Wyniki wyszukiwania - Biblioteka Nauki

1

Lithologically-related rare earth element variations the Mio-Pliocene Poznań Formation (Poland)

100%

Retka J.

Geological Quarterly

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2018

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tom Vol. 62, No. 1

146--154

EN

Concentrations of rare earth elements (REEs) were determined in 129 clay samples collected from the Mio-Pliocene Poznań Formation in Poland. The REEs occur in a relatively wide range from 58.2 to 1,709 mg/kg. Low North American Shale Composite (NASC)-normalized total REE contents with heavy rare earth element (HREE) depletion were noted in most of the samples analysed. Small variations were detected in the REE contents in the lithologies distinguished. Red clays are characterised by slightly lower REE concentrations relative to green and grey clays. All the Poznań Formation clays exhibit a negative Eu anomaly when normalized to the average of chondrites. Values increase according to the following sequence: grey clays < red clays < green clays. The NASC-normalized REE concentration curves show a positive Eu anomaly. The LaNASC/YbNASC ratio indicates HREE depletion. A small variation in this ratio was observed in the sequence green clays > grey clays > red clays. The variability of the REE contents of the Poznań Formation decreased from west to east.

2

The recycling-oriented material characterization of hard disk drives with special emphasis on NdFeB magnets

100%

Dańczak A. , Chojnacka I. , Matuska S. , Marcola K. , Leśniewicz A. , Wełna M. , Żak A. , Adamski Z. , Rycerz L.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 2

363--376

EN

Hard disk drives (HDDs) consist of many components made from various materials: e.g. aluminum, steel, copper and rare earth elements (REEs). Recycling and reuse of these materials is desirable for economic and environmental reasons. Developing of potential HDDs recycling methods requires knowledge about HDDs material characteristic. The study aims to explore knowledge about structure and chemical composition of HDDs main components with special emphasis on NdFeB magnets. HDDs collected for the experiments came from Desktop PCs and Notebooks. The dependence between the average mass of HDDs components and such parameters as producer, year and country of production and disk capacity was analyzed. Chemical composition of NdFeB magnets and the heaviest components (i.e. top cover, mounting chassis, platters and metallic plates from magnet assembly of actuator) was analyzed by various analytical methods. The heaviest HDDs main components: top cover and mounting chassis, with the highest recycling potential, are made of aluminum and steel respectively. The majority of HDDs components showed also the existence of different alloy additions: C, Mg, Si, P, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sn and Pb. NdFeB magnets constitute 2.2 ± 1.1% of the average HDD from Desktop PC (517.3 ± 64.2 g) and 3.2 ± 1.2% from Notebook (108.2 ± 24.3 g). The chemical composition of NdFeB magnets from collected HDDs changes in the wide range: Fe (53–62%), Nd (25–29%), Pr (2–13%), Dy (0.1– 1.4%), Ni (2–6%), Co (0.5–3.6%), B (0.8–1.0%). Recycling of permanent magnets based on NdFeB alloys is potential remedy to fill the gap in the supply of rare earth elements on the global REEs market.

3

Leaching kinetic study of Y and Eu from waste phosphors using hydrochloric acid solution containing hydrogen peroxide

100%

Yu M. , Jiang Z. , Mei G. , Chen X.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 2

238--248

EN

The leaching kinetics of Y and Eu from waste phosphors using a hydrochloric acid (HCl) solution containing hydrogen peroxide (H2O2) were investigated. Characterization of the waste phosphors was performed using XRD to ascertain the phases as (Y0.95Eu0.05)2O3 (red phosphors), (Ce0.67Tb0.33)MgAl11O19 (green phosphors), (Ba0.9Eu0.1)Mg2Al16O27 (blue phosphors), and SiO2 (quartz). The influence of factors such as HCl concentration, addition amount of H2O2, temperature, and reaction time on the leaching performance of Y and Eu was investigated. The maximum leaching recoveries of Y (99.87%) and Eu (88.72%) were obtained at 4 M HCl, 0.2 cm3/g H2O2, 60 ℃ temperature, and 180 min of reaction time at a liquid-to-solid ratio of 7.5 cm3/g. Leaching kinetic results showed the best fit with the shrinking sphere model (1-(1-x)1/3)=kct), ensuring that the overall leaching process was governed by a chemical control mechanism. Activation energies of 42.35 and 33.28 kJ/mol were acquired for leaching of Y and Eu, respectively, at 40-70 ℃, which further supports the proposed chemical control leaching process.

