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By D. Shaver, M. N. Badonie, J. Newcomer, V. T. McLemore, E. Owen

Rare earth elements and critical minerals have recently become of great economic interest because of their necessity for many new technologies and recent geopolitical unrest affecting the supply and import of resources. The San Juan and Raton basins in northern New Mexico are two structural coal basins that contain elevated concentrations of rare earth elements and critical minerals. These two New Mexican coal basins will be assessed geochemically and petrographically to identify vectors of the rare earth element and critical mineral enrichment. Coalbeds, coal seams, overlying, and underlying rock units will be sampled and characterized to determine any economic viability. Historic data will be compiled into a new and comprehensive coal geochemical database, which will grow with new analyses, and serve as the dataset for this project; this coal resource database will be made available to the public.

Feb 1, 2023

By Lukasz Maciag, Ryszard Andrzej Kotlinski, Ryszard Krzysztof Borówka, Dominik Zawadzki

Concentration and composition of rare earth elements (REE) and major elements in the sediment samples from the IOM H11 Fe-Mn nodule deposit, eastern part of the Clarion-Clipperton nodule field (located between the Clarion-Clipperton Fracture Zone - CCFZ; tropical Pacific), have been studied. We show the controls on REE concentrations and described vertical/horizontal variability of selected metals in pelagic sediments from the CCFZ. According to Kato et al. (2011), who analyzed 2000 seafloor sediment samples at 78 sites of the Pacific Ocean, deep-sea mud shows high concentrations (2230 ppm maximum) of ?REY and could be potential resource of these elements in the future. However, our work does not fully confirm that sediments in the IOM H11 are significantly enriched in REE.

Sep 1, 2014

By Hamid Mazouz, Mohammed Hakkar, Rim Jouraiphy, Fatima Ezzahra Arhouni, Ahmed Mahrou, Aziz Boukhair, Mohammed Fahad

The wet process is the most commonly used worldwide for phosphoric acid (PA) production, in which phosphate rock (PR) is reacted with strong acid mainly sulfuric acid. This work aims on studying the rare earth elements (REEs) distribution during the production of phosphoric acid using different qualities of phosphate through various industrial technologies. At the onset of this work, the process started with 12 samples of PR, PA, and phosphogypsum (PG) being taken simultaneously from two different Moroccan basins (Ouled Abdoun mine represented by K09 and Gantour mine depicted by G10, G20, BG) and various production lines at two processing platforms (Jorf Lasfar and Safi). Afterward, collected samples were prepared and analyzed for REE characterization using an inductively coupled plasma mass spectrometry (ICP-MS). Based on the analysis results, a transfer factor ( TFX) was introduced with the aim of gauging the REE distribution between PA and PG. The results showed that the total concentration of REEs in different phosphate qualities ranged from 411 to 631 ppm; the major part of this concentration was attributed to the four elements: Y, La, Ce, and Nd which constitute more than 77%. The REE distribution between PA and PG depends on neither the phosphate quality nor the industrial technology used since that the distribution results showed that 55 up to 66% of the initial REEs in phosphate rock ended up in the PG. The behavior of each REE was common except for the element scandium, which transferred mainly to the phosphoric acid.

Nov 3, 2021

By S. Hlajoane, L. S. Mokhahlane

The demand for rare earth elements has increased around the world due to their application in a variety of technological advancements. Previous studies have evaluated the potential of the rare earth elements and yttrium (REY) hosted within the Permian coal deposits of the main Karoo Basin (MKB) in Southern Africa. However, not a lot of scientific research has gone into the Triassic coal deposits. The Triassic coals in South Africa were the first coals to be exploited for their thermal use in the 1880s, but the discovery of the higher rank and more abundant Ecca coal deposits led to the Triassic coals remaining largely unexplored. The demand for rare earth elements has sparked interest in these coal deposits as potential sources for valuable minerals. Late Triassic coal deposits in Lesotho have previously not been well documented and these low-rank coals can be a potential source of rare earth elements. This study aims to characterize and evaluate the potential of REY in the Taung coal deposit, southwest of Lesotho. Coal and associated argillaceous samples from the Taung coal deposit were analyzed using microscopic petrography for coal characterization and an inductively coupled plasma mass spectrometry (ICP-MS) to determine the amount of rare earth elements. Taung coal is classified as middle medium rank D bituminous coal. The total REY content in Taung coal and its associated rocks range from 162.9 ppm to 855.1 ppm, which is significantly higher than the upper continental crustal (UCC) average. The average critical REY concentration of samples from the Taung coal deposit is 189.4 ppm, which is three times higher than that of the Chinese Bayan Obo deposit. Samples classified as very promising and promising because of their outlook coefficients, are found to contain up to 77% of critical REY. It is envisioned that the area could be a prime deposit for these REY.

