Experimental transformations of kaolinite to smectite

Imasuen, O.I.; Tazaki, Kazue; Fyfe, W. S.; Kohyama, Norihiko

doi:10.1016/0169-1317(89)90012-4

Cited by 11 publications

(5 citation statements)

References 8 publications

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“…Therefore, the formation of smectite is a very important problem in clay mineralogy or environmental science. Experimental syntheses of smectites under high temperature conditions (> 200~ have been extensively carried out to elucidate the formation mechanism of smectite during hydrothermal alteration and burial diagenesis (Mumpton and Roy, 1956;Koizumi and Roy, 1959;Levinson and Vian, 1966;Grandquist and Pollack, 1967;Komarneni and Breval, 1985;Imasuen et al, 1989). However, syntheses under low temperature conditions (< 200~ have been performed less frequently because 1) very long times are required to produce stable phases, and 2) amorphous metastable phases appear during the reaction that make thermodynamic evaluations difficult.…”

Section: Introductionmentioning

confidence: 99%

Formation of Clay Minerals During Low Temperature Experimental Alteration of Obsidian

Kawano

Tomita

Kamino

1993

Clays and clay miner.

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Abstract--Experimental alteration of obsidian in distilled-deionized water at 150 ~ 175 ~ 200 ~ and 225~ was studied. The alteration products were examined by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX) to evaluate the formation process of clay minerals. The surface composition of obsidian before and after alteration was examined by X-ray photoelectron spectroscopy (XPS), and concentrations of released elements in solution were measured to elucidate alteration and dissolution processes. TEM clearly showed that allophane appeared as the first reaction product in each experiment. With increasing reaction length, noncrystalline straight fibrous material was formed in the aggregates ofallophane particles as a metastable transitional phase, and tended to form curled or wavy bundles of fibers with longer reaction. The noncrystalline fibers were transformed into highly curled smectite exhibiting small circular forms less than 1.0 ~m in diameter as reaction progressed. EDX confirmed that the smectite consisted mainly of Si, A1, and small amounts of Ca, K, and Fe. XPS revealed the formation of a dealkalized leached layer on the surface of obsidian during the reaction. The concentration of released elements suggested that nonstoichiometric dissolution proceeded during the reaction.

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Section: Introductionmentioning

confidence: 99%

Formation of Clay Minerals During Low Temperature Experimental Alteration of Obsidian

Kawano

Tomita

Kamino

1993

Clays and clay miner.

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“…Results are unreplicated; that is, only one sample was analysed for each time and temperature combination. This is common in mineral dissolution and precipitation studies where reaction rates are studied in response to variables, such as temperature or pH [17,22,[27][28][29][30][31][32][33][34]] to derive reaction kinetics. A single time and temperature combination in the pressure vessel experiments (100 °C, 909 h) was conducted in triplicate to estimate variability; this approach has also been used elsewhere [35].…”

Section: Methodsmentioning

confidence: 99%

“…Their previous use in weathering studies has mostly concerned the alteration of single minerals during pedogenesis [16][17][18]. Reaction kinetics can be derived from these experiments and extrapolated to predict reaction rates under field conditions [17,19]. The drawback of pressure vessels compared to Soxhlet extractors for weathering simulations is that they do not allow for the effect of leaching, being a "closed" system.…”

Section: Laboratory Simulation Of Weatheringmentioning

confidence: 99%

“…Pressure vessels (also known as pressure bombs, Teflon bombs, Parr bombs) have been used to accelerate reactions and rapidly bring materials to chemical equilibrium, because they apply both elevated temperatures and pressures to the material under investigation. Their previous use in weathering studies has mostly concerned the alteration of single minerals during pedogenesis [16][17][18]. Reaction kinetics can be derived from these experiments and extrapolated to predict reaction rates under field conditions [17,19].…”

Section: Laboratory Simulation Of Weatheringmentioning

confidence: 99%

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Experimental Simulation of Long Term Weathering in Alkaline Bauxite Residue Tailings

Santini

Fey

Gilkes

2015

Metals

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Abstract:Bauxite residue is an alkaline, saline tailings material generated as a byproduct of the Bayer process used for alumina refining. Developing effective plans for the long term management of potential environmental impacts associated with storage of these tailings is dependent on understanding how the chemical and mineralogical properties of the tailings will change during weathering and transformation into a soil-like material. Hydrothermal treatment of bauxite residue was used to compress geological weathering timescales and examine potential mineral transformations during weathering. Gibbsite was rapidly converted to boehmite; this transformation was examined with in situ synchrotron XRD. Goethite, hematite, and calcite all precipitated over longer weathering timeframes, while tricalcium aluminate dissolved. pH, total alkalinity, and salinity (electrical conductivity) all decreased during weathering despite these experiments being performed under "closed" conditions (i.e., no leaching). This indicates the potential for auto-attenuation of the high alkalinity and salinity that presents challenges for long term environmental management, and suggests that management requirements will decrease during weathering as a result of these mineral transformations. OPEN ACCESSMetals 2015, 5 1242

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“…However, it is arguable that liming could result in a sharp decrease in the Mg concentration of the soil. On the other hand, the application of the kaolinite -smectite conversion mechanism (Imasuen et al, 1989b) will not only provide the suitable pH condition in the soil system but will also increase the capacity for cation retention and eliminate aluminium toxicity (Imasuen, et al, 1989a). The only snag with the conversion is that it is expensive to apply on a large -scale transformation under typical tropical soil temperature conditions; also it is achievable within a duration of over 25 years However, the use of rock powder from Mg-bearing rocks e.g serpentinite and olivine basalt with the clay soils acting as inert carriers would be cheaper while effecting a good degree of in situ conversion.…”

mentioning

confidence: 99%

Chemical Compositions of Soils in Parts of Edo State, Southwest Nigeria and their Relationship to Soil Productivity

Imasuen¹,

Onyeobi²

2013

Journal of Applied Sciences and Environmental Management

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Thirty eight (38) soil samples taken from locations accessible to the BeninOluku -Ifon -Uzebba -Afuze -Auchi -Ukpilla -Okene highway, covering a distance of approximately 185 kilometres and an area of about 12,000 square kilometers were subjected to chemical and mineralogical analyses with a view to determining the variability of their fertility status within the rainforest and savannah vegetational zones. Results show that the soils of the area consist predominantly of quartz, kaolinite, feldspar and sesquioxides of aluminium and iron, including goethite. They are generally acidic with very low cation retention and buffering capacities. Higher concentrations of the major oxides MgO, CaO and K 2 O were recorded in soils of the savannah zone while the soils of the rainforest zone are relatively deficient in these oxides. A chemical productivity index (CPI) of MgO + CaO + K 2 O/Al 2 O 3 is proposed for the soils of the area of study. @ JASEM http://dx.doi.org/10.4314/jasem.v17i3.6

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Experimental transformations of kaolinite to smectite

Cited by 11 publications

References 8 publications

Formation of Clay Minerals During Low Temperature Experimental Alteration of Obsidian

Formation of Clay Minerals During Low Temperature Experimental Alteration of Obsidian

Experimental Simulation of Long Term Weathering in Alkaline Bauxite Residue Tailings

Chemical Compositions of Soils in Parts of Edo State, Southwest Nigeria and their Relationship to Soil Productivity

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