Effect of compaction on the kinetics of thermal decomposition of dolomite under non-isothermal condition

Maitra, Saikat; Choudhury, A.; Das, H. S.; Pramanik, Jitendra

doi:10.1007/s10853-005-0843-0

Cited by 54 publications

(30 citation statements)

References 12 publications

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“…The characteristic endothermic peak due to α→β quartz inversion at ≈570ºC is only detected in Raos sample with the biggest SiO 2 content. Small endothermic peaks perceived in both Cuchia and Raos samples at 700º-900ºC are due to carbonate decomposition [49]. Finally, an endothermic effect over 1000ºC indicates a liquid phase formation in agreement with HSM results.…”

Section: Resultssupporting

confidence: 85%

Sintering behaviour of ceramic bodies from contaminated marine sediments

Romero

Andrés

Alonso

et al. 2008

Ceramics International

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The effect of the heating temperature on the properties of sintered ceramic bodies from three different contaminated marine sediments was investigated. The sintering behaviour was evaluated by means of the variation of shrinkage degree, bulk density, water absorption, open and closed porosity, while the phases transformation were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results have shown that the sintering process follows a viscous liquid phase mechanism due to the formation of a glassy phase. The optimum sintering temperature is 1125ºC for Astilleros and Cuchia sediments and 1150ºC for Raos sample. Above this temperature, a significant overfiring with an increase of closed porosity was observed. Water absorption values and mechanical properties as bending and compressive strengths of sintered bodies show that the investigated marine sediments are suitable to be used as secondary raw materials in ceramic tiles and bricks production.

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Section: Resultssupporting

confidence: 85%

Sintering behaviour of ceramic bodies from contaminated marine sediments

Romero

Andrés

Alonso

et al. 2008

Ceramics International

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“…The first two peaks are due to the dissociation of the 22 wt.% of dolomite present in TL. Two peaks were observed since dolomite thermal dissociation is a twostage decomposition process involving the following reactions (McIntosh et al, 1990;Maitra et al, 2005):…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Thermal weakening of the carbonate basement under Mt. Etna volcano (Italy): Implications for volcano instability

Heap

Mollo

Vinciguerra

et al. 2013

Journal of Volcanology and Geothermal Research

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The physical integrity of a sub-volcanic basement is crucial in controlling the stability of a volcanic edifice. For many volcanoes, this basement can comprise thick sequences of carbonates that are prone to significant thermally-induced alteration. These debilitating thermal reactions, facilitated by heat from proximal magma storage volumes, promote the weakening of the rock mass and likely therefore encourage edifice instability. Such instability can result in slow, gravitational spreading and episodic to continuous slippage of unstable flanks, and may also facilitate catastrophic flank collapse. Understanding the propensity of a particular sub-volcanic basement to such instability requires a detailed understanding of the influence of high temperatures on the chemical, physical, and mechanical properties of the rocks involved. The juxtaposition of a thick carbonate substratum and magmatic heat sources makes Mt. Etna volcano an ideal candidate for our study. We investigated experimentally the effect of temperature on two carbonate rocks that have been chosen to represent the deep, heterogeneous sedimentary substratum under Mt. Etna volcano. This study has demonstrated that thermalstressing resulted in a progressive and significant change in the physical properties of the two rocks. Porosity, wet (i.e., water-saturated) dynamic Poisson's ratio and wet Vp/Vs ratio all increased, whilst P-and S-wave velocities, bulk sample density, dynamic and static Young's modulus, dry Vp/Vs ratio, and dry dynamic Poisson's ratio all decreased. At temperatures of 800 °C, the carbonate in these rocks completely dissociated, resulting in a total mass loss of about 45% and the release of about 44 wt.% of CO 2 . Uniaxial deformation experiments showed that high in-situ temperatures (> 500°C) significantly reduced the strength of the carbonates and altered their deformation behaviour. Above 500 °C the rocks deformed in a ductile manner and A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTthe output of acoustic emissions was greatly reduced. We speculate that thermally-induced weakening and the ductile behaviour of the carbonate substratum could be a key factor in explaining the large-scale deformation observed at Mt. Etna volcano. Our findings are consistent with several field observations at Mt. Etna volcano and can quantitatively support the interpretation of (1) the irregularly low seismic velocity zones present within the sub-volcanic sedimentary basement, (2) the anomalously high CO 2 degassing observed, (3) the anomalously high Vp/Vs ratios and the rapid migration of fluids, and (4) the increasing instability of volcanic edifices in the lifespan of a magmatic system. We speculate that carbonate sub-volcanic basement may emerge as one of the decisive fundamentals in controlling volcanic stability.

