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Title

The experimental determination of hydromagnesite precipitation rates at 22.5-75 degrees C

Publication Year

2014

Author(s)
  • Berninger, U-N.
  • Jordan, G.
  • Schott, J.
  • Oelkers, E. H.
Source
MINERALOGICAL MAGAZINE Volume: 78 Issue: 6 Pages: 1405-1416 Published: 2014
ISSN
0026-461X eISSN: 1471-8022
Abstract

Natural hydromagnesite (Mg-5(CO3)(4)(OH)(2)center dot 4H(2)O) dissolution and precipitation experiments were performed in closed-system reactors as a function of temperature from 22.5 to 75 degrees C and at 8.6 < pH < 10.7. The equilibrium constants for the reaction Mg-5(CO3)(4)(OH)(2)center dot 4H(2)O + 6H(+) - 5Mg(2+) + 4HCO(3)(-) + 6H(2)O were determined by bracketing the final fluid compositions obtained from the dissolution and precipitation experiments. The resulting constants were found to be 10 (33.7 +/- 0.9), 10(30.5 +/- 0.5) and 10(26.5 +/- 0.5) at 22.5, 50 and 75 degrees C, respectively. Whereas dissolution rates were too fast to be determined from the experiments, precipitation rates were slower and quantified. The resulting BET surface area-normalized hydromagnesite precipitation rates increase by a factor of similar to 2 with pH decreasing from 10.7 to 8.6. Measured rates are approximately two orders of magnitude faster than corresponding forsterite dissolution rates, suggesting that the overall rates of the low-temperature carbonation of olivine are controlled by the relatively sluggish dissolution of the magnesium silicate mineral.

Author Keyword(s)
  • hydromagnesite
  • carbon storage
  • carbonate minerals
  • precipitation
KeyWord(s) Plus
  • FORSTERITE DISSOLUTION RATES
  • CARBFIX PILOT PROJECT
  • CO2 SEQUESTRATION
  • CARBON-DIOXIDE
  • MINERAL CARBONATION
  • THERMODYNAMIC PROPERTIES
  • CALCITE PRECIPITATION
  • KINETICS
  • TEMPERATURE
  • OLIVINE
ESI Discipline(s)
  • Geosciences
Web of Science Category(ies)
  • Mineralogy
Adress(es)

[Berninger, U-N.; Schott, J.; Oelkers, E. H.] CNRS UPS OMP, Geosci Environm Toulouse, F-31400 Toulouse, France; [Berninger, U-N.; Jordan, G.] LMU, Dept Geo & Umweltwissensch, D-80333 Munich, Germany; [Oelkers, E. H.] UCL, Dept Earth Sci, London WC1E 6BT, England

Reprint Adress

Berninger, UN (reprint author), CNRS UPS OMP, Geosci Environm Toulouse, 14 Ave Edouard Belin, F-31400 Toulouse, France.

Country(ies)
  • France
  • Germany
  • United Kingdom
CNRS - Adress(es)
  • Géosciences Environnement Toulouse (GET), UMR5563
  • Observatoire midi-Pyrénées (OMP), UMS831
Accession Number
WOS:000350888000007
uid:/WNTCN6VK
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