Heavy industry decarbonization has been one of the most difficult tasks in the battle against climate change. Cement and steel industries, for example, not only use fossil fuels intensively, but they also produce carbon dioxide as a byproduct of their fundamental production processes. Combined, these industries are responsible for a large percentage of the world’s CO₂ emissions. That’s why policymakers and engineers have been on the lookout for scalable, impactful solutions that can address emissions at their origin.
A breakthrough by scientists at Melbourne’s RMIT University may be the game-changer. They’ve created a method for immediately converting carbon dioxide gas into solid carbon, on the spot when it’s generated. Rather than yet another incremental innovation, this technology has the potential to fundamentally change the face of emissions reduction for heavy industry.
Key to the technology is a process called the “bubble column” method. Here’s the process: liquid metal is warmed to a relatively modest temperature—in the range of 100°C to 120°C—and carbon dioxide gas is pumped into it. As the gas bubbles up through the metal, much in the same way that bubbles in a glass of champagne work their way upward, the CO₂ molecules are shattered at high speed. What is left over? Crumb-like pieces of solid carbon. And it all occurs in a matter of a fraction of a second.
Project lead Associate Professor Torben Daeneke describes how this system is a development of previous work with liquid metals, but it’s now optimized for use in an industrial environment. It’s simpler to scale up, more efficient, and more easily integrated into the systems that are currently installed in the cement and steel industries.
That’s a big win. In co-lead Dr. Ken Chiang’s eyes, one of the most thrilling parts is that the tech might be compatible with current industrial machines, just with some tweaking to accommodate the liquid metal parts. That reduces the distance from laboratory breakthrough to practical application, often a significant barrier to entry for promising climate tech.
This technique also presents a strong alternative to conventional carbon capture and storage (CCS). CCS systems are generally based on compressing CO₂ into liquid form and injecting it far beneath the Earth’s surface. But this process is costly, complicated, and raises questions about long-term storage and leakage. The RMIT process sidesteps those concerns by turning CO₂ into a stable solid that’s less difficult to deal with—and potentially even reusable.
Solid carbon also has possible uses in construction, industry, or even advanced materials. Though those industries are still in the process of developing, the fact that they trap carbon in a stable form is already an improvement.
Another primary advantage is the low operating temperature of the system. Since it doesn’t need to provide the high temperatures found in most industrial reactions, it might be fueled by renewable energy sources, making it not only efficient at sequestering carbon but clean as well.
The technology is already being commercialized. RMIT has lodged a provisional patent and signed a multimillion-dollar agreement with ABR, an Australian environmental technology company working in cement and steel. Their next step is to develop a modular prototype—about the size of an intermodal shipping container—that can be tested under actual industrial conditions.
The team is also seeking feedback from other players in the industry to assist in customizing the system for various uses. As Dr. Chiang points out, there isn’t one solution to deal with industrial emissions, but this new approach may be an essential part of the solution.
As the world’s demand for cement and steel continues to grow with urbanization, such solutions are desperately needed. RMIT’s on-demand CO₂-to-solid-carbon technology is not only a technical breakthrough but also a possible revolution in how heavy industry transitions to sustainability, providing a cleaner, wiser route to net-zero.
