Purification Of Indium Research Articles

Efficient separation and purification of indium and gallium in spent Copper indium gallium diselenide (CIGS)

Copper indium gallium diselenide (CIGS), is a promising commercial thin-film solar cell, and its disposal after scrapping and recycling critical metals has attracted tremendous attention since CIGS can be considered an important type of urban mining. The main phase of spent CIGS is selenide, which is a hazardous contaminant that may have a potential impact on the environment and human body. In our previous study, selenium and copper in spent CIGS separated efficiently, while more scarce metals: indium and gallium were obtained in the form of mixed indium gallium oxide (IGO). Therefore, in this study, the separation and purification of indium and gallium was investigated in detail. The solution chemical behavior shows that the dissolution of indium gallium oxide (IGO) in an alkaline environment was significantly different. Selective alkali leaching is feasible to separate indium and gallium effectively. The process realized 97.26% gallium leaching out, while that of indium was 3.37%. Moreover, the mechanism of the leaching process and the removal of copper impurities were explored, with further purification, indium and gallium were obtained in the form of relatively pure indium oxide (96.04%) and gallium oxide (99.83%), respectively. This study will provide guidance for the recycling of critical metals from secondary waste.

Electrodeposition of Gallium and Indium from Non-aqueous Electrolytes

In this work, we studied the electrodeposition of gallium and indium from 1,2-dimethoxyethane (DME)-based and dimethyl sulfoxide (DMSO)-based electrolytes, respectively.1,2 Cyclic voltammetry in combination with rotating (ring) disk electrode and electrochemical quartz-crystal microbalance were used to identify the redox chemistry and electrodeposition behavior of both metals. Scanning electron microscopy (SEM) was used to investigate the structural morphology of the deposited materials.Gallium electrodeposition was studied from a bath composed of gallium(III) chloride, an inert background salt and DME. The electroreduction process occurred in two steps: (1) from gallium(III) to gallium(I), and (2) from gallium(I) to gallium(0). Metallic gallium was deposited as spheres with diameters of several hundreds of nanometers that were stacked on top of each other. X-ray photoelectron spectroscopy revealed that each gallium sphere was covered by a thin gallium oxide shell. These shells prevent individual gallium spheres from agglomerating to larger entities. Electrochemical experiments indicated that these oxide layers were electrically conductive. It was demonstrated that electrodeposition proceeded via a droplet-on-droplet electrodeposition mechanism. A growth mechanism for an individual growing gallium sphere was also postulated.Indium electrodeposition was studied from a bath composed of indium(III) methanesulfonate, a background salt and DMSO. indium(III) methanesulfonate was synthesized from methanesulfonic acid and indium(III) oxide. The latter is an intermediate formed during the purification of indium from primary and secondary resources. Conversion of indium(III) oxide into metallic indium could therefore lower the energetic cost of its production. Analogously to gallium, Indium(III) is reduced to indium(I), and then to indium(0). It was demonstrated that indium(I) disproportionates to indium(III) and indium(0), leading to the formation of micron-sized metallic indium particles in the electrolyte. At 26 °C, indium deposited as smooth, flat films whereas at 160 °C, it deposited as liquid indium droplets. Electrodeposition of indium above its melting point enables the process to be performed in a continuous manner; indium droplets accumulate and grow, and will ultimately glide off the electrode, and drop to the bottom of the cell, forming a liquid pool from which the metal can be tapped off.In the attached figure, SEM images of (1) gallium deposited at 26 °C and (2) indium, deposited at 26 °C and 160 °C are shown. Figure 1

Leaching and purification of indium from waste liquid crystal display panel after hydrothermal pretreatment: Optimum conditions determination and kinetic analysis