4

High-temperature carbothermal dephosphorization of Malaysian monazite

88%

Udayakumar S. , Sheikh Abdul Hamid S. A. R. , Baharun N. , Pownceby M.

Physicochemical Problems of Mineral Processing

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2021

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tom Vol. 57, iss. 6

140--155

EN

High-temperature carbothermal reduction experiments with graphite powder were conducted to assess the dephosphorization behavior of Malaysian monazite concentrate. Thermodynamic analysis of the possible dephosphorization reactions was conducted to evaluate the feasibility of the carbothermal reduction of the monazite phases. The effects of temperature, particle size, and monazite to carbon ratio were then investigated under different conditions. The carbothermal reduction experiments were conducted based on the Taguchi design method, and up to 97% of phosphorous removal was achieved under optimized conditions. The optimal conditions for dephosphorization were determined as; a reduction temperature of 1350 °C, a particle size of -75 μm, and monazite to carbon molar ratio of 0.3. Microstructural and phase characterization of the dephosphorized products revealed that CeO2, Nd2O3, La2O3, and Pr2O3 oxide phases were prominent, and no residual peaks of monazite remained in the reduced products. The information gained from the study can aid in the design of a suitable post-dephosphorization hydrometallurgical treatment for exploiting Malaysian monazite as a local source of REEs.

5

Comparative analysis of soil magnetic susceptibility and concentration of rare earth elements in soil of problematic areas

88%

Zawadzki J. , Fabijańczyk P.

Multidisciplinary Aspects of Production Engineering

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2019

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tom Vol. 2, Iss. 1

81--90

EN

Soil contamination with rare earth metals (REE) can have both direct and indirect connection with industrial activity and ore-exploration. In the studies conducted so far, the presence of rare earth elements in coal seams, coal combustion waste as well as fly ash was found. It is important that detailed studies of the REE content in soil were not carried out in Poland. Until now, in a few studies, a high content of cerium and lanthanum was found in relation to the average content of the torn ones in the world. This work focuses on the areas under the influence of the industry associated with the extraction and combustion of hard coal, but also with other types of industry. Analyzes of REE content in soil were conducted in selected areas of the Upper Silesian Industrial Region and Norway, located near the Bjornevatn mine. In study areas, soil samples were collected and used for chemical and magnetometric measurements. Firstly, concentrations of REE were determined, and after that soil samples were used to measure soil magnetic susceptibility. Finally, statistical analyses were performed in order to check the correlation between REE concentrations in soil and soil magnetic susceptibility.

6

Solubility of Eskisehir thorium/rare earth ores in sulphuric and nitric acids

88%

Kursun I. , Tombal T. D. , Terzi M.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 2

476--483

EN

Nuclear energy is considered as one of the most important energy resources in the world. Thorium (Th) has a significant potential to be used in electricity production by nuclear energy since its existence is not depended on the presence of another radioactive elements, and it has larger potential reserves than uranium. Bastnaesite ((Ce, La)CO3F) is one of the minerals from which Th can be economically extracted. In this study, solubility of bastnaesite containing ore obtained from Eskisehir, Turkey was investigated by leaching with H2SO4 and HNO3 in terms of leaching performance of thorium and some rare-earth elements (Ce, Nd, La). In this context, representative samples were taken from three different areas in Eskisehir-Kizilcaoren region, and a composite sample was prepared to be used for the leaching experiments. The effects of several parameters such as the solid ratio, leaching time, acid amount and pulp temperature, on dissolution efficiencies of Th, Nd, Ce and La was investigated. The best results were obtained using 3.42 mol/dm3 HNO3, solid–to–liquid ratio of 35%, 120 min leaching time and 60 oC temperature. Under these optimum conditions, the dissolution efficiencies of Th, Ce, Nd, and La were obtained as 94%, 82%, 77% and 70%, respectively.

