Yttrium recovery from primary and secondary sources: A review of ...

Waste Management xxx (2014) xxx–xxx

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Review

Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes Valentina Innocenzi a,⇑, Ida De Michelis a, Bernd Kopacek b, Francesco Vegliò a a b

Department of Industrial Engineering, of Information and Economy, University of L’Aquila, Via Giovanni Gronchi 18, Zona industriale di Pile, 67100 L’Aquila, Italy SAT, Austrian Society for Systems Engineering and Automation, Gurkasse 43/2, A-1140 Vienna, Austria

a r t i c l e

i n f o

Article history: Received 21 October 2013 Accepted 12 February 2014 Available online xxxx Keywords: Yttrium recovery Ores WEEE Lamps CRTs

a b s t r a c t Yttrium is important rare earths (REs) used in numerous fields, mainly in the phosphor powders for low-energy lighting. The uses of these elements, especially for high-tech products are increased in recent years and combined with the scarcity of the resources and the environmental impact of the technologies to extract them from ores make the recycling waste, that contain Y and other RE, a priority. The present review summarized the main hydrometallurgical technologies to extract Y from ores, contaminated solutions, WEEE and generic wastes. Before to discuss the works about the treatment of wastes, the processes to retrieval Y from ores are discussed, since the processes are similar and derived from those already developed for the extraction from primary sources. Particular attention was given to the recovery of Y from WEEE because the recycle of them is important not only for economical point of view, considering its value, but also for environmental impact that this could be generated if not properly disposal. Ó 2014 Elsevier Ltd. All rights reserved.

Contents 1. 2. 3. 4. 5. 6.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yttrium recovery from ores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yttrium recovery from contaminated solutions and wastewaters Yttrium recovery from generic waste and WEEE . . . . . . . . . . . . . . HydroWEEE and HydroWEEE demo . . . . . . . . . . . . . . . . . . . . . . . . Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1. Introduction Yttrium (Y) is a silvery-metallic dark grey lustrous metal that is relatively stable in air. Y has an atomic number of 88.91 and it has hexagonal crystal structure. It occurs in the periodic table in group 3, following strontium and coming before zirconium and niobium. Y has +3 has oxidization state and its oxide is Y2O3 http:// www.reehandbook.com/yttrium.html. This metal is mined from a

⇑ Corresponding author. Tel.: +39 0862434236.

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different of ore minerals (such as gadolinite, xenotime, and monazite). The applications of this metal are numerous, for example as phosphors in fluorescent lamps, it is also used to create cubic zirconia jewels, in fighter jet engines, as laser in industrial, medical, graphic technologies, in electronic components for missile defense systems, and others. The market of yttrium, like for other rare earths (REs), is very dynamic because these elements are strategic materials for various technological fields, and the fluctuation of supply and demand in recent years has caused a consequential wide price fluctuations in the market.

E-mail address: [email protected] (V. Innocenzi). http://dx.doi.org/10.1016/j.wasman.2014.02.010 0956-053X/Ó 2014 Elsevier Ltd. All rights reserved.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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Fig. 1. Trend of the prices of Y oxide.

RE prices grow since 2003 with a very strong increase in 2011; referring to the most current data the rare earth market is still dominated by China and there was a significant fall in prices during 2012 and the first months of 2013. This reduction was the natural consequence of the attempt of importing countries to extract RE from secondary sources or old mines http://unmig. sviluppoeconomico.gov.it/unmig/miniere/terrerare/terrerare.asp. Fig. 1 shows the price trend for yttrium oxide from August 2010 to March 2013. The economical values decreased in June and July, actually the prices are increasing. In August 2013 the prices for yttrium (99.9%) and yttrium oxide (99.999%) were around 60 USD/kg (min FOB Chi) and 30 USD/kg (CIF Europe), respectively www.metal-pages.com. The recovery of yttrium from various types of waste is very attractive and this manuscript offers an overview of most recent literature works that describe the retrieval of yttrium. The aim of

this present review is summarized the results of relevant articles that described the recovery of yttrium from ores, solutions and wastewater; generic waste and ewaste with particular attention to CRT and fluorescent lamps. 2. Yttrium recovery from ores The first technologies for the recovery of rare earths were adopted to extract them from the minerals and considering the goals of this manuscript below some recent scientific works, about this subject, are listed. Coltrinary and Kindig (1972) in their patent described a method to recover phosphates, yttrium and rare earth metal values from solid materials, phosphate ores or commercial concentrates and especially apatites, in a two-stage leaching process comprising: a first extraction with an aqueous acid solution to remove part of

Fig. 2. Block diagram for Coltinari and kinding’s process.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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Fig. 3. Block diagram Fava et al.’s process.

the phosphate, yttrium and a second extraction with stronger acid to remove the residual phosphate, yttrium and rare earth values. The recovery of yttrium (around 84.2%) was carried out by solvent extraction using organic immiscible solvent. In Fig. 2 is reported the entire process. Fava et al. (1987) reported a process to recover uranium, yttrium, thorium and other rare earths from phosphate rock during a wet process production of phosphoric acid. During the acid attack of the rock, aluminium and/or iron and silica were added. In this case the solutions of phosphoric acid di(alkylphenyl) phosphoric acid dissolved in organic solvent and in presence of trialkylphosphonine oxide. The metals were recovered from organic phase by stripping with a solutions containing hydrofluoric acid and phosphoric acid.

