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Liquid–liquid extraction and recovery of indium using Cyanex 923
Abstract
The extraction of In(III) from HCl, H2SO4, and HNO3 media using a 0.20moll−1 Cyanex 923 solution in toluene is investigated. In(III) is quantitatively extracted over a fairly wide range of HCl molarity while from H2SO4 and HNO3 media the extraction is quantitative at low acid concentration. The extracted metal ion has been recovered by stripping with 1.0moll−1 H2SO4. The stoichiometry of the In(III): Cyanex 923 complex is observed to be 1:2. The extraction of In(III) is insignificantly changed in diluents namely toluene, n-hexane, kerosene (160–200°C), cyclohexane, and xylene having more or less the same dielectric constants, whereas, it decreases with increasing polarity of diluents such as cyclohexanone and chloroform. The extractant is stable towards prolonged acid contact and there is a negligible loss in its extraction efficiency even after recycling for 20 times. The extraction behavior of some commonly associated metal ions namely V(IV), Ti(IV), Al(III), Cr(III), Fe(III), Ga(III), Sb(III), Tl(III), Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Pb(II), and Tl(I) has also been investigated. Based on the partition data the conditions have been identified for attaining some binary separations of In(III). These conditions are extended for the recovery of pure indium from zinc blend, zinc plating mud, and galena. The recovery of the metal ions is around 95% with purity approximately 99%.
... Toward the development of recovery techniques of In(III) and Ga(III), a variety of extractants such as organic phosphoric acids [2][3][4][5][6][7][8][9], amines [10,11], carboxylic acids [12] and oximes [6,12,13] have been actively studied for the selective extraction of In (III) and Ga (III). Gupta et al. reported that In (III) and Ga (III) were qualitative extracted at hydrochloric acid concentrations of over 0.01 M(= mol dm -3 ) and 1 M hydrochloric acids, respectively when Cyanex 923 in toluene was used [14]. ...
... The extraction equilibria for metal ions were determined using a batchwise method at 303 K for 24 h. Equal volumes (10 cm 3 ) of the aqueous phase and organic phase were mixed in a 50 cm 3 ...
... In addition, the extraction selectivity of EHTG was compared with that of DDT. DDT could not be carried out at pH eq higher than 3 because of the precipitation of Ga(OH) 3 . As seen from Figure 2 (a), the extraction order for the metals with EHTG was Cu(II)>In(III)>Ga(III)>Zn(II), while Al (III) was not extracted with EHGT. ...
Extraction selectivity of In(III) and Ga(III) was investigated using 2-ethylhexyl thioglycolate (EHTG) with a thiol group and an oxygen atom to recover these metals from zinc refinery residue and waste solar panels. The extraction order with EHTG was Cu(II)>In(III)>Ga(III)>Zn(II), while Al(III) was hardly extracted at all. While In(III) and Ga(III) were not extracted at all with 1-dodecanethiol (DDT) with contains only a thiol group although Zn(II) and Cu(II) were extracted. This indicates that the oxygen atom in the EHTG ester plays an important role in the extraction of these metals. The mutual separation of In(III), Ga(III), Zn(II) and Cu(II) is possible in almost one step with EHTG. The extraction equilibria of In(III) and Ga(III) with EHTG are also discussed. Furthermore, the stripping of In(III) and Ga(III) extracted into the organic phase was achieved using appropriate concentrations of NaOH and acids.
... Solvent extraction (SX) is a well-established technique, which is widely used in industry to remove and recover metal ions from aqueous phases. Various organic solvents such as LIX 973N [2], a mixture of different phosphine oxides (Cyanex 923) [3], bis-(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) [4][5], di(2-ethylhexyl)phosphoric acid (D 2 HPA) [6][7][8][9], tributyl phosphate (TBP), a mixture of D 2 EHPA and TBP [10] and PC88A [11][12]have been studied for indium extraction. Among them, organophosphorus extractants in kerosene are the most practical for the extraction of trivalent ions due to their stability, high distribution ratio for metal extraction, low water solubility and high selectivity for metal ions. ...
... Thus, SLM-SD is an efficient process for extraction/separation/recovery of valuable metals. As mentioned above, the extraction and separation of indium from LCD wastes by solvent extraction have been widely reported in the last few years [2][3][4][5][6][7][8][9][10][11][12]. However, there is no information regarding the simultaneous selective extraction and separation of In from LCD waste using the SLM-SD system. ...
... By increasing the acid concentration to 4 M, more than 88% of indium could be recovered by HCl whereas the recovery of indium using 6 M HNO 3 and H 2 SO 4 for stripping was only 30% and 36%, respectively. This finding differs to that from previous reports, which was found that 1 M H 2 SO 4 could strip indium from the extractant [4,[7][8]. This is probably due to the use of strong acid (3 M HCl) to leach indium from LCD waste in the first step of this study and thus, a higher acid concentration is required for back-extraction of the indium in the loaded organic phase. ...
The feasibility to recover indium (In) from discarded liquid crystal display (LCDs) panels by solvent extraction (SX) and a hollow fiber supported liquid membrane with strip dispersion (SLM-SD) system was investigated in this study. Di-(2-ethylhexyl)phosphoric acid (D2EHPA) was used as the extractant and the mobile carrier in SX and SLM-SD. The effect of different parameters such as pH, concentration of D2EHPA and stripping agents has been investigated for indium extraction. The average amount of indium in LCD screen was found to be 330 mg/kg and 70% of this indium was easily leached out by 3 M HCl in 30 min. An increase in the D2EHPA concentration from 0.025 to 0.25 M increased the extraction of indium and 79% of indium can be recovered by back-extraction with 2 M hydrochloric acid. For the SLM-SD system, more than 94% of indium can be recovered within 20 min under the same operating conditions. This indicates that the SLM-SD was more efficient for indium extraction than SX. However, a poor separation of iron and indium resulted on increasing the extraction time. Hence, process optimization for iron removal must be explored in a future work.
... A previous literature study [3] reviewed many organic molecules and showed that both solvating and acidic organophosphate extractants can separate indium from other metal ions dissolved in various acidic aqueous media. Examples of this type of extractants are bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) [4], bis-2,2-ethylhexyl phosphoric acid (D2EHPA) [5], and Cyanex 923 [6]. In more recent studies, Kang et al. [7] investigated the recovery of indium from etching waste by leaching with NaOH and HCl, followed by solvent extraction with 2-ethylhexyl phosphonic acid mono(2-ethylhexyl) ether (PC88A). ...
... Therefore, for the extraction of indium from 1 M H 2 SO 4 and stripping using 1 M HCl, the recommended D2EHPA concentration is 0.25 M. Figures 9 and 10, the effect of temperature on extraction constant, ex , was calculated for In, Fe, and Sn according to (4). ex for indium was calculated from the extraction reaction proposed in (5) and (6). Based on results shown in Figures 6 and 7, (7) to (10) were proposed for the extraction reactions for iron and tin, and these equations were used to calculate ex values for these two metals: ...
... By comparing the two systems, it can be seen that both Δ ∘ and Δ ∘ are lower in the chloride system compared to the sulfate system. The difference can be explained by (5) and (6). In sulfate media, for each extracted In 3+ ion, three H + ions were released to the aqueous phase, while for chloride 6 International Journal of Chemical Engineering media the ratio was 1 : 2. Therefore there was a greater increase in configurational entropy when indium was extracted from H 2 SO 4 . ...
Indium tin oxide (ITO) is currently the choice of electrode material in liquid crystal displays (LCDs). D2EHPA is known to be an extractant that can be used to selectively recover indium from 1 M sulfuric acid. In order to optimize the extraction and separation of indium from LCD waste, the effects of pH, temperature, time, and extractant concentration on the distribution ratios of In(III) and the major impurities such as Al(III), Cu(II), Fe(III), and Zn(II) were investigated. Metal concentrations in the aqueous feed were based on the concentrations found in the leach liquor of LCD panel glass at 0.1 g/mL S/L ratio. This study showed that extraction of indium could be increased at <293 K and stripping of indium could be increased at >293 K. Furthermore, by increasing D2EHPA concentration from 0.1 M to 0.25 M, extraction of indium could be increased from 70% to >95%.
