Selection of acid for weak acid processing of wollastonite for mineralisation of CO2

Ghoorah, Manisha, Dlugogorski, Bogdan Z., Balucan, Reydick D. and Kennedy, Eric M. (2014) Selection of acid for weak acid processing of wollastonite for mineralisation of CO2. Fuel, 122 277-286. doi:10.1016/j.fuel.2014.01.015

Author Ghoorah, Manisha
Dlugogorski, Bogdan Z.
Balucan, Reydick D.
Kennedy, Eric M.
Title Selection of acid for weak acid processing of wollastonite for mineralisation of CO2
Formatted title
Selection of acid for weak acid processing of wollastonite for mineralisation of CO2
Journal name Fuel   Check publisher's open access policy
ISSN 0016-2361
Publication date 2014-04-15
Sub-type Article (original research)
DOI 10.1016/j.fuel.2014.01.015
Volume 122
Start page 277
End page 286
Total pages 10
Place of publication Oxford, United Kingdom
Publisher Elsevier
Language eng
Formatted abstract
• Results report dissolution of wollastonite in formic, acetic and DL-lactic acids.
• Formic acid extracted 96% of Ca at 80 °C at a rate of 26(±7) × 10−5 mol m−2 s−1.
• Activation energy for formic acid corresponds to 11 ± 3 kJ mol−1.
• Ca2+ dissolution appears to be mass-transfer controlled with formic acid.

Typically, mineral carbonation comprises aqueous phase reactions involving the dissolution of naturally occurring magnesium and calcium silicate rocks, such as olivine, serpentinites and wollastonite, followed by the precipitation of magnesium and calcium carbonate minerals. In this report, we evaluated the effect of formic, acetic and DL-lactic acids on the calcium-leaching process from wollastonite between 22 °C and 80 °C and at atmospheric pressure. OLI Analyzer Studio 3.0 predicted equilibrium conversions of calcium and its speciation in the aqueous phase. Additionally, we measured dissolution rates, for a constant pH system, as a function of temperature for the three organic acids. All experiments involved the reaction of 17 ± 1 μm (volume mean diameter) ground rock samples with the acids in a stirred batch reactor equipped with in situ pH measurements. Inductively coupled plasma-optical emission spectrometry (ICP-OES) analysed the concentration of calcium ions in the leaching medium while scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) examined the morphology and surface chemical composition of the residual solid phase from dissolution experiments. We estimated the maximum dissolution rates of wollastonite in the limit of low but achievable pH and in the absence of diffusion limitation in pores and cracks of the SiO2 skin. At 80 °C, these rates correspond to 26(±7) × 10−5, 14(±3) × 10−5 and 17(±4) × 10−5 mol m−2 s−1 for formic, acetic and DL-lactic acids, respectively. The apparent activation energies amount to 11 ± 3, 47 ± 13 and 52 ± 14 kJ mol−1 for dissolution in formic, acetic and DL-lactic acids, respectively. These values indicate the initial diffusion limitation in the film around wollastonite particles for formic acid, and kinetic limitation for acetic and DL-lactic acids. The rates of dissolution rapidly decline for acetic and DL-lactic acids, but remain high for formic acid. The findings are altogether indicative of high performance of formic acid for extraction of Ca2+ for storing CO2. Further experiments are needed to assess the recycling of formic acid to determine its overall suitability as a Ca2+ carrier for the weak acid process.
Keyword Mineral carbonation
Formic acid
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2015 Collection
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Created: Fri, 07 Feb 2014, 00:39:51 EST by Reydick Balucan on behalf of School of Chemical Engineering