Indium is one of the components with great recycling value in waste LCDs. Degradation of organic materials and the remain of indium in the solid phase can be simultaneously achieved by hydrothermal pretreatment via parameter regulation. Indium was transferred from the solid phase to the liquid phase by using sulfuric acid after hydrothermal pretreatment. Di-(2-ethylhexyl) phosphoric acid diluted by sulfonated kerosene and hydrochloric acid were used as extractant and stripping agent respectively to purify and concentrate indium from acidic leaching solution. The results indicated that the leaching yield of indium reached 100% under the optimal condition of reaction time of 40 min, reaction temperature of 70–80 °C, acid concentration of 0.5 M and solid-liquid (S/L) ratio of 1:2 g/mL. Given conditions of extraction time of 3 min at the organic phase to aqueous phase (O/A) ratio of 1:10 by 20% D2EHPA and stripping time of 10 min at the (O/A) ratio of 10:1 by 4 M HCl, the recovery efficiency of indium reached 97.25%. In addition, acid leaching process did not change the surface topography and molecular structure of glass substrate and had no negative effect on subsequent recycling of glass. The kinetic equation of leaching yield and reaction time at the temperature of 80 °C is 1 − (1 − y)1/3 = 0.0215 t. The reaction activation energy of metal indium leaching process is 50.64 kJ/mol.

Selective recovery of indium from iron-rich solutions using an Aliquat 336 iodide supported ionic liquid phase (SILP)

Selective recovery of valuable metals from secondary (waste) sources is essential for better resource efficiency. However, low-grade waste streams typically have complex and variable compositions and low concentrations of valuable metals. Therefore, development of novel technologies, able to deal with these complex and variable waste streams, is necessary. In this work, we present a process for the separation and purification of indium from iron-rich matrix solutions making use of a supported ionic liquid phase (SILP). The SILP used in this study was synthesized by impregnating AmberliteXAD–16N with the iodide form of the quaternary ammonium salt Aliquat336. The SILP was characterized by infrared spectroscopy, elemental analysis, density, specific surface area and porosity and it was tested for the selective recovery of indium. Adsorption was preceded by the addition of an excess of iodide anions to the solution, to form indium iodide species, which were extracted to the ionic liquid of the SILP. A high selectivity for indium over iron could be achieved because iron iodide species are not stable in aqueous medium. The reaction kinetics and several adsorption parameters, including anion concentration, adsorbent mass, stripping and reusability of the adsorbent were investigated, using synthetic binary iron-indium solutions containing iron in large excess in comparison with indium, as is typically the case in low-grade ores or industrial process residues. Finally, the developed indium recovery process was validated on a real leachate of goethite residue. A pure indium solution of 49 mg L–1 was obtained with an indium-over-iron mass ratio of 7.9 and a selectivity factor equal to 5400.

The Separation of Indium and Copper from Spent Cu‐In Targets

Nowadays, the CIGS solar cells produced process, only 30% of the original target material is used, while the rest 70% need to be recycled in order to achieve the resources sustainable. Common methods to separate and recover indium include precipitation, solvent extraction, ion‐exchange, and electrolytic processes. This research is to investigate the recovery and purification of indium from spent sputtering targets so that the recovered and purified indium can be reused in the thin film and semiconductor industries. The processes selected include ion‐exchange resin, solvent extraction, and zone refining. Eventually, indium recovery using ion exchange and solvent extraction has high recoveries. Further purification was conducted by electrowinning and zone refining process. The indium product of zone refining can be used as raw material of indium sputtering target.

Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

Ultra high pure Indium metal is extensively used in optoelectronic devices. Indium and its alloys become potential candidates in aerospace, defense and communication sectors. Purification of Indium has been done by Instrolec-200 Refiner followed by Directional Melting/ Freezing and Solidification Systems. Major targeted impurities are Metallic impurities Ag, Al, As, Bi, Ca, Cu, Fe, Ga, Ge, Mg, Pb, Sb, Si, Sn, and Zn. Purified Indium is characterized by analytical techniques Inductively Coupled Plasma- Optical Emission Spectrophotometry and Inductively Coupled Plasma- Mass Spectrometry. Keywords—Indium, Purification, Instrolec-200 Refiner, Metallic impurities I-INTRODUCTION: SPHALERITE ores, Lead and Tin circuits, Zinc Flue Dust and Waste Liquors from Indium Plating are main resources from which Indium metal is recovered. Indium is minor metal in the earth's crust but it has unique and versatile combination of properties, Low melting point (156.5987 o C) and high boiling point (2072 o C) (5) . At -269.63 o C Indium becomes superconductor which makes it very useful in Cryogenics applications (4) . Ultra high pure Indium is used in several applications. Purification of Indium is very foremost operation. In purification process, if the purity of starting material remains low then even by using perfect and appropriate method, Ultra high pure and device grade product is very difficult to achieve. Multi Pass vertical zone refining is employed for purification of 3N pure Indium which is followed by Directional Melting/ Freezing and Solidification System. Purification is done with respect to some targeted impurities like Ag, Al, As, Bi, Ca, Cu, Fe, GA, Ge, Mg, Pb, Sb, Si, Sn, Zn and the results are obtained.

Purification of indium by vacuum distillation and its analysis

High purity (99.999% or 5N, mass fraction) indium (In) was obtained through vacuum distillation using a 2N (99%) In as input material under a dynamic vacuum of 5 Pa. The glow discharge mass spectrometry (GDMS) was applied for the analysis of input material and the distilled indium. The results indicate that high-volatile impurities namely Cd, Zn, Tl and Pb can be removed from the indium matrix at the low fraction stage of 1 223 K for 120 min; Low-volatile impurities such as Fe, Ni, Cu, Sn can be reduced at the high fraction stage of 1 323 K for 120 min. The separation coefficient βi and activity coefficient γi of impurities are calculated according to the experiments to fill the inadequate data of the thermodynamics.

Recovery and purification of indium from waste sputtering target by selective solvent extraction of Sn

A large volume of indium is being discarded from electronics factories in the forms of waste sputtering targets, polishing slurry, and etching slurry. Of these, waste sputtering targets consist mainly of indium together with tin (∼10 wt%) and a small amount of impurities of other metals. As such, it is more advantageous and environmentally benign to extract tin rather than indium for removal in terms of the purification process since much smaller amount of raffinate (∼1/25) and lead time (∼1/9) are required compared to conventional processes such as cementation and In-extraction. This study examined the process of removing Sn impurities from waste sputtering targets through a solvent extraction method. Among PC88A, D2EHPA, Alamin 336 and versatic acid, PC88A was selected as the most suitable solvent for the purpose of this study, and acid concentration (MH+) = 2 M, the volume ratio of organic to aqueous phase (O/A) = 3, and retention time = 10–15 min were determined as the optimal conditions to extract Sn impurities only, not indium. Acid concentration (MH+) = 3.0 M was the suitable condition to scrub indium containing small amounts in the organic phase from which Sn was extracted. Meanwhile, acid concentration (MH+) = 12.0 M was the appropriate condition for stripping the extracted Sn. When the Sn was removed in a pilot-scale continuous apparatus under the aforementioned conditions, it was confirmed that indium was purified with In concentration = 180 g L−1, Sn = 4–11 ppm. Indium in the purified solution was reduced, and then electrorefining was performed. As a result, 99.9976% pure indium ingots could be obtained.

ChemInform Abstract: Purification of Indium from Thallium Inclusions by the Process of Remelting Under Artificial Slags.

AbstractThe described purification method is based on the fact that the In‐halogen affinity is lower than that of the Tl‐halogen system.

The Measurement of Tracer Indium in Rain Samples

Abstract A radiochemical procedure developed to measure precisely nanogram amounts of the indium tracer used in the study of circulations and rain scavenging processes in severe convective storms is described. The tracer indium collected in rainwater is normally associated with sodium, manganese and arsenic as major impurities. The method, therefore, is devised to remove arsenic as sulphide by thioacetamide precipitation followed by the extraction of indium bromide with isopropyl ether. The ether extraction separates it from sodium, manganese and lanthanum which is used as a flux monitor. The final purification of indium, from iron and other extracted impurities like gallium, in a form suitable for counting, is done by cation exchange resin separation.