... Solvent extraction behavior of p-tert-butylcalix [4]arene tetrahydroxamic acid towards some trivalent as well as divalent cations was studied. The extraction selectivity of some cations followed the order Ga(III) > In(III) > Fe(III) > Cu(II) >> Zn(II), Ni(II). ...
... Among the various systems, the most often used are phosphorous-based extractants and resins [2][3][4][5]. ...
... Therefore, functionalized calixarenes are most promising candidates as highly selective and efficient solvent extraction reagents towards the target species. In our earlier reports, the solvent extraction behavior of calix [4]-, [5]-and [6]arene derivatives containing carboxylic acid groups was described [23,24]. These ligands selectively and very effectively extracted the trivalent metal cations Fe(III), In (III) and Ga(III) over the divalent cation Zn(II) as a function of pH. ...
Solvent extraction behavior of p-tert-butylcalix[4]arene tetrahydroxamic acid towards some trivalent as well as divalent cations was studied. The extraction selectivity of some cations followed the order Ga(III) > In(III) > Fe(III) > Cu(II) >> Zn(II), Ni(II). Since the extraction reagent exhibited high selectivity for Ga(III) and In(III), the detailed extraction behavior for Ga(III) and In(III) was investigated by slope analysis, the continuous variation method, and by loading tests. It was confirmed that both metals formed 1:1 complexes with the extraction reagent. Since the pKa values for hydroxamic acids are 8-9, there was 6-7 units of pH shift in the metal extraction caused by the complexation of Ga(III) indicating that this ligand served as an excellent reagent for selective extraction of Ga(III). The coordination site of the ligand for both metals was qualitatively investigated by IR spectra before and after metal loading on the ligand. The loaded Ga(III) was quantitatively stripped by using dilute acidic solutions and the ligand was regenerated.
... Für Cyanex 923 wurde eine quantitative Extraktion aus sulfatischen Medien bei pH > 1,5 im Phasenverhältnis von 1:1 beschrieben [18]. Diese Diskrepanz ist auf das von Gupta et. ...
... Diese Diskrepanz ist auf das von Gupta et. al. [18] benutzte höhere Phasenverhältnis zurückzuführen. ...
de Die Extraktion von Indium aus einer synthetischen, sulfathaltigen Lösung unter Verwendung von handelsüblichen Reagenzien (Cyanex 272, DEHPA und Cyanex 923) wird vergleichend bewertet. Die Extraktionsprofile von Indium (III) wurden im Hinblick auf die Reagenzkonzentration, den pH‐Wert der wässrigen Lösung und die Indiumkonzentration in einem niedrigen Phasenverhältnis von 1:10 untersucht. DEHPA und Cyanex 272 sind im Gegensatz zu Cyanex 923 sehr gut zur Extraktion von Indium geeignet. Die Reextraktion mit HCl und H2SO4 wird vergleichend betrachtet.
Abstract
en The extraction of indium from a synthetic sulfate‐containing solution using commercial reagents (Cyanex 272, DEHPA, and Cyanex 923) is evaluated on a comparative basis. The extraction profiles of indium (III) were examined with regard to the reagent concentration, the pH value of the aqueous solution, and the indium concentration in a low phase ratio of 1:10. DEHPA and Cyanex 272 are, in contrast to Cyanex 923, very well suited for the extraction of indium. Re‐extraction with HCl and H2SO4 is compared.
... (Findlay and Kasian, 1990;Paerl, 2009;Tang et al., 2011;Jovan et al., 2012) We, on the other hand, have studied the extraction behavior of indium, gallium, and zinc from a spent IGZO target in HCl solution. As for the extractants, D2EHPA has been utilized to separate indium from gallium (Lee et al., 2002) or zinc ; tributyl phosphate (Virolainen et al., 2011) was used to selectively extract indium from an indium tin oxide (ITO) leaching solution; and Cyanex 923 (Gupta et al., 2004), Cyanex 925 (Ahmed et al., 2013), and Cyanex 272 (Gupta et al., 2007) and other extractants have been adopted to extract indium in acid solutions (Gupta et al., 2004;Gupta et al., 2007;Ahmed et al., 2013;Zhang et al., 2015). To separate valuable metals (indium and gallium) from spent IGZO targets in a sustainable and commercially viable manner, a two-step SX process using commercially available extractants without diluting the leaching solution before extraction was proposed. ...
... (Findlay and Kasian, 1990;Paerl, 2009;Tang et al., 2011;Jovan et al., 2012) We, on the other hand, have studied the extraction behavior of indium, gallium, and zinc from a spent IGZO target in HCl solution. As for the extractants, D2EHPA has been utilized to separate indium from gallium (Lee et al., 2002) or zinc ; tributyl phosphate (Virolainen et al., 2011) was used to selectively extract indium from an indium tin oxide (ITO) leaching solution; and Cyanex 923 (Gupta et al., 2004), Cyanex 925 (Ahmed et al., 2013), and Cyanex 272 (Gupta et al., 2007) and other extractants have been adopted to extract indium in acid solutions (Gupta et al., 2004;Gupta et al., 2007;Ahmed et al., 2013;Zhang et al., 2015). To separate valuable metals (indium and gallium) from spent IGZO targets in a sustainable and commercially viable manner, a two-step SX process using commercially available extractants without diluting the leaching solution before extraction was proposed. ...
Indium, gallium, and zinc oxide (IGZO) is a semiconducting material that is widely used in the manufacturing of semiconductors, touch panels, displays, etc. This work aims to shed some light on the recovery and separation of indium, gallium, and zinc from spent IGZO targets by solvent extraction (SX). The process involved leaching, SX in high acidity, stripping, re-extraction in low acidity, and re-stripping, followed by the cementation of the gallium and indium with zinc dust. Triisobutyl phosphate (T-iso-BP) was employed as the extractant to separate the majority of zinc from indium and gallium in the leaching solution. The leaching solution was utilized directly without further adjustment, to avoid consuming an enormous amount of water. The loaded organic (LO) solution was then stripped with HCl solution at pH 2, moving the majority of indium and gallium from LO phase to aqueous phase. The extraction and stripping process enabled the transfer of indium and gallium from the leaching solution (8–8.5 mol/L HCl solution) to HCl solution at pH 2, without diluting the leaching solution with an enormous amount of water. The stripped solution was then extracted with di-(2-ethylhexyl) phosphoric acid to separate indium from gallium. The optimum extraction conditions and stripping conditions were studied. From the actual spent IGZO target, 97.8% of indium with a purity of 98.3% and 96.2% of gallium with a purity of 99.6% were separated and recovered.
... In particular, indium oxide combined with tin oxide (at an approximate mass ratio of 9:1) can be employed to produce the Indium Tin Oxide (ITO) films used in liquid crystal display (LCD) panels; this application accounts for nearly 80% of the total consumption of indium (Park et al., 2009). Because of the lack of independent indium ores, the world-wide indium production primarily depends on the by-product of Sphalerite and lead mineral ores, especially in China (Frenzel et al., 2016;Gupta et al., 2004;Zhang et al., 2016). Moreover, driven by the growing LCD market, the increasing indium demand further provides a challenge for the sustainable application of indium deposits. ...
... In the existing research studies concerning indium recycling from waste LCDs, hydrometallurgy involving leaching and extraction has been the most common method used. Because the appropriate extractant (P204, Cyanex923, PC88A) and techniques for leaching are well established in the massive indium production industry (Gupta et al., 2004;Jinhui et al., 2012;Kang et al., 2013), leaching can be the foremost step to recycle indium effectively from waste LCD. To liberate ITO efficiently and facilitate the subsequent leaching among the glass particles with acid, the mainstreams of research studies inevitably involved various crushing methods and applicable tools hammer (Hasegawa et al., 2013), ball mills and even high-energy ball milling (Lee et al., 2013) and explored the crushing time and optimum particle sizes (Ghosh et al., 2009). ...
The tremendous amount of end-of-life liquid crystal displays (LCDs) has become one of the prominent sources of waste electrical and electronic equipment (WEEE) in recent years. Despite the necessity of safe treatment, recycling indium is also a focus of waste LCD treatment because of the scarcity of indium. Based on the analyses of the structure of Indium Tin Oxide (ITO) glass, crushing is demonstrated to be not required. In the present research, a complete non-crushing leaching method was firstly adopted to recycle indium from waste LCDs, and the ultrasonic waves was applied in the leaching process. The results demonstrated that indium can be leached efficiently with even a low concentration of chloride acid (HCl) without extra heating. About 96.80% can be recovered in 60 mins, when the ITO glass was leached by 0.8 M HCl with an enhancement of 300 W ultrasonic waves. The indium leaching process is abridged free from crushing, and proves to be of higher efficiency. In addition, the ultrasonic wave influence on leaching process was also explained combing with micron-scale structure of ITO glass.
