Cement, the world’s leading construction material, accounts for around 8 per cent of all greenhouse gas emissions. If cement production were its own country, it would rank as the world’s third-largest emitter. And with the number of buildings worldwide expected to double by 2060, this amount is projected to grown exponentially.
A team of researchers at MIT has now come up with a new way of manufacturing cement that could eliminate these emissions altogether — without making the cost of this cheap building material too expensive.
According to a press release, the researchers decided to use an electrochemical process to replace the current production process, which is dependent on the use of fossil fuels. Instead of grinding up limestone and then cooking it with sand and clay at high heat produced by burning coal, the researchers propose using an electrolyzer powered by electricity generated from clean, renewable sources.
In the new process, the pulverized limestone is dissolved in one electrode, which then produces calcium hydroxide, generally known as lime, as a solid at the other electrode. The calcium hydroxide can then be processed in another step to produce the cement. In addition, the process releases high-purity carbon dioxide in the form of pure, concentrated steam, which can then be easily captured and harnessed to produce value-added products such as liquid fuel to replace gasoline or for applications such as in carbonated beverages.
Thanks to their new process, the researchers are able to produce the same cement product, something that will greatly facilitate its acceptance. The major challenge now is to scale it up and compete with a typical cement plant, which produces around 700,000 tons of cement per year.
