Naslov
Kinetic analysis of thermal decomposition of Ca(OH)_2 formed during hydration of commercial Portland cement by DSC

Autori
Zelić, Jelica ; Rušić, Davor ; Krstulović, Ruža

Izvornik
Journal of thermal analysis and calorimetry (1388-6150) 67 (2002), 3; 613-622

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Ca(OH)_2 portlandite ; DSC ; kinetic parameters ; non-isothermal kinetic ; reaction mechanism ; thermal decomposition.

Sažetak
In this paper, evaluation of kinetic parameters (the activation energy - E, the pre-exponential factor - A and the reaction order-n) with simultaneous determination of the possible reaction mechanism of thermal decomposition of calcium hydroxide (portlandite), Ca(OH)_2 formed during hydration of commercial Portland - slag cement, by means of differential scanning calorimetry (DSC) in non-isothermal conditions with a single heating-rate plot has been studied and discussed. The kinetic parameters and a mechanism function were calculated by fitting the experimental data to the integral, differential and rate equation methods.To determine the most probable mechanism, 30 forms of the solid-state mechanism functions, f(alpha(c)) have been tried. Having used the procedure developed and the appropriate program support, it has been established that the non-isothermal thermal decomposition of calcium hydroxide in the acceleratory period (0.004< α (c)<0.554)can be described by the rate equation: dα (c)/dT = A/β exp(-E/RT)f(α (c)), which is based on the concept of the mechanism reaction: f(α (c))=2(α (c))(1/2). The mechanism function as well as the values of the kinetic parameters are in good agreement with those given in literature.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

POVEZANOST RADA