... Für Cyanex 923 wurde eine quantitative Extraktion aus sulfatischen Medien bei pH > 1,5 im Phasenverhältnis von 1:1 beschrieben [18]. Diese Diskrepanz ist auf das von Gupta et. ...
... Diese Diskrepanz ist auf das von Gupta et. al. [18] benutzte höhere Phasenverhältnis zurückzuführen. ...
No abstract is available for this article.
... The leaching, extraction, and combustion processes can be explained by the following chemical equations: In the given composition of the leaching reagent, it can be assumed that indium should primarily be dissolved as InCl3. The extraction of indium chloro-complex by Cyanex 923 has been described in the literature through a solvation mechanism [22]. As discussed in the previous section, the extraction of indium from the leaching solution 'L1' was selective towards tin. ...
... The leaching, extraction, and combustion processes can be explained by the following chemical equations: In the given composition of the leaching reagent, it can be assumed that indium should primarily be dissolved as InCl 3 . The extraction of indium chloro-complex by Cyanex 923 has been described in the literature through a solvation mechanism [22]. As discussed in the previous section, the extraction of indium from the leaching solution "L1" was selective towards tin. ...
High-purity In2O3 nanoparticles were recovered from scrap indium tin oxide substrates
in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide
extractant, and combustion of the organic phase. The morphological and structural parameters of
the recovered nanoparticles were investigated to support the formation of the desired products.
These In2O3 nanoparticles were used for sensitive sensing of ammonia gas using a four-probe
electrode device. The proposed sensor offered very quick response time (around 10 s) and highly
sensitive detection of ammonia (at a detection limit of 1 ppm).
... Lately Cyanex 923, a mixture of four tri-alkylphosphine oxides (R 1 3 P=O, R 3 P=O, R 1 2 RP=O, R 1 R 2 P=O where R 1 = n-octyl and R = n-hexyl) has come up to the forefront as a good extractant because of its poor solubility, complete miscibility with common organic diluents and resistance to hydrolysis. Recently Cyanex 923 has been used for quantitative separation of several metal ions [12][13][14][15][16] . Solvent extraction of copper (II) from sulfate media using Cyanex 923 has been reported 17,18 . ...
... Research Journal of Chemistry and Environment _____________________________________ Vol.16 (3) Sept (2012) Res.J.Chem.Environ. (14) different ores. Known weight of ore was heated up to 700 0 C for 2 hours to remove organic matter. ...
The selective and effective liquid-liquid extra-ction method has been developed for separation of copper(II). Copper(II) was found to be quantitatively extracted using 0.1 M Cyanex 923 in toluene from 1.0 M ammonium thiocyanate and from organic phase, it can be quantitatively stripped with 3.0 M nitric acid. The optimum extraction conditions have been evaluated by studying parameters such as ammonium thiocyanate concentration, Cyanex 923 concentration, equilibration time, various diluents, diverse ions and stripping agents. Based on these results sequential separation of copper(II) from associated metal ions was achieved. The method is successfully employed for the determination of copper(II) in some micron-trients, alloys and aquatic plants. The reliability of method is assured by comparison of the results with those obtained using AAS.
... The recycling technologies for precious metals such as indium from BFD are progressive with the aims of enhancing recovery rate and reducing the environmental pollution. The researches in recent years mainly focus on optimizing the leaching and extraction process [99]. The raw materials for each technology may be different, but the method is feasible for BFD and its secondary dust recycling, especially for indium recovery. ...
A large amount of dust is formed as one of the primary by-products during the blast furnace ironmaking process. Besides iron and carbon, it contains a variety of valuable metals such as zinc, lead, and indium widely applied in many industry fields. However, it is difficult to recycle and reutilize blast furnace dust (BFD) due to complex composition, fine particle size, and strong hydrophobic property. The extensive utilization of BFD wastes precious metal resources and decreases the additional value of recovery. Environment-oriented technologies have raised great attention in the recycling of precious metals. This article presents an overview of various technologies and the prospect of utilization on the recovery of BFD. The source, composition, and characteristics of BFD, as well as the recycling technologies within the blast furnace system are analyzed. Fundamental studies regarding pyrometallurgy and hydrometallurgy for recycling valuable metals from BFD such as direct reduction, leaching, and extraction, as well as its advantages and challenges, are also discussed. There is also great potential for BFD in other fields, including flocculants, cement raw materials, and adsorbents. The diverse chemical properties of BFD make it a contender for selective separation and adsorption in water pollution treatment. The development of pyrometallurgy technologies is mainly to realize its green and clean production. The innovative technologies in hydrometallurgy mainly aim to improve the leaching and extraction efficiency of high-valued metals. The combination of pyrometallurgy and hydrometallurgy technologies achieves the environment-friendly and sustainable recycling for precious metals with a higher recovery rate.Graphical Abstract
... Inoue K., et al were studied the extraction of indium with PC-88A (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) from sulfuric acid [6] and cyanex 925 and trioctylphosphine oxide (TOPO) as an extractant to separate tin from indium in the low concentrated region of sulphuric acid in toluene as a solvent [7]. The mixture of 5-dodecyl-salicyldoxime and 2-hydroxy-5nonylacetophenone oxime (LIX-973 N) [8] and cyanex 923 was also used to extract In(III) [9]. However equilibrium extraction required use of modifier and high reagent concentration. ...
In this study, extraction of indium(III) was quantitative at pH 6.0 in toluene with 1 x 10-4 M acetyl derivative of calix(6)arene having shaking period of ten minutes. In(III) was stripped with 5 N HCL and determined photometrically. The thermodynamic functions ∆H 0 , ∆G 0 and ∆S 0 were evaluated by varying extraction temperature. The capacity of reagent to extracted metal ion was 150 ppm. Masking agent increases the selectivity of extraction. The extraction process was applied to foreign ion effect, synthetic mixture and analysis of IR LED sample. Obtained data were good agreement with reported value with RSD 0.22%.
... 16,17 Solvating extractants tested for indium extraction include tri-n-butylphosphate (TBP), 6,18 and the commercial mixtures of trialkylphosphine oxides Cyanex 923. 19,20 A current trend is the use of ionic liquids, either as extractants, diluents or both, for the rening of indium by solvent extraction. [21][22][23][24][25][26][27][28] In comparison to conventional molecular solvents, ionic liquids could lead to inherently safer and more sustainable separation processes because of their low ammability, high thermal stability and negligible vapor pressure. ...
A solvometallurgical process for the separation of indium(III) and zinc(II) from ethylene glycol solutions using the ionic liquid extractants Cyphos IL 101 and Aliquat 336 in an aromatic diluent has been investigated. The speciation of indium(III) in the two immiscible organic phases was investigated by Raman spectroscopy, infrared spectroscopy, EXAFS and ¹¹⁵In NMR spectroscopy. At low LiCl concentrations in ethylene glycol, the bridging (InCl3)2(EG)3 or mononuclear (InCl3)(EG)2 complex is proposed. At higher lithium chloride concentrations, the first coordination sphere changes to two oxygen atoms from one bidentate ethylene glycol ligand and four chloride anions ([In(EG)Cl4]⁻). In the less polar phase, indium(III) is present as a tetrahedral [InCl4]⁻ complex independent of the LiCl concentration. After the number of theoretical stages had been determined using a McCabe–Thiele diagram for extraction by Cyphos IL 101, the extraction and scrubbing processes were performed in lab-scale mixer–settlers to test the feasibility of working in continuous mode. Indium(III) was extracted quantitatively in four stages, with 19% co-extraction of zinc(II). The co-extracted zinc(II) was scrubbed selectively in six stages using an indium(III) scrub solution. Indium(III) was recovered from the loaded less polar organic phase as indium(III) hydroxide (98.5%) by precipitation stripping with an aqueous NaOH solution.
