Olivine dissolution kinetics at elevated temperatures and pressures
File(s)
Published version
Author(s)
Chen, Qiaoyun
Trusler, JP Martin
Type
Journal Article
Abstract
Experimental and modelling studies of the dissolution kinetics and surface chemistry of olivine in CO2-saturated water at elevated temperatures and CO2 pressures are reported. The apparent initial dissolution rates of olivine are reported at temperatures between 373 and 473 K and at pressures between 7.7 and 15.6 MPa. The influence of mass transfer effects on olivine dissolution and the formation of passivation layers were studied, and the minimum stirring speed at which mass transfer resistance was effectively eliminated was determined. The optimum temperature for olivine dissolution in the long term was determined to be approximately 423 K. This study provides the first data for olivine dissolution rates at temperatures above 423 K. The initial olivine dissolution rates did not show a monotonic increasing trend with the increase of temperature due to the formation of various passivation layers on the olivine particle surfaces at different temperatures. A simple model, dependent upon temperature and the activity of H+, was developed to represent the experimental data. This model is generally applicable under similar temperature and pressure conditions, and when the same type of passivation layer is present. Based on the proposed model, the PHREEQC geochemical simulator was used to predict the saturation indices of Fe2O3 (hematite), FeO(OH) (goethite), Fe(OH)3 (ferric hydroxide) and SiO2 (both quartz and amorphous silica). The pH and elemental concentrations were also predicted and these calculations served to partially rationalize the experimental results.
Date Issued
2025-12-01
Date Acceptance
2025-09-28
Citation
Chemical Engineering Journal, 2025, 525
ISSN
1385-8947
Publisher
Elsevier BV
Journal / Book Title
Chemical Engineering Journal
Volume
525
Copyright Statement
© 2025 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Publication Status
Published
Article Number
169095
Date Publish Online
2025-10-03