Reaction Mechanism for the Aqueous-Phase Mineral Carbonation of Heat-Activated Serpentine at Low Temperatures and Pressures in Flue Gas Conditions

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• 作者：Louis-C茅sar Pasquier ; Guy Mercier ; Jean-Fran莽ois Blais ; Emmanuelle Cecchi ; Sandra Kentish
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 6, 2014
• 年：2014
• 卷：48
• 期：9
• 页码：5163-5170
• 全文大小：395K
• 年卷期：v.48,no.9(May 6, 2014)
• ISSN：1520-5851

文摘

Mineral carbonation is known as one of the safest ways to sequester CO₂. Nevertheless, the slow kinetics and low carbonation rates constitute a major barrier for any possible industrial application. To date, no studies have focused on reacting serpentinite with a relatively low partial pressure of CO₂ (p_CO2) close to flue gas conditions. In this work, finely ground and heat-treated serpentinite [Mg₃Si₂O₅(OH)₄] extracted from mining residues was reacted with a 18.2 vol % CO₂ gas stream at moderate global pressures to investigate the effect on CO₂ solubility and Mg leaching. Serpentinite dissolution rates were also measured to define the rate-limiting step. Successive batches of gas were contacted with the same serpentinite to identify surface-limiting factors using scanning electron microscopy (SEM) analysis. Investigation of the serpentinite carbonation reaction mechanisms under conditions close to a direct flue gas treatment showed that increased dissolution rates could be achieved relative to prior work, with an average Mg dissolution rate of 3.55 脳 10^鈥?1 mol cm^鈥? s^鈥?. This study provides another perspective of the feasibility of applying a mineral carbonation process to reduce industrial greenhouse gas (GHG) emissions from large emission sources.