... As shown in this figure it is possible to concentrate the indium recovered 6 times, reaching a final concentration of 390 mg/L. This concentration is enough to guarantee that indium can be recovered from the solution by extraction with solvents [36]. Despite the decrease of volume of regenerative solution, the mass of In 3þ recovered was all cases is the same (0.1 mg). ...
In this work, a new mesoporous activated carbon (MC01) suitable for the adsorption of indium from aqueous solutions has been synthetized; with the final aim of pre-concentrating this ion metal. The new material was synthesized by replica method using sucrose and silica gel as raw materials, and adjusting both carbonization time and temperature to obtain a material whose surface is mainly constituted by phenolic groups. This way, its pH value in aqueous suspensions makes it suitable for indium adsorption. The mesoporous carbon is able to remove around 96% of the indium, attaining equilibrium in less than 15 min.
The study of the adsorption conditions indicates that the adsorbent dosage has a large impact on the process, being 10.0 mg/g the optimum dosage. On the contrary, the process is highly pH dependent since the adsorption capacity decreases by a 68% if the pH is lowered from 3.5 to 2; however, buffered media slightly affect the process, with a decrease of the indium adsorption capacity around 5%, due to the presence of foreign ions.
The recovery of the adsorbed indium was carried out employing HNO3 and HF solutions, proving that low pH values promote this phenomenon, reaching a recovery rate of 82% with a pH = 0.5 HNO3 solution. Additionally, the pre-concentration of indium was analyzed by diminishing the volume of regenerative solution. The results indicated that, when the volume of regenerative solution was decreased by one-eight part, the indium concentration increased six fold. Thus, adsorption is suitable for the pre-concentration of metallic indium ions in water solutions to be further recovered by any other technique, such as extraction.
... (Semkow et. al [12]) showed that sorption of three metal ions were different onto three sorbents but decreases sharply with increasing the concentration of HCl, due to the formation of InCl 3 , CdCl 2 and CuCl 2 at low acidity. ). ...
... In current years, various extractants are widely used and studied to separate and purify indium from wastes in the process of solvent extraction. Main extractants included (2-ethylhexyl) phosphoric acid (D2EHPA) , tributyl phosphate (TBP) (Yang et al., 2013), (Cyanex 923) (a mixture of different phosphine oxides) (Gupta et al., 2004), and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) (Kang et al., 2013). Yannick-Serge Zimmermann (Zimmermann et al., 2014) first investigated the capability of different nanofiltration membranes of extracting indium from copper-indium-gallium-selenide photovoltaic cell (CIGS) leachates under low pH conditions and low transmembrane pressure differences (<3 bar), and then retentates were subjected to a further selective liquid-liquid extraction. ...
... Thus, liquid-liquid extraction is often proposed to recover In selectively from the leaching solutions. Acidic [58,[91][92][93]98] (bis(2-ethylhexyl)phsosphoric acid -DEHPA, 2-ethylhexyl-2-ethylhexylphosphonic acid -EHEHPA, bis(2,4,4-trimethylpentyl)phosphinic acid -Cyanex 272), basic [98] (trioctylamine, mixture of tertiary amines -Adogen 364, tetrabutylammonium chloride) or solvating [91,92,[98][99][100][101] extractants (tributyl phosphate, trioctylphosphine oxide, mixture of trialkylphosphine oxides -Cyanex 923, Cyanex 925, methyl isobutyl ketone) are proposed as indium extractants. ...
E-waste amount is growing at about 4% annually, and has become the fastest growing waste stream in the industrialized world. Over 50 million tons of e-waste are produced globally each year, and some of them end up in landfills causing danger of toxic chemicals leakage over time. E-waste is also sent to developing countries where informal processing of waste electrical and electronic equipment (WEEE) causes serious health and pollution problems. A huge interest in recovery of valuable metals from WEEE is clearly visible in a great number of scientific, popular scientific publications or government and industrial reports
... Thus, liquid-liquid extraction is often proposed to recover In selectively from the leaching solutions. Acidic [58,[91][92][93]98] (bis(2-ethylhexyl)phsosphoric acid -DEHPA, 2-ethylhexyl-2-ethylhexylphosphonic acid -EHEHPA, bis(2,4,4-trimethylpentyl)phosphinic acid -Cyanex 272), basic [98] (trioctylamine, mixture of tertiary amines -Adogen 364, tetrabutylammonium chloride) or solvating [91,92,[98][99][100][101] extractants (tributyl phosphate, trioctylphosphine oxide, mixture of trialkylphosphine oxides -Cyanex 923, Cyanex 925, methyl isobutyl ketone) are proposed as indium extractants. ...
E-waste amount is growing at about 4% annually, and has become the fastest growing waste stream in the industrialized world. Over 50 million tons of e-waste are produced globally each year, and some of them end up in landfills causing danger of toxic chemicals leakage over time. E-waste is also sent to developing countries where informal processing of waste electrical and electronic equipment (WEEE) causes serious health and pollution problems. A huge interest in recovery of valuable metals from WEEE is clearly visible in a great number of scientific, popular scientific publications or government and industrial reports.
... Solvent extraction method has been widely used for indium recovery by many researchers. In recent years, organophosphates including Cyanex 272 (Gupta et al., 2007), Cyanex 923 (Gupta et al., 2004), LIX 984, D2EHPA, (Lupi and Pilone, 2014) and IONQUEST 801 (Agarwal et al., 2014) have attracted lot of attention, which could be efficient extracting agents for extraction of In(III) (Li et al., 2015b). Although solvent extraction is a practical approach with high efficiency, it suffers from, high operational costs of multi separation steps and loss of expensive and non-environmental friendly solvents (Navarro et al., 2009). ...
This papers details a simple, sustainable approach for the recovery and concentrating of indium from waste scrap LCD panels. After manual dismantling, the glass fraction of the panel was pulverized through a mechanical treatment, Indium from crushed glass was then mobilized in an acidic solution such as HCl:HNO3 lixiviant followed by an ultrasonic wave. Indium was successfully adsorbed by three macro porous polystyrene-divinylbenzene resins (Lewatit TP 208, Lewatit TP 260 and Amberlite IRA 743) and the influence of pH, weight of resin, contact time, temperature and type of resin on the efficiency of sorption process were investigated and the optimum condition was found. Theoretical calculations, indicated the In(III) phase formed through the leaching process was InCl3(aq). The adsorbed In(III) onto the resins was effectively desorbed in acidic medium to prepare concentrated indium solution. For the kinetic study, the adsorption onto Lewatit TP 208, Lewatit TP 260 and Amberlite IRA 743 could be fitted to pseudo second-order.
... Various preconcentration/separation tools are employed. Several researchers have studied the fundamental extraction behavior and the mutual extractive separation of group 13 metal cations using many kinds of extractants using liquid-liquid extraction [13][14][15][16][17][18][19]. Solid phase extraction (SPE) is also used for the separation and preconcentration of heavy metal ions [20][21][22][23][24][25][26][27][28][29]. ...
... The rare-earth metals such as praseodymium and samarium (El-Nadi 2010), various lanthanides and yttrium (Gupta et al. 2003), cerium and thorium (Jun et al. 1998), La, Ce, Pr, Nd and Sm (Lee et al. 2009), scandium (Li and Wang 1998), Y, La, Nd, Eu, Tb, Ho, Tm and Lu (Reddy et al. 1998) and Ytterbium (Weiwei et al. 2006) were also extracted by Cyanex 923 and reported. It is also used for extraction of different metal ions other than rare earths, such as Co, Ni, Cd, Zn, In, Sc, Hg, etc. (Meera et al. 2001;Gupta et al. 2004;Sarangi et al. 2007). So to know the extraction efficiency of Cyanex 923 for dysprosium a detailed study has been carried out. ...