7

Effect of Rare Earth Cerium Addition on Oxidation Behavior of Co-Al-W Alloys at 800°C

88%

Migas D. , Liptáková T. , Moskal G.

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tom Vol. 67, iss. 1

203--208

EN

The γ/γ′ Co-based alloys are a new class of cobalt superalloys, which are characterized by remarkable high temperature strength owing to strengthening by γ′-Co3(Al, X) phases. In this investigation, the effect of cerium addition on oxidation behavior of model Co-Al-W alloys was studied. The introduction of Ce aimed at improvement of the oxidation resistance of γ′-forming Co-based superalloys. The minor additions of cerium (0.1, 0.5 at.%) were added to the base alloy Co-9Al-9W. The alloys were prepared via induction vacuum melting (VIM). Further, a primary microstructure of the alloys was analyzed with particular regard to a segregation of Ce. The thermogravimetric analysis (TG) under non-isothermal conditions was used to preliminary estimate the oxidation behavior of alloys at different temperatures. During experiment, differential thermal analysis (DTA) was performed simultaneously. After this test, cyclic oxidation expermients was carried out at 800°C for 500 h. In as-cast state, Ce segregates to interdendritic areas and forms intermetallic phases. The effect connected with melting of interdendritic precipitates was observed at 1160°C. Ce-containing alloys were less prone of oxide spallation. Moreover, oxidation rate of these alloys substantially decreased after 100h of oxidation, whereas mass of the sample corresponding to base alloy continued to increase.

8

Effect of Magnet Scrap Size on the Extraction Behavior of Heavy Rare Earth Elements by Liquid Metal Extraction

88%

Nam S.-W. , Rasheed M. Z. , Park S.-M. , Lee S.-H. , Kim D.-H. , Kim T.-S.

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2020

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tom Vol. 65, iss. 4

1273--1276

EN

Liquid metal extraction (LME) process results in 100% neodymium (Nd) extraction but the highest extraction efficiency reportedfor Dysprosium (Dy) so far is 74%. Oxidation of Dy is the major limiting factor for incomplete Dy extraction. In order to enhance the extraction efficiency and to further investigate the limiting factors for incomplete extraction, experiments were carried out on six different particle sizes of under 200 μm, 200-300 μm, 300-700 μm, 700-1000 μm, 1000-2000 μm and over 2000 μm at 900°C with magnesium-to-magnet scrap ratio of 15:1 for 6, 24 and 48 hours, respectively. This research identified Dy2 Fe17 in addition toDy2 O3 phase to be responsible for incomplete extraction. The relationship between Dy2 Fe17 and Dy2O3 phase was investigated, and the overall extraction efficiency of Dy was enhanced to 97%.

9

Effect of Bismuth and Rare Earth Elements on Graphite Structure in Different Section Thicknesses of Spheroidal Graphite Cast Iron Castings

88%

Glavas Z. , Strkalj A. , Maldini K. , Kozina F.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 3

1547--1553

EN

Effects of additions of 0.00064, 0.001 and 0.0042 wt.% Bi on the graphite structure in the section thicknesses of 3, 12, 25, 38, 50, 75 and 100 mm of spheroidal graphite cast iron castings containing 2.11 wt.% Si and rare earth (RE) elements (Ce + La + Nd + Pr + Sm + Gd) in the range from 0.00297 to 0.00337 wt.% were analyzed in this paper. Addition of Bi was not necessary for obtaining high nodule count and nodularity higher than 80% in section thicknesses of 3, 12 and 25 mm. RE elements showed a beneficial effect on the nodule count and nodularity in these sections. Nodularity was below 80% in section thicknesses of 38, 50, 75 and 100 mm when Bi was not added. Detrimental effect of RE elements on graphite morphology in these sections was neutralized by adequate addition of Bi. Addition of 0.001 wt.% Bi (ratio of RE/Bi = 3.27) was enough to achieve nodularity above 80% in the section thickness of 38 mm. Nodularity was increased above 80% in section thicknesses of 50, 75 and 100 mm by addition of 0.0042 wt.% Bi (ratio of RE/Bi = 0.78). At the same time, Bi significantly increased the nodule count. Nodularity above 80% and the high nodule count in the section thicknesses of 75 and 100 mm were also achieved by using an external metallic chill in the mold. In this case, addition of Bi was not required.

