Supercritical fluid extraction of rare earth elements from luminescent material in waste fluorescent lamps

Shimizu, Ryosuke; Sawada, Kayo; Enokida, Youichi; Yamamoto, Ichiro

doi:10.1016/j.supflu.2004.08.004

Cited by 119 publications

(51 citation statements)

References 15 publications

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“…Supercritical CO 2 could find applications in the field of nonaqueous solvent extraction and solvent leaching [75][76][77][78]. Of particular interest are the promising combinations of supercritical CO 2 with TBP-HNO 3 and supercritical CO 2 with fluorinated b-diketones as solvents for direct solid leaching [79][80][81][82][83]. CO 2 becomes a supercritical fluid at its critical temperature (31.10°C) and critical pressure (72.8 atm) [84].…”

Section: Organic Solvents For Solvometallurgy Green Solventsmentioning

confidence: 99%

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Binnemans

Jones

2017

J. Sustain. Metall.

234

187

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This position paper introduces the reader to the concept of solvometallurgy, the term used to describe the extraction of metals from ores, industrial process residues, production scrap, and urban waste using non-aqueous solutions. Here, non-aqueous is not used to imply anhydrous, but rather a low water content. The unit operations are as follows: solvent leaching; separation of the residue; purification of the leach solution by non-aqueous solvent extraction or non-aqueous ion exchange; and metal recovery by precipitation or electrolysis in non-aqueous electrolytes. Solvometallurgy is similar to hydrometallurgy in that both the branches of extractive metallurgy use lowtemperature processes, but with solvometallurgy, there is no discrete water phase. Both branches use organic or inorganic solvents (excluding water in the case of solvometallurgy). However, for solvometallurgical processes to be sustainable, they must be based on green solvents, which means that all toxic or environmentally harmful solvents must be avoided. Solvometallurgy is complementary to pyrometallurgy and hydrometallurgy, but this new approach offers several advantages. First, the consumption of water is very limited, and so the generation of wastewater can be avoided. Second, the leaching and solvent extraction can be combined to form a single step, resulting in more simplified process flow sheets. Third, solvent leaching is often more selective than leaching with acidic aqueous solutions, leading to reduced acid consumption and fewer purification steps. Fourth, solvometallurgy is useful for the treatment of ores rich in soluble silica (e.g., eudialyte) because no silica gel is formed. In short, solvometallurgy is in a position to help develop the near-zero-waste metallurgical processes, and with levels of energy consumption that are much lower than those with the high-temperature processes. The Technology Readiness Level (TRL) of this emerging branch of extractive metallurgy is still low (TRL = 3-4), which is a disadvantage for short-term implementation, but offers a great opportunity for further research, development, and innovation.

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Section: Organic Solvents For Solvometallurgy Green Solventsmentioning

confidence: 99%

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Binnemans

Jones

2017

J. Sustain. Metall.

234

187

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“…Of these, YOX has the highest intrinsic value because it contains 80 wt % of the total RE content of the phosphor waste and is composed exclusively of the two critical RE elements, Y and Eu. Recent developments in the recycling of phosphor materials have largely focused on the recovery of Eu and Y from YOX (11,(30)(31)(32)(33)(34)(35)(36)(37)(38) (29). Currently, however, only one industrially applied recycling process exists for lamp phosphor waste (29,39).…”

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confidence: 99%

Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures

Bogart

Cole

Boreen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Rare earth (RE) metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare REs. To incentivize recycling, there is a clear need for the development of simple methods for targeted separations of mixtures of RE metal salts. Metal complexes of a tripodal hydroxylaminato ligand, TriNOx 3-, featured a size-sensitive aperture formed of its three η 2 -(N,O) ligand arms. Exposure of cations in the aperture induced a self-associative equilibrium comprising RE(TriNOx)THF and [RE(TriNOx)] 2 species. Differences in the equilibrium constants K dimer for early and late metals enabled simple separations through leaching. Separations were performed on RE1/RE2 mixtures, where RE1 = La-Sm and RE2 = Gd-Lu, with emphasis on Eu/Y separations for potential applications in the recycling of phosphor waste from compact fluorescent light bulbs. Using the leaching method, separations factors approaching 2,000 were obtained for early-late RE combinations. Following solvent optimization, >95% pure samples of Eu were obtained with a 67% recovery for the technologically relevant Eu/Y separation. (11)(12)(13)(14). Limitations associated with their beneficiation and separations, especially their solvent-, waste-, and energy intensities, have contributed to the concentration of suppliers in the People's Republic of China. Supply risks for these elements have emerged, particularly in the face of current and growing demand in the next 20 y (15, 16). Because the global marketplace for these elements is dominated by a single source (17), prices for primary rare earth (RE) materials are volatile (18). As a result, the US Department of Energy has classified many of these elements as "critical" (19). There is a clear need to find potential new supplies of these elements.Recent life cycle assessments have indicated that recycling of consumer materials is a promising alternative to conventional production processes (20). Despite this assertion, as recently as 2011, less than 1% of RE-containing materials were being recycled (21). These low recycling rates stem from a combination of sporadic collection procedures and lack of efficient separations and preprocessing steps (22)(23)(24)(25)(26)(27).To contribute to incentivizing the "urban mining" of REcontaining materials, we recently initiated efforts toward new, simplified methods in RE separations (28). Our initial work focused on the separation of neodymium (Nd) and dysprosium (Dy), two key components of neomagnets (Nd 2 Fe 14 B). We disclosed the development of the tripodal nitroxide ligand, [((2-t BuNO)C 6 H 4 CH 2 ) 3 N] 3− (TriNOx 3-), which induced a selfassociation equilibrium between monomeric Nd(TriNOx)THF/ dimeric [Nd(TriNOx)] 2 species. The position of this equilibrium was found to be strongly dependent on the size of the RE cation. We showed proof of concept that differences in the self-association equilibrium constants between Nd and Dy could be exploited to achieve 95% pure materials through a simple leachi...