Fig. 3 reports the simple flowsheet for the process. Feuling (1991a,b) described a method for recovery of yttrium and scandium from titanium ore. Yttrium was recovered by residue after treatment of titanium ore for the retrieval of scandium. This element was recovered by leaching with HCl, followed by solvent extraction with a polyalkyl phosphate – containing organic phase. Finally, scandium was recovered by precipitation using ammonium solution to produce scandium hydroxide that could be calcined to obtain scandium oxide. The residues contained also yttrium and lanthanides and could be recovered calcining the aqueous phase and obtaining oxides. The same author (1991) wrote another patent (US 5039336) in which the process for the recovery of scandium, yttrium and lanthanides from zircon sand was described. The treatment included

Fig. 4. Block diagram for Feuling’s processes.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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the leaching of the initial material with HCl (6 M), solvent extraction with TBP to extract Sc and Fe, stripping with HCl (0.1 M), precipitation with NHþ 4 and calcination to obtain Sc oxides. The aqueous phase of solvent extraction contained Y and other rare earths; this solution was contacted with TOPO, in the residual aqueous solution was added NH4OH to precipitate the rare earths that finally could be recovered as oxides by calcinations. Fig. 4 reports the flow sheet for the Feuling’s processes. Deshande et al. (1992) described a method to recover yttrium from an intermediate concentrate from Y rich minerals with around 60% of Y2O3. The adopted treatment included solvent extraction with DEHPA and PC88A systems. The solutions containing 93% pure yttrium oxide was treated by another cycle of solvent extraction with 50% of TBP in kerosene in presence of 1.0 M NH4SCN. The purity and the recovery of Y2O3 were greater than 99.9% and 90%, respectively. Yang et al. (1999) studied the extraction of yttrium and other rare earths from simulated RE ore leachate solutions using an electrostatic pseudo-liquid membrane (ESPLIM), followed by group separation of REs by a combined extraction/ESPLIM. The feed solution contained about 1.0 g/l mixed REEs, 10 g/l (NH4)2SO4, 5 g/l NH4Cl and other non-RE ions such as Ca, Al, Si, Fe and Pb; the organic phase contained 20% HDEHP as extractant and 80% (v/v)

kerosene as diluents, the stripping phase contained various concentrations of hydrochloric acid (0.32–6 mol/l). The main results obtained in this work were: the extraction percentage of total RE was over 95% while about 70% non-RE impurities were removed; the separation factors were 5.9 and 4.7 for Nd–Sm and Gd–Tb, respectively; a light RE (from La to Nd) product with >95% purity of LRE, an HRE (from Tb to Lu plus Y) product with >95% purity of HRE, and an intermediate RE concentrate was obtained. Vijayalakshmi et al. (2001) recovered Y from xenotime concentrate by leaching with sulphuric acid, precipitation of thorium using ammonia or sodium pyrophosphate. In the solutions, after thorium removal, oxalic acid was added to precipitate yttrium oxalates which were calcined to obtain yttrium oxide. This compound was leached with HCl and pure yttrium oxide (99%) was recovered after solvent extraction. The total recovery of final product was 98%. Fig. 5 shows the block scheme for this process. Jun et al. (2011) described the extraction of rare earths from the leach liquor of the weathered crust elution-deposited rare earth ores. The process included solvent extraction, ion exchange and liquid membrane. For the solvent extraction the rare earth recovery is up to over 96% by multi-stage extraction and the raffinate solution could be recycled for leaching. For the ion exchange method, the adsorption rate of 98.7% with resin operation capacity of 77.4 g/l. For the liquid membrane method, the rare earth recovery was over 98%, with rare earth concentration up to 95.2 g/l, about 70% impurities were removed, and the product purity was up to 95%. In their paper the authors discussed about the efficiency, the advance of these methods compared to the precipitation and they found that it was possible reduced the amount of chemicals, energy and resource. Jorjani et al. (2011) described a method to recover rare earths from Chadormalu apatite concentrate of Iran. In their works the authors studied the effects that influenced the leaching yields of this type of ore. The dissolution of the apatite was carried out with nitric acid and the investigated effects were pulp density, acidity, agitation rate and the time of reaction. They found that the best conditions for the leaching of rare earths were: 60% acidity, 30% solid to liquid ratio, 30 min of leaching, 200 rpm and 60 °C and 50 lm of diameter of the particles. The recoveries of lanthanum, cerium, neodymium and yttrium were around 74%, 59%, 72% and 73%, respectively, in the optimized conditions. The lab data were used to predict the mathematical models for the dissolution of the metals in function of the various factors.

3. Yttrium recovery from contaminated solutions and wastewaters

Fig. 5. Block diagram for Vijayalakshmi et al.’s processes.

