、活性炭为还原剂、SiCl4+ Cl2的气氛下氟碳铈-独居石混合精矿中非稀土元素Ca、Ba、Mg基本反应完全并和稀土元素的氯化产物共同存在于氯化产物水溶液中,Th的氯化产物主要存在于氯化产物的水不溶物中,小于1%的ThCl4在反应过程中挥发,沉积在450℃的温区,精矿中Fe的氯化产物沉积在300℃-150℃的温区,P的氯化产物主要沉积在低于150℃的温区内.通过水溶氯化反应产物可实现少量的没有氯化的物质和氯化物之间的分离以及Fe、P、Th的分离.

  9. Separation of Thorium From Mixed Bastnaesite-Monazite Concentrate%氟碳铈-独居石混合矿中钍的分离

    Institute of Scientific and Technical Information of China (English)

    张丽清; 王之昌; 王小欢; 于秀兰


    以氟碳铈矿-独居石混合稀土矿为研究对象,采用分步选择性碳热氯化-化学气相传输反应(SC-CVT),实现钍与其它稀土元素的分离.当氯化反应温度为500℃,以活性炭为还原剂、SiCl4为脱氟剂,在Cl2气氛下稀土矿反应2 h时,钍的氯化产物(ThCl4)挥发量小于1%;继而以AlCl3作配位体,800℃、Cl2气氛下传输反应O.5 h,ThCl4与配位体反应形成气态配合物ThAlCl7;温度降低时,ThAlCl7分解并沉积在600℃左右的温区内,AlCl3沉积在温度低于200℃的温区内,FeCl3主要沉积在200~350℃的温区内,从而实现放射性元素Th的分离和回收.

  10. Rare Earth Extraction from Mixed Bastnaesite-Monazite Concentrate by Carbochlorination-Oxidation%加碳氯化-氧化反应方法从氟碳铈矿-独居石混合精矿中提取稀土

    Institute of Scientific and Technical Information of China (English)

    张丽清; 张凤春; 姚淑华; 姜琳琳; 王小欢


    以活性炭为还原剂、氯气为氯化剂、SiCl4为除氟剂、O2和H2O混合气体为氧化剂,采用氯化-氧化反应方法从氟碳铈-独居石混合精矿中提取稀土元素.在脱氟剂SiCl4作用下,随着反应温度由500 ℃增至800 ℃,氟碳铈-独居石混合精矿稀土氯化率由92%增至99%,而无SiCl4时同样温度范围内,稀土氯化率为56%~88%,500 ℃氯化反应2 h时主要产物为稀土氯化物、氯化钙;当氯化反应温度小于500 ℃时,与原料比钍的氯化产物挥发量小于1.0%水洗氟碳铈-独居石混合精矿的焙砂,过滤并在空气中固化得到氯化产物,在550 ℃,O2+H2O气氛下氧化反应90 min,实现稀土元素和非稀土元素、铈和非铈稀土元素的分离.

  11. Extraction of Rare Earths from Mixed Bastnaesite-Monazite Concentrate by Carbochlorination Reaction%碳热氯化法分解包头混合稀土精矿提取稀土

    Institute of Scientific and Technical Information of China (English)

    王勇; 于秀兰; 舒燕; 王之昌



  12. Rare Earth Extraction and Separation from Bastnaesite-Monazite Mixed Concentrate by Chemical Vapor Transport%氟碳铈矿-独居石混合精矿分离提取稀土元素

    Institute of Scientific and Technical Information of China (English)

    张丽清; 王之昌; 雷鹏翔; 迟明玉; 杨冬梅


    以气态配合物LnAlnCl3n-3(Ln=稀土元素)为载体,研究了从氟碳铈矿-独居石混合精矿中提取分离稀土元素的分步氯化-化学气相传输反应. 精矿经第一步氯化反应分离回收非稀土元素P, Fe和Th后,生成的稀土氯化物在1000℃与配体反应生成气态配合物,并化学传输分离6 h, CaCl2和BaCl2留在残渣中. 研究发现,递减温度场和波浪温度场中的化学传输反应的分离效果不同,在波浪型温度场中的波谷附近稀土沉积量高且分离系数大.