10

Effect of MgB2 additives on structure, electrical and thermal properties of Eu1Ba2Cu3O7

88%

Akduran N.

Materials Science Poland

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2018

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tom Vol. 36, No. 4

609--615

EN

The effect of MgB2 addition on the Eu1Ba2Cu3O7 (EBCO) ceramics was systematically studied. Series of Eu1Ba2Cu3O7 + x(MgB2) samples (x = 0 wt.%, 0.05 wt.%, 0.1 wt.%, 1 wt.%, 3 wt.%) were prepared using traditional solid state method. X-ray powder diffraction measurements were used for phase identification. The lattice parameters and orthorombicity decreased with MgB2 addition. A standard four point measurement method was used to determine transition temperatures Tc of superconducting samples. Tc values of the samples were decreasing with MgB2 concentration. TGA results indicate thermal stability of doped samples.

11

Separation of rare earth elements from the leaching solution of waste phosphors by solvent extraction with Cyanex 272 and its mixture with Alamine 336

88%

Xing W. , Lee M. S.

Physicochemical Problems of Mineral Processing

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2020

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tom Vol. 56, iss. 1

184--194

EN

Waste phosphors contain rare earth elements (REEs) such as yttrium (Y), europium (Eu), cerium (Ce), terbium (Tb) and lanthanum (La). Separation of these REEs from the leaching solution of waste phosphors was investigated by solvent extraction with single Cyanex 272, binary mixture (mixture of Cyanex 272 and Alamine 336), ionic liquid (prepared by Cyanex 272 and Aliquat 336) in kerosene. The effect of solution pH and extractants concentration was mainly investigated. The results indicated that Y(III) was selectively extracted by single Cyanex 272 over the other four REEs from the HCl solution with initial pH range from 3 to 5. Synergistic extraction with the binary mixture was enough for the extraction of Y(III), Tb(III) and Eu(III) with a small amount of Ce(III). Scrubbing with pure Y(III) solution with intermediate acidity was effective in scrubbing Ce(III) from the loaded binary mixture organic phase. Stripping behavior of the Y(III), Tb(III) and Eu(III) by HCl solution was similar to each other. Tb(III) and Eu(III) can be separated by extraction with the binary mixture followed by scrubbing with pure Tb(III) solution. McCabe-Thiele diagrams were constructed for the extraction of Y(III) by single Cyanex 272 and that of Tb(III) by the mixture. A process was proposed for the separation of REEs from the leaching solution of waste phosphors by solvent extraction.

12

Rare Earth Elements – a Novelty in Energy Security

88%

Bielawski R.

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2020

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tom Vol. 21, nr 4

134--149

EN

This study analyses the role of rare earth elements (REE) as critical resources for the energy security. This research presents the developments in the global REE extraction, i.e. the dominance of the Republic of China, which attempts to maintain and control its monopoly. The typical and novel uses of rare earth metals were presented in various applications, such as in advanced electronic and information technologies utilised in the aerospace and energy industries. Bearing in mind their vital importance to the manufacturing of high-tech products, the REE deposits are of strategic importance for the USA, the Republic of China and for the European Union. Striving to maintain the independence of raw materials, the USA is focused on the search for raw materials on its territory and furthermore on waiving the legal restrictions with respect to their extraction. China is primarily occupied with maintaining the monopoly and control over the global market of critical raw materials, including REE. The activities within the European Union concentrate on the exploration in search for the REE deposits in Europe and ensuring the continuity of supplies by maintaining good diplomatic relations with partners – the USA and Japan. In addition, extensive REE recycling initiatives are being undertaken in the EU. Further rare earth metals extraction is anticipated to extend to the outer space. However, developing the economically viable methods of extraction remains the major challenge faced by space mining, given that it requires establishing an expensive, permanent space infrastructure. What is more, mining and processing of rare earth metals raises serious environmental concerns, as it involves such hazards as radioactive products, toxic chemical compounds and waste generation. With respect to the environmental protection, this study also addresses the issues of REE substitutes and recycling. It is concluded that the environmental protection practices regarding the long-term extraction and use of REE (with a 2030 horizon) will bring substantial long-term financial benefits.

