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Title: CO 2 Absorption and Magnesium Carbonate Precipitation in MgCl 2–NH 3–NH 4Cl Solutions: Implications for Carbon Capture and Storage

CO 2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO 2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO 2. In this study, adopting a novel wetted wall column reactor, we systematically explore the rates and mechanisms of carbon transformation from CO 2 gas to carbonates in MgCl 2–NH 3–NH 4Cl solutions. We find that reactive diffusion in liquid film of the wetted wall column is the rate-limiting step of CO 2 absorption when proceeding chiefly through interactions between CO 2(aq) and NH 3(aq). We further quantified the reaction kinetic constant of the CO 2–NH 3 reaction. Our results indicate that higher initial concentration of NH 4Cl ( ≥2mol∙L -1) leads to the precipitation of roguinite [(NH 4) 2Mg(CO 3) 2∙4H 2O], while nesquehonite appears to be the dominant Mg-carbonate without NH 4Cl addition. We also noticed dypingite formation via phase transformation in hot water. This study provides new insight into the reaction kinetics of CO 2 mineral carbonation that indicates the potential of this technique for futuremore » application to industrial-scale CO 2 sequestration.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [1]
  1. Nanjing Univ. (China). School of Earth Sciences and Engineering
  2. Univ. of Southern California, Los Angeles, CA (United States). Department of Earth Sciences
  3. Nanjing Univ. (China). School of Earth Sciences and Engineering; George Washington Univ., Washington, DC (United States). Department of Chemistry
Publication Date:
Grant/Contract Number:
FG02-02ER15366
Type:
Accepted Manuscript
Journal Name:
Minerals
Additional Journal Information:
Journal Volume: 7; Journal Issue: 9; Journal ID: ISSN 2075-163X
Publisher:
MDPI
Research Org:
George Washington Univ., Washington, DC (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 58 GEOSCIENCES; absorption rate; carbon dioxide; carbon capture and storage; magnesium carbonate
OSTI Identifier:
1429294