  13. 从尾矿中回收氟碳铈矿和独居石的浮选研究%Flotation of Bastnaesite and Monazite in Dressing Plant Tailing

    Institute of Scientific and Technical Information of China (English)

    徐金球; 李芳积; 曾兴兰



  14. Study on Characteristics of Carbochlorination of Mixed Bastnaesite-Monazite Concentrate%氟碳铈矿-独居石混合精矿碳热氯化反应

    Institute of Scientific and Technical Information of China (English)

    张丽清; 王之昌; 尤健; 迟明玉; 杨冬梅; 雷鹏翔


    研究了氟碳铈矿-独居石混合精矿的高温氯化反应, 发现在活性脱氟剂存在下, 在500~800 ℃之间, 稀土氯化率由无脱氟剂时的55%~88%增至92%~99%. 当氯化反应温度低于600 ℃时, 氯化产物的酸不溶物的量随着温度的升高而降低; 而当温度高于900 ℃时, 酸不溶物的量明显增加. 脱氟剂的作用可以使氟碳铈矿-独居石混合精矿氯化反应在600 ℃的低温下进行, 这和1000~1200 ℃的Goldschmidt加碳氯化工艺明显不同.

  15. The Status of Radioactive Pollution during the Mineral Processing and Smelting from Sichuan Bastnaesite%四川氟碳铈矿选冶工艺过程放射性污染现状

    Institute of Scientific and Technical Information of China (English)

    王敏; 方方; 帅震清; 丁卫撑; 朱景良


    Through detecting the contents of radon in air in rare earth mines and radionuclides in wastewater and solid wastes,the status of radioactive pollution in development and utilization of rare earth in Sichuan was analyzed.%通过分析四川省稀土开发利用中放射性污染的状况,从放射性环境保护的角度对废渣、废水、废气三类样品进行了放射性检测和分析,得出了四川省稀土开发利用过程中所产生的放射性污染现状.

  16. Mining and Exploitation of Rare Earth Elements in Africa as an Engagement Strategy in US Africa Command (United States)


    extraction difficult and costly, since they pose the risk of radiation leaks.”8 “In the few cases in which the rare-earth ion can be oxidized or... solvents are then applied to the bastnaesite to separate out the rare earths. Once separated, they are reprocessed to increase the purity level...material was the rare earth element flourocarbonate bastnaesite.29 The discouraged miners moved on. The Molybdenum Corporation laid claim to the

  17. Extraction of Rare Earths from Mixed Bastnaesite-Monazite Concentrate by Carbochlorination Reaction with AlCl3 as Defluorinating Agent%采用AlCl3脱氟-碳热氯化法从混合稀土精矿中提取稀土

    Institute of Scientific and Technical Information of China (English)

    于秀兰; 王之昌; 王勇; 董德千; 刘嘉


    研究了氟碳铈矿-独居石混合精矿经AlCl3脱氟和加碳氯化反应提取稀土的工艺及反应机理,考察了反应时间、温度和脱氟剂对稀土提取率的影响.结果表明,在脱氟剂AlCl3存在下,600℃已获高提取率(93%),800℃时氯化反应2 h,稀土提取率高达97.4%.采用XRD法分析了不同温度下混合稀土精矿碳热氯化2 h后酸不溶物的物相组成,探讨了AlCl3脱氟-碳热氯化法从混合稀土精矿中除氟并提取氯化稀土的反应机理.

