What is carbon mineralization?

As defined by the U.S. Geological Survey, “carbon mineralization is the process by which carbon dioxide becomes a solid mineral, such as a carbonate…The biggest advantage of carbon mineralization is that the carbon cannot escape back to the atmosphere.” This generally occurs by injecting carbon dioxide underground into certain rock formations so the carbon dioxide takes on a solid form: trapped and unable to reach the atmosphere. 

How does carbon mineralization work?

Two of the main methods in which carbon mineralization occurs are ex-situ carbon mineralization and in-situ carbon mineralization. With ex-situ carbon mineralization, carbon dioxide solids are transported to a site to react with fluids—like water—and gas. In-situ carbon mineralization is the opposite—fluids containing carbon dioxide are funneled through rock formations in which it solidifies. Both of these methods result in carbon dioxide trapped in a solidified form. 

In a third method of carbon mineralization, surificial mineralization, carbon dioxide reacts with alkaline substances—such as mine tailings, smelter slags, or sedimentary formations—which result in the carbon dioxide taking on a solidified form. In the case of in-situ carbon mineralization or surificial mineralization, carbon dioxide can react with surface water rather than an artificial fluid, replicating natural processes of carbon mineralization.

Currently, the biggest drawbacks and barriers preventing carbon mineralization from taking hold as a major climate solution lie in cost and research uncertainties regarding environmental risks. In terms of cost, the price for carbon mineralization is high: 5 million dollars per well to inject carbon dioxide into rock formations. Further, the risks for groundwater and its susceptibility to contamination through this method is unknown, and the potential side effects of contaminating water formations could be devastating for ecological communities which thrive off of these water systems.

Who is our guest?

Dr. Rob Jackson is a professor and senior research fellow at Stanford University, and author of Into the Clear Blue Sky, a novel on climate solutions. His lab focuses on using scientific knowledge to shape climate policies and reduce the environmental footprint of human activities. Currently, he chairs the Global Carbon Project, an effort to measure and control greenhouse gas emissions.

Resources

• USGS: U.S. Geological Survey
• ScienceDirect: A holistic overview of the in-situ and ex-situ carbon mineralization: Methods, mechanisms, and technical challenges
• National Center for Biotechnology Information: Negative Emissions Technologies and Reliable Sequestration: A Research Agenda.
• Frontiers: An Overview of the Status and Challenges of CO2 Storage in Minerals and Geological Formations

Further Reading

• The New York Times: How Oman’s Rocks Could Help Save the Planet
• Climate Break: Rerun: Using Concrete for Carbon Removal with Dr. Erica Dodds

For a transcript, please visit https://climatebreak.org/carbon-capture-mineralization-with-dr-rob-jackson/