References
1 “Glass is the hidden gem in a carbon-neutral future,” Nature 2021, 599(7883), 7–8.
2 Jensen, L. (Ed.), “Sustainable development goals report 2022,” United Nations. 2022. Accessed 20 Feb. 2023. Available here.
3 “Develop carbon sequestration methods,” National Academy of Engineering’s Grand Challenges for Engineering. n.d. Accessed 10 March 2023. Available here.
4 Adam Willsey, “3 common glass types: Properties and applications,” Kopp Glass, 14 July 2015. Accessed 18 Jan. 2023. Available here.
5 S.M. Karazi, I.U. Ahad, and K.Y. Benyounis, “Laser micromachining for transparent materials,” Reference Module in Materials Science and Materials Engineering 2017.
6 E.R. Vance, B.D. Begg, and D.J. Gregg, “10–Immobilization of high-level radioactive waste and used nuclear fuel for safe disposal in geological repository systems,” Editor(s): Michael J. Apted and Joonhong Ahn, in Woodhead Publishing Series in Energy: Geological Repository Systems for Safe Disposal of Spent Nuclear Fuels and Radioactive Waste (Second Edition), Woodhead Publishing, 2017, pp 269–295.
deciphering the discipline
A regular column offering the student perspective of the next generation of ceramic and glass scientists, organized by the ACerS President’s Council of Student Advisors.
Sierra Astle and
Shaylee Traugh
Guest columnists
LionGlass: A phosphate-based approach to carbon-neutral glass manufacturing
From windows, cups, and windshields to smartphone screens and even tissue scaffolds, glass is inescapable in today’s world. Though its uses in civilization are beneficial, this material does not just impact our lives—glass manufacturing also impacts the environment, and not always in a good way.
Every year, approximately 86 million tons of carbon dioxide is produced from the manufacturing of glass.1 The carbon dioxide comes from using fossil fuels to heat the high-temperature melting furnaces, as well as from the reaction products of the carbonate batch materials.
Pursuing carbon neutrality in the glass manufacturing sector would help address several of the United Nations Sustainable Development Goals.2 These goals include responsible consumption and production and climate action. This progress in glass manufacturing would also contribute to one of the National Academy of Engineering’s 14 grand challenges, developing carbon sequestration methods.3 If less CO2 is being produced, then less CO2 needs to be captured and stored.
Glass manufacturers can work toward a carbon-neutral future with the help of materials scientists by creating compositions with a low melting temperature and that release little to no CO2 when processed.
Phosphate-based glasses are the perfect place for materials scientists to start looking for new, improved, and more sustainable glass. Currently, soda lime silicate glasses account for approximately 90% of all glass made.4 These glasses are used to produce many everyday items, such as windows,5 but they require high melting temperatures of 1,450–1,500°C and release CO2.
The use of phosphate as a main component in glass allows it to be made without the use of carbonate materials, such as limestone or soda ash. As such, subsequent CO2 emissions are lowered. Additionally, phosphate-based glasses often have lower melting temperatures than silicate glass, which would lead to a higher energy efficiency and lower melting cost.6
A new low-carbon, low-energy consumption phosphate-based glass is currently being explored at The Pennsylvania State University (Figure 1). Dubbed LionGlass, it is being engineered to have a melting point 20–33% lower than the melting temperature of standard soda lime silicate glasses.
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Figure 1. Bar of LionGlass made at The Pennsylvania State University for mechanical testing.
Credit: Shaylee Traugh
LionGlass is also being batched, melted, and tested for various properties needed in window applications. For example, windows need a certain mechanical strength, such as resistance to scratches or crack propagation. They must also have acceptable thermal properties—a window that lets all the heat out of a home is hardly cost effective or green!
Because glass is inescapable, we must make it more sustainable for our Earth. Phosphate-based glasses such as LionGlass have the potential to help improve the sustainability of future glass manufacturing.
About the authors:
Sierra Astle is an undergraduate at The Pennsylvania State University, studying materials science and engineering. Following graduation in spring 2023, she plans to pursue a Ph.D. in materials science and engineering. In her free time, Sierra enjoys learning guitar, hiking, and trying new recipes.
Shaylee Traugh graduated from The Pennsylvania State University with a B.S. in materials science and engineering in 2019. She worked as a process engineer for 3 years before returning to Penn State, where she is a first-year Ph.D. student in John Mauro’s group studying glass. Shaylee enjoys visiting wineries with her partner and experiencing new hiking trails.
