In-Situ Carbon Mineralization & Basalt Storage Lab

In-situ carbon mineralization is an advanced permanent carbon storage technology where captured carbon dioxide is dissolved into water and injected into reactive, divalent-cation-rich volcanic rocks (such as flood basalt, oceanic crust, or mantle peridotite). Divalent cations—principally calcium (Ca2+), magnesium (Mg2+), and ferrous iron (Fe2+)—rapidly dissolve from silicate minerals (like olivine, plagioclase, and pyroxene) upon contact with slightly acidic carbonic acid. These free cations react with dissolved bicarbonate to precipitate solid, immobile carbonate minerals (calcite CaCO3, magnesite MgCO3, and siderite FeCO3). As demonstrated at CarbFix in Iceland, over 95% of the injected CO2 permanently turns into solid stone within less than two years, eliminating any risk of leakage for geological time (>10,000 years).

In conventional Carbon Capture and Storage (CCS), supercritical CO2 is injected into deep sedimentary sandstone formations or depleted oil fields where it remains as a buoyant fluid trapped beneath an impermeable caprock seal. This requires decades of post-injection seismic monitoring, pressure management, and legal liability tracking against seismic faults or abandoned well leakage. In contrast, in-situ mineralization permanently binds CO2 into solid carbonate rocks. Because carbonated water is denser than formation groundwater, the injected fluid sinks rather than rises. Once crystallized into solid stone, the carbon cannot escape even if an earthquake or fault fracturing occurs.

The CarbFix dissolution method pre-dissolves CO2 gas into water under moderate pressure (20 to 30 bar) either at the surface or inside the injection wellbore before the fluid enters the reservoir. Dissolving 1 metric ton of CO2 requires approximately 20 to 27 cubic meters of water. In coastal regions or offshore sub-seabed basalt formations, abundant seawater or non-potable brackish saline groundwater is used, avoiding any freshwater depletion. Carbonated water immediately releases aqueous carbonic acid (H2CO3) that accelerates rock leaching while ensuring the fluid is gravitationally stable.

Basalt (volcanic lava rock) contains 15% to 25% reactive divalent metal oxides (CaO, MgO, FeO) and possesses high volcanic vesicular porosity (10-30%) and fracture permeability, supporting fast fluid circulation and 95% mineralization within 18 to 24 months. Peridotite (ultramafic mantle rock, as found in Oman and the US) is composed almost entirely of olivine and serpentine, offering an immense theoretical capacity of up to 0.62 tons of CO2 per ton of rock. Furthermore, olivine carbonation (Mg2SiO4 + 2CO2 -> 2MgCO3 + SiO2) is strongly exothermic (ΔH = -89 kJ/mol CO2), releasing thermal energy that naturally heats the formation to accelerate kinetics.

In-situ mineral storage is remarkably cost-effective, with levelized costs of storage (LCOS) ranging between $18 and $42 per metric ton of CO2 stored, covering deep injection well drilling, water pumping power, and surface MRV arrays. Under the US Inflation Reduction Act Section 45Q, permanent geological storage earns $85 per metric ton for industrial point-source capture and $180 per metric ton for Direct Air Capture (DAC). In addition, durable carbon removal off-take contracts on voluntary carbon markets (VCM) currently trade between $150 and $350 per ton. With operating margins of $50 to $150 per ton, mineral storage projects routinely achieve simple capital paybacks under 3 to 5 years.