A study published in Nature suggests a new approach to accelerating carbon dioxide removal from the atmosphere using naturally abundant minerals. Researchers propose using calcium silicates, which react quickly with CO2 and are similar to compounds already used in farming.
Since the Industrial Revolution, humans have released 2650 billion tons of CO2 into the atmosphere, raising its concentration by 50%. Traditional methods, such as planting forests or capturing CO2 with chemical filters, come with limitations. Forests release CO2 again when they burn or decay, while carbon capture plants require significant energy and resources.
Carbon mineralization involves spreading crushed alkaline rocks on soils to bind CO2. However, natural weathering takes millennia, and even enhanced weathering doesn’t react fast enough. The study proposes using calcium silicates instead of magnesium silicates, which react quickly with CO2.
Researchers found that combining calcium oxide with magnesium silicates and heating the mixture results in a rapid binding of CO2. This process is faster than natural weathering, taking only months to bind all the CO2 they can hold. The researchers also propose making calcium oxide by heating limestone, which transforms it into CaO – the same process used to make Portland cement.
The cost of CO2 removal using this method is estimated to be around $100 per ton, significantly lower than traditional carbon capture methods. Farmers might be willing to pay for these materials as they already add calcium carbonate and other alkaline substances to their soils. However, field trials are necessary to ensure the new minerals don’t harm soil ecosystems.
Researchers have initiated such trials in Louisiana and New Jersey, providing hope for a scalable solution to accelerate CO2 removal from the atmosphere.
Source: https://www.science.org/content/article/farm-fertilizer-could-suck-carbon-dioxide-atmosphere