Large-Scale Carbon Mineralization Through Non-Carbonate Rock Oxalatization
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Solution Overview
Problem
Current carbon capture and storage (CCUS) technologies lack scalability and stability for large-scale carbon emission control, with geological mineralization being limited by slow kinetics due to unfavorable geological conditions.
Innovation Solution
A mineralization method called 'oxalatization' involving the use of oxalic acid to form metal oxalates or oxalate hydrates with non-carbonate rocks and minerals, which accelerates carbon mineralization through higher solubility and molar carbon uptake capacity compared to carbonation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If geological carbon mineralization is performed in situ in mafic/ultramafic rocks, then stable and large-scale CO2 storage is achieved, but the kinetics of direct carbonation is slow due to unfavorable geological conditions
Solution Approach 1:
The patent introduces oxalic acid as an intermediary substance to facilitate carbon mineralization. Instead of directly carbonating rocks (which is slow), oxalic acid first reacts with metal oxides to form metal oxalates, which then decompose to release CO2 in situ within the rock matrix. This two-step mechanism with oxalic acid as mediator dramatically accelerates the overall carbon storage rate while maintaining stability.
Solution Approach 2:
The patent changes the chemical parameters of the mineralization process by using oxalic acid instead of direct CO2 injection. Oxalic acid provides higher solubility and reactivity with metal oxides, transforming the reaction kinetics from slow direct carbonation to rapid oxalatization followed by decomposition, thereby improving productivity while preserving the stability of final carbonate formation.
2Productivity
If oxalic acid is used to accelerate carbon mineralization, then productivity and carbon uptake capacity are improved, but the process complexity increases compared to direct carbonation
Solution Approach 1:
Oxalic acid serves as a chemical intermediary that simplifies the overall process by providing a high-solubility, high-reactivity pathway. Rather than attempting to force rapid direct carbonation (which would require complex engineering controls), the patent uses oxalic acid to naturally accelerate the reaction through its superior chemical properties, then allows in-situ decomposition to achieve the final carbon storage goal.
3Device complexity
If conventional carbonation methods are used, then the process is simple, but the CO2 uptake capacity is limited to 0.2% by weight of cement
Solution Approach 1:
The patent fundamentally changes the chemical reaction pathway from direct carbonation to oxalatization followed by decomposition. This parameter change enables much higher CO2 uptake capacity because oxalic acid can dissolve and react with far more metal oxide than direct CO2 can, and the subsequent decomposition releases concentrated CO2 in situ, achieving carbon storage volumes far exceeding the 0.2% weight limit of conventional methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Oxalatization achieves rapid and efficient carbon mineralization, converting up to 85% of metal oxides to oxalates within days, offering a stable and scalable solution for permanent carbon storage.
Implementation Method 1
contacting oxalic acid with a component chosen from non-carbonate rocks, non-carbonate minerals, or mixtures thereof under conditions to cause formation of one or both of a metal oxalate or metal oxalate hydrate
Data Source
AI summary
The present invention is broadly concerned with mineralization methods that assist in permanent carbon storage. The methods provide a storage mechanism for oxalic acid generated by existing or future-developed carbon capture and conversion methods that convert CO2 to oxalic acid. That oxalic acid can be injected into a subsurface rock formation containing non-carbonate rock to form oxalates or oxalate hydrates. Alternatively, oxalic acid can be mixed with mine tailings, well drilling dirt, crushed rocks, etc., that contain desired non-carbonate rock minerals, to promote mineralization.