The Process

Mineral carbonation typically involves the following steps:

• CO2 is captured from industrial sources or directly from the air. 
• The captured CO2 is dissolved in water, forming carbonic acid. 
• The CO2-rich solution reacts with calcium or magnesium-rich rocks, such as basalt or peridotite. 
• Stable carbonate minerals (e.g., calcite, magnesite) form and precipitate out of the solution. 
 

Key Advantages 
• Mineral carbonates are extremely stable and can store CO2 for geological timescales without risk of leakage. 
• The process produces environmentally benign materials, reducing long-term monitoring requirements. 
• Global potential for mineral carbonation far exceeds anthropogenic CO2 emissions. 
• Can be applied both ex-situ (above ground) and in-situ (underground). 
 

In-Situ Mineral Carbonation

In-situ mineral carbonation involves injecting CO2 directly into suitable geological formations:

 
• Basaltic and ultramafic rocks are ideal due to their high content of calcium and magnesium. 
• In favorable conditions, significant carbonation can occur within months to years. 
• Vast basaltic formations on the ocean floor offer enormous storage capacity. 
 

Ex-Situ Mineral Carbonation

Ex-situ processes involve reacting CO2 with mined minerals or industrial waste products:

• Can use natural minerals (e.g., olivine, serpentine) or alkaline industrial wastes (e.g., steel slag, cement kiln dust). 
• Allows for optimization of reaction conditions to enhance carbonation rates. 
• Carbonated products may have applications in construction or other industries. 
 

Challenges and Ongoing Research 
• Reducing the energy needed for mineral preprocessing and carbonation reactions. 
• Accelerating carbonation rates to make the process more economically viable. 
• Optimizing water consumption, especially for in-situ applications. 
• Developing more cost-effective methods for CO2 capture and mineral carbonation. 
 

Innovative Approaches 
• Using regenerable pH buffers to control solution chemistry and enhance carbonation rates.
• Exploring the use of enzymes (e.g., carbonic anhydrase) to speed up CO2 hydration and carbonation. 
• Combining direct air capture with mineral carbonation for negative emissions. 
 

Future Prospects

Mineral carbonation offers a promising pathway for long-term, secure carbon storage. As technology advances and costs decrease, it has the potential to play a significant role in mitigating climate change. Key areas for future development include:

• Scaling up successful pilot projects to industrial levels. 
• Integrating mineral carbonation with existing industrial processes. 
• Exploring offshore storage options in basaltic formations. 
• Developing regulatory frameworks for large-scale implementation. 

By converting CO2 into stable mineral carbonates, we can effectively "lock away" carbon for millennia, providing a powerful tool in our efforts to combat climate change and achieve global emissions reduction goals.