Cement is indeed a problem for decarbonisation policies, as production not only requires a lot of energy (mostly of fossil origin), but the process itself also generates a lot of CO2. But now a way out seems to be emerging thanks to technology developed by a team of researchers and scientists fromMIT in Boston az Dalhousie University: It is possible to create economical concrete with zero carbon emissions using the most advanced electrochemistry. Noble systems, is the name of a startup founded by researcher Leah Ellis and Professor Yet-Ming Chiang, which started with at least two certainties: the first is that 4 billion tons of cement will be produced on the planet every day (Source: Mineral Commodity Summaries 2023 ); the second is CO emissions2 related far exceed the impact of aviation or maritime transport. In the face of very high demand, the response to environmental policies remains too weak: here is an opportunity for innovation.
How cement is made today
L’cement industry annually releases approximately 2.6 billion tons of carbon dioxide into the atmosphere and is responsible for approximately 7% of CO emissions2 global totals. The reason for this is the fact that during production we rely on a mixture composed of limestone (sedimentary rock that contains calcium, oxygen and carbon), sand and clay, naturally ground and then cooked in ovens at temperatures of up to 1500°C. To reach such a threshold, traditional sources are mostly used – with all the critical environmental problems upstream and downstream consequences – and to top it off, CO emissions2 60% of the entire production cycle is associated with the chemical reactions of the process. Heat and chemistry actually convert the limestone into lime, which in turn combines with the silica present in the sand and clay. The result is a mixture that, after mixing with water, sand and gravel, is simply placed on the construction site and turns into solid concrete after drying. In short, there is an energy problem for the operation of the machinery and a lime conversion problem, which involves the removal of carbon dioxide (then released into the atmosphere).
Building
Concrete is stronger (and greener) with coffee grounds
by Simone Cosimi
How Sublime Systems works
The Somerville, Massachusetts-based startup is actually betting on the same industrial electrochemical concepts that already underlie the production of aluminum, magnesium, copper, hydrogen, etc. In this case, the system converts limestone into lime at room temperature, making it easier to capture CO2 produced during the conversion process and reduce overall energy consumption,” explains MIT Technology Review. In practice, energy from renewable sources can be used because there is no need to reach very high temperature peaks. Furthermore, dispersion is reduced because the electricity itself triggers the chemical reactions necessary for the production of cement.
The secret is in the electrolyzer, which is commonly used, for example, to split water into its components, producing hydrogen and oxygen. In this case, “one electrode produces a solution that extracts the calcium from the inert minerals, leaving behind a reactive silicate. The other electrode produces alkalinity, which precipitates the calcium (also known as lime) as a pure, reactive solid. The reactive calcium and silicates are mixed in low-temperature process to create the final product: Sublime Cement,” the company assures. This type of concrete is considered high-performance and low-carbon: “it has similar ultimate strength, durability, deformability and setting time to concrete” commonly used for buildings and infrastructure, according to ASTM C1157.Something similar to the common “grey” portland cement widely used in every city in the world.
Decarbonization
A green building startup that wants to change the rules of the game in the world of dinosaurs
by Eleonora Chiodová
Sublime Cement, one million tons per year from 2026
Four years after the first development phase, Sublime Systems is able to produce approximately 100 tons of cement per year thanks to a pilot line that opened in 2022. That’s not much when you consider that it would take a week to fill a single concrete mixer, and it would take three or four loads to put up a typical single-family home in the United States. The current production serves to identify new partners and provide samples that enable concrete block testing. In short, we try to understand scalability also in relation to types of engineering projects. “I think people are rightfully skeptical of new concrete. Well, this is not — and is not — new concrete,” Ellis said.
The prospect is to build a new commercial demonstration plant capable of producing tens of thousands of tons of cement per year by early 2026, and then in 2028 to inaugurate the first major plant capable of reaching one million tons per year as usual. ones. “Starting cement is probably one of the most difficult things you can imagine. Not only is it technically difficult, but it also requires a lot of capital. It’s huge. And it’s not sexy… everyone uses and owns cement, but no “I don’t see it, Ellis concluded.