Materials recovery from waste liquid crystal displays: A focus on indium

Danilo Fontana, Federica Forte, Roberta De Carolis, Mario Grosso

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

In the present work the recovery of indium and of the polarizing film from waste liquid crystal displays was experimentally investigated in the laboratory. First of all, the polarizing film was removed by employing a number of different techniques, including thermal and chemical treatments. Leaching of indium was then performed with HCl 6. N, which allowed solubilisation of approximately 90% In (i.e. 260. mg In per kg of glass) at room temperature, without shredding. Indium recovery from the aqueous phase was then investigated through solvent extraction with polyethylene glycol (PEG)-based aqueous biphasic systems. Indium extraction tests through the PEG-ammonium sulphate-water system were conducted as a function of PEG concentration, salt concentration and molecular weight of PEG, using 1,10 phenanthroline as a ligand. The experimental results demonstrated that indium partitioning between the bottom (salt-rich) and the top (PEG-rich) phase is quite independent on the composition of the system, since 80-95% indium is extracted in the bottom phase and 5-20% in the top phase; it was also found that when PEG concentration is increased, the ratio between the bottom and the upper phase volumes decreases, resulting in an increase of indium concentration in the bottom phase (at [PEG]. =. 25% w/w, indium concentration in the bottom phase is ~30% higher than the initial concentration before the extraction).
Original languageEnglish
Pages (from-to)325 - 333
Number of pages9
JournalWaste Management
Volume45
DOIs
Publication statusPublished - 28 Apr 2015
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Waste Management and Disposal

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