Abstract
Carbonation of magnesium and calcium silicates has emerged as an interesting option for long term storage of captured CO 2 . However, carbonated minerals are not stable in acidic environments. This study was conducted to determine if synthetically carbonated minerals dissolve in acidic rain and release CO 2 . Synthetic magnesium and calcium carbonates were leached in nitric acid solutions of various acidities, as well as rainwater, and the stability of the minerals was investigated with various methods. The experimental study was complemented with thermodynamic equilibrium calculations using Gibbs energy minimization software (HSC 4.0). The leaching of base ions from the two carbonate minerals was found to behave similarly and depend mainly upon the acidity of the solution. The fraction of Mg and Ca dissolved after several days of stabilization in separate solutions with initial pH 1 was 9% for both carbonates, while the fraction of dissolved minerals in a solution with initial pH > 2 was less than 1%. FT-IR analyses of the reactor atmosphere revealed that CO 2 gas was more rapidly released from calcium carbonate than from magnesium carbonate. However, only 1.5% of the CO 2 stored in the calcium carbonate was released as gas at pH 1 against 0.0% for magnesium carbonate. No notable CO 2 release occurred when leaching magnesium and calcium carbonates in solutions of pH 2. The solid residue analyses showed that the fixed CO 2 content of the carbonates that had been exposed to nitric acid was even higher than before the treatment.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.