Thermoanalytical Methods: Fundamental Principles and Features

Kinetic Insight into the Effect of Self-Generated CO2 on the Thermal Decomposition of Inorganic Carbonates in an Inert Gas Atmosphere: ZnCO3 and CaCO3

“…The TG–DTG–EGA­( c (CO 2 )) curves for these thermal decomposition processes under linear non-isothermal conditions were systematically recorded at different β values (0.5 ≤ β/K min –1 ≤ 10): scanning temperature ranges for the thermal decomposition of ZnCO 3 in a stream of dry N 2 and air were 423–823 and 473–873 K, respectively; those for the thermal decomposition of CaCO 3 in both a stream of dry N 2 and air were 573–1173 K. In the measurements under CRTA modes, the sample was linearly heated at a β value of 2 K min –1 , whereas, during the thermal decomposition process, the mass loss rate was regulated to be different constant values ( C ) in the ranges of 3–18 and 2.5–15 μg min –1 for the ZnCO 3 and CaCO 3 samples, respectively. The TG–DTA instrument was calibrated prior to the sample measurements regarding the measured temperature and mass change value using standard methods . The sample temperature was calibrated using the DTA signal for the melting of Ga, In, Sn, Pb, Zn, Al, and Ag (purity ≥99.99%, Nilaco) at a β value of 5 K min –1 in a stream of dry N 2 ( q v = 300 cm 3 min –1 ), whereas the mass change value was calibrated using a standard weight of 2.00 mg and further validated using mass loss curves for the thermal decomposition of CaC 2 O 4 ·H 2 O ( m 0 = 5.0 mg, ≥99.9985%, Alfa Aesar) recorded by heating linearly at a β value of 5 K min –1 in a stream of dry N 2 ( q v = 300 cm 3 min –1 ).…”

“…The TG−DTA instrument was calibrated prior to the sample measurements regarding the measured temperature and mass change value using standard methods. 69 The sample temperature was calibrated using the DTA signal for the melting of Ga, In, Sn, Pb, Zn, Al, and Ag (purity ≥99.99%, Nilaco) at a β value of 5 K min −1 in a stream of dry N 2 (q v = 300 cm 3 min −1 ), whereas the mass change value was calibrated using a standard weight of 2.00 mg and further validated using mass loss curves for the thermal decomposition of CaC 2 O 4 •H 2 O (m 0 = 5.0 mg, ≥99.9985%, Alfa Aesar) recorded by heating linearly at a β value of 5 K min −1 in a stream of dry N 2 (q v = 300 cm 3 min −1 ). The CO 2 meter was also calibrated using standard gas of N 2 (≥99.999%) and N 2 −CO 2 mixed gas (c(CO 2 ): 4000 ppm).…”

Efflorescence kinetics of sodium carbonate decahydrate: a universal description as a function of temperature, degree of reaction, and water vapor pressure

“…Prior to kinetic data measurements using the humidity-controlled TG system, the instrument was calibrated according to the measured sample temperature and mass change using standard methods. 58 Temperature calibration was performed with reference to the melting point of Ga by measuring the onset temperature of the endothermic DTA signal for the melting of Ga (purity: >6N%, Nilaco) at a β value of 12 K h −1 in a stream of N 2 –H 2 O mixed gas with several selected p (H 2 O) values used for the kinetic measurements. The mass change value was calibrated by the addition/removal of a standard weight of 5 mg in an open atmosphere.…”