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Taking the fear out of flat panels

While older-style cathode ray tube (CRT) TVs are still in use in homes around the country, and are expected to comprise a significant amount of the waste electrical and electronic equipment (WEEE) waste stream for a few more years, it is flat panel displays (FPDs) that are the WEEE waste stream of the future.

“It is anticipated that, in the next three to five years, the number of FPDs in the waste stream will noticeably increase and hence a commercially viable recycling process will be necessary,” states WRAP’s report Demonstration of Flat Panel Display Recycling Technologies published last September.

It quotes figures commissioned by WRAP and calculated by Optimat suggesting that, by 2016/17, there will be 146,567 tonnes of FPD WEEE in the waste stream, made up of discarded desktop monitors, notebook PCs, plasma TVs and liquid crystal display (LCD) TVs. In 2012 alone, it estimated that more than 3.5 million LCD TVs will be put on the market - an indicator of the growth in sales, and later waste, of this stream of electronic waste.

The main issue with the treatment of FPDs is the use of backlights in their displays. These commonly use mercury-containing cold compact fluorescent lamps (CCFLs), making such items ‘hazardous’ under the European Waste Catalogue. Removal of the mercury is required for treatment, and this brings with it significant health and safety implications.

One recycler that has taken on the challenge of FPDs is Preston-based Recycling Lives. At the end of March, the company opened what it believed was the first dedicated FPD processing centre in England.

When the £250,000 plant was announced, strategic development manager David Allen said: “All aspects of the process have been carefully considered and the processing line which has been developed is something we are very proud of. It is very important to us that we have a line which is a flagship FPD facility which sets the trend for how to correctly handle these units.”

Recycling Lives has incorporated procedures gleaned from CRT recycling into its FPD recycling plant, to improve speed and efficiency. It hopes to be able to process up to 1,000 units a day at full capacity. And to handle the hazardous mercury found in FPD backlights, the plant has invested in health and safety testing, mercury analysing equipment and a specially designed mercury-safe dismantling room, as well as protective equipment and training for its staff.

When FPDs come into the plant, they are first visually assessed to see if they are suitable for refurbishment or recycling. Units that pass the visual inspection undergo three further tests: a PAT test, screen test and sound test. If they pass, they are deemed suitable for re-sale and are stickered with a bar code for audit purposes. Those that do not pass the tests go into the recycling stream where they are dismantled by hand.

The metal and plastic components are removed, leaving the screen and mercury-filled fluorescent tubes, which move by conveyor belt into a sealed room. Staff working in the mercury-safe room are kitted out in heavy-duty face masks and body suits while they manually separate the backlights from the FPD screens. Staff are rotated at regular, short intervals and the air in the room is replaced every 60 seconds, with the mercury being sucked out into a separate unit and stored away from all other areas in preparation for external recycling.

While the opening of the Recycling Lives facility is good news, there is still interest in the potential of a plant that uses greater automation. WRAP’s work in this area trialled the shredding of FPD units after manual removal of the backlights, which were then sorted into component materials using existing automated sorting techniques, with some success.

But tests into whether mercury decontamination was feasible in a scenario where whole FPDs would be shredded in an enclosed environment, with material being fed into a bulk washing process, produced inconclusive results that material could be effectively washed of mercury. It concluded that further work was needed to determine a suitable washing medium that could recover mercury on a safe and commercial scale.

Other organisations that have looked into FPD recycling include the Innovative Electronics Manufacturing Research Centre (IeMRC), based at Loughborough University, the University of Central Lancashire and York University.

Speaking at an LCD recycling seminar last year, IeMRC industrial director Martin Goosey explained: “LCD recycling is still in its early days, with no single preferred treatment route. Some sort of manual intervention is preferred but may not be viable, and there is a need to consider the impact of mercury.”

He said the issue with manual disassembly was that it is very labour-intensive, requiring patience and concentration to remove the fluorescent tubes without breaking them, while automated disassembly would see higher capital costs and lower labour costs, and involve a considerable refining and purification process. Goosey noted the processing issues posed by mercury-containing backlights, but pointed out that new technology was moving away from CCFL backlights towards the use of LEDs.

The University of Central Lancashire’s centre for waste management director Dr Karl Williams outlined three main treatment options for handling LCD waste: manual disassembly, shredding or a combination of the two. He said the economics of treatment methods was the ultimate driver.

One issue raised by Williams was product design: “Under the WEEE Directive, electronic equipment is meant to be designed for disassembly. But we have had trials where 154 screws were found in an LCD TV, which makes manual disassembly difficult.”

Williams explained that because of high demand, manufacturers buy a variety of LCD panels for use in their products so that, when it comes to disassembly, products produced by the same manufacturers can be composed of panels from different sources. This means there is no standard panel, which affects the effectiveness of disassembly.

He also flagged up the shift towards using LED backlights rather than CCFLs, with manufacturers such as Sharp having already announced that mercury-containing backlights will not be used in its products by 2012, and Dell and Apple also moving away from their use. “From the recycling perspective, dealing with mercury will be relatively short term,” Williams explained, predicting that, within five years, mercury within display equipment would be gone.

The Reflated LCD recycling project, headed by C-Tech Innovation, has been looking into the potential of recycling LCDs. It found another problem was with the recycling of the glass panels. The logistics of recycling them into new glass panels was found to be uneconomical because the waste stream was generated in the West but the manufacturing hub was in the Far East.

Conventional glass recycling approaches were also deemed unsuitable due to the varying chemical compositions of the glass in LCD screens, but potential has been identified in using the material for fibreglass. The project also found manual disassembly to be safer but slower, and that while the technology and knowledge is also available for recycling the liquid crystals themselves, it is not currently economically viable.

As with all emerging waste streams, volumes and the economics will shape the waste treatment options that develop for FPD WEEE. But it is certainly one of the growing waste streams to keep an eye on.

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