New aspects of the decomposition kinetics of calcite

Mulokozi, A. M.; Lugwisha, Esther

doi:10.1016/0040-6031(92)80034-t

Cited by 20 publications

(9 citation statements)

References 16 publications

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“…We now believe the effect to be a result of a mechanistic transition. Potassium oxalate shows this behaviour too [7]. As in our previous study on the kinetics of decomposition of NdCzO4C1 [1] and SmCzO4C1 [2], the results of the present investigation fit well into the general theoretical framework [8,9] relating the thermal decomposition behaviour to the nature of the bonding.…”

Section: Resultssupporting

confidence: 75%

Activation energy of thermal decomposition of LaC2O4Br

Lugwisha

Mulokozi

Masabo

1991

Journal of Thermal Analysis

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The activation energy of the thermal decomposition of finely _~round LaC204Br was determined according to the method of Ozawa as Ea = 203.83 kJ tool-. As compared to the value for the parent oxalate La2(C204)3 Ea= 130 ~/mol), this value is higher by about 70 kJ/mol, which is consistent with the increased interaction between the metal and oxalate ions. The substitution of Br by C1 does not affect the decomposition kinetics profoundly.

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Section: Resultssupporting

confidence: 75%

Activation energy of thermal decomposition of LaC2O4Br

Lugwisha

Mulokozi

Masabo

1991

Journal of Thermal Analysis

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“…Some works 1,4,10 on the decomposition of carbonate indicated the phase‐boundary reaction as a decomposition mechanism. Although some other works 5,6 also suggested that a diffusion‐controlled mechanism is valid for the decomposition of the carbonates, but in the present investigation it was observed that under the non‐isothermal conditions of the decomposition reaction, the nature of diffusion varied among the carbonates. The decomposition of MgCO 3 and CaCO 3 followed a two‐dimensional diffusion‐controlled mechanism ( D 2 ) and the decomposition of SrCO 3 and BaCO 3 followed the Ginstling–Brounshtein model based on the diffusion‐controlled mechanism ( D 4 ).…”

Section: Resultscontrasting

confidence: 56%

“…Mulokozi and Lugwisha 5 studied the decomposition kinetics of calcite under isothermal conditions. The authors concluded that for minimizing the effects of heat and mass transfer, the decomposition kinetics of calcite is split by the restriction of CO 2 transport up to a degree of conversion α between 0.45 and 0.69, when the channels in the CaO(s) surrounding the reactant provide the only diffusion path.…”

Section: Introductionmentioning

confidence: 99%

Non‐Isothermal Decomposition Kinetics of Alkaline Earth Metal Carbonates

Maitra¹,

Bandyopadhyay²,

Das³

et al. 2007

Journal of the American Ceramic Society

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The kinetics of thermal decomposition of four synthetic alkaline earth metal carbonates (MgCO3, CaCO3, SrCO3, and BaCO3) was studied under non‐isothermal conditions using thermo‐gravimetry. The activation energy and the pre‐exponential factor for the decomposition reactions were determined using the Agarwal and Sivasubramanium integral approximation method. A new method was developed using a Turbo‐C‐based computer program to evaluate the integral of the kinetic equation. It was observed that the decomposition reaction of MgCO3 and CaCO3 followed two‐dimensional diffusion‐controlled kinetics and the decomposition reaction of SrCO3 and BaCO3 followed a Ginstling–Brounshtein model‐based diffusion‐controlled kinetics.

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“…rate of heat evolution) and pressure of the environment. Many researchers have studied the kinetics of thermal decomposition of carbonate minerals (Powell and Searcy 1980;Warne et al 1981;Iwafuchi et al 1983;Borgwardt 1985;Yariv 1989;McInosh et al 1990;Rubiera et al 1991;McCauley and Johnson 1991;Mulokozi and Lugwisha 1992;Ersoy-Merichoyu et al 1993;Shoval et al 1993;Xiao et al 1997). A general review of the literature on the decomposition of carbonates indicates that a great deal of variability exists in the reported values of the decomposition temperatures, activation energies and rates of decomposition.…”

Section: Introductionmentioning

confidence: 95%

Thermal decomposition of natural dolomite

Gunasekaran¹,

Anbalagan

2007

Bull Mater Sci

190

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Thermal decomposition behaviour of dolomite sample has been studied by thermogravimetric (TG) measurements. Differential thermal analysis (DTA) curve of dolomite shows two peaks at 777⋅8°C and 834°C. The two endothermic peaks observed in dolomite are essentially due to decarbonation of dolomite and calcite, respectively. The TG data of the decomposition steps have also been analysed using various differential, difference-differential and integral methods, viz. Freeman-Carroll, Horowitz-Metzger, Coats-Redfern methods. Values of activation entropy, Arrhenius factor, and order of reaction have been approximated and compared. Measured activation energies vary between 97 and 147 kJ mol -1 . The large fluctuation in activation energy is attributed to the presence of impurities such as SiO 2 , Al 2 O 3 , Fe 2 O 3 , Cl -etc in the samples. FTIR and XRD analyses confirm the decomposition reaction. SEM observation of the heat-treated samples at 950°C shows cluster of grains, indicating the structural transformation.

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New aspects of the decomposition kinetics of calcite

Cited by 20 publications

References 16 publications

Activation energy of thermal decomposition of LaC2O4Br

Activation energy of thermal decomposition of LaC2O4Br

Non‐Isothermal Decomposition Kinetics of Alkaline Earth Metal Carbonates

Thermal decomposition of natural dolomite

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