The dissolution kinetics of Iceland spar single crystals

Compton, Richard G.; Daly, Pádraig

doi:10.1016/0021-9797(84)90016-x

Cited by 38 publications

(36 citation statements)

References 27 publications

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“…In these pH regions mass transfer has a significant contribution in the determining step of their overall reaction. This conclusion is novel, is first reported, and is not in conflect with other earlier reported results (2,3,5,7,(11)(12)(13).…”

Section: Discussioncontrasting

confidence: 46%

The Kinetics of Dissolution of the Carbonate Minerals of Phosphate Ores using Dilute Acetic Acid Solutions: The Case of pH Range from 3.96 to 6.40

Economou

Vaimakis

Papamichael

2002

Journal of Colloid and Interface Science

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Section: Discussioncontrasting

confidence: 46%

The Kinetics of Dissolution of the Carbonate Minerals of Phosphate Ores using Dilute Acetic Acid Solutions: The Case of pH Range from 3.96 to 6.40

Economou

Vaimakis

Papamichael

2002

Journal of Colloid and Interface Science

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“…Most of the previous work which found a surface kinetics contribution had been done in CO2 /water systems 6 -8 ' 13 or in systems where a noninhibiting buffer Was present. 12 In all of these cases, the Levich development was used for the experimental analyses. This development has a built in assumption of a first order surface kinetics rate expression.…”

Section: Surface Kinetics Rate Expressionmentioning

confidence: 99%

Limestone Dissolution in Flue Gas Scrubbing: Effect of Sulfite

Gage

Rochelle

1992

Journal of the Air & Waste Management Association

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Batch limestone dissolution experiments were carried out in a pti stat apparatus at 55°C with CO 2 sparging and dissolved sulfite. Particle size distribution, utilization, sulfite in solution, limestone type, and the approach to calcite equilibrium were all found to contribute to the limestone reactivity. In the absence of sulfite, limestone dissolution was controlled solely by mass transfer. For a given stone under mass transfer control, film thickness was found to be independent of pH. The dissolution rate in the presence of sulfite was controlled by a combined surface kinetics/mass transfer regime. SEM micrographs supported this conclusion. A surface rate correlation was developed which accounted for observed inhibition by an inverse dependence on calcium sulfite concentration at the limestone surface. While the form of the rate expression was applicable to all stones, the surface rate constant was stone dependent. A computer code which accounted for mass transfer with surface kinetics was tested against experimental observations of four limestone types. Changes in pH and the concentrations of calcium, carbonate, sulfite, sulfate, and adipic acid were accurately modeled.

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“…The process of dissolution of calcium carbonate in aqueous solution has received continuous attention by chemists, geologists, soil scientists and others for over a century (see, for example, Boguski 1876; Boguski & Kajander 1877;Spring 1887Spring , 1888Brunner 1904;King & Liu 1933;Moelwyn-Hughes 1933;Gortikov & Panteleva 1937;Tominaga 1939;Erga & Terjesen 1956;Kaye 1957;Weyl 1958;Terjesen et al 1961;Sippel & Glover 1964;Nestaas & Terjesen 1969;Boomer et al 1972;Wentzler & Apian 1972;Berner & Morse 1974;Morse 1974;Lund et al 1975;Barton & Vatanathan 1976;Plummer & Wigley 1976;Sjoberg 1976;Plummer et al 1978;Sjoberg 1978;Morse & Berner 1979;Plummer et al 1979;Dreybrodt 1981;Sverdrup & Bjerle 1982;Morse 1983;Reddy 1983;Sjoberg 1983;Compton & Daly 1984;Sjoberg & Rickard 1984;Baumann et al 1985;Buhmann & Dreybrodt 1985a, b;Daly 1985;Sjoberg & Rickard 1985;von Tress et al 1985;Compton & Daly 1987;…”

Section: Introductionmentioning

confidence: 99%

The dissolution of calcite in aqueous solution at pH < 4: kinetics and mechanism

Compton

Unwin

1990

Phil. Trans. R. Soc. Lond. A

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The requirements of any experimental investigation of a reaction, such as dissolution or precipitation, at the solid-liquid interface are delineated, and it is shown that no previously adopted experimental method successfully meets all of these criteria. A new strategy for studying such reactions is therefore proposed, and described specifically for the dissolution kinetics of calcium carbonate in acidic aqueous solution. This technique involves locating a calcite crystal in part of one wall of a rectangular duct, through which reactant flows under laminar conditions, and positioning either an amperometric or potentiometric detector electrode immediately adjacent to and downstream of the crystal. The rate of the reaction at the crystal surface is then followed by measuring the concentration of the reactant or products reaching the electrode as a function of solution flow rate. In this way both transport (to the crystal and detection system) and the surface topography of the crystal are defined and controllable, and, most importantly, the concentrations interrogated by the detector electrode are those pertaining at the crystal surface and not the bulk values, which are those probed with other (previous) methods. A mechanistic model for the dissolution reaction at pH < 4, H + + CaCO 3 → C a 2 + + HCO 3 − , is developed, and it is recognized that half-, first- and second-order reactions in surface H + constitute possible candidate heterogeneous processes. The model also takes the following homogeneous (solution) reactions into account: HCO 3 − + H + ⇌ H 2 C O 3 ⟶ k H 2 C O 3 C O 2 + H 2 O , K H 2 C O 3 = a H + a HCO 3 − / a H 2 C O 3 The backward implicit finite difference method is used to provide theory for the proposed flow cell experiment. Specifically this relates the rate of an n th order process at the crystal surface to the transport-limited current at an amperometric detector electrode, as a function of solution flow rate and cell-crystal-electrode geometry. The computational method selected allows both the full parabolic velocity profile and any value of n to be considered. The validity of the numerical approach is checked by invoking the Lévêque approximation (linearizing the parabolic velocity profile) and solving the problem analytically for n = 0 and 1. The numerical method is extended so that both parallel heterogeneous and homogeneous reactions are covered, specifically so that theory describing the mechanistic model can be derived as related to the flow cell experiment. The design and construction of the necessary experimental apparatus is described, along with experiments devised to prove the validity of the experimental approach. The results of flow cell dissolution experiments carried out with 0.25–1.0 mM HCl solutions are presented, and it is shown for the first time that the reaction between H + and calcite is not transport-controlled. Assuming k H 2 C O 3 = 20 s − 1 and K H 2 C O 3 = 3.06 × 1 0 − 4 M , a best fit to the data is obtained for a first-order heterogeneous process with a rate constant of (0.043 ± 0.015) cm s -1 .

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The dissolution kinetics of Iceland spar single crystals

Cited by 38 publications

References 27 publications

The Kinetics of Dissolution of the Carbonate Minerals of Phosphate Ores using Dilute Acetic Acid Solutions: The Case of pH Range from 3.96 to 6.40

The Kinetics of Dissolution of the Carbonate Minerals of Phosphate Ores using Dilute Acetic Acid Solutions: The Case of pH Range from 3.96 to 6.40

Limestone Dissolution in Flue Gas Scrubbing: Effect of Sulfite

The dissolution of calcite in aqueous solution at pH < 4: kinetics and mechanism

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