The solvent extraction of dysprosium from an aqueous solution containing 1 g L⁻¹ Dy and 0.2 M NaNO3 by Cyanex 923 was carried out. From some preliminary experiments, it was observed that the extraction of Dy in the presence of NaNO3 was more than that in the presence of NaCl and Na2SO4. The influence of equilibration time, equilibrium pH, extractant concentration, temperature, salt concentration and stripping agents were investigated. The McCabe–Thiele diagrams for extraction and stripping were constructed with 0.2 M Cyanex 923 and 0.1% sulphuric acid, respectively. The extraction of Dy was 98.4% in three countercurrent stages at pH 1.5 and A:O phase ratio of 2:1. The loaded organic was stripped with HCl, HNO3 and H2SO4 and the stripping efficiencies of these acids followed the trend HCl < HNO3 < H2SO4. The McCabe–Thiele diagram for stripping with H2SO4 showed two stages at A:O ratio of 2:3 for quantitative stripping. The species extracted to the organic phase was determined to be . The change in enthalpy (ΔH), entropy (ΔS) and free energy change (ΔG) were calculated to be –45.86 kJ mol⁻¹, −120.63 J mol−1 K⁻¹ and 33.58 to −39.82 kJ mol⁻¹, respectively. Also, the synergistic effect of D2EHPA, Cyanex 272 and PC88A with Cyanex 923 was investigated.
... Indium(III) can be effectively extracted by Cyanex 923 dissolved in toluene from HCl, H 2 SO 4 and HNO 3 solutions. Indium can be stripped off selectively from the organic phase with a final recovery of 95% and 99% purity (Gupta et al., 2004). Leaching of crushed LCD glass was investigated by using HCl, HNO 3 and H 2 SO 4 . ...
The present paper deals with physico-mechanical pre-treatments for dismantling of spent liquid crystal displays (LCDs) and further recovery of valuable fractions like plastic, glass and indium. After a wide experimental campaign, two processes were designed, tested and optimized. In the wet process, 20%, 15% and 40% by weight of the feeding panels are recovered as plastic, glass and indium concentrate, respectively. Instead, in the dry process, only two fractions were separated: around 11% and 85% by weight are recovered as plastic and glass/indium mixture. Indium, that concentrated in the -212μm fraction, was completely dissolved by sulphuric acid leaching (0.75molL(-1) H2SO4 solution, 80°C, 10%vol H2O2, pulp density 10%wt/vol, leaching time 3h). 100% of indium can be extracted from the pregnant solution with 5%wt/vol Amberlite™ resin, at room temperature and pH 3 in 24h. Indium was thus re-extracted from the resin by means of a 2molL(-1) H2SO4 solution, at room temperature and S/L of 40%wt/vol.
... The separation scheme developed for synthetic mixture (Fig. 12) was applied to zinc plating mud leach liquor for the recovery of Zn(II). As leach liquor contains reasonably high concentration of Fe(III), a minimum of 100-fold molar excess of ascorbic acid was added to reduce Fe(III) to Fe(II) to minimize the co-extraction of Fe(III) along with Zn(II) [63]. ...
Indium recovery from spent liquid crystal displays (LCDs) of monitors was studied by using microwave pyrolysis as a pretreatment step prior to hydrometallurgical processes including acid leaching, solvent extraction, and stripping. After microwave pyrolysis at 150 W for a processing time of 50 min, the hydrometallurgical processes were carried out to sequentially solubilize and increase the purity of indium ions in the product solution. The leaching efficiency of indium was approximately 98 % when using 0.5 M of sulfuric acid at a solid-to-liquid ratio (S/L) of 0.1 g/mL. Afterwards, the indium ions in the leachate were extracted by using 20 % di(2-ethylhexyl)phosphoric acid (D2EHPA) in kerosene. The purity of indium ions in the organic phase was approximately 87 % at an oil-to-aqueous ratio (O/A) of 1/10. Finally, the indium ions in the extract were stripped by using 6 M of hydrochloric acid at an O/A ratio of 10/1. The purity of indium ions in the aqueous phase was as high as 99.98 %. The final recovery rate of indium from spent LCDs was approximately 75 %, substantially higher than those that were obtained by using shredding or grinding pretreatment. The maximum processing capacity of microwave pyrolysis of spent LCDs could be approximately 500 g, which means that it would only need 0.5 kWh of electricity for the microwave pyrolysis of 1 kg of spent LCDs. According to the experimental results and advantages, it can be concluded that microwave pyrolysis is an effective technique for the pretreatment of spent LCDs.
Gallium arsenide is used in semiconductor industries worldwide. Numerous waste etching solutions are produced during the processes of GaAs wafer production. Therefore, a complete and eco-friendly technology should be established to recover gallium as a gallium chloride solution and remove arsenic ion from waste GaAs etching solution. In this study, the gallium trichloride and arsenic trisulfide powders were dissolved in ammonia solutions to prepare the simulated solutions, and the pH value was adjusted to pH 2 by nitric acid. In the extraction step, the GaAs etching solutions were extracted using 0.5 M Cyanex 272 solutions in kerosene at pH 2 and 0.1 O/A ratio for 5 min. The extraction efficiency attained 77.4%, which had an optimal ratio of concentration, and the four steps extraction efficiency attained 99.5%. After extraction, iron sulfate heptahydrates were added into the raffinate, and the arsenic ions were precipitated. The removed rate attained 99.9% when the Fe/As ratio was 10. In the stripping step, the organic phase was stripped with 0.5 M hydrochloric acid at 1 O/A ratio for 3 min, and 97.5% gallium was stripped. Finally, the purity of gallium chloride solution was 99.95% and the gallium was seven times the concentration of the etching solutions.
With inimitable chemical and physical properties makes indium critical for a wide variety of high technology, chemical, metallurgical and pharmaceutical industries. As conferred by its location in the periodic table near the borderline between metals and non-metals; indium shows ductility, malleability, conductivity and transparency. In particular, the last two properties are the main reason for indium use in the semiconductor industry for flat panel displays and screens manufacturing by far the most important applications of indium in technical uses. The present study emphasized the extraction ability of a phosphonium based ionic liquid Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl) phosphinate) towards indium(III) extraction from acidic chloride medium. The effect of various parameters such as equilibrium time, acid concentration, chloride ion and hydrogen ion was investigated on In(III) extraction. Quantitative extraction of 97.2% was attained with 0.005 mol/L Cyphos IL 104 in toluene at 2.0 mol/L HCl. The effect of thermodynamic parameters i.e., ΔH°, ΔS° and ΔG° were also studied which suggested that the extraction process was endothermic and spontaneous that moves in the forward direction. Using 0.1 mol/L HCl, 100% of indium(III) was recovered from the loaded organic phase.
In this study, activated carbon (AC) modified by sodium dodecyl sulphate (SDS), written as SDS/AC, has been proposed for preconcentration and determination of indium from aqueous solutions in a solid phase extraction technique. AC was put on the membrane filter in the column, and SDS was added into sample solutions. Subsequently, with the SDS modification on AC, the preconcentration of indium onto the adsorbent was simultaneously performed in the flow system as solid-phase extraction. After the preconcentration step, indium retained on SDS/AC was eluted with 1 mol L⁻¹ HNO3, and the indium concentration in collected eluent was determined by electrothermal atomic absorption spectrometry (ETAAS). Some important analytical parameters, such as the conditions of adsorbent, sample solution, eluent and interfering elements, were investigated and optimised for the quantitative determination of trace indium. In the case of sample solution of 200 mL at 1 μg L⁻¹ indium, the enrichment factor and the relative standard deviation (n= 5) were 363% and 3.8%, respectively. The detection limits (3S/N) were calculated to be 0.2 ng L⁻¹. This developed procedure was successfully applied into the separation and determination of trace amount of indium from environmental samples.
Continuous counter-current foam separation (CCFS) with simultaneous injections of metal and surfactant solutions respectively into rising foam bed was applied to In(III) recovery from sulfuric acid solutions containing ternary metal ions of In/Cu/Zn. Through the screening tests of the surfactants in both conventional batch foam separation and CCFS, anionic organophosphate surfactant which has similar structure to phosphoric acid extractant (D2EHPA) was selected as the metal collector, with an addition of a nonionic co-surfactant as the foam stabilizer. The optimized surfactant combination was shown anionic A219B/nonionic POOE20 in this study; the complete recovery of In(III) was attained with the enrichment ratio of 5.5, whereas those of the other metals were suppressed in trace level, resulting in the excellent selective recovery. Moreover, metal solutions of quaternary In/Fe/Cu/Zn were also examined, and a dose of reductant for interfering Fe(III) into the metal solution was executed for improving the separation efficiency; the dose of ascorbic acid could invert the affinity order of A219B from Fe > In to In > Fe. The percent recovery and enrichment ratio of In(III) were 97% and 5.5, while the separation factors of In/Fe, In/Cu and In/Zn were 93, 1300 and 1300 respectively. This is our first favorable case for expanding the choice range of target metal ions in CCFS using anionic surfactants.