Nov 6, 2024

By F. Dutoy, M. B. Stella, C. F. Carrozza

Rare earth elements (REEs) are indispensable components in the manufacturing of high-tech devices, renewable energy technologies, and defence applications. As global demand for these elements continues to rise, there is a pressing need to optimize extraction processes for both efficiency and environmental sustainability. This study explores approaches to rare earth extraction using Ionquest® 801 and integrates a predictive modelling to enhance process understanding and optimization. We conducted a screening test varying pH process to evaluate the best extraction efficiency. Starting pregnant leach solution (PLS), solution was prepared in the lab with the following rare earth elements: La, Ce, Gd, Dy, and Υ, at 0.02 M for each element. The data obtained were used to develop empirical and mechanistic models to predict rare earth extraction yields and flowsheet. Further tests were performed by mixing specific concentrations of different extractant and/or phase modifier. Our experimental results demonstrated the effectiveness of the proposedextraction methods, highlighting improvements in both yield and selectivity. The developedmodels successfully captured the complex relationships between process parameters and extraction efficiency, providing valuable insights for process optimization.

Nov 6, 2024

By S. Jayasekera, A. M. T. S. Bandara, J. Kyle, E. Koenigsberger, L. Koenigsberger

The extraction of rare earth oxides from fluoroapatite rich phosphate concentrates often involves a weak acid leach of fluoroapatite and a sulphuric acid bake of the leach residue followed by water leach and precipitation to obtain an intermediate product. The main aim of this study was to determine and rationalize the solubility of rare earth metal ions in synthetic solutions representing various process liquors at the temperatures 40, 60 and 80oC. The liquors contained different acid and metal ion concentrations with respect to sulphuric acid, phosphoric acid and sulphate salts of sodium, magnesium, aluminium, potassium, calcium and iron(III). A solid of mixed rare earth carbonates was used as the source of rare earth metal ions. The solubility tests and characterization of solids using XRD were conducted at Murdoch University laboratories as part of the process development for the Arafura Resources Nolans rare earth project. The composition of initial carbonate solids and the solids and solutions formed after saturation were analysed for rare earth and other elements at TSW Analytical Laboratories in Perth using ICP-MS and ICP-OES. The precipitated solid in sodium-rich acidic sulphate solutions is the double salt NaRE(SO4)2 based on the solid assays. However, in acidic solutions free of sodium or of low concentrations of sodium the precipitated solid appears to be RE2(SO4)3.

Jan 1, 2014

By Adam Powell, Matthew Earlam

INFINIUM, Inc. is scaling up a new molten salt electrolysis process for producing rare earth metals. Instead of conventional carbon anodes, this process uses Pure Oxygen Anodes™ which employ a stabilized zirconia solid electrolyte between the molten salt and anode. This eliminates two problems with today's rare earth metal production technology. First, it eliminates carbon anodes and contamination of the product by carbon and its impurities, enabling 10-100 times larger batch size than current practice, and lower labor costs. Second, it eliminates emissions of perfluorocarbons (PFC) such as CF4 and C2F6, which are very problematic greenhouse gases with 6000+ times the global warming potential of CO2. The zirconia also enables a sealed vessel with no LiF emissions, creates a reducing environment enabling use of low-cost welded steel vessels, and either produces a high-purity oxygen by-product or can use natural gas to reduce the necessary electrical energy with no HF production. This paper will describe the technology and its current status for rare earth metal production.

