Red mud as a carbon sink : variability, affecting factors and environmental significance

Si, C; Ma, Y; Lin, C

Abstract

The capacity of red mud to sequester CO2 varied markedly due to differences in bauxite type, processing
and disposal methods. Calcium carbonates were the dominant mineral phases responsible for the carbon
sequestration in the investigated red mud types. The carbon sequestration capacity of red mud was not
fully exploited due to shortages of soluble divalent cations for formation of stable carbonate minerals.
Titanate and silicate ions were the two major oxyanions that appeared to strongly compete with carbonate
ions for the available soluble Ca. Supply of additional soluble Ca and Mg could be a viable pathway for
maximizing carbon sequestration in red mud and simultaneously reducing the causticity of red mud. It
is roughly estimated that over 100 million tonnes of CO2 have been unintentionally sequestered in red
mud around the world to date through the natural weathering of historically produced red mud. Based on
the current production rate of red mud, it is likely that some 6 million tonnes of CO2 will be sequestered
annually through atmospheric carbonation. If appropriate technologies are in place for incorporating
binding cations into red mud, approximately 6 million tonnes of additional CO2 can be captured and
stored in the red mud while the hazardousness of red mud is simultaneously reduced.

Citation

Si, C., Ma, Y., & Lin, C. (2012). Red mud as a carbon sink : variability, affecting factors and environmental significance. Journal of Hazardous Materials, 245, 54-59. https://doi.org/10.1016/j.jhazmat.2012.11.024

• Journal Article Type: Article
• Acceptance Date: Nov 10, 2012
• Publication Date: Nov 20, 2012
• Deposit Date: Mar 22, 2016
• Journal: Journal of Hazardous Materials
• Print ISSN: 0304-3894
• Electronic ISSN: 1873-3336
• Publisher: Elsevier
• Volume: 245
• Pages: 54-59
• DOI: https://doi.org/10.1016/j.jhazmat.2012.11.024
• Publisher URL: http://dx.doi.org/10.1016/j.jhazmat.2012.11.024
• Related Public URLs: http://www.journals.elsevier.com/journal-of-hazardous-materials/