Sustainable recycling of flat panel displays

The Swedish joint R&D project “Sustainable Recycling of Flat Panel Displays” is an initiative to develop a comprehensive solution for the recycling of flat screen TVs and computer monitors, particularly those based on liquid crystal technology. This report presents selected findings made within the project.

Summary

manufacturers of flat screen TVs and monitors, WEEE collection organization, WEEE recyclers, recycling equipment suppliers and environmental labeling organizations a better understanding is provided of the complex conditions influencing the life cycle of flat screens.

This report presents selected findings made within the project. The results presented are specifically related to process for indium recovery from LCD glass, recovery and re-use of optical components and sustainability rating of different recycling scenarios involving mainly large-scale shredding, manual dismantling or semi-automated dismantling.

A process has been developed by Chalmers for indium recovery from LCD glass. The process, which involves leaching of the indium-tin oxide layer, and then subsequent extraction, has been studied in terms of kinetics and yield with regards to choice of leachants, extractants and various process parameters. The best conditions identified in this study gave indium contents in the range 0.20-0.25 g/kg glass at a yield of nearly 90 percent. However, to achieve economical sustainability of the process relatively large volumes of LCD glass needs to be treated every year. The required volumes will not be available in the Swedish waste stream until 2015.

In another work package of the project, we investigated ways of recovering a higher monetary value than currently from discarded flat screens. We found that recovery and re-use of LCD optical components in high-end applications would be a potential way of achieving economical sustainability of LCD recycling particularly for small to medium scale recyclers. As the main properties of many components are not significantly affected by their lifetime in a flat screen, they are well suited for re-use, generally not in LCD screens, but in other applications where their optical properties can improve current product performance. The main application in which we have evaluated recovered components is LED fittings for general illumination. Using the optical components of the LCD backlight unit, which constitute 25-30 weight percent of a 17 inch LCD monitor, enables energy-efficient flat LED luminaries to be produced at a favorable cost level. As a spin-off from the project, serial production of LED fittings has been initiated.

Coworkers: Hanna Ljungkvist, Tomas Rydberg

Year: 2016.0

Report number: C210

Authors: Hanna Ljungkvist, Tomas Rydberg, Karin Garmer Johan Felix