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“…For example, in Japan, 31 ores, including the rare earth elements as a group, have been designated as rare metals in terms of the concern in securing a stable supply of resources (Kawamoto 2008). Consequently, other than the refinery production, the reclaim processing of rare metals from secondary resources, such as process discards from the rare metal-consuming manufacturing schemes (Hsieh et al 2009, Liu et al 2009, Kang et al 2011, Li et al 2011, Park 2011, Virolainen et al 2011, Hasegawa et al 2013b or end-oflife electronic products (Shimizu et al 2005, Cui & Zhang 2008, Rabah 2008, Bertuol et al 2009, Binnemans et al 2013, Hasegawa et al 2013c, Hasegawa et al 2013a, received sincere focus from the researchers.Municipal solid waste (MSW) management is in crisis in many of the world's largest urban areas as populations are continued to grow, which creates an increase in the waste quantities, while disposal places, such as sanitary landfills around the periphery of the cities, are decreasing. The alternative approach that has caught the attention of decision makers is the mass burn incineration that is increasingly practiced in the OECD (Organisation for Economic Co-operation and Development) countries (Anonymous 1999).…”

mentioning

confidence: 99%

Recovery of the Rare Metals from Various Waste Ashes with the Aid of Temperature and Ultrasound Irradiation Using Chelants

Hasegawa

Rahman

Egawa

et al. 2014

Water Air Soil Pollut

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The incineration fly ash (IFA), molten fly ash (MFA), thermal power plant fly ash (TPP-FA), and nonferrous metal processing plant ash (MMA) have been screened in terms of the following rare-termed metal contents: B, Ce, Co, Dy, Eu, Ga, Gd, Hf, In, Li, Lu, Mn, Nb, Nd, Ni, Pr, Rb, Sb, Se, Sm, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, and Yb. The pseudo-potential for recycling of the waste ashes, as compared to the cumulative concentration in the crust (mg kg -1 ), was determined as follows: MMA > IFA > MFA > TPP-FA. The comparison with the crude ore contents indicates that the MMA is the best resource for reprocessing. The recovery of the target metals using aminopolycarboxylate chelants (APCs) has been attempted at varying experimental conditions and ultrasound-induced environment. A better APC-induced extraction yield can be achieved at 0.10 mol L -1 concentration of chelant, or if the system temperature was maintained between 60 to 80 °C. Nevertheless, the mechanochemical reaction induced by the ultrasound irradiation has been, so far, the better option for rare metal dissolution with chelants as it can be conducted at a minimum chelant concentration (0.01 mol L -1 ) and at room temperature (25±0.5 °C).Keywords: Rare metals; Recovery; Fly ash; Solid waste; Aminopolycarboxylate chelant; Ultrasound irradiation 2Water, Air, & Soil Pollution, 225(9): 2112 The original publication is available at: http://dx.doi.org/10.1007/s11270-014-2112-9 IntroductionThe consumption rates of the metals are continually increasing due to the diversification in applications. On the contrary, the supply of metals becomes more and more limited because the resources are nonrenewable (Guinée et al. 1999). The natural deposits of some metals, which have been increasingly consumed as a key material in clean energy applications or in designing alluring daily life gadgets, are unevenly distributed in the world and have an unsteady supply chain or fluctuating market price according to the policy of the resource country (Dodson et al. 2012, Massari & Ruberti 2013. The terminology, rare metal, is thus introduced to interpret such metals, which is not an academically defined one, and there is no consensus on which element it pertains (AIST Rare Metal Task Force 2008, Kooroshy et al. 2010). For example, in Japan, 31 ores, including the rare earth elements as a group, have been designated as rare metals in terms of the concern in securing a stable supply of resources (Kawamoto 2008). Consequently, other than the refinery production, the reclaim processing of rare metals from secondary resources, such as process discards from the rare metal-consuming manufacturing schemes (Hsieh et al. 2009, Liu et al. 2009, Kang et al. 2011, Li et al. 2011, Park 2011, Virolainen et al. 2011, Hasegawa et al. 2013b or end-oflife electronic products (Shimizu et al. 2005, Cui & Zhang 2008, Rabah 2008, Bertuol et al. 2009, Binnemans et al. 2013, Hasegawa et al. 2013c, Hasegawa et al. 2013a, received sincere focus from the researchers.Municipal solid waste (MSW) manageme...

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Supercritical fluid extraction of rare earth elements from luminescent material in waste fluorescent lamps

Cited by 119 publications

References 15 publications

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures

Recovery of the Rare Metals from Various Waste Ashes with the Aid of Temperature and Ultrasound Irradiation Using Chelants

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