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

Abstract

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...

Production of no-carrier-added 135La at an 18 MeV cyclotron and its purification for investigations at a concentration range down to 10−15 mol/L

“…The spectrum of this fraction is given in Figure 3a. La is eluted specifically with 6 M HNO 3 in the first three fractions (11)(12)(13) as expected from an extrapolated d -value below 0.01 [19]. The -ray spectrum of the main La fraction is given in Figure 3b.…”

“…Therefore, a detailed understanding of ore chemistry and separation methods is needed [4][5][6][7][8][9][10][11][12]. To study these processes, the use of the radiotracer technique is a marvellous method to observe the chemical behaviour of such elements.…”

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

“…193 Ultrasound can be used for the improved extraction of the chelant-assisted rare metal. 193 Ultrasound can be used for the improved extraction of the chelant-assisted rare metal.…”

Solid residues from Italian municipal solid waste incinerators: A source for “critical” raw materials

“…Critical Raw Materials (CRM) are chemical elements and minerals such as Be, Co, Cr, Ga, Ge, In, Mg, Nb, Sb, W, Platinum Group Elements (PGEs), Rare Earth Elements (REE), borates, coking coal, fluorspar, graphite, magnesite, phosphate rock, silicon metal, which are important for the technological development. In this regard, recent works reported the total content of CRM in solid residues from incineration plants (Hasegawa et al, 2014), also inspecting the annual flow for several elements (Morf et al, 2013;Allegrini et al, 2014).…”

“…The number of literature sources used to define the range in the tables is reported in parentheses. The sources were:Allegrini et al (2014),Hasegawa et al (2014), Sekito et al (2014), De Boom and Degrez (2012,Bayuseno and Schmahl (2010),Muchova et al (2009),Hyks (2009),Zhao et al (2008),Chung et al (2007),Jung and Osako (2007),Wan et al (2006),Fujimori et al (2004),Chandler et al (1997),Kida et al (1996). b The upper continental crust (UCC) mean values are fromRudnick and Gao (2014).…”