13

Chemical and morphological characterization of polymetallic (Mn-Fe) nodules from the Clarion-Clipperton Zone in the Pacific Ocean

75%

Kozłowska-Roman A. , Mikulski S.

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tom Vol. 65, No. 4

art. no. 57

EN

Geochemical studies (WD-XRF, ICP-MS, and GF-AAS) have shown that polymetallic nodules from the eastern Clarion-Clipperton Zone (CCZ) in the Pacific Ocean are enriched in several metals such as Cu (mean 1.16%), Ni (1.15%), Co (0.15%), and Zn (0.14%), as well as remarkable contents of Mo (0.059%), V (0.04%), Ce (0.019%), Nd (0.011%), Li (0.015), and Pt (43 ppb). The average content of REE, together with Y and Sc, is 620 ppm. In nodules from the CCZ metal concentrations are often much higher than those reported in nodules from other ocean basins in the world. The bulk-nodule mean value of the Mn/Fe ratio is 5.3, which is characteristic for a mixed (hydrogenetic and diagenetic) origin of the nodules. Microprobe investigation revealed two different chemical compositions of the layers, and ascertained their general metal content. The nodules analyzed are composed mainly of concentric-collomorphic laminae of Mn and Fe (oxy)hydroxides which crystallized around mineral nuclei (e.g., quartz, clay minerals), bioclasts or rock fragments. They are from 3.3 to 7.6 cm in diameter. The chemical and physical properties of the laminae allowed distinction of two genetic types: hydrogenetic and diagenetic. Those formed as a result of hydrogenesis had increased values of Co, Si, Cl and S, while formed diagenetically showed increased levels of Cu, Ni, Mg, Zn and K. These lamina types are characterized by different growth structures, reflectivity, density and Mn/Fe ratios. The ratio of the diagenetic layers to hydrogenetic layers (192/53) in representative polymetallic nodules shows that the nodules of this study are of mixed hydrogenetic-diagenetic type. A mixed genesis was also shown by discriminant diagrams, with these CCZ samples being located at the transition between typical hydrogenetic and diagenetic fields.

14

Microstructural Characterization of the As-cast AZ91 Magnesium Alloy with Rare Earth Elements

75%

Grzybowska A. , Braszczyńska-Malik K.

Archives of Foundry Engineering

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2012

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tom Vol. 12, iss. 2s

23--26

EN

Microstructural analysis of as-cast Mg-9Al-0.9Zn-xRE (x = 0, 1, 2, 3, 5 wt.%) magnesium alloys is presented. Light microscopy (LM) and scanning electron microscopy (SEM+EDX) were used to characterized the obtained material. The results revealed that the as-cast AZ91 alloy consists of α – Mg matrix, binary eutectic α + γ (where γ is Mg17Al12). While rare earth elements were introduced to the Mg-Al-Zn alloy new Al11RE3 phase was formed. Additionally, in the experimental alloys instead of Al-Mn phase, ternary Al-Mn-RE compound was observed. What is more, the influence of RE addition on the area fraction of eutectic and needle-like phase was analysed. With increasing addition of RE, the amount of γ phase decreased, but the amount of Al11RE3 phase increased.

15

Complex Processing of Phosphogypsum - a Way of Recycling Dumps with Reception of Commodity Production of Wide Application

75%

Lutskiy D. , Litvinova T. , Ignatovich A. , Fialkovskiy I.

Journal of Ecological Engineering

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2018

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tom Vol. 19, nr 2

221--225

EN

The article analyzes the information on modern developments in the utilization of phosphogypsum. Only a few directions give the prospect of large-scale use of both freshly formed phosphogypsum and phosphogypsum accumulated in dumps. Under the conditions of the Russian Federation, it is promising to use phosphogypsum for the production of building materials, as well as for agriculture, for reclamation of soil and the creation of mounds of a certain type. The possibility of using phosphogypsum as a raw material for obtaining rare-earth elements is shown.

16

Microstructure of Mg-Al alloy with rare earth elements

75%

Braszczyńska-Malik K. N. , Żydek A.

