Document Type

Article

Publication Date

6-2012

Keywords

calcium carbonate, polymorph, aragonite, mineral carbonation, ultrasound, crystal morphology

Abstract

The objective of this work was to promote the formation of the aragonite polymorph of calcium carbonate, which has some valuable applications in industry, via the mineral carbonation route. The combination of ultrasound with magnesium ions promoted the formation of pure aragonite crystals at optimum conditions. It was possible to synthesize high purity aragonite precipitates at temperatures ranging from 24 oC to 70 oC, with the resulting powders possessing varying particle size distributions (from sub-micron up to 20 μm) and crystal morphologies (from acicular needles to novel hubbard squash-like particles). Several process parameters were found to influence the produced calcium carbonate polymorph ratios (aragonite over calcite). Higher values of magnesium-to-calcium ratio, intermediate ultrasound amplitude (60%), continuous ultrasound application (100% cycle), introduction of ultrasound pre-breakage, lowering of the CO2 flow rate, and increase in the relative concentration (g/L Ca(OH)2), all promoted aragonite formation. A potential route for industrial production of this material has been identified via a fed-batch process, which effectively reutilizes magnesium chloride while maintaining high aragonite yield. The results presented herein are significantly superior to aragonite formation using only single promoting techniques, typically found in literature, and go beyond by focusing on pure (>99%) aragonite formation.

Comments

9 November 2016: At the time of publication, Sheridan College author Rafael M. Santos was associated with the Katholieke Universiteit Leuven in Belgium.

Faculty

Faculty of Applied Science & Technology

School

School of Chemical and Environmental Sciences

Journal

Chemical Engineering Research and Design

Version

Post-print

Peer Reviewed/Refereed Publication

yes

Funder

PGS-D support from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Terms of Use

Terms of Use for Works posted in SOURCE.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Original Publication Citation

Santos, R. M., Ceulemans, P., & Van Gerven, T. (2012). Synthesis of pure aragonite by sonochemical mineral carbonation. Chemical Engineering Research and Design, 90(6), 715-725. doi:10.1016/j.cherd.2011.11.022

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