Accelerated weathering of limestone for CO2 mitigation opportunities for the stone and cement industries

Large amounts of limestone fines coproduced during the processing of crushed limestone may be useful in the sequestration of carbon dioxide (CO ₂). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO₂ from fossil fuel-fired power plants and other point-sources such as cement manufacturing. AWL reactants are readily available, inexpensive, and environmentally benign. Waste CO ₂ is hydrated with water to produce carbonic acid, which then reacts with and is neutralized by limestone fines, thus converting CO₂ gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities within about 10 km of the coastline. The majority of U.S. coastal power generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufactures, and research scientists.