Authors: Lisa O’Donoghue and Paul Moroney
Summary: Research Report 201 detailing the Investigation of Liquid Crystal Displays as a Source of Indium
Filesize: 4,818 KB
The objectives of the research were to investigate and explore the potential for indium recovery from LCDs.
A review of the requirement for LCD recycling from a policy perspective was undertaken. The WEEE Directive contains specific clauses that required the appropriate recycling of LCD displays. The Directive is now also being augmented by the industrial standards such as WEEELABEX which contains more specific targets regarding handling and recycling LCDs including threshold values for mercury and consideration of indium tin oxide fractions. As the WEEELABEX standard is currently in the process of being developed into the CENELEC standard monitoring and inputting to the developments is important from a national policy perspective.
In order to develop a cost-effective solution for recovering indium from LCDs, it is first necessary to understand the amount of indium contained within LCDs and the currently available recovery methods. Findings from 10 samples tested revealed that indium levels varied significantly (38 to 292 mg indium per kg glass panel) which will ideally require a recovery process that is sensitive to these range of variations. Reported recovery methods include traditional hydrometallurgy as well as novel techniques such as lift-off method, sub critical water process, bio-treatments and mechano-chemical treatments. While specific novel techniques such as lift-off and critical water processes potentially offer a good balance between cost, environmental impact, efficiency and time, they are at the early stages of testing and development and have not yet entered the market place. These processes are detailed and reviewed within this desk based study and represent a foundation of knowledge on which to develop and test a future solution.https://www.epa.ie/media/epa-2020/publications/research/Thumb-201.jpg