  18. Carbon and Oxygen Isotopic Characteristics of REE—Fluorocarbonate Minerals and Their Genetic Implications,Bayan Obo Deposit,Inner Mongloia,China

    Institute of Scientific and Technical Information of China (English)

    方涛; 裘愉卓; 等


    REE-fluorocarbonates as major REE minerals in the Bayan Obo deposit,the largest REE deposit in the world,were analyzed for their stable isotopic compositions,The δ13 C and δ18 O values of huanghoite,cebaite and bastnaesite from late-stage veins vary in the ranges of 7.8--4.0‰ and 6.7-9.4‰,respectively,These data are relatively similar to those of bastnaesites from banded ores:δ13C-5.6--5.2‰ andδ18O3.6-5.5‰.The REE fluorocarbonates from both late-staege veins and banded ores are characterized by lower δ13 C and δ18O values,especially the δ18O values of bastnaesites from banded ores.Compared with them,the disseminated bastnaesits the dolomite-type ores possess rather highδ13 C and δ18O values,i.e.,-2.1-0.4‰ and 8.6-12.9‰ respectively.The high values are typical of the sedimentary host dolomite rocks as well as of the dolomite-type-ores.The carbon and oxygen isotopic characteristics of REE fluorocarbonate minerals provide new evidence for the hypothesis on the origin of Bayan Obo deposit-epigenetic hydrothermal metasomatism.

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

    Institute of Scientific and Technical Information of China (English)

    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

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

    Institute of Scientific and Technical Information of China (English)

    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.

  1. Partitioning properties of rare earth ores in China

    Institute of Scientific and Technical Information of China (English)

    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.

  2. Study on Roasting Decomposition of Mixed Rare Earth Concentrate in CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)


    The decomposed process of bastnaesite, monazite and mixed rare earth concentrate in CaO-CaCl-CaCl2 was studied by means of TG-DTA method. The relationship among decomposition ratio, roasting temperature, and CaO-NaCl addition was studied by the quadratic regression orthogonal analysis, and then the regression equation was obtained. Through analysis, the optimum process conditions of mixed rare earth concentrate decomposed by CaO-CaCl-CaCl2 were obtained as follows: roasting temperature: 700 ℃, CaO addition: 15%, NaCl-CaCl2 addition: 10%, roasting time: 60 min, the decomposition ratio: 91.3%.

  3. International strategic minerals inventory summary report; rare-earth oxides (United States)

    Jackson, W.D.; Christiansen, Grey


    Bastnaesite, monazite, and xenotime are currently the most important rare-earth minerals. Bastnaesite occurs as a primary mineral in carbonatites. Monazite and xenotime also can be found in primary deposits but are recovered principally from heavy-mineral placers that are mined for titanium or tin. Each of these minerals has a different composition of the 15 rare-earth elements. World resources of economically exploitable rare-earth oxides (REO) are estimated at 93.4 million metric tons in place, composed of 93 percent in primary deposits and 7 percent in placers. The average mineral composition is 83 percent bastnaesite, 13 percent monazite, and 4 percent of 10 other minerals. Annual global production is about 67,000 metric tons of which 41 percent is from placers and 59 percent is from primary deposits; mining methods consist of open pits (94 percent) and dredging (6 percent). This output could be doubled if the operations that do not currently recover rare earths would do so. Resources are more than sufficient to meet the demand for the predictable future. About 52 percent of the world's REO resources are located in China. Ranking of other countries is as follows: Namibia (22 percent), the United States (15 percent), Australia (6 percent), and India (3 percent); the remainder is in several other countries. Conversely, 38 percent of the production is in China, 33 percent in the United States, 12 percent in Australia, and 5 percent each in Malaysia and India. Several other countries, including Brazil, Canada, South Africa, Sri Lanka, and Thailand, make up the remainder. Markets for rare earths are mainly in the metallurgical, magnet, ceramic, electronic, chemical, and optical industries. Rare earths improve the physical and rolling properties of iron and steel and add corrosion resistance and strength to structural members at high temperatures. Samarium and neodymium are used in lightweight, powerful magnets for electric motors. Cerium and yttrium increase the

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

    Institute of Scientific and Technical Information of China (English)

    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.