In this section some scientific works that include the treatment of wastewater and more generally solutions to recover mainly yttrium, are summarized. The adopted techniques comprise ionexchange, solvent extraction, absorption, use of membranes and resins. Heytmeijer (1983) in his patent described a method for recovering yttrium and europium from phosphors or contaminated solutions. The liquids containing yttrium, europium and other impurities were passed through a cation resin exchange column. This column was of the sulphonated styrene divinylbenzene type. When the exchange resin indicated cation exhaustion, the column was rinsed with deionized water in order to remove the excess yttrium and europium. The column was eluted with a low concentration acid solution (0.01–0.1 N). The effluent solution contained divalent impurities as ions as chloride ions, trivalent and higher valence species remained in the column that was stripped with a high concentration acid (>1 N) and rinsed with deionized water.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

V. Innocenzi et al. / Waste Management xxx (2014) xxx–xxx

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Fig. 6. Block diagram for Herman R. Heymeijer’s process.

The obtained solution contained yttrium, europium and other high valence ions as well as chloride ions. The solution was heated and oxalic acid was added to precipitate yttrium and europium as oxalates. The precipitate was rinsed, dried and calcinated to obtained yttrium oxide and europium oxide. Fig. 6 shows the flowsheet for this process. Gu et al. (1994) studied the yttrium recovery from wastewater by electrostatic pseudo-liquid membrane (ESPLIM). The paper was a summary of a laboratory and pilot plant tests. The effects of the applied field, extractant concentration, feed concentration, pH and flow rate on Y(III) extraction were studied for optimizing the process. The continuous steady-state operation of the process shows that Y(III) could be effectively recovered from wastewater containing 1.0 g/l Y(III), and with a one-step operation, Y(III) could be concentrated to 232.4 g/l. The test also proved that ESPLIM was a simple process with high efficiency and low consumption of reagents and energy. Karavaiko et al. (1996) in their work described a biosorption of yttrium and scandium from solutions. The method allowed separation of scandium and yttrium from each other and from Fe, Al, Ti, Si, and Ca in hydrometallurgical processing of ores and waste. It was shown that the sorption of the elements increased if the pH of solution grow; 85–98% of scandium was sorbed within 10–30 min with most of tested biomass. They reported that the presence of impurities as Al, Fe and Ti inhibited the sorption of Sc and Y. After four cycle 98.8% of Sc and 87% of Y was extracted from red mud leach liquors by Saccharomyces cerevisiae and Aspergillus terreus, respectively. Singh et al. (2012) studied a process to recover yttrium from phosphoric acid solution which contained also uranium. The method included four step: solvent extraction of Y and U from solution using DNPPA–TOPO and D2EHPA–TBP, yttrium was selectively stripped from organic phase then could be precipitated using

Fig. 7. Block diagram for Singh et al.’s process.

sulphate salt; finally yttrium double sulphate salt was dissolved and precipitated with oxalic acid to produce pure yttrium product. It was found that 10% (w/v) Na2SO4 + 30% H2SO4 and H2SO4 (30–40%) were the most preferable conditions with more than 95% of yttrium recovered and less than 0.2% of uranium lost in the yttrium strip liquor. From the resultant strip liquor, more than 98% of yttrium was precipitated in the form of sodium yttrium double sulphate salt under the optimized conditions of 10% (w/v) Na2SO4, 60 ± 1 °C and aging time of 45 min. Pure yttrium oxide with more than 99% was obtained. Sodium contained in the yttrium oxide product was removed by washing steps using distilled water and it could be completely removed using liquid to solid ratio of 50, 80 ± 5 °C for 30 min. Fig. 7 shows the block scheme of the Singh et al.’s process. 4. Yttrium recovery from generic waste and WEEE In this section the recovery of yttrium from waste and WEEE is discussed, in particular from fluorescent powders of lamps, cathode ray tubes (CRTs) and spent optical glass. WEEE contains many hazardous components (Table 1) and often at the end of their useful life are disposed in the landfills or in the incinerators. This disposal leads to considerable

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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Table 1 List of the main hazardous elements contained in the WEEE (Allsopp et al., 2006). Materials and components

Description

Batteries CRTs (Cathode ray tubes) Mercury containing components, such as switches LCDs (Liquid crystal displays)

Heavy metals such as lead, mercury and cadmium are present in batteries Lead in the cone glass and cadmium/zinc/yttrium sulphide in the fluorescent coating Mercury is used in thermostats, sensors, relays and swatches, for example, on printed circuit boards

