New insights into Mn2+ and Mg2+ inhibition of calcite growth

Mills, Jennifer V.; Barnhart, Holly A.; DePaolo, Donald J.; Lammers, Laura N.

doi:10.1016/j.gca.2022.06.015

Cited by 19 publications

(3 citation statements)

References 117 publications

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“…This allows Mg to be incorporated more easily into protodolomite, which is reflected in an increase in reaction rate and stoichiometry (mol% MgCO 3 ). The hydration of Mg ions has long been considered a kinetic inhibitor in the formation of dolomite and calcite alike (Bischoff, 1968; Lippmann, 1973; de Leeuw & Parker, 2001; Jones & Xiao, 2005; Fenter et al ., 2007; Vandeginste et al ., 2019; Hashim & Kaczmarek, 2021b; Aufort et al ., 2022; Mills et al ., 2022). In the case of dolomite, strong Mg hydration renders adsorption onto growth surfaces and incorporation into the crystal lattice difficult (Lippmann, 1973).…”

Section: Discussionmentioning

confidence: 99%

Effects of sodium and potassium concentrations on dolomite formation rate, stoichiometry and crystallographic characteristics

et al. 2023

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This study uses high temperature (215°C) dolomitization experiments to explore the effects of sodium (Na) and potassium (K), two common constituents of natural fluids, on dolomite formation rate, stoichiometry and crystallographic characteristics. In these experiments, aragonite ooids were dolomitized in Mg–Ca–Cl solutions with either no additional salt, or in solutions containing NaCl or KCl at different concentrations. Results show that Na solutions, and to a lesser extent K solutions, correlate with faster reaction rates and that Na at hypersaline fluid concentrations produces dolomites with higher stoichiometry, higher micro‐strain and lower cation ordering. Potassium has a different effect on the dolomite than Na at similar concentrations. Unlike Na, K does not cause micro‐strain but leads to dolomite with smaller unit cell parameters. It is proposed that Na and K catalyse dolomite precipitation and increase stoichiometry by weakening Mg hydration bonds which consequently facilitates Mg incorporation into dolomite. The decrease in dolomite cation ordering at higher Na concentrations may stem from the incorporation of Na into dolomite which strains the crystal lattice and reduces cation order. On the basis that high‐temperature experiments are applicable to natural dolomites, several implications pertinent to natural dolomites are drawn from the results. Firstly, the data suggest that the higher concentrations of Na and K in evaporative fluids (i.e. higher salinity) can explain why dolomite is generally more abundant and more stoichiometric in evaporative settings. Secondly, the results challenge a key prediction of the mixing zone dolomitization model by showing that higher Na and K concentrations increase, rather than decrease, both dolomitization rate and stoichiometry. Thirdly, the observed decrease in dolomite cation ordering with increasing Na and K concentrations implies that evaporative fluids would produce less stable dolomite that may be more prone to subsequent recrystallization and thus resetting of primary geochemical signatures.

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Section: Discussionmentioning

confidence: 99%

Effects of sodium and potassium concentrations on dolomite formation rate, stoichiometry and crystallographic characteristics

et al. 2023

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“…Under these conditions, the replacement of gypsum by calcium carbonate is thermodynamically favorable and lowers the solution pH as alkalinity is consumed. 46 To complete the cycle, the sulfate-bearing effluent from the precipitation reactor was filtered using a 0.45 μm Nylon filter to separate suspended solids and continuously recirculated into the cathode chamber of the electrolyzer. Together, the integrated process described by reactions 6 – 8 gives reaction 5 overall.…”

Section: Materials and Methodsmentioning

confidence: 99%

Electrolytic Sulfuric Acid Production with Carbon Mineralization for Permanent Carbon Dioxide Removal

Lammers

Duan

Anaya

et al. 2023

ACS Sustainable Chem. Eng.

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Several billion metric tons per year of durable carbon dioxide removal (CDR) will be needed by mid-century to prevent catastrophic climate warming, and many new approaches must be rapidly scaled to ensure this target is met. Geologically permanent sequestration of carbon dioxide (CO 2 ) in carbonate minerals�carbon mineralization�requires two moles of alkalinity and one mole of a CO 2 -reactive metal such as calcium or magnesium per mole of CO 2 captured. Chemical weathering of geological materials can supply both ingredients, but weathering reactions must be accelerated to achieve targets for durable CDR. Here, a scalable CDR and mineralization process is reported in which water electrolysis is used to produce sulfuric acid for accelerated weathering, while a base is used to permanently sequester CO 2 from air into carbonate minerals. The process can be integrated into existing extractive processes by reacting produced sulfuric acid with critical element feedstocks that neutralize acidity (e.g., rock phosphorus or ultramafic rock mine tailings), with calcium-and magnesium-bearing sulfate wastes electrolytically upcycled. The highest reported efficiency of electrolytic sulfuric acid production is achieved by maintaining catholyte feed conditions that minimize Faradaic losses by hydroxide permeation of the membrane-separated electrochemical cell. The industrial implementation of this process provides a pathway to gigaton-scale CO 2 removal and sequestration during the production of critical elements needed for decarbonizing global energy infrastructure and feeding the world.

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“…Note that more recent studies observed the recession/growth of pristine surface and kink sites of calcite surfaces using atomic force microscopes allows mechanistic insights into particle dissolution/crystallisation at the nanoscale level with or without calcite dissolution/growth inhibitors to be inferred. 15,[22][23][24][25][26][27] Most notably, the dissolution step velocities of obtuse h481i and acute h441i sites on a pristine (104) calcite surface were found to reduced by 97% and 18% with the addition of 0.8 mM Mg 2+ , respectively. 15 In contrast the work in this paper concerns the overall rate of macroscopic dissolution of micron-sized calcite crystals as entire single entities.…”

Section: Introductionmentioning

confidence: 98%

The solubility product controls the rate of calcite dissolution in pure water and seawater

Yang,

Tan,

Batchelor-McAuley

et al. 2024

Chem. Sci.

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New insights into Mn2+ and Mg2+ inhibition of calcite growth

Cited by 19 publications

References 117 publications

Effects of sodium and potassium concentrations on dolomite formation rate, stoichiometry and crystallographic characteristics

Effects of sodium and potassium concentrations on dolomite formation rate, stoichiometry and crystallographic characteristics

Electrolytic Sulfuric Acid Production with Carbon Mineralization for Permanent Carbon Dioxide Removal

The solubility product controls the rate of calcite dissolution in pure water and seawater

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