On the effect of aqueous Ca on magnesite growth – Insight into trace element inhibition of carbonate mineral precipitation

Berninger, Ulf-Niklas; Jordan, Guntram; Lindner, Michael W.; Reul, A.; Schott, Jacques; Oelkers, Eric H.

doi:10.1016/j.gca.2016.01.019

Cited by 14 publications

(4 citation statements)

References 91 publications

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“…In this regard, McKenzie et al proposed that bisulfide delivered by sulfate reducing bacteria in sedimentary environments, although dilute, could catalyze the formation of natural dolomite (CaMg(CO 3 ) 2 ) . Hence, to accelerate the synthesis of anhydrous MgCO 3 under standard conditions, efforts have focused on the addition of salts, , complexing compounds, alcohols, and microorganisms . However, there is a lack of understanding of additive identity and concentration, with few comprehensive studies resolving the effects of solution additives on the fundamental processes controlling the process of Mg 2+ dehydration.…”

Section: Introductionmentioning

confidence: 99%

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation

Toroz

Song

Uddin

et al. 2022

Crystal Growth & Design

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Formed via aqueous carbonation of Mg 2+ ions, the crystallization of magnesite (MgCO 3 ) is a promising route to carbon capture and reuse, albeit limited by the slow precipitation of MgCO 3 . Although magnesite is naturally abundant, forming at low temperature conditions, its industrial production is an energy-intensive process due to the temperatures required to prevent the formation of hydrated phases. The principal difficulty in aqueous conditions arises from the very strong Mg 2+ •••H 2 O interaction, with high barriers to Mg 2+ dehydration. Using atomistic simulations, we have investigated the influence of 30 additive anions (X n− , n = 1− 3), ranging from simple halides to more complex molecules, on the first two steps of MgCO 3 aggregation from solution, as follows: Mg 2+ dehydration and subsequent prenucleative Mg 2+ •••CO 3 2− pairing. We have computed the thermodynamic stabilities of solvent shared ion pairs () and contact ion pairs (Mg 2+ •••X n− ) to reveal the propensity of solution additives to inhibit or promote Mg 2+ •••CO 3 2− formation. We have determined the stabilization of undercoordinated hydrated Mg 2+ states with a vacant coordination site to which CO 3 2− can bind, subsequently initiating MgCO 3 nucleation or Mg 2+ incorporation into the crystal lattice. Extensive molecular dynamics simulations of electrolyte solutions containing Na 2 CO 3 with different sources of Mg 2+ (i.e., MgCl 2 , MgSO 4 , and Mg(CH 3 COO) 2 ) further show that the degree of dehydration of Mg 2+ and the structure of prenucleation MgCO 3 clusters change depending on the counterion identity. Through a fundamental understanding of the role of solution additives in the mechanism of Mg 2+ dehydration, our results help to rationalize previously reported experimental observation of the effect of solvation environments on the growth of magnesite. This understanding may contribute to identifying the solution composition and conditions that could promote the low-temperature CO 2 conversion into MgCO 3 at industrially relevant scales.

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Section: Introductionmentioning

confidence: 99%

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation

Toroz

Song

Uddin

et al. 2022

Crystal Growth & Design

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“…For example, solubility changes observed in the experimental system calcite with strontium-bearing solutions did not match predictions, which lead to the development of the layer-by-layer theory. − This theory can be employed to qualitatively explain growth observations but does not allow for predictions. Similarly, for the mineral magnesite (MgCO 3 ) growing in calcium-containing solutions, incorporation into the solid was demonstrated without an effect on the crystal growth rate, which cannot be explained by any of the above-mentioned concepts . Given the wide range of behaviors reported, an investigation is warranted of the effect of an impurity on the crystal growth rate correlated to direct measurements of its incorporation into the crystal structure.…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, for the mineral magnesite (MgCO 3 ) growing in calcium-containing solutions, incorporation into the solid was demonstrated without an effect on the crystal growth rate, which cannot be explained by any of the above-mentioned concepts. 33 Given the wide range of behaviors reported, an investigation is warranted of the effect of an impurity on the crystal growth rate correlated to direct measurements of its incorporation into the crystal structure. This would allow for better predictions because it would allow us to test hypotheses for which mechanism described above is most likely to act on a system under given solution conditions.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the Effects of Strontium Incorporation on Barite Growth—In Situ and Ex Situ Observations Using Multiscale Chemical Imaging

