Reaction rate-surface area relationships during the early stages of weathering—I. Initial observations

Holdren, George R.; Speyer, Patricia M.

doi:10.1016/0016-7037(85)90162-0

Cited by 163 publications

(35 citation statements)

References 19 publications

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“…After the removal of microparticles (c.f. Holdren and Berner, 1979), studies of mineral surfaces by scanning electron microscopy have illustrated the occurrence of dissolution at preferential sites, producing characteristic lens-shaped etch pits and cross-hatchings (Tazaki, 1976;Berner, 198 1). The preferential dissolution of these sites of atomic uncoordination (e.g.…”

Section: Effects Of Particle Sizementioning

confidence: 97%

“…In addition to the effects of mechanical comminution on the grain size, and hence the specific surface area discussed previously, crushing and abrasion have important effects on the morphology of the individual mineral grains which may enhance the solubility of the solid and the rate constant for dissolution (Petrovic, 1981a;1981b). These include: (i) brittle fracture, which may affect the kinetics of dissolution by increasing the density of surface reaction sites through cleavage fracture, dislocation and abrasion; (ii) localized plastic deformation, where grains are subject to substantial compressive and shear stresses producing significant subsurface structural damage to the mineral lattice (amorphous zones); and (iii) the production of sub-micron, super-soluble particles which adhere tightly to larger grain surfaces (Holdren and Berner, 1979). These grains are highly unstable in solution, and dissolve at an accelerated rate as the surface free energy of the particle becomes a significant fraction of the total free energy of the grain to which it adheres (Petrovic, 1981b).…”

Section: Effects Of Crushingmentioning

confidence: 99%

“…Studies have been carried out under high p(C02) conditions (Busenberg and Clemency, 1975), in buffered (Wollast, 1967;Petrovic et al, 1976;Nicholson et al, 1988;Zhang et al, 1993) and acidified solutions (Deju and Bhappa, 1965;Holdren and Berner, 1979;Chou et al, 1989;McKibben and Barnes, 1986;Acker and Bricker, 1992;Casey et al, 1988) and temperature has varied between 25 and 200°C (e.g. Busenberg and Clemency, 1975;Petrovic et af., 1976;Lagache, 1965;1976;Nagy and Lasaga, 1992).…”

Section: Introductionmentioning

confidence: 98%

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Experimental Investigations of the Weathering of Suspended Sediment by Alpine Glacial Meltwater

1996

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The magnitude and processes of solute acquisition by dilute meltwater in contact with suspended sediment in the channelized component of the hydroglacial system have been investigated through a suite of controlled laboratory experiments. Constrained by field data from Haut Glacier d'Arolla, Valais, Switzerland the effects of the water to rock ratio, particle size, crushing, repeated wetting and the availability of protons on the rate of solute acquisition are demonstrated. These 'free-drift' experiments suggest that the rock flour is extremely geochemically reactive and that dilute quickflow waters are certain to acquire solute from suspended sediment. These data have important implications for hydrological interpretations based on the solute content of glacial meltwater, mixing model calculations, geochemical denudation rates and solute provenance studies.

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Section: Effects Of Particle Sizementioning

confidence: 97%

Section: Effects Of Crushingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Experimental Investigations of the Weathering of Suspended Sediment by Alpine Glacial Meltwater

1996

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“…Brought to you by | University of Queensland -UQ Library Authenticated Download Date | 12/7/15 7:57 AM (5) 2.15 ± 0.10 Equation (29) 2.91 ± 0.02 Equation (14) Love and Whittaker 1954, Farin and Avnir 1987, Avnir 1989 Upper Columbus dolomite (CaCO (5) 2.07 ± 0.06 Equation (29) 2.58 ± 0.01 Equation (14) Love and Whittaker 1954, Farin and Avnir 1987, Avnir 1989 Niagara dolomite (CaCO 2.32 ± 0.08 Equation (29) (5) 2.05 ± 0.08 Equation (29) 3.02 ± 0.07 Equation (14) Walter 1984, Farin and Avnir 1987, Avnir 1989 Fungia skeletal carbonate CaCO 3 Acidic dissolution in seawater 51-513 (5) 1.98 ± 0.07 Equation (29) 2.73 ± 0.05 Equation (14) Walter 1984, Farin andAvnir 1987 Clypeaster, skeletal carbonate (5) 2.15 ± 0.07 Equation (29) 2.69 ± 0.04 Equation (14) Walter 1984, Farin andAvnir 1987 Hybla alkali feldspar (potassium aluminosilicate) Dissolution in HCl (pH 3) 56-400 (4) 3.0 ± 0.1 Equation (29) Holdren andSpeyer 1985, Farin and…”

