Do carbonate precipitates affect dissolution kinetics?2: Diopside

Diopside dissolution rates were measured in mixed-flow reactors at neutral and basic pH at 25 °C and 70 °C. Experiments were performed in aqueous solutions 1) supersaturated with respect to calcite for up to 63 days, and 2) strongly undersaturated with respect to calcite and other secondary phases f...

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Main Authors: Stockmann, G., Wolff-Boenisch, Domenik, Gislason, S., Oelkers, E.
Format: Journal Article
Published: Elsevier Science BV 2013
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/37391
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author Stockmann, G.
Wolff-Boenisch, Domenik
Gislason, S.
Oelkers, E.
author_facet Stockmann, G.
Wolff-Boenisch, Domenik
Gislason, S.
Oelkers, E.
author_sort Stockmann, G.
building Curtin Institutional Repository
collection Online Access
description Diopside dissolution rates were measured in mixed-flow reactors at neutral and basic pH at 25 °C and 70 °C. Experiments were performed in aqueous solutions 1) supersaturated with respect to calcite for up to 63 days, and 2) strongly undersaturated with respect to calcite and other secondary phases for up to 164 days. Inlet solutions were comprised of NaHCO3, CaCl2, NH4Cl, NaOH, and/or HCl with ionic strengths ranging from 0.01 to 0.09 mol/kg. In the experiments performed at 25 °C, calcite nucleated and grew extensively on both the diopside surfaces, and as b1000 µm discrete crystals in experiments performed in CO3-bearing inlet solutions but no precipitates were formed on or adjacent to the diopside in experiments performed in CO3-free inlet solutions.Measured diopside dissolution rates in calcite precipitating experiments at 25 °C based on Si are both 1) time independent, and 2) equal to that of corresponding control experiments performed in NaHCO3-free inlet solutions. These observations indicate that diopside dissolution rates are unaffected by the simultaneous precipitation of calcite. Calcite likely forms a porous coating on diopside, which allows ions from the dissolving diopside to betransported readily to the bulk fluid. It seems therefore likely that carbonate precipitationwill not slowpyroxene dissolution during carbon storage efforts.
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spelling curtin-20.500.11937-373912017-02-28T01:45:43Z Do carbonate precipitates affect dissolution kinetics?2: Diopside Stockmann, G. Wolff-Boenisch, Domenik Gislason, S. Oelkers, E. Mixed-flow reactors Diopside Calcite coating CO2 sequestration Dissolution kinetics Carbonatization Diopside dissolution rates were measured in mixed-flow reactors at neutral and basic pH at 25 °C and 70 °C. Experiments were performed in aqueous solutions 1) supersaturated with respect to calcite for up to 63 days, and 2) strongly undersaturated with respect to calcite and other secondary phases for up to 164 days. Inlet solutions were comprised of NaHCO3, CaCl2, NH4Cl, NaOH, and/or HCl with ionic strengths ranging from 0.01 to 0.09 mol/kg. In the experiments performed at 25 °C, calcite nucleated and grew extensively on both the diopside surfaces, and as b1000 µm discrete crystals in experiments performed in CO3-bearing inlet solutions but no precipitates were formed on or adjacent to the diopside in experiments performed in CO3-free inlet solutions.Measured diopside dissolution rates in calcite precipitating experiments at 25 °C based on Si are both 1) time independent, and 2) equal to that of corresponding control experiments performed in NaHCO3-free inlet solutions. These observations indicate that diopside dissolution rates are unaffected by the simultaneous precipitation of calcite. Calcite likely forms a porous coating on diopside, which allows ions from the dissolving diopside to betransported readily to the bulk fluid. It seems therefore likely that carbonate precipitationwill not slowpyroxene dissolution during carbon storage efforts. 2013 Journal Article http://hdl.handle.net/20.500.11937/37391 Elsevier Science BV restricted
spellingShingle Mixed-flow reactors
Diopside
Calcite coating
CO2 sequestration
Dissolution kinetics
Carbonatization
Stockmann, G.
Wolff-Boenisch, Domenik
Gislason, S.
Oelkers, E.
Do carbonate precipitates affect dissolution kinetics?2: Diopside
title Do carbonate precipitates affect dissolution kinetics?2: Diopside
title_full Do carbonate precipitates affect dissolution kinetics?2: Diopside
title_fullStr Do carbonate precipitates affect dissolution kinetics?2: Diopside
title_full_unstemmed Do carbonate precipitates affect dissolution kinetics?2: Diopside
title_short Do carbonate precipitates affect dissolution kinetics?2: Diopside
title_sort do carbonate precipitates affect dissolution kinetics?2: diopside
topic Mixed-flow reactors
Diopside
Calcite coating
CO2 sequestration
Dissolution kinetics
Carbonatization
url http://hdl.handle.net/20.500.11937/37391