Concrete is the most widely used material in the world, but it comes at a huge environmental cost. The production of cement, the main ingredient in concrete, produces approximately 2.5 billion tons of carbon dioxide per year, or approximately 8% of the world's total carbon dioxide. Researchers are working to find more sustainable ways to produce cement.

 

Cement production generates greenhouse gas emissions at every stage, starting with the production of clinker, a cement precursor. This process requires the conversion of calcium carbonate into calcium oxide, releasing carbon dioxide. This reaction requires temperatures as high as 1,400 degrees Celsius, which necessitates the burning of large amounts of fossil fuels.

The most common type of cement is Portland cement, which is typically made from limestone and minerals such as calcium silicate. This process is energy-intensive and generates significant amounts of carbon dioxide.

 

To mitigate the environmental impact of Portland cement production, researchers from the University of Michigan and the University of California have developed a method to capture carbon dioxide from this process and convert it into metal oxalate, a precursor to sustainable alternative construction materials.

 

This research stems from the Center for Closing the Carbon Cycle (4C) project, funded by the U.S. Department of Energy, to explore practical methods for capturing and reusing carbon dioxide. Instead of just releasing carbon dioxide into the atmosphere
Once carbon dioxide is converted to solid metal oxalate, it is not released back into the atmosphere as carbon dioxide under normal conditions.

 

McCrory said, “It’s a true capture process because you’re creating a solid from it, but it’s also a useful capture process because you’re creating a useful, valuable material that can be used in subsequent steps.” The next step involves further research into how to scale up the process to produce a solid product. In another recent study, researchers in Japan created a cement-free soil hardener from recycled glass and construction waste.

 

The team believes their method could eventually be scaled up for industrial use. Much work remains to optimize the production of the final solid product, but the required low lead levels are a crucial step in making this process environmentally responsible.
“We’re still a long way off, but I think it’s a viable process. Part of the reason we want to reduce the lead catalyst dosage to parts per billion is the challenge of scaling up a catalyst with a high lead content. Otherwise, it wouldn’t make sense environmentally,” McCrory said.

 

Reference: Bangkokbiz