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“…De los resultados anteriores se puede observar que las energías de activación en este trabajo son mucho menores a las reportadas en la literatura, esto puede deberse a que la muestra que se analizó fue compactada a 100MPa, ya que se ha reportado que al incremento en la compactación de carbonatos disminuye la E a (9). Adicionalmente los experimentos de cinética se realizaron para un sistema ternario, por consiguiente se espera que el SrO reaccione con la Al 2 O 3 y el SrSO 4 para formar compuestos de Estroncio.…”

Section: /N ) Estos Resultados Son Similares a Los Reportadosunclassified

Estudio cinético de la descomposición térmica del carbonato de Estroncio en el sistema SrCO3-Al2O3-SrSO4

G¹,

T²,

R³

2008

Bol. Soc. Esp. Ceram. Vidr.

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La cinética de descomposición térmica del carbonato de Estroncio (SrCO 3 ) en el sistema SrCO 3 -Al 2 O 3 -SrSO 4 se estudió por medio de análisis térmico gravimétrico (ATG), utilizando el método isotérmico. Se prepararon mezclas de polvos 3:3:1 molar de SrCO 3 , Al 2 O 3 y SrSO 4 grado reactivo, las cuales fueron homogenizadas y tratadas a temperaturas entre 750 hasta 1100°C, por periodo de 4 horas. Adicionalmente se estudio el efecto del tiempo de activación mecánica del SrCO 3 sobre la cinética de descomposición. Se obtuvieron curvas representativas de la pérdida de peso de las muestras al incrementar la temperatura, a partir de ellas se realizó el estudio cinético. Para el rango de temperatura de 750 a 900°C, el mecanismo de reacción que rige el proceso de descomposición corresponde a una contracción geométrica mediante la frontera de grano (R 1.1 ) con una energía de activación (E a ) de 106.21KJmol -1 . En el rango de temperatura de 950 a 1100°C, el mecanismo de reacción que rige la descomposición corresponde a un proceso de nucleación y crecimiento (P 1.1 ), con un valor de E a de 44.87KJmol -1 . La energía de activación disminuye conforme se incrementa el tiempo de activado mecánico hasta un 35% para el caso de siete horas. Palabras clave: cinética, análisis termo gravimétrico, método isotérmico, activación mecánica, energía de activación. Kinetics of Thermal decomposition of strontium carbonate in the SrCO 3 -Al 2 O 3 -SrSO 4 systemThe thermal decomposition of strontium carbonate in the SrCO 3 -Al 2 O 3 -SrSO 4 system was studied by thermal analysis under isothermal experiments. Powder of reactive grade of SrCO 3 , Al 2 O 3 y SrSO 4 in molar ratio 3:3:1 were prepared. The powders were heat treated from 750 to 1000 °C for 4 h. Loss weight for each temperature was registered and the kinetics parameter were determine using the classical fit method. The effect of mechanical activation of SrCO 3 was studied as well. The reaction mechanism for 750 to 900 °C temperature range corresponded to a geometric shrinkage in the grain boundary (R 1.1 ) with an activation energy of 106. 21 Kjmol -1 . The reaction mechanism for 900 to 1100 °C temperature range corresponded to a nucleation and growing (P 1.1 ) with an activation energy of 44.87 Kjmol -1 . The activation energy was reduced in 35% for the samples that contained SrCO 3 mechanically activated.

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Effect of compaction on the kinetics of thermal decomposition of dolomite under non-isothermal condition

Cited by 54 publications

References 12 publications

Sintering behaviour of ceramic bodies from contaminated marine sediments

Sintering behaviour of ceramic bodies from contaminated marine sediments

Thermal weakening of the carbonate basement under Mt. Etna volcano (Italy): Implications for volcano instability

Estudio cinético de la descomposición térmica del carbonato de Estroncio en el sistema SrCO<sub>3</sub>-Al<sub>2</sub>O<sub>3</sub>-SrSO<sub>4</sub>

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