An efficient rough vacuum-chlorinated separation method for the recovery of indium from waste liquid crystal display panels

Ma, E.; Lu, Rixin; Xu, Zhenming

doi:10.1039/c2gc36241d

Cited by 85 publications

(49 citation statements)

References 16 publications

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“…Due to the successful decrease of indium and the recorded concentrations of HCl and HBr in the off gas it can be concluded that the amount of halide in the displays' plastics is sufficient for a complete indium halogenation so that no additive is required. Of course, the indium volatilization can also be realized at lower temperatures by adding an excess of NH 4 Cl, as was demonstrated in other papers [12][13][14][15], as well as in this work. However, both thermochemical calculations and experiments have shown that even though a successful halogenation would have happened, at least 700 • C is necessary to achieve a complete evaporation of the indium halides from the display material.…”

Section: Discussionsupporting

confidence: 72%

“…All of these were conducted by using HCl as the halogenation agent. Ma et al [12] examined the vacuum chlorination of LCD glass powder, whereby HCl was generated by the thermal decomposition of NH 4 Cl, which was blended with the glass powder. Prior to the chlorination process, the polymers from the displays were removed via a pyrolysis step.…”

Section: Current Research On Indium Volatilization From Displays Thromentioning

confidence: 99%

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Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Flerus

Swiontek

Bokelmann

et al. 2018

Metals

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The present study focuses on the pyrolysis of discarded smartphone displays in order to investigate if a halogenation and volatilization of indium is possible without a supplementary halogenation agent. After the conduction of several pyrolysis experiments it was found that the indium evaporation is highly temperature-dependent. At temperatures of 750 • C or higher the indium concentration in the pyrolysis residue was pushed below the detection limit of 20 ppm, which proved that a complete indium volatilization by using only the halides originating from the plastic fraction of the displays is possible. A continuous analysis of the pyrolysis gas via FTIR showed that the amounts of HBr, HCl and CO increase strongly at elevated temperatures. The subsequent thermodynamic consideration by means of FactSage confirmed the synergetic effect of CO on the halogenation of indium oxide. Furthermore, HBr is predicted to be a stronger halogenation agent compared to HCl.

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Section: Discussionsupporting

confidence: 72%

Section: Current Research On Indium Volatilization From Displays Thromentioning

confidence: 99%

Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Flerus

Swiontek

Bokelmann

et al. 2018

Metals

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“…Within the temperature range from 0 to 100°C, the change of Gibbs free energy of reaction Equations and are much less than zero. Generally, the change of Gibbs free energy of −10.1 kcal/mol was set as a boundary, when ΔG < −10.1 kcal/mol, the reaction in Equations and can be thought to occur spontaneously to the right. In addition, the equilibrium constant K is relatively big enough, indicating that the reaction in Equations and can react more thoroughly.…”

Section: Resultsmentioning

confidence: 99%

Alkaline electrochemical leaching of Sn and Pb from the surface of waste printed circuit board and the stripping of gold by methanesulfonic acid

Zhang

Chenglong

Zheng

et al. 2019

Env Prog and Sustain Energy

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The variety of metals and organic in the waste printed circuit board (PCB) that makes them harmful to environment but also contain high economic value. The precious metals of gold on the surface of waste PCB has a high recovery value. In this article, a cleaner hydrometallurgical process for production of Sn, Pb, and Au from the surface of waste PCB was developed. With the alkaline electrochemical leaching, 100% of Sn and Pb in the solder can be extracted at NaOH concentration of 3 mol/L, current density of 300A/m2, and temperature over 8°C after electrochemical leaching of 120 min, and the components can be removed simultaneously. With the technique of methane sulfonic acid etching, the copper and nickel undered the gold plate were leached and then the gold foil can be collected. The optimum conditions of methane sulfonic acid etching technique was explored: under the room temperature, with the solid‐liquid ratio of 1:5, the amount of the hydrogen peroxide is 20%, and the volume fraction of methane sulfonic acid is 15%, the soaking time of the phone board is 150 min (the coating flaking time varied slightly due to the type difference of plates), the recovering rate of gold may be up to 95%. In addition, the method has a good selectivity for element Au, the stripped gold can be melted directly, while the treated waste PCB can be used for other metal or nonmetal recovering, the solution can also be recycled after recovering copper and nickel.

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“…Ma et al (2012) took a novel chlorinating agent ammonia chloride (NH 4 Cl) instead of the hydrogen chloride gas. The optimal conditions for reaction was at 673 K and input adequate amount of NH 4 Cl with a molar ratio of 6:1 (Cl/In) for 10 min, and controlled rough vacuum atmosphere at around 0.09 MPa.…”

Section: Vacuum-chlorinated Separationmentioning

confidence: 99%

Recycling indium from waste LCDs: A review

Zhang

Wang

et al. 2015

Resources, Conservation and Recycling

199

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An efficient rough vacuum-chlorinated separation method for the recovery of indium from waste liquid crystal display panels

Cited by 85 publications

References 16 publications

Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Alkaline electrochemical leaching of Sn and Pb from the surface of waste printed circuit board and the stripping of gold by methanesulfonic acid

Recycling indium from waste LCDs: A review

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