A radiotracer technique has been used to achieve the carrier-free separation of 115mIn from its parent ¹¹⁵Cd in hydrochloric acid medium on a chromatographic column packed with TODGA-impregnated silica gel. At 8 M HCl, both cations are bound at the chelating site, which results in maximum adsorption. When the column is treated with 2 M HCl, the daughter complex gets desorbed and is eluted from the column, whereas the parent remains undisturbed. Pure silica gel does not adsorb radioactivity under these conditions. The radiochemical purity of daughter was checked by its half-life (4.49 h).
Considering the growing demand for In(III) and Ga(III) for the manufacture of advanced materials, it is necessary to develop efficient separation processes for recovery of these metals from primary and secondary resources. In the present work, separation of In(III) and Ga(III) from different aqueous mediums by solvent extraction, ion exchange, and solvent-impregnated resins/gels was reviewed. Although complete separation of In(III) from Ga(III) is possible using ion exchange or solvent-impregnated resins/gels, these methods are limited in industrial applications due to low adsorption capacity for metals. Solvent extraction with amines, acidic, and neutral extractants is commonly employed to separate these two metal ions. Amines and neutral extractants can extract both In(III) and Ga(III) and then these metals are separated by selective stripping. By contrast, solvent extraction with acidic extractants including commercial and synthetic extractants results in complete separation of In(III) and Ga(III). Compared to common commercial extractants such as D2EHPA, PC88A, Cyanex 272, and Cyanex 301, synthetic extractants offer higher extraction and separation efficiency, but extraction kinetics and stripping efficiency in these systems should be improved in the future.
Porous nickel phosphates, denoted as VSB-1 (Versailles-Santa Barbara-1) and VSB-5 (Versailles-Santa Barbara-5), are crystalline metal phosphate microporous molecular sieves with zeolitic properties. These nickel phosphates could be used as functional catalysts and adsorbents due to interesting properties to readily accommodate many transition metal elements in their frameworks besides zeolitic properties as well as the presence of framework nickel (II) ions. In this account, we provide an overview of selected results regarding their catalytic and sorption applications which have been published in the literature. VSB-1 and VSB-5 are similar to zeolites in many aspects and may be suitable for use as adsorbents for the separation of molecular species and as catalysts or catalyst supports. Particularly, these materials possess unique catalytic properties suitable for several reactions that do not require strong acidity. Isomorphous substitution of Ni²⁺ with divalent or trivalent transition metals in a nickel phosphate structure can generate new redox centers and Brønsted-Lewis acid centers, providing interesting catalytic properties. Based on an understanding of the formation mechanism of nickel phosphate, VSB-5 was used in electrochemical applications and showed unusual surface chemistry of coordinatively unsaturated Ni²⁺ sites accessible in its pores.
de Der Bedarf an Indium steigt mit dem Wachstum der Elektronikbranche, in der es vorwiegend eingesetzt wird. Daher wurde anhand einer Modelllösung, die in ihrer wesentlichen Zusammensetzung dem Erz Sphalerit entsprach, ein mehrstufiges Extraktionsverfahren zur Gewinnung von Indium entwickelt. Die ursprünglich sehr niedrige Indiumkonzentration in der Lösung wurde durch mehrere aufeinanderfolgende Extraktions‐ und Reextraktionsschritte deutlich erhöht. Das vorgestellte Verfahren zeichnet sich durch einen geringen Chemikalienbedarf und eine hohe Reinheit des gewonnenen Indiumoxids aus.
Abstract
en The demand for indium is rising with the growth of the electronics industry, where it is mainly used. Therefore, a multistage extraction process was developed to separate indium from a model solution whose composition was adequate to sphalerite ore. The initially very low concentration of indium in the solution was significantly increased by several successive extraction and reextraction steps. The process described is characterized by a low requirement for chemicals and a high purity of the obtained indium oxide.
As the waste of ZnO base display panel increased in recent years, it is a big issue to treat the spent gallium zinc oxides (GZO) and indium gallium zinc oxides (IGZO) targets. A recovery process of indium, gallium, and zinc has been studied. The process was arranged to leach the targets by nitric acid and extract the rare metal individually. To optimized the separation of indium and gallium, the pH value, concentration of extractant and stripping agents, organic-aqueous ratio and reaction time were investigated. In the first step, indium was extracted by Di-(2-ethylhexyl) phosphoric acid (D2EHPA) to the organic phase. By controlling the conditions, gallium and zinc remained in the aqueous. After indium extraction, gallium was extracted by same extraction agent in different conditions with almost no zinc extracted. Indium and gallium were then stripped by hydrochloric acid separately. With the optimal conditions, the recovery of both indium and gallium could be up to 99.9%. After separation, these three metals were recycled and reused by precipitation and calcination as metal oxides with the purity over 99.5% and then back to the manufacture processes eventually.
Particle accelerators have played a key role for the production of radioisotopes since the 1940s, and medical cyclotrons (11–20-MeV protons), in particular, are currently of central importance for the production of short-lived positron emitters for diagnostic applications in nuclear medicine. Commercially, cyclotrons in the 20–35-MeV proton energy range are used to produce a variety of gamma-emitting radioisotopes. In addition, many high-energy accelerators of several different types which accelerate primarily protons play a role in the production of medical radioisotopes, including those which have important roles in therapy. In this chapter, the basic fundamentals of accelerator production and yield calculations are discussed in addition to key therapeutic radioisotopes and comments on their applications as unsealed sources radiopharmaceuticals in nuclear medicine.
The adsorption and desorption characteristics for indium recovery from aqueous solutions using commercially available iminodiacetate resin Lewatit®TP207 (TP207) was investigated. The polymer resin had indium adsorption capacity of 55 mgIn/gTP207 at 25̊C and desorption efficiency of 99% in pH 0.8 acid aqueous solution. Furthermore, it was observed that TP207 had performance result of 99% after four times cycle test to confirm the reusability. The results show that TP207 polymer resin provides high efficient desorption property in acid solution and reusability in cycle test of adsorption-desorption. This results offer a simple and effective recovery process for indium.
A novel solvent-impregnated resin (SIR) with trialkylphosphate Cyanex 923 as extractants and macroporous resin HZ830 as substrate was prepared to adsorb In(III) from HCl solutions. The effects of HCl concentration on adsorption were investigated within the range of 0.5 to 7 mol L− 1, and results showed that adsorption capacity was greatest at 2 mol L− 1 HCl. The adsorption mechanism of In(III) in chloride medium suggested that In(III) was apt to be adsorbed as a neutral species InCl3. As the anionic species InCl4− it tended to be adsorbed in the form of ion pairs combined with protons. The extraction stoichiometry of In (III) with SIR was studied, and the extracted species were found to be InCl3·nL and HInCl4·nL (n = 2, 3). The isothermal adsorption of In(III) fit the Langmuir model. Kinetic data indicated that the adsorption process was consistent with a pseudo second order model, and the sorption rate was mainly controlled by an intraparticle diffusion step. A column experiment showed that In(III) could be eluted from SIR with 2 mol L− 1 sulfuric acid, and the SIR showed good stability and reusability after five adsorption-elution cycles. When the SIR was applied for In(III) adsorption from waste liquid crystal display (LCD) leaching solution containing 102.15 mg L− 1 In(III), the adsorption efficiency exceeded 90% with 0.30 g adsorbent.
Oxides of indium and yttrium are two of the key components in Flat Panel Displays (FPDs). In recent years the need to recycle these metal oxides from waste FPDs has been growing. In this work a process to recycle indium and yttrium based on acid leaching and solvent extraction was proposed and studied. Solid waste was leached by acid at S/L ratio = 0.1 g/ml, HCl was found to be more effective than HNO3, possibly due to the formation of soluble metal chloride complexes. The extraction of indium using Cyanex 923 and yttrium using DEHPA from chloride media studied using lab-scale mixer-settlers at a flow rate of 3 ml/min. Leachate of real FPD waste was used as aqueous feed. Good separation between indium, yttrium and other impurities such as iron, copper and aluminum could be achieved by extraction from 1 M HCl with 0.25 M Cyanex 923 diluted in kerosene, followed by stripping with 1 M HNO3 and further purification with 0.2 M DEHPA diluted in kerosene.
