This technology uses formate-based ligands to speed up the extraction of calcium and magnesium from rocks, enabling faster, more energy-efficient carbon capture and storage by turning CO2 into stable minerals without harsh chemicals or intensive grinding.
Background
The field of carbon capture and storage (CCS) is critical in the global effort to mitigate climate change by reducing atmospheric carbon dioxide (CO2) levels. One promising CCS strategy is mineralization, which involves converting CO2 into stable carbonate minerals by reacting it with naturally occurring rocks such as ultramafic and mafic formations (e.g., basalt). These rocks are abundant and have the theoretical capacity to permanently store vast amounts of CO2.
However, the practical implementation of mineralization at scale is hindered by the inherently slow rate at which these minerals dissolve and release the necessary metal ions (such as calcium and magnesium) required for carbonation. Accelerating this dissolution process is essential for making mineralization a viable and impactful solution for large-scale CO2 sequestration.
Current approaches to mineral dissolution in CCS primarily rely on proton-promoted mechanisms, which are fundamentally limited by the alkaline nature of ultramafic and mafic rocks. In these environments, proton transport is restricted, resulting in shallow penetration of reactive species and inefficient extraction of metal ions. To compensate, conventional methods often require energy-intensive pretreatments such as fine grinding, thermal treatment, or the use of strong acids, all of which significantly increase operational costs, energy consumption, and even secondary CO2 emissions.
These drawbacks undermine the environmental and economic benefits of mineralization-based CCS, creating a pressing need for alternative approaches that can overcome the rate-limiting step of mineral dissolution without incurring prohibitive energy or material costs.
Technology description
This technology utilizes specific ligands, such as formate species, to dramatically accelerate the dissolution of silicate minerals in ultramafic and mafic rocks, thereby enhancing the mineralization of CO2 for carbon capture and storage (CCS).
Unlike traditional proton-promoted methods, which are limited by slow proton transport in alkaline environments and require energy-intensive pretreatment like fine grinding or acid leaching, the ligand-based approach enables the ligands to permeate deep into the rock matrix via osmosis. These ligands interact with metal ions—primarily calcium and magnesium—extracting them from the mineral lattice in a manner that is strong enough to facilitate dissolution but weak enough to allow subsequent release for carbonation with captured CO2.
The process works with a variety of minerals, including basalt, stromatolite, and calcium silicate, and can be tailored for both direct and indirect mineralization pathways. Key operational parameters include ligand concentration, temperature, and the stability constant of the metal-ligand complex, all of which are optimized to maximize dissolution rates and carbonate precipitation while minimizing energy input.
What differentiates this technology is its ability to overcome the fundamental kinetic bottleneck of mineral dissolution in CCS applications, particularly in alkaline rock environments where conventional acid-based methods are inefficient. By leveraging the unique properties of formate ligands, the technology achieves over tenfold increases in dissolution rates for basalt and up to fifteenfold for certain calcium-rich minerals, all while reducing the need for costly and energy-intensive pretreatment steps.
The ligand-promoted mechanism is not subject to the counter-diffusion limitations of acids and bases, allowing for deeper penetration and more uniform extraction of metal ions. Furthermore, the process can be integrated into a sustainable, closed-loop system where formate is regenerated and recycled, further reducing environmental impact and operational costs. This combination of high efficiency, scalability, and sustainability positions the technology as a transformative solution for large-scale carbon capture, direct air capture, and even hydrogen generation, offering a practical pathway to more effective and environmentally friendly CCS.
Benefits
- Significantly accelerates mineral dissolution rates, enhancing CO2 mineralization efficiency (e.g., over tenfold increase for basalt).
- Reduces energy consumption by minimizing the need for intensive grinding, thermal treatment, or acid leaching.
- Enables deeper penetration into rock matrices via ligand osmosis, overcoming limitations of proton transport in alkaline environments.
- Facilitates effective extraction and subsequent release of metal ions (Ca²⁺, Mg²⁺) for carbonation, improving mineralization yield.
- Supports both direct and indirect mineralization pathways, offering operational flexibility.
- Utilizes formate ligands that can be sustainably produced, regenerated, and recycled, promoting environmental and economic viability.
- Applicable to a wide range of ultramafic and mafic rocks and calcium-bearing minerals, broadening potential CCS applications.
Commercial applications
- Direct air capture mineralization
- Industrial CO2 emissions sequestration
- Geological carbon storage enhancement
- Low-energy carbon-negative cement production
- Hydrogen generation from mineral reactions
Additional information
This technology enhances CO2 mineralization in rocks by employing specific ligands, such as formate species, to accelerate silicate mineral dissolution. Ligands permeate the rock matrix, extract metal ions (calcium, magnesium) by forming complexes, and then release them for carbonation with captured CO2. This process significantly increases dissolution rates, reducing energy requirements for large-scale carbon capture and storage.
US Provisional Application Filed – US 63/786,237