Weber¹,

Bracco

Poplawsky³

et al. 2018

Crystal Growth & Design

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Impurity ions influence mineral growth rates through a variety of kinetic and thermodynamic processes that also affect partitioning of the impurity ion between the solid and solution. Here, the effect of an impurity ion, strontium, on Barite (BaSO4) (001) growth rates was studied using a combination of high-resolution in situ microscopy with ex situ chemical imaging techniques. In the presence of strontium, ⟨120⟩ steps roughened and bifurcated. The overall Barite growth rate also decreased with increasing aqueous strontium-to-barium ratio ([Sr]/[Ba] aq ) < 1. Analysis of the reacted solids using chemical imaging techniques indicated strontium incorporated uniformly across all step orientations into the Barite growth hillock for [Sr]/[Ba] aq < 1. However, at [Sr]/[Ba] aq > 5, steps with an apparent [010] orientation were expressed and growth in the [010] step direction led to an increase in the overall growth rate of the surface. Strontium became preferentially incorporated into the [010] step direction, rather than being homogeneously distributed. The [Sr]/[Ba] s in the newly grown solid was found to correlate directly with that of solutions at [Sr]/[Ba] aq < 5, but not for higher [Sr]/[Ba] aq . Solid composition analyses indicate that thermodynamic equilibrium was not achieved. However, kinetic transport modeling successfully reproduces the shift in growth mechanism.

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“…In this regard, McKenzey et al proposed that bisulfide delivered by sulphate reducing bacteria in sedimentary environments could catalyze natural dolomite, CaMg(CO3)2, formation. 10 To accelerate the synthesis of anhydrous MgCO3 under standard conditions, efforts have focused on the addition of salts, 11,12 complexing compounds, 13 alcohol molecules, 14 and microorganisms. 15 However, there is a lack of a comprehensive study regarding the effects of solution additives in the fundamental processes controlling the Mg 2+ dehydration process.…”

Section: Introductionmentioning

confidence: 99%

Solution additives promoting the onset of MgCO3 nucleation

Toroz

Song

Uddin

et al. 2021

Preprint

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Formed via aqueous carbonation of Mg2+ ions, the crystallization of magnesite (MgCO3) is a promising carbon capture and reuse technology, albeit limited by the slow precipitation of MgCO3. Although magnesite is naturally abundant, forming at low temperature conditions, its production is an energy-intensive process due to the temperatures required to prevent the formation of hydrated phases. The principle difficulty arises from the very strong Mg2+···H2O interaction, raising barriers to dehydration. Using atomistic simulations, we have investigated the influence of thirty additive anions (Xn–, n = 1–3), ranging from simple halides to more complex molecules, on the first two steps of MgCO3 aggregation from solution: Mg2+ dehydration and Mg2+∙∙∙CO32– pairing. We have computed the thermodynamic stability of solvent shared ion pairs, Mg2+···H2O···Xn–, and contact ion pairs, Mg2+···Xn–, with Mg2+ to reveal the propensity of solution additives to inhibit Mg2+∙∙∙CO32– formation. We have determined the stabilization of undercoordinated hydrated Mg2+ states with a vacant coordination site to which CO32– can bind, subsequently initiating MgCO3 nucleation or Mg2+ incorporation into the crystal lattice. Extensive molecular dynamics simulations of electrolyte solutions containing Na2CO3 with different sources of Mg2+, MgCl2, MgSO4 and Mg(CH3COO)2, further shows that the degree of dehydration of Mg2+ and the structure of prenucleation MgCO3 clusters changes depending on the type counterion. Through a fundamental understanding of the role of solution additives in the mechanism of Mg2+ dehydration, our computational study can rationalize previously reported experimental observation of the effect of solvation environments on the growth of magnesite. This understanding may contribute to identifying solution composition conditions that could promote the low-temperature CO2 conversion into MgCO3.

show abstract

On the effect of aqueous Ca on magnesite growth – Insight into trace element inhibition of carbonate mineral precipitation

Cited by 14 publications

References 91 publications

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation

Unraveling the Effects of Strontium Incorporation on Barite Growth—In Situ and Ex Situ Observations Using Multiscale Chemical Imaging

Solution additives promoting the onset of MgCO3 nucleation

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On the effect of aqueous Ca on magnesite growth – Insight into trace element inhibition of carbonate mineral precipitation

Cited by 14 publications

References 91 publications

A Database of Solution Additives Promoting Mg2+ Dehydration and the Onset of MgCO3 Nucleation

A Database of Solution Additives Promoting Mg2+ Dehydration and the Onset of MgCO3 Nucleation

Unraveling the Effects of Strontium Incorporation on Barite Growth—In Situ and Ex Situ Observations Using Multiscale Chemical Imaging

Solution additives promoting the onset of MgCO3 nucleation

Contact Info

Product

Resources

About

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation

A Database of Solution Additives Promoting Mg²⁺ Dehydration and the Onset of MgCO₃ Nucleation