Printed circuit boards Plastics containing halogenated flame Solder

LCDs of greater than 100 cm2 have to be removed from WEEE. LCDs are used in mobile phones and flat screen computer monitors and may contain mercury In the printed circuit boards, cadmium occurs in certain components. Other hazardous metals are present During incineration/combustion of the plastics, halogenated flame retardants can produce toxic components Lead/tin and other trace metals

environmental damage. Within the European Union, two directives were adopted, the directive of The European Parliament and the European Council on WEEE and the directive on the restriction of the certain hazardous substances in electrical and electronic equipment (RoHS). These directives indicate that the Member States are responsible for not correct disposal of WEEE and encourage the development of new technologies for the treatment of these waste. The main aims was to reduce the environmental impact that WEEE produce after their uses and to recover the fundamental metals for European Union such as rare earths (classified as critical elements) and the precious metals (Allsopp et al., 2006). Among of these rare earths there is yttrium that it is especially used in the fluorescent powders of lamps and CRTs. Lamp phosphors are rich in of heavy rare earths Tb, Eu and Y. Presently many hydrometallurgical processes were developed with the aim to recover these elements contained in the phosphors. The processes are very similar to the treatments used for the extraction of REEs from ores and include dissolution of the materials using acids and recovery of RE by precipitation or by solvent extraction. Following a list of scientific works that describe methods to recover yttrium from fluorescent lamps is reported. Tooru et al. (2001) studied a process for separation and recovery of RE contained in fluorescent lamp waste. Yttrium and europium were recovered by three processes consisting of pneumatic classification, sulphuric acid leaching and oxalate precipitation methods. The recovery was about 65% and the purity of the products was 98.2%. The best results of the dissolution were obtained in these conditions: 1.5 kmol/m3 of acid, 343 K, leaching time of 1 h and pulp density of 30 kg/m3. In these conditions the leaching degree was 92% for Y and 98%for Eu.

Fig. 8. Block diagram for Tooru et al.’s process.

Fig. 8 reports the flowsheet for this process. Shimizu et al. (2005) studied the recovery of rare earths using supercritical carbon dioxide (SF-CO2) containing tri-n-butyl phosphate (TBP) complexes with HNO3 and H2O. Aqueous droplets were generated in an extraction experiment from a reaction with metal oxides and a complex prepared from vigorous mixing of TBP with concentrated nitric acid (15.5 mol dm3 (M)). The molecular ratio of TBP:HNO3:H2O in the complex was 1.0:1.8:0.6. The extraction yields for Y and Eu increased to over 99% after the static extraction for 120 min at 15 MPa, 333 K. Otsuki et al. (2007) studied the heterocoagulation of fluorescent powders in order to investigate the mechanism of two –liquid flotation when separating a mixture of fluorescent powders (red, green and blue phosphors). They found that the heterocoagulation of one of fluorescent powders and n-heptane in DMF solvent (N,N,-dimethylformamide) was feasible in the presence of surfactant: DDA (dodecylamine acetate) for green phophosrs, sodium 1-octanesulphonate. The fluorescent powders were firstly covered by surfactant and then aggregated with other powders covered by surfactant. Then, the aggregates were attached on the surface of non polar droplet, migrated to the interface of two phases whereas the other powders precipitate in polar solvent. The recoveries and the grade were 95.2% and 90% for green product, 91.8% and 92.2% for blue product, 90.9% and 95.3% for red product, respectively. Rabah (2008) studied the recovery of Y and Eu from fluorescent lamps: the tubes were broken under 30% aqueous acetone to avoid emission of mercury vapour to the atmosphere, and the powder was collected by brushing. Metals available in the powder were pressure leached using sulphuric/nitric acid mixture for 4 h at 125 °C and 5 MPa. The leaching yields were 96.4% for Y and 92.8% for Eu. Sulphate salt of europium and yttrium was converted to thiocyanate at low temperature. Trimethyl-benzylammonium chloride solvent was used to selectively extract Eu and Y from the thiocyanate solution. The metal loaded in the organic solvent was recovered by N-tributylphosphate in 1 M nitric acid at 125 °C to produce nitrate salts of Eu and Y. Europium nitrate was separated from yttrium nitrate by dissolving in ethyl alcohol. Thermal reduction using hydrogen gas at 850 °C and 1575 °C produced europium and yttrium metals, respectively (Fig. 9). In 2010, Toro et al. (RS 20100479) studied the recovery of base and precious metals from fluorescent powders and installation for implementing such method. Porob et al. (2011) in their patent (WO 2011/106167A1) described a method to recover rare earths from fluorescent material that included several steps. Initially, the phosphor was fired with an alkaline material to decompose the phosphor into a mixture of oxides, after the residue was extracted from mixture and treated to separate individual RE salts or compounds. The residue was dissolved in acid attack using HNO3, H2SO4 or HCl at high temperature (i.e. 150 °C). Afterward the residue RE salts could be separated

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Trimethylbenzylammonium chloride N-tributylphosphate methyl ethyl ketone ethyl alcohol

N-butylphosphate Nitric acid. Hydrogen

Ethyl alcohol

Hydrogen

Eu metals

Y metals Fig. 9. Block diagram for Rahab’s process.

from solution by solvent extraction, crystallization or precipitation process (Fig. 10). Otto and Wojtalewicz-kasprzac, 2012 described a selective method to recover rare earths from fluorescent powders. At the first the powder was separate by mechanical techniques, the phosphors were sieved with a mesh width between 20 and 25 lm. After this pretreatment the material was processed as follows: leaching with HCl at low temperature (95%

Vijayalakshmi et al. (2001)

Xenotime

Leaching with sulfuric acid Thorium precipitation with ammonia Yttrium precipitation with oxalic acid Leaching with hydrochloric acid Solvent extraction

