Displaying items by tag: mineralisation

US: A team from the Massachusetts Institute of Technology (MIT) has developed a new method to sequester CO₂ in concrete before curing it. The method is based on the addition of bicarbonate of soda, which reacts with cement to produce a calcium carbonate-calcium silicone hydrate composite. The Journal of Engineering has reported that the method adds the benefits of CO₂ mineralisation during production and casting, doubling the mechanical performance of early-stage concrete. It also eliminates the effects of carbonation reactions in cured concrete, which weaken the concrete by lowering its alkalinity, which accelerates the corrosion of rebar. The method has the potential to sequester 15% of CO₂ emissions from cement production.

The team said “The pre-curing capacity of concrete to sequester CO₂ has been largely underestimated and underutilised. Our new discovery could further be combined with other recent innovations in the development of lower carbon footprint concrete admixtures to provide much greener, and even carbon-negative, construction materials.”

Canada/US: Holcim North America has invested in Blue Planet to support the development and commercialisation of its mineralisation technology. Blue Planet’s process sequesters CO₂ with building waste feedstock such as recycled concrete, cement kiln dust (CKD) and slag to produce new aggregate products. Each tonne of Blue Planet’s aggregate can mineralize up to 440kg of captured CO₂. Lafarge Canada, Holcim US, and Blue Planet will start a multi-year collaboration to help identify potential to use the mineralisation technology to further lower the carbon footprint of the companies’ cement, aggregates and concrete operations, with the potential to expand to other operations in the Holcim Group around the world.

“This is an important step for us in North America. Our vision is to transform our St Constant Plant in Montreal into a carbon campus that ultimately advances commercialisation of mineralisation technologies, including Blue Planet’s products,” said David Redfern, president and chief executive officer, Lafarge Canada. “We look forward to advancing our Net Zero strategy by leveraging mineralization technology that allows us to use the CO₂ from our own cement plants to produce carbon neutral or carbon negative sand and gravel products.”