Increased thermal stability of nesquehonite (MgCO3 center dot 3H(2)O) in the presence of humidity and CO2: Implications for low-temperature CO2 storage

摘要

Nesquehonite (MgCO3 center dot 3H(2)O) has in the past been proposed as a low-cost, long-term mineral host for CO2. Here, stability of the phase was investigated under low temperatures (50 degrees C, 100 degrees C), moderate water vapour pressures (pH(2)O = 0.02-0.04 atm) and in both open and closed experimental systems. Specifically, this study explores CO2 storage security in nesquehonite exposed to (1) atmospheric humidity, (2) self-generated humidity, and (3) humidity in simulated flue gases during ex situ carbonation. Both CO2 and N-2 were used as carrier gases for H2O vapour to establish the influence of CO2 on nesquehonite decomposition under humid conditions.