# Carbon dioxide sequestration in Limestone

The chemical reaction where dissolved carbon dioxide forms carbonic acid and then reacts with various calcium containing minerals to form calcium carbonate and bicarbonate is rather slow. I know that several years ago there was research into possible ways to speed up the reaction, possibly as a candidate for a truly long term way to scrub $\mathrm{CO}_2$ from the atmosphere. The inspiration for this idea is to speed up the part of the geologic carbon cycle that regulates atmospheric $\mathrm{CO}_2$ concentration.

Does anyone know how the research into catalysts or processes to speed this up are going?

This process does not rely on catalysts, but it addresses the essence of the question. The process described is to inject liquefied carbon dioxide into basalt formations, even if the basalt is very old. This makes the it plausible that we could scrub the excess $\mathrm{CO}_2$ from the atmosphere by:

1. growing plants,
2. burning those plants, capturing the CO2, and
3. burying that carbon using, partly, the energy from the burned plants.
• Yes, but nature has already converted plants to more energy efficient hydrocarbon compounds (oil & gas) via heat and pressure. – MaxW Jan 17 '17 at 22:59
• Going via plants seems rather an overelaborate way of getting carbon dioxide. Why not just capture it from the atmosphere chemically? Or, just grow plants and don't burn them. – matt_black Feb 17 '17 at 8:21
• @matt_black Simple - concentration. This process goes this fast because the carbon dioxide is highly concentrated. Doing that mechanically from the atmosphere requires the input of energy. Doing it from an exhaust flue requires less energy because it's more concentrated. – Sean Lake Feb 17 '17 at 19:32
• @SeanLake You still don't need to grow plants and burn them as we already burn vast quantities of coal, oil and gas and could put the capture sequestration on their exhausts. – matt_black Feb 17 '17 at 19:38
• @matt_black Preventing fossil carbon from entering the atmosphere doesn't remove carbon that was dumped there in the past, which is the goal. – Sean Lake Feb 17 '17 at 19:40