If successful, the feasibility study could offer a solution to the UK's problem of excess green glass in used cullet.
There has traditionally been more green glass in the UK waste stream than needed by UK-based glass reprocessors because the UK imports a lot of wine in green bottles, but makes mainly clear and amber spirit and beer bottles.
”It would at a stroke resolve the UK's glass problems“
Andy Dawe, WRAP
Andy Dawe, WRAP's material sector manager for glass, explained: “It would at a stroke resolve the problems about colour separation and excess green which we have in the UK.”
The three-month trial is being done in partnership with Glass Technology Services, the technical arm of the British Glass Manufacturers' Federation and the University of Sheffield. It involves both a review of other attempts worldwide to remove colour from glass and a practical trial of different methods.
The trials involve adding different chemicals to coloured cullet and heating in a furnace until the glass goes clear. But the most efficient and cost-effective method of doing this have yet to be uncovered.
Mr Dawe explained: “We are still looking at different options and we will obviously need to focus on one or two options and decide which ones are worthy of continuing with further work.”
But he warned the goal of a method of turning large quantities of green glass to clear was still some way off. “It's not going to happen, certainly not in the next few years,” he said. “But we hope to achieve some steps towards that which would allow us to incorporate a higher percentage of green glass into a clear glass furnace without influencing the ultimate colour of that material.”
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