As one of the most widely used scarce metals located at the column of IIIA in the periodic table, indium has drawn more and more attention due to its semiconductor and optoelectronic performance. While the reduction of indium minerals, as one of secondary resources, the amount of waste liquid crystal display (LCD) has been accumulated considerably. Indium tin oxide (ITO) film which is the main functional fraction of LCD has consumed more than 70% of the indium production worldwide. Therefore, it is necessary to recycle indium from waste LCDs. Some researches have been done for proper treatment to recycle indium from waste LCD which is a primary part of waste electric and electronic equipment (WEEE).
In this paper, the main characteristics of indium and the waste management status of end-of-life LCDs are introduced. And we mainly focus on the highly developed single recycling and reusing techniques. In addition, several combined recycling processes are evaluated. Furthermore, on the foundation of techniques and processes mentioned above, the promising related single techniques and the improvements on whole treatment process of waste LCDs are suggested.
Analytical procedures for the determination of indium in zinc powder, zinc oxide, and zinc blende have been presented. A simple and very sensitive spectrophotometric method based on the mixed complex of In(III) with Chrome Azurol S and benzyldodecyldimethylammo- nium bromide (e = 1.74 × 105 L mol1 cm1) has been applied. Before determination, In(III) was separated from macro- and micro-components by extraction with butyl acetate. Fe(III) was previously reduced to Fe(II) with ascorbic acid to prevent its co-extraction. The content of indium (in mg g1) was estimated from the calibration plot (constructed after extraction in the concentration range: 0.120.48 mg mL1; r = 0.9991) and amounted to: for zinc powder 33.1, for ZnO 17.1, for zinc blende 23.3, respectively. Precision was satisfactory % RSD (n = 6) ranged from 4.9 for zinc powder to 8.5 for ZnO. Average recovery of indium standard was better than 95%. An ICPAES comparative analysis gave very close results.
A dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFOD) was developed for preconcentration and determination of indium in real samples. In this method, an appropriate mixture of acetone (as disperser solvent) and 1-undecanol (as extracting solvent) containing dithizone (as chelating agent) was rapidly injected into the aqueous samples of indium. In this step, the cloudy solution was formed and the complexes of In-dithizone was extracted into 1-undecanol. After the phase separation, the absorbance of the extracted indium was measured at 510 nm. Under the optimum condition, the calibration graph was linear in the range of 30-230 mu g L-1 with detection limit of 9 mu g L-1. The relative standard deviation (RSD, n = 6) was 1.04 %. The developed method was successfully applied to extract and determine indium in real samples.
A direct solvent-extraction process was developed to selectively recover indium from solutions generated by reductive leaching of zinc residues. This approach avoids the traditional steps of intermediate precipitation, solid–liquid separation, and re-leaching. Copper in the leach solution is easily removed by cementation with iron powder and the remaining Fe(III) is reduced to the ferrous state, which avoids the possibility of its co-extraction with indium. Indium is effectively extracted from the zinc sulfate solution by 20%(v/v) di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in kerosene at an initial pH of 0.5 and aqueous-to-organic phase ratio (A:O) of 6:1using three countercurrent stages. Indium extraction is 96.1%, zinc and iron are barely extracted, and the separation factors of indium with respect to zinc and iron are3640 and 4809, respectively. Completely stripping of indium from the loaded organic phase is achieved using 4 mol/L HCl at an A:O of 1:6. A scheme for direct solvent extraction of indium in zinc hydrometallurgical processing is suggested, by which indium can be concentrated into a small volume of strip solution containing 11 g/L of indium, which is 85 times its concentration in the feed solution.
Solvent extraction offers a better option for gallium recovery among many techniques. The liquid–liquid extraction of gallium(III)–copper(II) solution from hydrochloric acid medium using di-2-ethyl-hexylphosphoric acid (D2EHPA) in kerosene was studied. The effect of the reagent concentration and other parameters on the extraction of gallium(III)–copper(II) was also studied. The stoichiometry of the extracted species of gallium(III) was determined based on the slope analysis method. The maximum extraction efficiency of gallium was 99.9%. The gallium that contained organic phase could be stripped completely by 1 M HCl.
Extracting indium from water quenching slag, which contains poor indium, by two process of leaching, the effect of different oxidants and dosages on the leaching rate of indium in water quenching slag were studied. The leaching conditions: temperature 80 °C, leaching time 2 h, the liquid to solid ratio of neutral leaching 8︰1, the liquid to solid ratio of acid leaching 2︰1, initial concentration of sulfuric acid 500 g·L-1, adding different oxidants, the concentration was detected by crystal violet spectrophotometry. Test results showed that the leaching rate of indium was significantly improved by adding hydrogen peroxide and potassium permanganate. Compared with the effect of different oxidants, the effect of potassium permanganate was significantly higher than that of hydrogen peroxide on the leaching rate of indium.
A new chelating polymeric sorbent has been developed using impregnation of Amberlite XAD-7 resin with a newly-synthesized hexadentates naphthol-derivative Schiff base 1-[(1E,9E)-10-(2-hydroxy-1-naphthyl)-4,7-dioxa-2,9-diaza-1,9-decadienyl]-2-naphth (EHND). The impregnated resin showed high binding affinity for Ga(III) and In(III) ions and was used for their preconcentration prior to determination by flame AAS. The optimum pH values for the quantitative sorption of Ga(III) and In(III) are 4.0-6.0 and 4.5-8.0, respectively, and their desorptions can be achieved by using 5 mL of 1 M HNO3. The sorption capacities of the resin for gallium and indium were 1.1 and 1.3 mg g-1, respectively. The enrichment factor for preconcentration of gallium and indium was found to be 200. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 2.5% for both elements. The practical applicability of the polymer was tested with synthetic seawater, natural waters, wastewater and human blood serum.
The extraction of yttrium and some trivalent lanthanides from thiocyanate and nitrate solutions using Cyanex 923 { TRPO ) in xylene as an extractant has been investigated. It has been found that these trivalent metal ions are extracted from thiocyanate solution as M(SCN)3.n TRPO ; n in general having the values of 4 and 3 for the lighter and the heavier lanthanides respectively. On the other hand, from nitrate solutions these trivalent metal ions are extracted as M(NO3)3 3 TRPO. The equilibrium constants of the extracted complexes have been obtained by non-linear regression analysis. In both the thiocyanate and nitrate systems, the distribution ratios of trivalent lanthanides are found to increase with decreasing ionic radii and the distribution ratio of yttrium lies along with those of the middle lanthanides. The separation factors between these trivalent metal ions were evaluated and compared with those obtained using commercially important extraction reagents like tributylphosphate (TBP), trioctylphosphine oxide (TOPO) and di-2-ethylhexylphosphoric acid (DEHPA). The separation possibilities between yttrium and the trivalent lanthanides have also been discussed.
The history of commercial processes for zirconium/hafnium production and separation is reviewed. A new technology is then proposed as a potential alternative for zirconium/hafnium separation in a simpler, cleaner way than achieved with current processes. Primary sources of zirconium always contain small amounts of hafnium that must be removed during production of zirconium metal for nuclear applications. This separation is usually carried out by a solvent extraction process, developed in the 1950s, that selectively extracts hafnium, as a thiocyanate complex, using methyl isobutyl ketone (MIBK). Environmental problems inherent to this process are the high aqueous solubility and low flash point of MIBK, and possible gaseous contaminants formation generated by the decomposition of the thiocyanic complexes in hydrochloric acid medium (H2S, HCN, mercaptan's formation). The present work shows how these problems could be avoided by using organophosphorous extractants that were unavailable when the MIBK process was developed.
Solvent extraction of indium (III) and gallium (III) from nitric acid or aqueous mixture of nitric acid and sodium nitrate solution was investigated using four kinds of acidic extractants, i. e. di (2-ethylhexyl) phosphoric acid (D2EHPA), 2 ethylhexyl 2-ethylhexylphosphonic acid (EHEHPA), di (2, 4, 4'-trimethylpentyl) phosphinic acid (DTMPPA) and 2 bromododecanoic acid (2-BDA), and using toluene as a diluent to identify the extracted species and to evaluate their extraction equilibrium constants. Indium (III) was extracted as the monomeric complex of the type, InR3.3HR, with all extractants. On the other hand, gallium (III) was extracted as the monomeric complex of the type, GaR3, with D2EHPA and EHEHPA while as the complex of the type, GaR3, with DTMPPA and 2-BDA.For both metals, the extraction equilibrium constant increases in the sequence, 2-BDA<DTMPPA<EHEHPA <D2EHPA, which is in accordance with the sequence of acidity of these extractants. The equilibrium constants of indium (III) are greater than those of gallium (III) with all extractants and their ratio increases also in the same sequence as mentioned earlier; the ratio with D2EHPA is above as great as 105.