Section: Interpretation Of Dissolution Mechanismmentioning

confidence: 99%

Fractal analysis in particle dissolution: a review

Bao

Long

et al. 2014

Reviews in Chemical Engineering

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Abstract:Fractal is a geometric language to describe the objects, the systems, and the phenomenon spatially and temporally. This paper reviews the literature on fractal models developed to describe the dissolution of particles. Dissolution, the process by which a solid forms a homogeneous mixture with a solution, is the behavior of a population of particles rather than a single one in most of the cases. The fractal models developed for the particle population are reviewed on the basis of two key particle surface properties, namely, the surface fractal nature and the chemical reactivity of particle surfaces. In terms of the surface fractal nature, fractals have been used to describe the change in the superficial roughness of particles, surface area-particle size relation, and particle size distribution (PSD). In terms of the reactive fractal dimensions, the models that describe the dissolution process have been developed to obtain the empirical noninteger exponent, the reactive fractal dimension that can dictate the chemical reactivity of a solid surface. The comparison between the surface fractal dimension and the reactive fractal dimension provides the dissolution mechanisms in many aspects of surface morphology. Further research is necessary to modify the current models to coincide with the real industrial processes and production and to develop the specific models for a better understanding of many processes involving the dissolution of particles encountered in many areas, including pharmaceutical and chemical applications and hydrometallurgy.

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“…The slightly higher An content reported by Holdren & Speyer (1987) is probably due to plagioclase inclusions in powders of the bulk sample. Holdren & Speyer (1985 and Hodson et al (1997) were concerned with the relationship between surface area [as measured by the Brunauer, Emmett & Teller (BET) gas-adsorption method, see later] and reaction rate.…”

Section: Starting Materials For Dissolution Experiments: Feldspars Frmentioning

confidence: 99%

Minerals Are Not Just Chemical Compounds

Parsons¹,

Lee²

2005

The Canadian Mineralogist

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Mineral grains are not just chemical compounds; they possess microtexture. The properties of crystallographically nearperfect "gem-quality" alkali feldspar crystals are contrasted here with those of ordinary, "garden-variety" specimens, exemplifi ed by perthitic phenocrysts from the granite at Shap, northern England. These are representative of common alkali feldspars in the crust. Two well-studied gem-quality materials (Madagascar orthoclase and Eifel sanidine) vary at the source in microtextural and other properties. Some crystals of Eifel sanidine exhibit much more rapid Si-Al ordering than ordinary feldspars, probably because of the presence of a hydrogen species. The complex microtextures of two feldspars from pegmatites that have been used in studies of dissolution rate, Perth perthite and Keystone microcline, are described and compared with textures in the Shap feldspars. Microtextures, in particular misfi t dislocations on regular exsolution-lamellae of albite, are crucially important in chemical dissolution and mechanical degradation during natural weathering in acid peat soils at Shap. In contrast, during laboratory dissolution-rate experiments carried out far from equilibrium, natural defects are less important than edges and steps produced during the grinding of the samples. Diagenetic replacement-type reactions in an overlying conglomerate at Shap are also strongly sensitive to microtexture. In arkosic sandstones in the Jurassic Fulmar Formation of the central North Sea, the detrital alkali feldspar inventory has been subject to microtextural winnowing, with relatively defect-free varieties of alkali feldspar being relatively more abundant than would be expected from the distribution of rock types known in the North Sea catchment.Keywords: mineral microtexture, alkali feldspar, exsolution, dislocations, dissolution-reprecipitation, dissolution, replacement, gem-quality minerals, weathering, diagenesis. SOMMAIRELes grains de minéraux ne sont pas simplement des composés chimiques; ils possèdent une microtexture. Les propriétés de cristaux gemmes de feldspath alcalin sont ici comparées avec celles de cristaux perthitiques tout-à-fait ordinaires provenant du granite de Shap, au nord de l'Angleterre. Ces derniers seraient représentatifs des feldspaths communs de la croûte. Deux matériaux gemmes bien étudiés, l'orthose du Madagascar et la sanidine d'Eifel, sont pris de populations variables à la source dans leur microtexture et leurs propriétés. Certains cristaux provenant de l'Eifel font preuve d'une mise en ordre Si-Al beaucoup plus rapide que ces feldspaths ordinaires, probablement à cause d'une espèce hydrogénée. Les microtextures complexes de deux feldspaths provenant de pegmatites et utilisés dans les études du taux de dissolution, la perthite de Perth et le microcline de Keystone, sont décrites et comparées aux textures des feldspaths provenant de Shap. Ces microtextures, en particulier les dislocations dues au décalage le long des lamelles d'exsolution d'albite, sont très importantes dans ...

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Reaction rate-surface area relationships during the early stages of weathering—I. Initial observations

Cited by 163 publications

References 19 publications

Experimental Investigations of the Weathering of Suspended Sediment by Alpine Glacial Meltwater

Experimental Investigations of the Weathering of Suspended Sediment by Alpine Glacial Meltwater

Fractal analysis in particle dissolution: a review

Minerals Are Not Just Chemical Compounds

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