Recovery of indium from the etching solution of indium tin oxide by solvent extraction

Abstract

The etching waste solution from the indium-consuming fabrication processes is considered as the viable resource for indium recovery. The extraction equilibrium of indium(III) from a hydrochloride acid solution using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as an extractant and dissolved in kerosene by solvent extraction was studied. To optimize the extraction and separation of indium from etching waste solution, the effects of O/A ratio, pH, and extractant concentration on the distribution ratios of In(III) and selective precipitation of alumina, cerium, and iron from indium were also investigated in this work. The experimental results showed that satisfactory separation of alumina, cerium, and iron from indium was achieved with 0.3 M D2EHPA at room temperature and pH values ranging from 1 to 1.5. In this process, 92% of indium could be extracted from 0.74 to 8.62 g/L at an O/A ratio of 1:1. Quantitative stripping experiments of indium by HCl showed that the preferred O/A phase ratio was 1:2 or less at HCl concentration of 2.0 M to attain a high indium recovery and minimum iron coextraction. Where maximum purity is desired, the extraction is desirably carried out in three theoretical extraction stages. Based on these results, the aqueous and organic phase parameters can be easily manipulated to attain a high separation efficiency of indium(III) from commonly associated elements.

Flüssig/Flüssig‐Extraktion von Indium aus sauren Lösungen

“…3.2 erläutert wurde, kann die Extraktion mit Gl. (8) beschrieben werden. Wird für sie die effektive Gleichgewichtskonstante formuliert, liefert der Term p aus der Steigung der Geraden der Auftragung der Abhängigkeit von log D ð Þ À 6=4pH À 3=4SO 2À 4 auf log(c Ex ) den entsprechenden Wert.…”

“…Beim Sputtern von ITO gehen mit derzeitig eingesetzten Technologien mindestens 70 % als Abfall verloren [2]. Daher konzentrieren sich viele aktuelle Forschungen auf die Verarbeitung dieser indiumreichen Abfälle [3][4][5][6][7][8]. Abgesehen von eher reinem ITO-Abfall werden große Anstrengungen unternommen, um das Metall auch aus indiumarmen Abfällen sowie aus End-of-Life(EoL)-und End-of-Use(EoU)-Produkten zu gewinnen.…”

Microalgae: a sustainable adsorbent with high potential for upconcentration of indium(iii) from liquid process and waste streams

“…For example, In(III) from waste liquid crystal display (LCD) panels is barely recycled (European Commission, 2017;Sun et al, 2017). For these reasons, there has been a growing interest in the recovery of In(III) from secondary sources, such as leachates from polymetallic sludge produced during zinc refining and waste solutions from ITO etching processes (Chou et al, 2016;Orko et al, 2016). For instance, jarosite (MFe 3 (SO 4 ) 2 (OH) 6 , where M is a metal cation (e.g., Na, K, Pb) or ammonium) is a solid industrial byproduct produced from the iron removal in the hydrometallurgical zinc winning process (Wegscheider et al, 2017.…”

Highly Efficient Indium(III) Collection from Water by a Reaction with a Layered Titanate (Na2Ti3O7)

“…The potential toxicity of indium has been suggested, which also motivates study on the concentration of indium species from aqueous environments. Methods, such as chemical precipitation, solvent extraction, membrane filtration, electrochemical deposition, and adsorption, have been proposed so far for the concentration of indium(III) from water.…”