Jan 1, 2014

By Y. Lahaye, O. Martinsson, B. I. Palsson

"Four main and three minor rare-earth-element (REE)-bearing minerals were identified and quantified in the Kiirunavaara apatite iron ore tailings using optical microscopy, an electron probe microanalyzer (EPMA) and a mineral liberation analyzer, and their chemical compositions were analyzed by the EPMA and laser ablation inductively coupled plasmamass spectrometry. REEs are shown to be contained in the minerals apatite, monazite, allanite, titanite, zircon, thorite and synchysite. In zircon, thorite and synchysite, they occurred in only trace amounts and contributed limited amounts to the total REE budget, and these are consequently of minor importance. Monazite occurred as inclusions in apatite and as free particles, 90 percent liberated. Allanite occurred to some degree in mixed grains with magnetite but also as free particles. Monazite mainly reported to the apatite concentrate, while allanite and titanite largely went to the tailings, the latter preferably to those fractions smaller than 38 µm. The amount of titanite in the finest tailings fraction was 2.3 weight percent, containing close to 1 percent REEs, with heavy rare earth elements (HREEs) making up 28 percent of the total REEs. However, a texturally distinct group of titanite grains showed an HREE/REE ratio of up to 67 percent. Furthermore, titanum dioxide analyses indicate that titanite is preferentially released into the tailings from the secondary magnetic separation step in the concentrator. Our data therefore suggest that titanite, occasionally enriched in HREEs, can be extracted from the processing stream and might thus be considered a new source for REEs at Kiirunavaara and similar deposits.IntroductionDeposits of apatite iron ores are the major source for iron in the European Union and are exploited by Luossavaara-Kiirunavaara AB (LKAB) in several mines in the Kiruna-Malmberget area in northern Sweden. Kiirunavaara is the largest of the apatite iron orebodies in Sweden, comprising more than 2 Gt of iron ore with 60 to 68 percent iron (Fe). At the end of 2015, the total accumulated production of crude ore from openpit and underground mining since the start of mining was 1,566 Mt, with ore reserves of 644 Mt grading 46.3 percent Fe (LKAB, 2016). The deposit defines a steeply dipping tabular body, approximately 6 km long and up to 180 m thick, extending at least 1,500 m below the surface. It is situated in the middle part of the Palaeoproterozoic Kiirunavaara Group of volcanic rocks and follows the contact between a thick pile of trachyandesitic lava and overlying pyroclastics (Martinsson, 2004)."

Jan 1, 2017

By I. Filippova, L. Filippov

"The by-product potential of light rare-earth elements (LREE, La, Ce, Nd) and rare-metals (W, Nb, Sn) within the St Austell kaolin deposits (UK) is related to the kaolinisation process, which liberates the accessory heavy minerals of the host granite in the clay matrix and allows their separation in the waste streams. As a consequence these minerals are pre-concentrated in the micaceous residue which displays relatively high LREE content (around 170 ppm) hosted by monazite which is mainly distributed (up to 95%) in the -100 µm fraction. A combined gravity/flotation concentration flowsheet, starting with classification of the residue into 3 size fractions (+150 µm, 150-53 µm and -53µm) was developed. This study presents the results of the clay-rich -53 µm size fraction beneficiation by flotation using sodium oleate and hydroxamate as collectors.The effect of dispersant addition during de-sliming operations on flotation efficiency was also investigated. The LREE grade in the floated product obtained with sodium oleate increased from 3370 ppm to 5350 ppm and recovery from 30% to 80% with dispersant which is attributed to clay coating. Comparison of flotation performance and Falcon Ultra-Fine (UF) concentration of monazite to previous results obtained with Falcon Semi-Batch (SB) gravity concentrator on the unscreened raw residue clearly shows that flotation of the fine residue is more efficient than Falcon UF and Falcon SB. Indeed Falcon UF produced high recoveries (87-95%) but with almost no enrichment (1.3-1.4 ratios) whereas Falcon SB concentration of unscreened residue produced higher grades (up to 0.6 % LREE) but with low recoveries (17-22 %). These preliminary results show that LREE can be pre-concentrated suggesting that the micaceous residue stream (and the associated tailings dams) could be considered as a potential resource for these metals."