Purity Y2O3 99% Recovery Y2O3 98%

Jun et al. (2011)

Rare earths ores

Leaching Solvent extraction Ion exchange

Extraction rate >95% Adsorption rate >98.7% Liquid membrane recovery >95% Purity of the product >95%

Jorjani et al. (2011)

Chadormaly apatite concentrate

Leaching study

Heytmeijer (1983)

Contaminated solutions

Absorption with resin Stripping Precipitation with oxalic acid Calcination

Gu et al. (1994)

Wastewater

Electrostatic pseudo-liquid membrane

Karavaiko et al. (1996)

Red mud leach liquors

Biosorption by Saccharomyces cerevisiae and Aspergillus terreus

Y extraction 87%

Singh et al. (2012)

Phosphoric acid solution with uranium

Solvent extraction with DNPPA-TOPO and D2EHPA-TBP Stripping Precipitation using sulphate salt Dissolution Precipitation with oxalic acid Calcination

Y oxide grade 99% Y recovery 95%

Tooru et al. (2001)

Fluorescent lamps

Sulphuric acid leaching Precipitation by oxalic acid

Recovery RE 65% Grade of the product 98.2%

Shimizu et al. (2005)

Fluorescent lamps

Extraction by supercritical carbon dioxide containing TBP complexes with HNO3 and H2O

Extraction yields >99% for Y and Eu

Otsuki et al. (2007)

Fluorescent powders

Hetero coagulation of fine particles in polar organic solvent

Recoveries 95.2% green product 91.8% blue product 90.9% for red product Grade: 90% green product, 91.8% 92.2% blue product 95.3% red product

Rabah (2008)

Fluorescent lamps

Nitric/sulphuric acid leaching Thiocyanate conversion Solvent extraction using trimethyl-benzylammonium chloride Stripping by N-tributylphosphate Thermal reduction using hydrogen gas

Leaching yields 96.4% Y 92.8% Eu

Porob et al. (2011)

Fluorescent materials

Fire of initial material with an alkaline material Acid leaching of the residue (HNO3, H2SO4 or HCl) at high temperature (i.e. 150 °C) Solvent extraction of RE, crystallization or precipitation process

Otto and Wojtalewiczkasprzac (2012)

Fluorescent lamps

Selective leaching: Leaching with HCl at low temperature to leach all rare earths except the Y2O3:Eu3+ Leaching with HCl or sulphuric acid at 60–90 °C

Liquid membrane

Recoveries: 74% La 59% Ce 72% Nb 73% Y

(continued on next page)

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Table 2 (continued) Authors

Material

Main phases of the process

Main results

Leaching with sulphuric acid at 120–230 °C to dissolve LaPO4: Ce3+, Tb3+ Dissolution with 35% of NaOH solution at 150 °C to dissolve (Ce, Tb)MgAl11O19 and BaMgAl10 Yang et al. (2013)

Fluorescent lamps

Leaching with acid Solvent extraction using ionic liquids N,N-dioctyldiglycol amic acid (DODGAA)

De Michelis et al. (2011)

Fluorescent lamps

Nitric/chloridric and sulphuric acid leaching Precipitation with oxalic acid

Y Recovery 90% Grade Y oxalate 99%

Innocenzi et al. (2013a,b)

Fluorescent lamps and CRT

Sulphuric acid leaching Purification with sodium hydroxide and sulphide Precipitation with oxalic acid

Y Recovery 55% Grade Y oxide >99%

Vaclav (2007)

Concentrate of luminophores

Leaching with inorganic acid Solvent extraction using organic phase (i.e. EDEHP) diluted in organic diluents Stripping with inorganic acid

Tedjar et al. (2007, 2010)

CRT

Sulphuric acid leaching Precipitation of Y adding NaOH or KOH and alkaline fluoride (sodium or potassium) Treatment with a solution of 30% NaOH to precipitate Y:Eu(OH)3

Lee et al. (2009)

CRT

Mixing with NaOH solution Vibrating with ultrasonic for 30 min to obtain an effect to soak out Al Sulphuric acid leaching Vibrating to soak with ultrasonic for 123 min at 70 °C to obtain an effect to soak out Eu and Y totally and 57% of Zn Recovery of Zn adding thioacetamide Eu and Y hydroxides recovery adding NaOH

Dexpert-Ghys et al. (2009)

CRT

Thermo-chemical treatments

Resende and Morais (2010)

CRT

Sulphuric acid leaching Solvent extraction

Innocenzi et al. (2013b)

CRT

Sulphuric acid leaching Purification with sodium hydroxide and sulphide Precipitation with oxalic acid Calcination

Y Recovery 75–80% Grade Y oxide >95%

Pan et al. (2013)

Phosphors of TV screens

Roasting with ammonia chloride Dissolution with water Purification with sodium sulphide Precipitation with oxalic acid Calcination

Y content 98.10% Eu content 96.30%

Ochsenkühn-Petropulu et al. (1996)

