Most televisions and personal computers are landfilled, where the leaded glass used to make the cathode ray tube (CRT) poses groundwater pollution risks. A much larger number than previously thought are exported - some possibly illegally - to developing countries in Africa and the Far East.
However, markets for CRT glass, and possibly for television and computer monitor housings, are urgently needed if the UK is to meet its requirements under the WEEE Directive.
The Directive sets reuse/recycling and recovery targets for various categories of equipment, based on the weight of equipment that is separately collected. These must be achieved by December 2006.
One set of targets applies to IT and telecom equipment and consumer goods - categories that include televisions and computer monitors. The targets require 75% of such equipment that is separately collected to be recovered and 65% to be reused or recycled.
Because TVs and monitors are among the heaviest appliances that fall within this category, and because the CRT accounts for 50-85% of their total weight, it will be almost impossible to meet the targets without recycling CRT glass.
But a follow-up report by ICER for the Government's Waste and Resources Action Programme has found a number of potential markets for the glass. Many of these, said WRAP's glass manager, Andy Dawe, are expected to be commercially available within the next two years.
ICER estimates that some 105,000 tonnes of CRT glass entered the waste stream in 2002, of which two-thirds came from televisions and one-third from computer monitors. The total amount will have changed little by 2012, although by this time 90% of the glass will come from televisions, due to the switch to liquid crystal display technology.
CRTs are comprised of three sections. The neck contains up to 40% lead oxide and the funnel or cone up to 25%, while the screen, which accounts for two-thirds of the CRT glass, is made of glass containing barium oxide and strontium oxide.
A potentially major new market for panel glass is as flux in brick and ceramic manufacture. Research by the ceramics research body CERAM has shown that this would reduce the amount of energy used in the firing process to a greater extent than if container glass was used. However, the use of glass as flux could increase production costs because of the need to grind the glass very finely - a process that would also increase energy consumption.
The application "has the potential to use a significant amount of the UK's waste CRT panel glass," says ICER. If all brick manufacturers used 5%, some 370,000 tonnes of CRT glass would be needed - more than five times the annual arisings of panel glass.
Experience in Norway shows that panel glass could also be used to make foam glass, an insulation material. But there is limited demand for foam glass in the UK. Domestic production facilities are being considered but the application would only use some 3,000 tonnes of panel glass per year, rising to 9,000 tonnes.
Research by Staffordshire University has shown that panel glass could also be used to make decorative bricks and cladding tiles. The product compares well with conventional materials in terms of cost and has the potential to use "significant quantities" of panel glass, but "considerable market research is needed to develop a market for this niche product."
Mixed CRT glass could also replace sand as flux in copper smelting and some lead smelting - provided the lead can be recovered and the lead level in the resulting slag is low enough to be used in secondary applications such as road aggregates.
Post-consumer panel and funnel glass could also be used in the manufacture of new CRTs, along with waste glass arising from the manufacturing process.
Such closed-loop recycling is now "a real possibility", says WRAP, as the technical barriers to using post-consumer CRT glass have been overcome. Nearly 10% of the UK's waste CRT glass could be used in the manufacture of new TV screens next year. This could rise to 20% "if it proves technically and commercially feasible to use over 50% cullet in the production of new funnel glass and 30% in panel glass."
In order to aid recycling, says ICER, it will be important that CRTs arrive at treatment facilities "intact". Several firms already offer to collect CRTs. ICER is developing a code of practice against which such companies can be audited to gain ICER accreditation.
Information from reprocessors who handle CRTs shows that "little" recycling of the plastics from monitor casings is being carried out, says ICER. The situation will change only when higher volumes of material are available for processing, the WEEE Directive targets have to be met and producer responsibility - placing financial and legal responsibility for recycling on equipment manufacturers - comes into force.