Jan 1, 2016

By Y. Tang

"Rare earth elements (REEs) have many key applications in traditional and advanced technologies. A shortage of several critical REEs is expected due to the discrepancy between the availability of REEs from REE deposits and the REE demand from the market. REE recovery and separation from secondary resources such as uranium wastes and recycled materials might help balance the shortfall in a cost-effective way. This paper presents data concerning the recovery of heavy REEs (HREEs) from uranium raffinate. It also discusses the design, commissioning, and operation of a solvent extraction pilot plant for the separation of REEs.RÉSUMÉ Les éléments des terres rares (ÉTR) trouvent de nombreuses applications importantes dans les technologies classiques et de pointe. On prévoit une pénurie de plusieurs ÉTR critiques en raison des divergences constatées entre la disponibilité des ÉTR provenant de gisement d’éléments des terres rares, et la demande d’ÉTR sur le marché. La récupération et la séparation des ÉTR à partir de ressources secondaires telles que les déchets générés par le traitement du minerai d’uranium et les matériaux recyclés pourraient contribuer à équilibrer cette pénurie de manière rentable. Cet article présente des données relatives à la récupération des ÉTR lourds (HREE, de l’anglais heavy REEs) à partir de raffinat d’uranium. Il aborde également la question de la conception, de la mise en service et de l’exploitation d’une usine pilote d’extraction par solvants pour la séparation des ÉTR INTRODUCTIONSignificant amounts of strategic specialty heavy rare earth elements (HREEs) are present in waste streams in Saskatchewan uranium operations. Selective precipitation including neutralization, oxalate, and double-salt precipitation, as well as sulfide precipitation, ion exchange (IX), and solvent extraction (SX) are commonly used technologies for the recovery and purification of rare earth element (REE) solutions. REE oxalate precipitation can effectively remove Fe, Al, Ca, Si, and other impurities by taking advantage of the solubility difference between REE oxalates and impurities in the acidic solution (Xu, 2005)."

Jan 1, 2018

By Tetsuya Uda

Our recent achievements of rare earth separation technique[1,2] and new process idea for rare earth magnet recycling[3] are reviewed, (1) Binary chloride mixtures of rare earths were separated by a new selective reduction-vacuum distillation process. According to our experimental results, apparent separation factors were 8.1 for the Pr-Nd chloride mixture and 570 for the Nd-Sm chloride mixture. These values are much higher than conventional solvent extraction methods. (2) A study of recycling process of magnet sludge was carried out. The rare earths in the neodymium magnet sludge were extracted by chlorination with FeCI2, An activated carbon was used as a de-oxidation reagent Metallic iron in the sludge was not chlorinated because the iron monochloride is not stable, The extracted rare earth chlorides were easily separated from Fe-alloy and the excess of FeCh by vacuum distillation, 96 % of neodymium and 94 % of dysprosium in the sludge were extraeted into chloride phase, By the vacuum distillation, a mixture of neodymium and dysprosium trichlorides of 99.2 % purity was recovered, On the other hand, the rare earth chlorides can be converted to the corresponding oxides by a pyrohydrolysis reaction accompanied by a formation of HCl gas, The HCI gas can chlorinate metallic iron to FeCh, Therefore, a new recycling process for rare earth magnet waste can be realized as a chlorine circulation type process. During the process, only carbon and water are consumed and there are no toxic pollutants, Moreover, the obtained rare earth oxide can be directly used as raw material in the conventional oxide electrolysis process,

Jan 1, 2003

By A. Quilodran, B. Jakovljevic, T. McCallum, P. Wong

"Rare earth separation by solvent extraction (SX) requires multiple separation plants each consisting of many extract, scrub, and strip stages to separate the individual metals. SX modeling advances have brought benefits to circuit design and process optimization by quickly narrowing test conditions without the need for exhaustive laboratory studies. Modeling can be used to optimize circuit configuration, O/A ratios, and acidities, which allows for CAPEX and OPEX savings. A comparison between pilot plant data and the results expected from modeling is presented for rare earth separations with CYANEX® 572.INTRODUCTIONRare earth separations can be difficult due to limited separation between the elements (Xie, Zhang, Dreisinger, & Doyle, 2014). This requires relatively complex solvent extraction circuits utilizing multiple extract, scrub, and strip stages as well as multiple SX configurations to achieve the desired metal purities. Designing rare earth circuits can be complex, and significant time and testing may be necessary to determine the required staging and optimal conditions.Circuit modeling for rare earth separations has been introduced to the industry using CYANEX® 572 extractant (Soderstrom, McCallum, Jakovljevic, & Quilodran, 2014). CYANEX® 572 is an acidic organophosphorus extractant formulation which has a weaker ligand-metal complex strength than that of the traditionally used phosphonic acid extractants. This allows efficient extraction while requiring a significantly lower acid concentration for stripping (Wang, Li, Zhao, Dong, & Sun, 2015). The reduced acid requirement in strip is expected to provide OPEX savings.The modeling can be utilized to quickly determine the required acidity and organic/aqueous (O/A) ratio for a given separation. It is also expected to reduce CAPEX requirements as optimal staging can be determined, and implemented.CYANEX® 572, combined with modeling, was utilized to produce a purified dysprosium (Dy) stream. To achieve this separation, multiple SX circuits were designed and operational conditions specified to separate Dy from the mixed rare earth chloride feed."

