Direct mineralization of atmospheric CO₂using natural rocks in Japan

Gas-solid mineralization of atmospheric CO2 using naturally abundant surface rocks under ambient conditions and without thermochemical treatment was analyzed for application in Japan. Based on an empirically-verified theoretical framework, a tiered greenhouse containing finely ground rocks was designed with low-speed induced airflow to realize CO2 mineralization reactions over 1 year. Negative CO2 emissions were calculated accounting for CO2 emissions from energy generation, materials production, and removal of vegetation and soil. Under practicable operating conditions, negative emissions using crystalline surface rocks in Japan can reach ∼7.6 Gt-CO2/y achieved across 726 sites. The average energy requirement was calculated to be 1.5 GJ t-1-CO2 with an average land requirement of 1.1 km2 per Mt-CO2 annual removal capacity. Carbon debt is paid off after 60 d of operation.