Production of 'green cement'

A new cement manufacturing process has the potential to create carbon-negative building materials, a new paper in Advanced Sustainable Systems has found. The technology could be used in paint, plaster, and concrete.

Seawater electrolysis could be a carbon-neutral way to produce cement and other building materials. (Source: Northwestern University)

The cement industry currently contributes around 8% of global CO₂ emissions, making it the world's fourth-largest emitter, mainly due to the extraction of raw materials from mountains, rivers and seabeds, the report said.

Faced with this situation, researchers at Northwestern University (USA), in collaboration with the innovation department of the Cemex Cement Group in Switzerland, developed a more environmentally friendly cement. They used the technique of seawater electrolysis (a method of splitting water molecules with electricity) to create hydrogen, chlorine, oxygen and especially calcium carbonate (CaCO₃), the main ingredient for cement.

In the experiment, the team introduced electrodes into seawater, adjusted the voltage, and injected CO₂ at different rates and volumes to control the pH. This fine-tuning allowed control of the volume, chemical composition, and crystal structure of the CaCO₃, resulting in minerals with different porosity or density. However, the current electrolysis rate is still too slow to meet industrial needs. Therefore, the team is continuing to investigate the mechanism of mineral formation during electrolysis and ways to increase production.

This discovery opens up the prospect of adapting the electrolysis process to produce a variety of minerals and aggregates for the construction industry. If done with electricity from renewable sources, this process would not only be carbon neutral but also contribute to reducing the amount of CO₂ in the atmosphere.

Source: https://baoquocte.vn/san-xuat-xi-mang-xanh-311511.html