Jan 1, 2016

By G. D. Sandrock

The science and technology of roan temperature rechargeable metal hydrides began about 1969 with the discoveries that the intermetallic Compounds LaNi5 and TiFe could be, conveniently hydrided and dehydrided at roan temperature and modest H2 pressures. Subsequently, this lead to the development of a broad family of REE-containing AB5 hydrides and numerous applications that make use of the extraordinary H2-absorption and reaction-heat properties of these materials. Some of the applications include H2 storage, compression and separation, as well as heat pumping, heat to mechanical energy conversion and electric energy storage. This paper briefly reviews the fundamental phenomenology of metal hydrides, the history of the use of REE's in rechargeable metal hydrides, the practical engineering properties of these materials and the applications that have evolved around them. The rechargeable nickel metal hydride battery, a new vial alternative to NiCd cells, stands at the forefront of the applications.

Jan 1, 1992

By J. L. Jambor, T. C. Birkett, W. D. Sinclair

Abstract -The rare-earth elements (REE) form a significant part of the group of so-called "high­ technology" metals whose glamour has attracted both the scientific community and the mining industry. Despite this attraction, world production of REE declined abruptly in 1985 and only recently has begun to approach production levels of 1984. The decline in 1985 was primarily due to decreased demand for light REE used as catalysts in the production of lead-bearing gasoline. Incorporated within the current trend toward increased production of REE is an increasing demand for higher value elements such as yttrium and other members of the heavy REE group, and for specific REE rather than mixed products . The former demand has made some Canadian deposits and prospects economically attractive despite a surplus of REE reserves on a world scale. The chief attractions of Canadian deposits such as Strange Lake, Labrador-Quebec, Thor Lake, Northwest Territories, and Kipawa, Quebec, are that they are relatively rich in yttrium and other heavy REE compared to light REE, and that they offer a potential security of supply to counterbalance the rapidly escalating dominance of China in the world market.

Jan 1, 1992

By Neil E. Ryan

Because of their chemical reactivity and affinity for oxygen, rare-earth elements are difficult to extract, and due to their close chemical similarity, it is an exacting task to separate one from the other. Nevertheless, these same characteristics can be used to benefit other metals by enhancing their resistance to high-temperture oxidation/corrosion and by inhibiting their corrosion in aqueous environments. This paper gives an overview of the use of rare-earths: [a] as alloy additions, [b] in coatings, and [c] when added to hostile environments, to retard rates of high- temperature oxidation and inhibit aqueous corrosion.

Jan 1, 1992

"How Wall Street Darling Molycorp Undermined the U.S. Economy, Degraded our National Security and Distorted the Global Economic Balance and How These Falsehoods Continue to be Promoted Even Today INTRODUCTION & SUMMARY In 2007 the Molycorp Mountain Pass rare earth mine was resurrected from its desert-grave in California by its then-owner Chevron Mining. Responding to elevated rare earth prices Chevron began processing on-site rare earth concentrates left over from past mining operations that were terminated in 1998i. Chinese demand had sparked what was being described as a commodities super-cycleii. Commodity prices were on the move. Wall Street smelled opportunity. In 2008 Goldman Sachs, Pegasus Partners, Resource Capital Funds, Traxys North America LLC and Carint Group LLC acquired the mining assets from Chevron. In an environment of ever-declining ethical standards and regulatory consequences the private capital group and their investment bankers would bring Molycorp to market. Molycorp, with its high powered investment banking team of Morgan Stanley and J.P. Morganiii, easily dominated the contest. Molycorp promoted itself, largely based on its past operating history and proven reserves, as the best company to challenge China’s monopoly control over the production of rare earths: a group of elements critical to most advanced technologies and U.S. defense systemsiv. Most of Wall Street’s hottest investment sectors were dependent on these materials: alternative energy, green technologies, computing, personal communications, advanced electronics and defense systems. By late 2010 there were dozens of prospective rare earth start-up ‘mining companies’ seeking capital. Eventually the number of prospective rare earth mining companies seeking capital exceeded 400, despite the reality that supply requirements of this market were disproportionally small when compared to other natural resource sectorsv. In the world of finance ‘smart money’ picks the winners. Consequently just twovi projects attracted nearly all of the capital (Molycorp and Lynas). Wall street picked Molycorpvii. This paper will primarily focus on Molycorp. By early 2010 the words “Molycorp” and “Rare Earths” electrified many people in the mining industry, most non-Chinese manufacturing technology companies, U.S. & allied defense contractors, technocrats in the U.S. national security community and eager investors across most of the world’s stock markets. It was the hottest story of the yearviii. The financial, technology and defense press coverage verged on euphoric: heaping fuel on fuel until the highly combustible Molycorp-pyre cast a long shadow over all of its rivalsix. When the IPO match was lit the spectacular flaming pyre sucked all of the oxygen out of the rare earth spacex. Molycorp was ranked the most lucrative IPO of 2010, resulting in record breaking profits to its private investors and massive returns for its early stock holding investors."