Red mud

Leaching with nitric acid Solvent extraction

Recoveries: 90% Y >70% heavy lanthanides (Dy, Er, Yb) >50% middle RE (Nd, Sm, Eu, Gd) (La, Ce, Pr) >30% light lanthanides

Jiang et al. (2005)

Spent optical glass

Conversion RE to hydroxide form Acid leaching with HCl

Mixture of RECl3 Recoveries: 99.4% La 100% Y and Gd

Matsuda et al. (2013)

Spent optical glass

Alkali fusion Precipitation with ammonium oxalate Alkali leaching followed by sodium hydroxide Solvent extraction with D2EHPA

71.1% La recovery 83.4% grade of final product Distribution 99.95% La, 98.65% Y 95.18% Gd

It was found that at pH = 1, the stoichiometric ratio of B/A (A: S2, B: Zn2+, etc.) was 1:1, the stoichiometric ratio of B/A (A: Y3+, B: C2 O2 4 , etc.) was 2:1, the content of Y and Eu could be reached 98.10% and 96.30%, respectively. Finally several authors studied the recovery of yttrium from other wastes. Ochsenkühn-Petropulu et al. (1996) reported a study in which yttrium and lanthanides recoveries from red mud come from alumina production were described. The process included leaching

Recovery of Zn Eu and Y hydroxides recovery

with nitric acid under moderate conditions and solvent extraction for the separation of the individual lanthanides. The achieved recovery percentages were for Y about 90%, for the investigated heavy lanthanides (Dy, Er, Yb) up to 70%, for the middle ones (Nd, Sm, Eu, Gd) up to 50% and for the group of light lanthanides (La, Ce, Pr) up to 30%. Jiang et al. (2005) studied the recovery of yttrium and other rare earths from spent optical glass containing 43.12% lanthanum oxide, 9.37% yttrium oxide and 4.60% gadolinium oxide. The pro-

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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the time increased. Also, increasing HCl concentration, temperature, liquid/solid ratio and leaching time, RE extraction yields rose. The authors found a recovery of 99.4% for La and 100% for Y and Gd under the following conditions: 55% NaOH aqueous solution, a liquid/solid ratio of 2 at 413 K for 60 min followed by leaching the residual solids in 6 M HCl and a liquid-to-solid ratio of 4 at 368 K for 30 min. Matsuda et al. (2013) studied the recovery of rare earths from waste optical glass using precipitation and solvent extraction. In this manuscript the authors described two different types of experiments. In the first the grade and recovery for La were 83.4% and 71.1%, respectively using alkali fusion with an equivalent mixture of the fusing agent of sodium carbonate and potassium carbonate, and precipitation with ammonium oxalate. In the second series of test the distribution of 99.95% La, 98.65% Y and 95.18% Gd from waste optical glass was achieved by alkali leaching followed by sodium hydroxide and solvent extraction with D2EHPA. Table 2 summarizes the literature works and some patents related to recover yttrium from different kind of waste and ewaste.

Fig. 21. Simple block diagram for the mobile plant used to prove the treatment for the recovery yttrium from fluorescent lamps and CRT within HydroWEEE project.

cess included the initial conversion of RE from a borosilicate phase to the hydroxide form using sodium hydroxide followed by hydrochloric acid leaching of the residual solids from the conversion (Fig. 20). The research’s results showed that the RE dissolution grew if NaOH concentration, temperature, liquid/solid ratio and

5. HydroWEEE and HydroWEEE demo The researches (De Michelis et al., 2011; Innocenzi et al., 2013a, 2013b) were realized within the ID FP7-SME-2008-1 HydroWEEE (2009–2012) and FP7-ENV-2012 – two stage HydroWEEE demo (2012–2016) project. The aim of these projects was to study the innovative hydrometallurgical process to recover metals from WEEE, with particular interest for fluorescent powders of CRTs and lamps. In the first project a mobile plant was used to test hydro-

Fig. 22. Mobile plant photos. (a) Particular of the scrubber; (b) electrical panel and electrolysis cell; (c) filter pres and reactor for leaching and precipitation operations.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010

