Borosilicate glass, vital for pharma and labs, resists traditional recycling due to its high melting temperature, but ‘glass laser morphing’ from EU-funded project, EVERGLASS, offers a new route to re-using this valuable material.
When it comes to glass materials, not all are created equally – especially borosilicate. Unlike your everyday soda-lime glass commonly used in bottles and jars, borosilicate is engineered for thermal shock resistance and chemical stability, making it the material of choice for laboratory equipment and pharmaceutical containers. Yet the very engineering that imparts heat-resistance and durability also delivers a glass with a very high melting point – and herein lies the problem.
Soda-lime glass melts at around 1500°C and can be efficiently recycled in large glass furnaces. Borosilicate glass, however, melts at around 1650°C, making it incompatible with standard furnaces. On top of this, reaching borosilicate’s higher melting temperature in such a furnace would demand significantly more energy, raising operational costs. And any cross-contamination between borosilicate and soda-lime glass batches would lead to defective products and even more waste.
Landfills Full of Pharma-Grade Glass
These issues raise very real recycling challenges for the industries that rely on borosilicate glass – namely pharma. As Juan Pou, Professor of Applied Physics at the University of Vigo, Spain, points out, almost no pharma-grade borosilicate glass is recycled, and instead is incinerated and passed on to landfill. Remember the millions of tough, little vials manufactured during the Covid-19 pandemic to store vaccines in? That’s where they are now and will remain for a very long time.
According to UK waste management firm, Waste Managed, any glass in landfill can take hundreds to thousands of years to break down and may release toxic substances along the way.
Meanwhile land-filling borosilicate glass also means discarding valuable resources. Boron – a key element in borosilicate glass – has been identified as a ‘strategic raw material‘ in the European Union’s Critical Raw Materials Act due to its importance in applications including advanced batteries and nuclear energy.
“We have no sources of boron in the EU and the UK – all of our borate minerals are imported from Turkey for example, so we’re seeing a lot of interest in recycling borosilicate glass,” highlights Pou. In Europe, at least 70% of soda lime glass is already recycled,” he adds. “But if we could raise the recycling of borosilicate glass from virtually nothing to just 20 to 30% that would have an amazing environmental impact.”
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A Different Way
Since January 2024, Pou is the project coordinator of the EU-funded EVERGLASS project. He and colleagues have been working hard to develop a laboratory-scale, glass laser morphing prototype to recycle borosilicate and other glasses into new products. The device is designed to avoid the use of traditional furnaces and instead relies on a laser as part of a more modular system, to efficiently and cheaply melt the glass.
Prior to laser morphing, the glass is sorted according to composition and then cleaned, crushed and milled to a fine powder. In the lab, the researchers have been painstakingly characterizing the properties of the glass powder, working out the best viscosities, thermal and mechanical properties as well as range of powder particle sizes for laser-melting.
“Our idea is to develop a prototype that can [work with] a very wide particle size,” says Pou’s colleague and EVERGLASS researcher, Dr María Jesus Pascual, from the Institute of Ceramics and Glass in Spain. “This way we can use as much of the waste glass as possible.”
Once prepared, the glass powder is mixed with air so it can continuously flow like a fluid across the laser and be efficiently heated to temperatures as high as 2000ºC – hot enough to melt the glass. According to Pou, controlling the powder flow is critical to ensure the molten glass melts evenly.
“We have been solving problems on how the energy can be coupled from the laser to the powder,” he says. “We also need to make sure we select the right laser power – too much power and you’ll vaporise the glass, yet too little power, and the glass will not melt.”
The researchers have also developed a kinematic platform that precisely positions the molten glass so it can be shaped directly by the laser, without using moulds. They have already produced their first simple, sturdy geometric shapes which don’t break. They now intend to create both dense and porous, large and small pieces, in ever more complex shapes.
As Pascual points out, recycled borosilicate glass pieces will not meet the stringent regulations for pharmaceutical glass packaging, yet a world of applications remains. Cookware is one clear option, but the researcher also reckons recycled borosilicate could be shaped into filters and supports for catalysts used in gas and liquid purification and organic reactions and even combined with different glasses.
“This [flexibility] and its modular character are key advantages of laser processing over glass melting in a furnace,” said. “The variety of possible products is huge.”
Approaching Industry
So, what now? Work on the prototype continues with Pou commenting:
“We are still optimizing all parameters, which is very, very tricky… our prototype is not so user-friendly right now, but this will soon change.”
Come the end of the project in December 2026, the lab-scale prototype will be well and truly proven. With the necessary funds, an industrial-scale pilot facility could be in place by the early 2030s. Once out in the real world, both Pou and Pascual envisage that either a glass waste management firm will handle the initial powder preparation, or this step will take place at the recycling site. They believe that either a few large laser-morphing systems will be used to recycle the glass, or numerous small devices could be sited across Galicia, the rest of Spain and, eventually, further afield.
“We could make an in-house system that could be installed in a hospital basement so staff could directly recycle their material there,” says Pou. “If we [achieve] this here in Galicia, then other people may then copy such as system – this is our dream.”
