Czech glassmaking with a US partner: Extending the life of glass furnaces and accelerating the green industrial transformation

What is your project about and how is it unique?

Our project involves developing new experimental and modelling methods that should finally accurately describe and predict (not just “estimate from practice”) the corrosion of refractory materials in glass furnaces. The current state of affairs is still very empirical: corrosion is determined by a combination of diffusion-controlled dissolution, glass flow (Marangoni and density convection), and the formation of corrosion sublayers with different properties. This is a very complicated system for physical and chemical description. In my opinion, the project received grant funding because it connects basic research with very specific applications and is built on a strong bilateral cooperation with the US Department of Energy’s Pacific Northwest National Laboratory (PNNL), one of the world’s glass science leaders.

What is the specific goal of your bilateral project and what methods do you plan to develop?

Our goal is to obtain a predictive model enabling us to estimate the corrosion rate and dominant mechanisms from the chemical composition of glass and refractory materials. To get there, we are developing a rotational corrosion test with rotating refractory plates in a glass melt. Thus, the flow is defined and symmetrical, so that the resulting material loss profiles can be used to mathematically determine diffusion coefficients, solubility, and interfacial kinetic parameters. We pay special attention to the meniscus, where—due to the dissolution of refractory components in the melt—surface tension changes combine to create a vortex flow that significantly accelerates corrosion.

Why is extending the life of glass furnaces crucial for the Czech and global glass industry? What economic impacts do you anticipate?

Glass manufacturers are under pressure to switch from running furnaces on fossil fuels to running them on electricity. Electric furnaces are very energy efficient but expensive and currently shorten the life of linings, especially around electrodes. Every overhaul of a furnace is a huge investment and means a long manufacturing downtime. If we find a way to manage corrosion in electric furnaces more efficiently, that would significantly improve their operating economics.

How will the project specifically contribute to reducing the energy consumption of furnaces or the recycling of materials?

We are not directly involved in the design of new furnaces or recycling technologies, but we are providing the missing physical and chemical basis for these. A better description of corrosion will enable development of more efficient linings and glass compositions that can last longer under the same or even higher loads. In terms of practical use, this means less frequent replacements, lower material consumption, and better use of electric furnaces that are, ideally, connected to renewable energy sources. However, the specific technical solutions will be up to the manufacturing partners.

In the US, you worked on modelling nuclear waste vitrification. Do you also apply some of these mathematical models to classic glass furnaces in this project funded by the Ministry of Education, Youth, and Sports?

Yes, we use the same type of computational fluid dynamics (CFD) modelling for a melting furnace as was developed for the vitrification of radioactive waste, but we are extending it to include a more detailed description of corrosion. In US projects, it turned out that without high-quality input data (i.e. diffusion coefficients, component solubility, and relationships between glass compositions and corrosion rates) the model necessarily remains simplified and with empirical limitations. The current project is the answer to this shortcoming. Our plan is to generate data and relationships that will allow the corrosion part of the model to be more precise and transferrable to classic glass furnaces.

Who is your US partner in this collaboration and what unique technologies do they bring to corrosion analysis?

The main partner is the Pacific Northwest National Laboratory, with whom I have been collaborating since 2010. The US side has detailed CFD models of entire melting units and experience with vitrification of highly corrosive waste glasses. In turn, we are contributing new mathematical models, specialized dynamic corrosion experiments, and the ability to modify them quickly. The result is a combination of cutting-edge numerical modelling with experiments designed specifically for these models.

What unexpected challenges have you encountered in past projects and how are you addressing them here?

We often encounter the problem that an experiment that seems simple is difficult to perform in practice due to temperature gradients, material reactivity, or poor reproducibility, for example. We have found that having a strong experimental team that can quickly rebuild an apparatus and adjust protocols is key. Here, a combination of experienced researchers and active students takes care of this. Thanks to this, we can respond in weeks, not months, which is essential for collaboration with modellers.

Do you collaborate with anyone else at UCT Prague?

Yes, the UCT Prague Laboratory of Inorganic Materials is a joint working place with the Institute of Rock Structure and Mechanics of the Czech Academy of Sciences. At UCT, we cooperate closely with central laboratories (X-ray diffraction and fluorescence analysis, solution analysis) and also with the Department of Metals and Corrosion Engineering, especially in the characterization of corrosion layers using scanning electron and transmission microscopy. These links are crucial for the project, as they allow us to perform a complete material analysis from the macro to the microscale.

How do you involve students? What roles do they play in experiments? Are you looking for additional reinforcements for your team?

Students are the backbone of the experimental part of the project: they operate the equipment and participate in data evaluation and in the preparation of models. Thanks to this and similar international grants, we can send doctoral students and sometimes Master’s students to US National Laboratories for several months, which is a huge professional and personal leap for them. We are constantly looking for new reinforcements; the desire to devote themselves to experimental (sometimes routine and time-consuming) work in a glass laboratory is important. In our new project, I would like to emphasize the merits of Master’s student Radek Pezel, who has been working on the problem of corrosion in our laboratory since he was an undergrad, and whose results constitute the basis for a significant part of the project.

How is this project different from your previous grants?

The main difference is that it was conceived from the beginning as a truly bilateral project. Not just “consultation” activities but joint research with a clear division of labour on both sides. In addition, the project also funds two-way internships and coordinated experimental campaigns on both locations, which is not usually the case with standard national or European projects. This allows us to fully utilize and further develop our long-standing contacts with the US Department of Energy’s National Laboratories.

What applications do you expect in the commercial sector after 2029, when the project ends?

We expect that the result of this project will be practically usable models that will allow the glass industry to better design glass and refractory compositions and more accurately estimate furnace lifespan without the need to perform long and expensive tests for each new combination. In the field of nuclear energy, these models should contribute to the optimization of the composition of vitrification glasses so that they can process even more corrosive wastes while still maintaining acceptable wear on the vitrification furnace lining. However, the actual implementation of these models into design and operational tools will be up to companies and our US partner institutions.