The extraction of tervalent gallium, indium, and thallium has been studied with trioctylphosphine oxide (TOPO) in n-hexane from hydrochloric acid solutions in which the ionic concentration was kept at 4.0 mol dm−3 by replacing hydrogen ions with sodium ions. From the results it is concluded that the extracted species are GaCl3(TOPO)2, HGaCl4(TOPO)3 and also most probably H2GaCl5(TOPO)3 for Ga(III), InCl3 (TOPO)2 for In(III), and HTlCl4(TOPO)3 for Tl(III). The extraction constants were calculated as, Kex0,3 = [MCl3(TOPO)2]org[MCl3]−1 [TOPO]org−2 are >104.4 for Ga(III), 104.9 for In(III), and Kex1,4 = [HTlCl4(TOPO)3]org[H+]−1[Cl−]−1 × [TlCl3]−1[TOPO]org−3, is 109.7.
The extraction of microquantities of Ca, Sr, Ba, Sc, Mn, Co, Cu, Zn, Ga, Cd, In, Pb, Bi, Zr, Hf, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and U from HNO3 solutions by (diphenylphosphinylmethyl)phenylphosphinic acid in organic diluents has been studied.The effect of HNO3 concentration in the aqueous phase and that of the extractant in the organic phase on the metal extraction are considered. (Diphenylphosphinylmethyl)phenylphosphinic acid possesses an extraordinary affinity for actinides and rare-earth elements. The extractive efficiency and selectivity of this compound toward rare-earth metal ions are compared with those of some multifunctional acidic and neutral organophosphorus extractants.
The solvent extraction of indium(III)from mixed 0.5 to 1 mol.L hydrochloric acid + 2 to 4 mol.L sulphuric acid solutions simulating flue dust leaching solutions was investigated. In addition to In(III) typically present at about 1 g.L-', the flue dust leaching solutions contain As(III), Cd(II), Cu(II) Fe(IH) and Zn(II), with concentrations ranging between 3 and 25 g.L1. After preliminary investigation, bis(2,4,4-trimethylpentyl)phosphinodithioic acid Cyanex 301® was selected as extractant. Indium(III) is efficiently extracted by Cyanex 301® in the range of hydrochloric acid and sulphuric acid concentrations encountered in the flue dust leaching solutions. However, such an extraction is not at all selective with respect to As(III), Cd(II), Cu(II) and Fe(III), and only partially selective with respect to Zn(II). Thus, it is recommended to eliminate As(III) and Cu(II) from the solutions by cementation ori iron prior to extraction of In(III) by Cyanex 301(r). Moreover, during the cementation of arsenic and copper, iron(III) is reduced into iron(II) which is not extracted by Cyanex 301®from such acidic solutions. As a result, only Cd(II) and, at a lesser degree, Zn(III) interfere with the extraction of In(III). In fact, these two metal species can be separated from indium(III) by selective stripping in appropriate hydrochloric acid media (typically 4.5 - 5 mol.LHCI). Finally, indium(III) can be recovered from the organic Cyanex 301®solution by stripping with a more concentrated (typically 7 mol.L-')hydrochloric acid solution.
The distribution of In(III) between aqueous HCl solutions and organic phases of tricaprylamine in kerosene has been described. The dependence of extraction on acidity, salting agent, metal and extractant concentration, was investigated. Extraction mechanism was proposed on the basis of results obtained. The effect of temperature and organic additives on extraction has also been examined.
The synergistic extraction of gallium(III) and indium(III) with 2,4-pentanedione (Hacac) in heptane and carbon tetrachloride has been studied using 3,5-dichlorophenol (DCP) as the synergist. A remarkable enhancement of the extraction of both metals(III) with 0.01 mol dm(-3) Hacac was observed upon the addition of 0.05 mol dm(-3) DCP, especially in heptane. From an extraction-equilibrium study, the synergistic enhancement was ascribed to the formation of outer-sphere complexes, M(acac)(3).n(DCP) (M=Ga or In; n=1 - 3), in the organic phase. Furthermore, using the synthetic metal(III) chelates hydrogen-bond formation between M(acac)(3) and DCP was observed by IR and H-1 NMR in carbon tetrachloride. The effect of DCP on the separation efficiency of gallium(III) and indium(III) from aluminium(III) was discussed by means of the equilibrium constants such as the formation constants of outer-sphere complexes as well as the extraction constants obtained so far. It was concluded that the present synergism caused by outer-sphere complexation improved not only the extraction efficiency, but also the separation efficiency of those metals(III).
The solvent extraction of lanthanum(III), europium(III), lutetium(III), scandium(III), and indium(III) in 0.1 mol dm-3 sodium nitrate solutions with 2-thenoyltrifluoroacetone (Htta) in the absence and presence of tetrabutylammonium ions (tba+) into carbon tetrachloride was measured. The extraction of lanthanum(III), europium(III), and lutetium(III) was greatly enhanced by the addition of tba+; this could be explained in terms of the extraction of a ternary complex, M(tta)4-tba+. However,the extractions of scandium(III) and indium(III) were nearly the same when tba+ was added. The data were treated on the basis of the formation equilibrium of the ternary complex from the neutral chelate, M(tta)3, with the extracted ion-pairs of the reagents, tta-tba+, in the organic phase. It was concluded that the degree of association of M(tta)3 with the ion-pair, tta-tba+, is greater in the order La(tta)3 almost-equal-to Eu(tta)3>Lu(tta)3, or that the stability of the ternary complex in the organic phase is higher in the order La(tta)4-tba+ almost-equal-to Eu(tta)4-tba+>Lu(tta)4-tba+. This is similar to those of adduct metal chelates of Htta with tributylphosphate (TBP) in synergistic extraction systems.
A new phosphine oxide extractant, commercially known as Cyanex 923, has been studied in order to be applied in the recovery of gold from either cyanide or chloride aqueous media. Au(CN)2− is extracted by this reagent throughout the whole pH range. The presence of lithium salts in the media improves the extraction. The extraction mechanism proposed can be explained in terms of a solvating reaction, the species formed in the organic phase being the following: Li+Au(CN)2−3(R3PO). The stripping can be performed by low ionic strength solutions such as dilute KCN solutions, and the reaction is enhanced by an increase in temperature. In chloride media, the extractant is able to extract gold (III) in the entire range of acid concentrations. The amount of extraction agent required, to achieve the same level of extraction, in this medium is much lower than in the cyanide media. The temperature has a negative effect on the extraction. Another difference observed between the two media, is that the presence of ionic salts in chloride media has no influence on the extraction, which may be attributed to the fact that the extracted species, HAuCl4, is a protonated instead of an ionic species. © 1998 SCI
Studies have been carried out in the extraction of Cd(II) along with Al(III), Fe(III), In(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pb(II) from hydrochloric acid medium using Cyanex 923. The effect of different variables influencing the extraction of Cd(II) such as the concentration of acid, metal ion and extractant and the nature of the diluent has been investigated. The extracting species of Cd(II) is proposed. Based on the partition data, some binary separations of topical interest from Cd(II) have been achieved. The potential of the extractant for the recovery of pure cadmium from some zinc and copper matrices is assessed.
The extraction processes of indium(III) from media of various complexing ability, chloride and nitrate, in toluene or chloroform, have been elucidated. Indium is extracted from 1 M nitrate medium as In(PBI)$_3$ with HPBI alone and as In(PBI)$_3$(TOPO)$_2$ with TOPO-HPBI mixtures, while it is extracted from 1 M chloride medium as In(PBI)$_3$ and InClx(PBI)$_{3-x}$(TOPO)$_2$. The complexation of In in the aqueous phases, the extraction of nitric acid and various solute-solute and solute-diluent interactions in the organic phases must be taken into account in the processes. The results are compared with those obtained previously with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one under the same conditions.