Archives of Foundry Engineering

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2008

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tom Vol. 8, iss. 1 spec.

23--26

EN

The microstructure analyses of experimental AZ91 magnesium alloy with addition of 1.5 wt. % of rare earth elements was presented. The investigated AZ91 + 1.5RE alloy was fabricated by addition of cerium rich misch metal to molten commercial AZ91 alloy and gravity cast. As a result, α solid solution, α+γ binary eutectic, discontinuous precipitates of γ phase, Al11Mn3 phase with needle-like morphology, Al2RE and Al10RE2Mn7 particulate phases were revealed.

17

Effect of Bismuth and Rare Earth Elements on Graphite Structure in Different Section Thicknesses of Spheroidal Graphite Cast Iron Castings

75%

Glavas Z. , Strkalj A. , Maldini K. , Kozina F.

|

18

Lantanowce - metale krytyczne technologicznie. Dlaczego są tak istotne?

75%

Arciszewska Ż. , Godlewska-Żyłkiewicz B.

Analityka : nauka i praktyka

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2021

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tom nr 2

41--46

PL

Szybki rozwój nowych technologii wykorzystujących lantanowce powoduje ogromny popyt na te metale. Istnieje więc konieczność zintensyfikowania poszukiwań zasobów pierwiastków ziem rzadkich oraz opracowania procedur opłacalnego ich odzyskiwania ze źródeł wtórnych.

19

Processes and Technologies for the Recycling of Spent Fluorescent Lamps

75%

Kujawski W. , Pospiech B.

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nr 3

80-85

EN

The growing industrial application of rare earth metals led to great interest in the new technologies for the recycling and recovery of REEs from diverse sources. This work reviews the various methods for the recycling of spent fluorescent lamps. The spent fluorescent lamps are potential source of important rare earth elements (REEs) such as: yttrium, terbium, europium, lanthanum and cerium. The characteristics of REEs properties and construction of typical fl uorescent lamps is described. The work compares also current technologies which can be utilized for an efficient recovery of REEs from phosphors powders coming from spent fluorescent lamps. The work is especially focused on the hydrometallurgical and pyrometallurgical processes. It was concluded that hydrometallurgical processes are especially useful for the recovery of REEs from spent fluorescent lamps. Moreover, the methods used for recycling of REEs are identical or very similar to those utilized for the raw ores processing.

20

Evaluation of alkali processing for the recycling of rare earth values from spent fluorescent lamps

75%

Shukla N. , Tanvar H. , Dhawan N.

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tom Vol. 56, iss. 4

710--722

EN

Phosphor samples collected after crushing and sieving of discarded fluorescent lamps comprise approximately 31 % rare earth elements in the form of Y1.90Eu0.10O3, Al11Ce0.67MgO19Tb0.33, and Al10.09Ba0.96Mg0.91O17: Eu2+ phase. Direct leaching and mechanical activation assisted leaching are incapable of recovering Ce, Tb values from the Al11Ce0.67MgO19Tb0.33 phase. Heat treatment with NaOH was found successful for dissociation of Ce, Tb phase via substitution of rare-earth ion by Na+ ion to form rare earth oxide and water-soluble NaAlO2. Y, Eu, Ce, and Tb values were recovered from heattreated mass in a two-step leaching process followed by recovery from the leach solution by oxalic acid precipitation. Over 95 % extraction rate was attained after heat treatment at 400 °C with 150 wt-% NaOH for 1 h. It was found that Y, Eu containing phase does not take part in the heat treatment process whereas the Ce, Tb phase undergoes a solid-state chemical reaction with NaOH via product layer diffusion model with 41.5 kJ/mol activation energy. Approximately 15 g mixed oxide (purity >95 %) of Y (79 %), Eu (7 %), Ce (5 %), and Tb (4 %) could be recovered from 100 units of discarded FLs. Microwave treatment of phosphor and NaOH (50 wt-%) yielded approximately 42 % Y, 100 % Eu, 65 % Ce, and 70 % Tb recovery in just 5 min. Approximately 9 g of REO and 5 g of cerium enriched leach residue were recovered from the microwave route within 5 min and depicted high microwave potential application in the recovery of Ce and Tb values from waste phosphor sample.