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metallurgical processes to extract Y, and others metals from WEEE in a high purity. Several fractions (lamps, CRTs, LCDs, PCBs and Li.ion batteries) could be treating in the same plant in batches. The subject of the HydroWEEE demo projects is to build 2 industrial, real-life demonstration plants (1 stationary and 1 mobile) in order to test the performance and to prove the viability of the processes from an integrated point of view (technical, economical, operational, social) including the assessment of its risks and benefits to the society and the environmental. The projects, also, includes the improvement of the processes to recover metals from WEEE that were study during the first projects and to introduce the integrated treatment of solid and liquid wastes for each process. Figs. 21 and 22 show, respectively, the simple flowsheet and some photos of the mobile plant used for the pilot plant tests in the HydroWEEE projects. The main equipments are: reactor, tank, filter press, electrolysis cell and the scrubber. In this plant lamps, CRTs processes were tested in according to works cited before. The average value of purity of the oxalates is around 70% of rare earths oxalates with total recovery for Y of 90%. In the HydroWEEE demo project the process will be optimized to increase the yields of recovery, the purity and to add the integrated wastewater treatment. 6. Conclusions This paper is an overview of the most recent scientific literature that describe yttrium recovery from different sources. The main hydrometallurgical processes for Y retrieval from ores, wastewater and contaminated solutions, generic wastes and WEEE are reported with particular interest for fluorescent powders from lamps and CRTs, also studied in the HydroWEEE projects. The high importance of yttrium, like the other rare earths, has led in recent years to increase the development of technologies for the recovery from primary sources and also from secondary source. The economical feasibility of the processes is influenced by market price of the RE and in the future will need to develop more sustainable processes so that the treatments, especially for WEEE, could be realized on industrial scale. Acknowledgments The author acknowledge the partners of HydroWEEE projects founded by European Union (University of L’Aquila, Italy; SAT, Austria; University of Ancona, Italia; University of Rome, La Sapienza, Italy; Pupin Institute, Serbia; Relight Srl, Rho, Italy; Greentronics, Romania; SET-Trade, Serbia). References Allsopp, M., Santillo, D., Johnston, P., 2006. Environmental and human healthy concerns in the processing of electrical and electronic waste. GRL-TN-04-2006. Chen, M., Zhang, F., Zhu, J., 2009. Lead recovery and feasibility of foam glass production from funnel glass of dismantled cathode ray tube through pyrovacuum process. J. Hazard. Mater. 161, 1109–1113. Coltrinary, E.L., Kindig, J.K., 1972. Two – stage countercurrent leaching process for the recovery of phosphates, yttrium and rare earths values. US Patent 3647361. De Michelis, I., Ferella, F., Fioravante Varelli, E., Vegliò, F., 2011. Treatment of exhaust fluorescent lamps to recover yttrium: experimental and process analyses. Waste Manage. (Oxford) 31, 2559–2568. Deshande, S.M., Mishra, S.L., Gajankush, R.B., Thakur, N.V., Koppiker, K.S., 1992. Recovery of high purity Y2O3 by solvent extraction route using organophosphorus extractants. Miner. Process. Extract. Metall. Rev.: Int. J. 10, 267– 273. Dexpert-Ghys, J., Regnier, S., Canac, S., Beaudette, T., Guillot, P., Caillier, B., Mauricot, R., Navarro, J., Sekhri, S., 2009. Re-processing CRT phosphors for mercury-free application. J. Lumin. 129, 1968–1972. Fava, J., Puiseux, A., Tognet J.P., 1987. Essentially complete recovery of uranium, yttrium, thorium and rare earth from phosphate rock during wet-process production of phosphoric acid therefrom. US Patent 4636369. Feuling, R.J., 1991a. Recovery of scandium, yttrium, and lanthanides from titanium ore. US Patent 5049363. Feuling, R.J., 1991b. Recovery of scandium, yttrium, and lanthanides from zircon sand. US Patent US 5039336.