Jan 1, 2017

By F. G. Heivilin

We are no longer short of viable Rare Earth deposits. As little as 2 years ago China mined and produced 97% ofthe world?s rare earths. Only a few deposits were in an advanced stage of exploration and development. Now Technical Metals Research (TMR) Gareth Hatch *5 reports that 347 deposits are being developed by 265 companies down from 440 on July 6th. Their Index of Advanced projects lists 45 projects in 14 countries. They will sustain the world for centuries to come and many good deposits are yet to be found. The problem is mining 14 elements in balance. Each of the deposits listing production in the chart has a unique set of minerals which they think will give them a cost advantage. Which of these will make it to production is a question. Most of the Advanced won?t be mined soon, but which ones? China is still in the driver?s seat in Light Rare Earth production (LREO) with one deposit with 35 million ton Baiyunebo deposit in Inner Mongolia which is part of a working iron ore deposit. The number of HREE deposits have been reduced and they attempting to eliminate unpermitted mines. This report will tell you what a Rare Earth is, how rare they are, why they are important, and where they are being developed which includes Australia, the United States, Africa, Greenland, Brazil and Canada.

Feb 27, 2013

By Z. Jin, D. DePaoli, P. Zhang

"Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P2O5 ), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C, REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P2O5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 µm, was separated from leached phosphogypsum through elutriation, in which the P2O5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum. IntroductionPhosphogypsum is a byproduct generated during the industrial wet process of phosphoric acid production, in which sulfuric acid is used to digest phosphate rock. Gypsum (CaSO4·2H2O), the main component of phosphogypsum, usually accounts for 65 to 95 percent of phosphogypsum by weight.There are small quantities of impurities in phosphogypsum, such as phosphates (H3PO4, Ca(H2PO4)2·H2O, CaHPO4·2H2O and Ca3(PO4)2), fluorides (NaF, Na2SiF6, Na3AlF6, Na3FeF6 and CaF), sulfates, trace metals and radioactive elements (Rutherford, Dudas and Arocena, 1996). Global phosphogypsum generation is estimated at 200 Mt/a (Parreira, Kobayashi and Silvestre, 2003; Yang et al., 2009), but only about 15 percent is recycled as building materials, agricultural fertilizers or soil stabilization amendments (Tayibi Choura and Lopez, 2009)."

Jan 1, 2017

By T. Surkova

For the moment reserves of high-grade ores are practically depleted requiring ever-increased involvement of low assay raw materials, such as black-shale ores, in industrial operations. Black-shale ores are constituted of minerals containing such valuable components as vanadium, uranium, molybdenum, manganese, and rare-earth elements (REE). We studied technogenic solutions of black-shale ores processing, after uranium, molybdenum, and vanadium were recovered. Mentioned solutions contain rare-earth elements in substantial quantities (S REE 70-100 mg/dm3) that is very important factor taking into consideration the world demand ever-increasing last years. Higher concentrations of iron and aluminum inhibiting REE sorption and extraction recovery are found in solutions. We propose a method of hydrolytic deposition to cleaning solutions from impurity elements (Fe, Al). Study of hydrolytic deposition kinetics allowed identifying optimal conditions to run this process. Rare-earth elements may be recovered from purified solutions through sorption process followed by their further deposition from eluates in form of concentrates. Keywords: black-shale ores, rare-earth elements, a method of hydrolytic deposition, impurity elements, sorption

Sep 1, 2012

By J. B. Hedrick

In 2004, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Major uses for these commodities were in automotive catalytic converters, petroleum fluid-cracking catalysts, permanent magnets, glass-polishing compounds, ceramics, metal-alloying additives, phosphors and rechargeable batteries. Consumption of refined rare-earth products decreased. The United States was a major importer and exporter of rare earths in 2004. Yttrium was not mined or refined in the United States in 2004. Imports from China, France and Japan accounted for most of the U.S. supply of yttrium compounds for refined yttrium products.

Jan 1, 2005