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Experimental determination of barite dissolution and precipitation rates as a function of temperature and aqueous fluid composition

Zhen-Wu, BY; Dideriksen, K; Olsson, J; Raahauge, PJ; Stipp, SLS; Oelkers, EH; (2016) Experimental determination of barite dissolution and precipitation rates as a function of temperature and aqueous fluid composition. Geochimica et Cosmochimica Acta , 194 pp. 193-210. 10.1016/j.gca.2016.08.041. Green open access

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Abstract

Barite dissolution and precipitation rates were investigated in closed system reactors, in which total aqueous NaCl concentrations ranged from 0 to 1.5 molal, pH from 2 to 9, and temperature from 25 to 90 °C. Measured barite dissolution and precipitation rates exhibited a reaction order of 0.2 and 1, respectively, with respect to the barite saturation state. Although these different reaction orders suggest distinctly different mechanisms for dissolution and precipitation, the rates for both processes approach equilibrium with a similar slope on a rate versus saturation state plot, consistent with the concept of micro-reversibility. Barite dissolution rate constants increase as a linear function of the square root of ionic strength but vary only slightly with pH. The dissolution rate dependence on temperature is consistent with an activation energy of 25 ± 2 kJ mol−1. Barite dissolution and precipitation rates are not significantly affected by the presence of aqueous calcium, magnesium or strontium. The rates measured in the study were generated in fluids similar to those found in sedimentary basins, ocean floor sediments and oil field reservoirs so the data may provide close estimates for the reactivity of barite during a variety of natural and industrial processes.

Type: Article
Title: Experimental determination of barite dissolution and precipitation rates as a function of temperature and aqueous fluid composition
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.gca.2016.08.041
Publisher version: http://dx.doi.org/10.1016/j.gca.2016.08.041
Language: English
Additional information: Copyright © 2016 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Keywords: BaSO4; Dissolution; Precipitation; Kinetics; Ionic strength; pH; Calcium; Magnesium; Strontium; Mixing ratios
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1521889
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