Gu, Z., Wu, Q., Zheng, Z., Li, Z., Jiang, Y., Tang, C., Lin, P., 1994. Laboratory and pilot plant test of yttrium recovery from wastewater by electrostatic pseudo liquid membrane. J. Memb. Sci. 93, 137–147. Heytmeijer, H.R., 1983. Recovery of yttrium and europium from contaminated solutions. US Patent 4386056 A. Innocenzi, V., De Michelis, I., Ferella, F., Veglio’, F., 2013a. Recovery of yttrium from cathode ray tubes and lamps fluorescent powders: experimental results and economic simulation. Waste Manage. (Oxford) 33, 2390–2396. Innocenzi, V., De Michelis, I., Ferella, F., Beolchini, F., Kopacek, B., Veglio’, F., 2013b. Recovery of yttrium from fluorescent powder of cathode ray tube, CRT: Zn removal by sulphide precipitation. Waste Manage. (Oxford) 33, 2364–2371. Jiang, Y., Shibayama, A., Liu, K., Fujita, T., 2005. A hydrometallurgical process for extraction of lanthanum, yttrium and gadolinium from spent optical glass. Hydrometallurgy 76, 1–9. Jorjani, E., Bagherieh, A.H., Chelgani, S.C., 2011. Rare earths elements leaching from Chadormalu apatite concentrate: laboratory studies and regression predictions. Korean J. Chem. Eng. 28, 557–562. Jun, T., Jinqun, Y., Kaihong, C., Guohua, R., Mintao, J., Ruan, C., 2011. Int. J. Miner. Process. 98, 125–131. Karavaiko, G.I., Kareva, A.S., Avakian, Z.A., Zakharova, V.I., Korenevsky, A.A., 1996. Biotechnol. Lett. 18, 1291–1296. Lee, C.H., Cin, C.H., Tsai, S.L., Lin, M.D., Chen, H.Y., Wu, Y.H., 2009. A method for recycling fluorescent powder of scrap cathode ray tube. TW200916552. Ling, T.C., Poon, C.S., 2011. Utilization of recycled glass derived from cathode ray tube glass as fine aggregate in cement mortar. J. Hazard. Mater. 192, 451–456. Matsuda, M., Shibayama, A., Matsushima, K., Jiang, Y., Fujita, T., Kikukawa, T., 2013. Recovery of rare earth from waste optical glass by precipitation and solvent extraction. Shigen – to – Sozaim 119, 668–674. Menad, N., 1999. Cathode ray tube recycling. Resour. Conserv. Recycl. 26, 143–154. Nnrom, I.C., Osibanjo, O., Ogwvegbu, M.O.C., 2011. Global disposal strategies for waste cathode ray tubes. Resour. Conserv. Recycl. 55, 275–290. Ochsenkühn-Petropulu, M., Lyberopulu, Th., Ochsenkühn, K.M., Parissakis, G., 1996. Recovery of lanthanides and yttrium from red mud by selective leaching. Anal. Chim. Acta 319, 249–254. Otsuki, A., Dodbiba, G., Fujita, T., 2007. Two-liquid flotation: heterocoagulation of fine particles in polar organic solvent. Mater. Trans. 48, 1095–1104. Otto, R., Wojtalewicz-kasprzac, A., 2012. Method for recovery of rare earths from fluorescent lamps. US Patent 0027651 A1. Pan, X., Peng, L., Chen, W., Wang, J., Chen, Z., 2013. Recovery of Y and Eu from waste phosphors of CRT TVs and the preparation of yttrium europium oxide. Appl. Mech. Mater. 295–298, 1840–1845. Parthasarathy, P., Keshav, A.B., Anantha Murthy, K.S., 2008. E-waste recycling – best option for resource recovery and sustainable enviroment. Res. J. Chem. Environ. 12, 93–98. Porob, D.G., Srivastava, A.M., Ramachandran, G.C., Nammalwar, P.K., Comanzo, H.A., 2011. Rare earth recovered from fluorescent material and associated method. WO 2011 (106167), A1. Rabah, M.A., 2008. Recyclables recovery of europium and yttrium metals and some salts from spent fluorescent lamps. Waste Manage. (Oxford) 28, 218–325. Resende, L.V., Morais, C.A., 2010. Study of the recovery of rare earth elements from computer monitor scraps – leaching experiments. Miner. Eng. 23, 277–280. Shimizu, R., Sawada, K., Enokida, Y., Yamamoto, I., 2005. Supercritical fluid extraction of rare earth elements from luminescent material in waste fluorescent lamps. J. Supercrit. Fluids 33, 235–241. Singh, D.K., Anitha, M., Yadav, K.K., Kotekar, M.K., Vijayalakshmi, R., Singh, H., 2012. Simultaneous recovery of yttrium and uranium using D2EHPA–TBP and DNPPA–TOPO from phosphoric acid. Desalination Water Treat. 38, 236–244. Tedjar, F., Foudraz, J.C., Desmuee, I., Pasquier, C., Martorana, S., 2007. Integral recycling method for cathodic tubes. WO 2007 (003722), A1. Tedjar, F., Foudraz, J.C., Desmuee, I., Pasquier, C., Martorana, S., 2010. Method for integral recycling for cathode ray tubes. US 20100062673. Tooru, T., Aketomi, T., Takayuki, S., Nobuhiro, N., Shinji, H., Kazuyoshi, S., 2001. Separation and recovery of rare earth elements from phosphor sludge in processing plant of waste fluorescent lamp by pneumatic classification and sulfuric acidic leaching. J. Min. Mater. Process. Inst. JPN 117, 579–585. Toro, L., Vegliò, F., Beolchini F., Pagnanelli, F., De Michelis, I., Varelli, E., Ferella, F., 2010. Recovery of base and precious metals from fluorescent powders and installation for implementing such method. Application number RS 20100479. Vaclav, G., 2007. Method of extracting Europium (III) and yttrium (III) from concentrate of luminophore dust or sludge. EP 1817437. Vijayalakshmi, R., Mishra, S.L., Singh, H., Gupta, C.K., 2001. Processing of xenotime concentrate by sulphuric acid digestion and selective thorium precipitation for separation of rare earths. Hydrometallurgy 61, 75–80. Xing, M., Zhang, F., 2011. Nano lead particle synthesis from waste cathode rayfunnel glass. J. Hazard. Mater. 194, 407–413. Yang, X.J., Gu, Z.M., Fane, A.G., 1999. Multicomponent separation by a combined extraction/electrostatic pseudo-liquid membrane (II): extraction and group separation of rare earths from simulated rare earth ore leach solutions. Hydrometallurgy 53, 19–29. Yang, F., Kubota, F., Baba, Y., Kamiya, N., Goto, M., 2013. Selective extraction and recovery of rare earths from phosphor powders in waste fluorescent lamps using an ionic liquid system. J. Hazard. Mater. 254–255, 79–88. Yot, P.G., Méar, F.O., 2011. Characterization of lead, barium and strontium leachalability from foam glasses elaborated using waste cathode ray-tube glasses. J. Hazard. Mater. 185, 236–241.

Please cite this article in press as: Innocenzi, V., et al. Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes. Waste Management (2014), http://dx.doi.org/10.1016/j.wasman.2014.02.010