Stripping conditions to prevent the accumulation of rare earth elements and iron on the organic phase in the solvent extraction circuit at Skorpion Zinc

Alberts, Estelle; Dorfling, C.

doi:10.1016/j.mineng.2012.09.005

Cited by 8 publications

(3 citation statements)

References 21 publications

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“…In particular, iron is known to be difficult to strip. Among the typical mineral acids, stripping is easiest in a concentrated HCl medium (for example, 5 M, Alberts and Dorfling, 2013). Some iron can be stripped in a concentrated H2SO4 medium; however, the equilibrium is not as favorable as with HCl.…”

Section: Liquid-liquid Extractionmentioning

confidence: 99%

Two alternative process routes for recovering pure indium from waste liquid crystal display panels

Virolainen

Huhtanen

Laitinen

et al. 2020

Journal of Cleaner Production

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Recovering indium from liquid crystal display (LCD) screen waste is important from a sustainability point of view for several reasons: the environmentally hazardous metals are not landfilled, the recovery process involves lower CO2 emissions than primary production, and supply from secondary sources matches the continuously increasing demand of indium. In this study, two alternative process routes for recycling the critical metal, indium, from LCD panel waste were studied and compared using laboratory and bench-scale experiments. The first process was a conventional hydrometallurgical process that involves manual dismantling, hammer mill crushing of the glass, cross-current sulfuric acid leaching of the metals, and liquid-liquid extraction separation of indium. Using this process, over 99% pure indium solution can be produced with a recovery yield of over 70%. The second process is novel because it includes (manual) scraping of the indium tin oxide (ITO) layer from the glass panels, followed by sulfuric acid leaching of the metals. The yield of indium was over 80%, and the purity of the resulting solution was over 99%. The solutions obtained from either of the suggested processes were sufficiently pure for cementing indium in high purity. The novel process appears much more straightforward and economically more feasible because the polarizing filter need not be removed and the liquid-liquid extraction purification step is excluded. Moreover, less amount of leaching acid is required.

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Section: Liquid-liquid Extractionmentioning

confidence: 99%

Two alternative process routes for recovering pure indium from waste liquid crystal display panels

Virolainen

Huhtanen

Laitinen

et al. 2020

Journal of Cleaner Production

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“…In chemical recycling, the accumulation of polymeric materials and metal impurities must be handled by periodic treatment of the process streams. Impurity metals in the liquid-liquid extraction organic phase can be stripped, for example, to HCl [32], and the aqueous streams containing the organic and inorganic impurities may be treated by precipitation and/or membrane filtration.…”

Section: Recycling Potential Of Process Chemicalsmentioning

confidence: 99%

Membrane Filtration Enhanced Hydrometallurgical Recovery Process of Indium from Waste LCD Panels

Lahti

Vázquez

Virolainen

et al. 2020

J. Sustain. Metall.

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Insufficient recycling of a continuously increasing amount of liquid crystal display (LCD) waste leads to the waste of potentially recyclable materials, especially rare and critical indium. Moreover, landfilling of LCD waste increases the potential for environmental risk. This paper describes a recycling process combining membrane filtration unit processes to hydrometallurgical indium recovery process. The LCD panels were crushed and leached with 1 M H2SO4. 97.4% yields on average were obtained, and a novel finding was made about fast kinetics (2 min for the maximum indium yield). Ultrafiltration was used to remove the dissolved organic material from the leachate, which was concentrated with nanofiltration before liquid–liquid extraction for indium purification. The results showed that commercial polymeric membranes removed more than 90% (from over 3000 mg/L to under 200 mg/L) of the dissolved organic compounds, thus potentially significantly diminishing the detriments caused by these compounds in the liquid–liquid extraction step. The concentration of the leachate with nanofiltration enables the use of smaller processing equipment and to save chemicals in the further steps of the process. The indium content in the leachate was more than five times higher after nanofiltration than after leaching (126 mg/L vs. 677 mg/L). In liquid–liquid extraction, the phase separation took place in only 34 s with the membrane-treated leachate, while with the untreated leachate it remained incomplete even after three hours. The purity of indium was increased from 10 to 74%. From the obtained HCl solution, a 95.5% pure indium product with 69.3% yield was obtained by cementation. Graphical Abstract

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“…This means that the iron accumulates in the organic, limiting the amount of extractant available for zinc to bind onto. For this reason, an organic stream is bled from the storage tank and contacted with 6 M HCl, which strips the iron from the organic (Alberts and Dorfling, 2013). During this process, the HCl becomes deactivated and must be regenerated in the Skorpion Zinc HCl plant.…”

mentioning

confidence: 99%

Investigation of secondary zinc oxides as an alternative feed to the Skorpion Zinc process: Part 2 - Process considerations and economic analysis

Lottering

Dorfling

2018

J. S. Afr. Inst. Min. Metall.

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Stripping conditions to prevent the accumulation of rare earth elements and iron on the organic phase in the solvent extraction circuit at Skorpion Zinc

Cited by 8 publications

References 21 publications

Two alternative process routes for recovering pure indium from waste liquid crystal display panels

Two alternative process routes for recovering pure indium from waste liquid crystal display panels

Membrane Filtration Enhanced Hydrometallurgical Recovery Process of Indium from Waste LCD Panels

Investigation of secondary zinc oxides as an alternative feed to the Skorpion Zinc process: Part 2 - Process considerations and economic analysis

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