Dissolution of silica from montmorillonite: effect of solution chemistry

Lahann, Richard W.; Roberson, Herman E.

doi:10.1016/0016-7037(80)90193-3

Cited by 28 publications

(19 citation statements)

References 9 publications

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“…It is significant that the only claysolution systems to display the low "initial" expandability phenomenon were those with the greatest K § Na § ratio (i.e., Na-saturated clay, 400 ppm K solution). Lahann and Roberson (1980) indicated that under these solution conditions after 24 hr at 270~ K § occupies about 80-85% of the exchange sites on the clay. The sample is effectively K-saturated, and any clay layers with sufficient charge to dehydrate K will appear as nonexpandable layers.…”

Section: Discussionmentioning

confidence: 86%

“…Dissolved silica in reaction solutions frequently reaches a maximum value within the first 24 hr of the experiment (Lahann and Roberson, 1980). Either no further change in dissolved silica was observed or silica concentration declined and then rose again.…”

Section: Discussionmentioning

confidence: 95%

“…As the negative charge on the silicate layer builds up, so does the selectivity of the clay for K + (Sawhney, 1970). Lahann and Roberson (1980) showed that increasing the proportion of K + exchange ions on a montmorillonite increases the rate of Si removal. It is possible that K § uptake precedes and accelerates layer charge development.…”

Section: Discussionmentioning

confidence: 99%

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Smectite to Illite Conversion Rates: Effects of Solution Chemistry

Roberson

1981

Clays and clay miner.

154

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Abstract--Mixed-layer illite/smectite (I/S) was formed by reacting the Chambers or Polkville montmorillonite hydrothermally at 270 ~ and 350~ from several hours to more than 15 weeks. Reactions were conducted in closed vessels containing K or mixed K-Na, K-Ca, or K-Mg solutions of varying concentrations. The reaction rate and the rate of ordering of I/S for the reaction smectite + K § ~ mixed-layer I/S + SiO2 was inhibited by the addition of Na § Ca 2+, and Mg2+; the inhibitory strength of Na +, Ca 2 § and Mg 2+, on an equivalent basis, increased approximately in the ratio 1:10:30. The first order reaction-rate constants for the reactions at 270 ~ and 350~ indicate an activation energy of about 30 kcal/mole.In the experimental system studied, the reaction smectite -~ mixed-layer I/S appeared to proceed by solid state transformation, as suggested by: (1) rapid dissolution of large amounts of silica, probably creating an AI-enriched residue; (2) similarity of particle size and morphology of the mixed-layer products to those of the original montmorillonite, implying no extensive dissolution of A13+; and (3) relatively high activation energy compared to published values for silicate dissolution.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 95%

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Smectite to Illite Conversion Rates: Effects of Solution Chemistry

Roberson

1981

Clays and clay miner.

154

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“…The presence of Ca in solution inhibits effectively the substitution of Si by AI in montmorillonite (Lahann and Roberson, 1980). Therefore, the presence of Ca in the interlayer of montmorillonite also retarded the increase of layer charge due to the substitution of Si by A1, which resulted in the smaller %NEK in the Ca-montmorillonite at a given temperature (Figure 4a).…”

Section: Mechanism Of K-fixation By Claysmentioning

confidence: 99%

“…The effects of interlayer cations on the reaction of montmorillonite to interstratified phases were also examined Copyright 9 1983, The Clay Minerals Society by Eberl (1978aEberl ( , 1978b. In addition, Lahann and Roberson (1980) determined the effect of solution chemistry for the dissolution of Si from montmoriUonite under hydrothermal conditions.…”

Section: Introductionmentioning

confidence: 99%

Potassium Fixation by Clay Minerals during Hydrothermal Treatment

Inoue

1983

Clays and clay miner.

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Abstract--The amount of K fixed in K-and Ca-saturated montmodUonite, vermiculite (trioctahedral), rectorite-type and IMII-ordered mica/montmorillonites was measured as a function of time (1-64 days), temperature (25~176 pH (6.0, 9.7, and 10.7), and K-concentration (0.02 and 1.0 M) in solution. The amount of K fixed by the clays generally increased with increasing temperature, pH, and K-concentration and reached saturation in response to each experimental condition in 5 or 6 days. The K-montmorillonite and K-vermiculite fixed considerable amounts of K even at 25~ Fixed K in moutmoriUonite increased with an increase of the layer charge which is also influenced significantly by the interlayer cation, In detail, the behavior in K-fixation was specific to each clay.The type of structural transformation with K-fixation was different for each clay. In montmorillonite, especially, the type of transformation was related to the cationic composition of the system; in K homoionic system, montmorillonite transformed rapidly into iUite/montmorillonite with about 40% expandable layers at 300~ and in a mixed cation system with Ca and K, it reacted gradually to random illite/montmorillonites with increasing temperature. These data indicate that the cation-exchange process of a natural pore solution plays an important role in the gradual transformation of detrital montmoriUonite to illite.

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The effect of polycationic system on the expandability of the smectite as a backfill material

Jang

Koh³

et al. 2000

Geosci J

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Dissolution of silica from montmorillonite: effect of solution chemistry

Cited by 28 publications

References 9 publications

Smectite to Illite Conversion Rates: Effects of Solution Chemistry

Smectite to Illite Conversion Rates: Effects of Solution Chemistry

Potassium Fixation by Clay Minerals during Hydrothermal Treatment

The effect of polycationic system on the expandability of the smectite as a backfill material

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