  5. Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin (United States)

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang


    Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints

  6. Decomposition of the mixed rare earth concentrate by microwave-assisted method

    Institute of Scientific and Technical Information of China (English)

    黄宇坤; 张廷安; 刘江; 豆志河; 田俊行


    A novel process was proposed to strengthen the decomposition of the mixed rare earth concentrate by utilizing the micro-wave radiation. Mineralogical information on the mechanisms by which microwave heating improved the leaching behavior of rare earth elements (REEs),and an interpretation of the interrelationship between mineralogy, decomposition process, and leaching proc-ess were provided in this study. The influences of the temperature, time of microwave heating and contents of NaOH (mass ratio of NaOH to mixed rare earth concentrate) on the decomposition of mixed rare earth concentrate were investigated. The results revealed that the temperature was the main factor affecting the decomposition process. The recovery of REEs by hydrochloric acid leaching reached 93.28% under the microwave heating conditions: 140 ºC, 30 min and 35.35% NaOH. The BET specific surface area and SEM analysis indicated that the particles of mixed rare earth concentrate were non-hole, while the particles presented a porous structure af-ter heating the concentrate by microwave radiation. For the microwave treated sample after water leaching, the BET specific surface area was 11.04 m2/g, which was higher than the corresponding values (6.94 m2/g) for the mixed rare earth concentrate. This result could be attributed to the phase changes of bastnaesite and monazite, and a number of cracks induced by thermal stress. The increase of BET specific surface area resulted in an increase of the recovery of REEs by promoting interaction within the system of acid leaching.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  8. Rare earth minerals and resources in the world

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, P.E.D. [Rockwell International Corp., Thousand, Oaks, CA (US); Boatner, L.A. [Oak Ridge National Lab., TN (US)


    'The use of ceramic monazite, (La,Ce)PO{sub 4}, 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 ThSiO{sub 4} 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 PO{sub 4} 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

  12. A Unique Yttrofluorite-Hosted Giant Heavy Rare Earth Deposit: Round Top Mountain, Hudspeth County, Texas, USA (United States)

    Pingitore, N. E.; Clague, J. W.; Gorski, D.


    Round Top Mountain is a surface-exposed peraluminous rhyolite laccolith, enriched in heavy rare earth elements, as well as niobium-tantalum, beryllium, lithium, fluorine, tin, rubidium, thorium, and uranium. The extreme extent of the deposit (diameter one mile) makes it a target for recovery of valuable yttrium and HREEs, and possibly other scarce elements. The Texas Bureau of Economic Geology estimated the laccolith mass as at least 1.6 billion tons. A Preliminary Economic Assessment for Texas Rare Earth Resources listed an inferred mineral resource of 430,598,000 kg REOs (rare earth oxides), with over 70% Y+HREEs (YHREE). Put in global perspective, China is thought to produce ~25,000 tons YHREE per year, and exports but a small fraction of that. Because of the extremely fine grain size of the late-phase fluorine-carried critical fluid mineralization, it has not been clear which minerals host the YHREEs. X-ray Absorption Spectroscopy experiments at the Stanford Synchrotron Radiation Lightsource revealed that virtually all of the YHREE content resides in yttrofluorite, rather than in the other reported REE minerals in the deposit, bastnaesite and xenotime. The extended x-ray absorption fine structure (XAFS) spectra of the sample suite were all quite similar, and proved a close match to known model compound specimens of yttrofluorite from two locations, in Sweden and New Mexico. Small spectral variation between the two model compounds and among the samples is attributable to the variable elemental composition and altervalent substitutional nature of yttrofluorite (Ca [1-x] Y,REE [x])F[2+x]. We found no other reported deposit in the world in which yttrofluorite is the exclusive, or even more than a minor, YHREE host mineral. Leaching experiments show that the YHREEs are easily liberated by dissolution with dilute sulfuric acid, due to the solubility of yttrofluorite. Flotation separation of the yttrofluorite had been demonstrated, but was rendered inefficient by the

  13. 山东微山稀土矿矿床成因:来自云母Rb-Sr年龄、激光Nd同位素及流体包裹体的证据%Genesis of the Weishan REE deposit, Shandong Province: Evidences from Rb-Sr isochron age, LA-MC-ICPMS Nd isotopic compositions and fluid inclusions

    Institute of Scientific and Technical Information of China (English)

