On the potential for CO 2 mineral storage in continental flood basalts – PHREEQC batch- and 1D diffusion–reaction simulations

摘要: Continental flood basalts (CFB) are considered as potential CO2 storage sites because of their high reactivity and abundant divalent metal ions that can potentially trap carbon for geological timescales. Moreover, laterally extensive CFB found in many place the world within reasonable distances from major point emission sources. Based on mineral glass composition Columbia River Basalt (CRB) we estimated to store secondary carbonates. We simulated system using kinetic dependent dissolution primary basalt-minerals (pyroxene, feldspar glass) local equilibrium assumption phases (weathering products). The simulations were divided into closed-system batch at a constant pressure 100 bar with sensitivity studies temperature reactive surface area, an evaluation H2O scCO2, finally 1D diffusion giving pressures varying 0 100 bar. Although uncertainty area corresponding reaction rates large, have identified factors control maximum extent carbonation. showed formation carbonates basalt 40 C may be limited siderite possibly FeMg Calcium was largely consumed by zeolite oxide instead forming At higher temperatures (60 – 100 C), magnesite is suggested form together ankerite. stored solid carbonates, if supplied reactions unlimited, shown depend availability pore space hydration carbonation increase volume clog space. For systems such scCO2 phase amount water, total water present basalt.