Optimization of Indium Recovery and Separation from LCD Waste by Solvent Extraction with Bis(2-ethylhexyl) Phosphate (D2EHPA)

Abstract

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%.

Separation of Heavy Rare-Earth Elements from Light Rare-Earth Elements Via Solvent Extraction from a Neodymium Magnet Leachate and the Effects of Diluents

“…The separation factor represents the selectivity between these two metals in the extraction [26]. Many authors [26,27] have reported that the extraction of the REEs with organophosphorous extractants (here called HR) occurs according to the reaction path described in Eq. 3: ð3Þ where M 3?…”

Flüssig/Flüssig‐Extraktion von Indium aus sauren Lösungen

“…Ein Schwerpunkt der gegenwärtigen Untersuchungen liegt auf dem Recycling von LCD-Bildschirmen mithilfe der Flüssig/Flüssig-Extraktion. Das am intensivsten untersuchte Extraktionsmittel ist DEHPA (Bis (2-ethylhexyl)phosphat), das zur Konzentration und Abtrennung von Indium von Begleitmetallen eingesetzt wird [9][10][11][12]. Zwar extrahiert es Indium effektiv bei niedrigem pH-Wert, das extrahierte Metall ist jedoch aus der organischen Phase nur mit konzentrierten Säuren und damit auch nur schwer wiederzugewinnen, was der Grund für die Suche nach alternativen Extraktionsmitteln war.…”

Recovery of Indium from LCD Waste by Solvent Extraction and the Supported Liquid Membrane with Strip Dispersion Using D₂EHPA as the Extractant

“…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.…”

“…Moreover, n-octanol was found to be the worse diluent for this system. Later in 2014, Yang and his research team [8] have studied the effects of pH, concentration of extractant, temperature and stripping agents for indium extraction. They found that more indium was extracted when the operating temperature was lower than 293 K and 1 M H 2 SO 4 was the best stripping agent to recover indium from the loaded organic phase.…”

“…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.…”