    蓝廷广; 范宏瑞; 胡芳芳; 杨奎锋; 王永


    Weishan REE deposit, a pegmatite-type REE deposit related to alkaline rocks, is located in Luxi Block, southeastern North China Craton. Muscovite Rb-Sr isochron yields an age of 119.5 Ma, which belonged to the Early Cretaceous large-scale mineralization in the North China Craton. LA-ICPMS Nd isotopic compositions of bastnaesite and monazite indicate that the source of the REE deposit is the enriched lithospheric mantle. Four types of fluid inclusions have been identified in quartz, fluorite and barite, including (1) H2O inclusions (H), (2) pure CO2 inclusions (C), (3) H2O+CO2 inclusions (HC) and (4) H2O+CO2+daughter mineral inclusions (HCD). The H inclusions are secondary while others are primary. The daughter minerals in HCD inclusions include thenardite, barite, celestine, calcite, aphthitalite and glauberite. The homogenization and capture pressures of HC and HCD inclusions range from 205-433 ℃ and 120-200 Mpa, respectively. Coupled with the existence of abundant daughter minerals and S stable isotopic compositions, it can be deduced that the initial ore-forming fluidswere high-temperature, moderate-pressure and high-concentration orthomagmatic fluids, which were characterized by enrichment of HCO-3/CO2-3, SO2-4 and F~ and multi-component (e.g., Na+, K+, Ca+, Ba2+, Sr2+ and REE3+). The coexistence of C, HC and HCD inclusions and the wide range of liquid/vapor ratios between these inclusions suggest that fluid unmixing may have occurred during ore-forming process. REE were most probably transported as [REEF]2+ and precipitated through fluid unmixing. Fluids mixing, which contributed little to the REE precipitation, also happened in the late stage of the ore-forming process.%微山稀土矿位于华北克拉通东南缘的鲁西地块,为与碱性岩相关的伟晶岩型稀土矿床.根据单颗粒云母Rb-Sr定年,其形成于119.5 Ma,属于华北克拉通早白垩世大规模成矿事件的一部分.稀土矿物氟碳铈矿和独居石的激光Nd同位素研

  14. Geology and description of thorium and rare-earth deposits in the southern Bear Lodge Mountains, northeastern Wyoming (United States)

    Staatz, M.H.


    areas that total 1.69 km 2 . These deposits could be mined by open pit. The Bear Lodge disseminated deposits have one of the largest resources of both total rare earths and thorium in the United States, and although the grade of both commodities is lower than some other deposits, their large size and relative cheapness of mining make them an important future resource. Vein deposits in the Bear Lodge Mountains include all tabular bodies at least 5 cm thick. Twenty-six veins were noted in this area. These veins are thin and short; the longest vein was traced for only 137 m. Minerals vary greatly in the amount present. Gangue minerals are commonly potassium feldspar, quartz, or cristobalite intermixed with varying amounts of limonite, hematite, and various manganese oxides. Rare earths and thorium occur in the minerals monazite, brockite, and bastnaesite. Thorium content of 35 samples ranged from 0.01 to 1.2 percent, and the total rare-earth content of 21 samples from 0.23 to 9.8 percent. Indicated reserves were calculated to a depth of one-third the exposed length of the vein. Inferred reserves lie in a block surrounding indicated reserves. Indicated reserves of all veins are only 50 t of Th0 2 and 1,360 t of total rare-earth oxides; inferred reserves are 250 t of Th0 2 and 6,810 t of total rare-earth oxides. The Bear Lodge dome, which underlies the greater part of this area, is formed by multiple intrusive bodies of Tertiary age that dome up the surrounding sedimentary rocks. In the southern part of the core, the younger intrusive bodies surround and partly replace a granite of Precambrian age. This granite is approximately 2.6 b.y. old. The sedimentary rocks around the core are (from oldest to youngest): Deadwood Formation of Late Cambrian and Early Ordovician age, Whitewood Limestone of Late Ordovician age, Pahasapa Limestone of Early Mississippian age, Minnelusa Sandstone of Pennsylvanian and Early Permian age, Opeche Formation of Permian age, Minnek