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LCD recycling project: green and valuable

20 Sep 2006

A project to extract the materials from redundant liquid crystal displays is expected not only to make these materials safe, but also to recycle millions of dollars worth of valuable chemicals.

Scientists at the University of York are to play a key role in new research aimed at recycling discarded liquid crystal displays.

Some 40 million LCD television sets were sold worldwide in 2005, with expected sales likely to exceed 100 million by 2009. But the chemicals they contain are potentially hazardous. and technological advances are so rapid that society is already discarding millions of LCD screens each year.

A team in the Department of Chemistry at the University of York has won a competition, organized by the UK government's Department of Trade & Industry, to investigate ways of extracting and recycling liquid crystals from waste LCD devices.

And York estimates that the value of recycled LCD material from the UK alone could be as much as $60 million (EUR 47.3 million) per year.

The consortium of nine partners is supported by both the Resource Efficiency and Displays & Lighting Knowledge Transfer Networks. The DTI is funding 50% of the total project development bid, which is worth £1.7 million ($3.20 million).

LCD screens usually comprise two glass sheets, between which a thin film of viscous liquid crystal material is deposited.

The material may be a mixture of up to 20 different compounds, typically polar organic compounds that are often fluorinated. EU legislation now prevents disposal of electronic materials in landfill. Incineration, the other disposal route, has also been banned.

"The amount of LCD waste is increasing at an alarming rate and, with disposal in landfill or incineration no longer acceptable, new solutions are needed," said Avtar Matharu, of York's Department of Chemistry. "We have developed a technology that offers a clean, efficient way to recover the mixture of liquid crystals from waste LCD devices."

"Once recovered, the liquid crystal mixture will be recycled in new LCDs or the mixture could be separated into individual components for re-sale. For example, you could take the material from a TV and re-use it in simple watch or calculator displays."

"This project stems from a DTI Challenge feasibility study to extract the liquid crystals from LC displays, which were previously incinerated at the end of their lifetimes, a practice which may soon be prohibited."

Other partners in the consortium are looking at the recycling of glass and the recovery of valuable indium tin oxide (ITO); there is a global shortage of indium. The group is also looking at the recovery of the metal and plastics used in the mountings, surrounds and diffusers of the LCD displays. Diffusers are often backlit with mercury lamps and this mercury is another attractive target for recovery.

Active dis-assembly is another important aspect of the project. The LC material stuck between the glass layers needs to be isolated easily. For example, this could be simplified by the insertion of "intelligent" polymers between the two panels that would help "pop" them apart when they need to be dismantled.

Economics of recycling LCD displays

Early figures from the consortium show that, beyond being an environmentally focused initiative, recycling LCD materials will actually be a significant source of income.

As more such displays are recycled there will be significant volumes of materials: possibly as much as 8000 t of glass and up to 1 t of indium per year. Considering the LC organic materials, figures from the EU's Waste Electrical and Electronic Equipment (WEEE) Directive show that in the UK alone up to 7 t of the 20 types of polar organic materials are thrown away.

The consortium estimates that the potential value of these materials in total could be as much as $50 to 60 million.

"Setting up the recycling company is our aim and as far as we know at the moment nobody else world-wide is developing this type of system," Matharu said. "And following the initial announcement of our development we have received contact from a number of major developers of LCD displays."

The LCD recycling project, which started last month (August), will last three years. York's particular involvement is the development of process for the extraction of the LCs themselves - the volatile organics - although particular details of the techniques are under patent (and still under wraps).

"It's possible that we could license any developed technology in the future to establish a network of LC display recycling centres world wide," Matharu said.

York University's Liquid Crystal Group is one of the world leaders in this technology. It stems from Professor John Goodby who recently moved to York from the University of Hull to launch York's Centre for Liquid Crystals, which employs 26 full-time researchers.

• Other consortium partners include: C-Tech Innovation, AXr, NIS, Active Disassembly Research, Glass Technology Services, Botanix, Engelhard Sales, and Sims Group.

HÜBNER PhotonicsIDS Imaging Development SystemsKentek CorporationEdmund Optics GmbHLASEROPTIK GmbHCHROMA TECHNOLOGY CORP.JenLab GmbH
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