TY - JOUR
T1 - Isothermal and non-isothermal sublimation kinetics of zirconium tetrachloride (ZrCl4) for producing nuclear grade Zr
AU - Shin, Jae Hong
AU - Choi, Mi Sun
AU - Min, Dong Joon
AU - Park, Joo Hyun
PY - 2014/2/14
Y1 - 2014/2/14
N2 - Sublimation of ZrCl4 is important for the production of nuclear grade metallic Zr in Kroll's process. The sublimation kinetics of ZrCl 4 was investigated by thermogravimetric analysis under both isothermal and non-isothermal conditions. The sublimation rate of ZrCl 4 increased with increasing temperature under isothermal conditions. ZrCl4 sublimation was confirmed to be a zero-order process under isothermal conditions, whereas it was first-order kinetics under non-isothermal conditions. The activation energy of ZrCl4 sublimation under isothermal conditions was 21.7 kJ mol-1. The activation energy for non-isothermal sublimation was 101.4 kJ mol-1 and 108.1 kJ mol -1 with the Kissinger method and Flynn-Wall-Ozawa method, respectively. These non-isothermal activation energies were very close to the heat of sublimation (103.3 kJ mol-1). Sublimation occurs by two elementary steps: surface reaction and desorption. Therefore, the overall activation energy of ZrCl4 sublimation is 104.8 (±3.4) kJ mol-1. The activation energy of the surface reaction and desorption steps are proposed to be 83.1 kJ mol-1 and 21.7 kJ mol-1, respectively.
AB - Sublimation of ZrCl4 is important for the production of nuclear grade metallic Zr in Kroll's process. The sublimation kinetics of ZrCl 4 was investigated by thermogravimetric analysis under both isothermal and non-isothermal conditions. The sublimation rate of ZrCl 4 increased with increasing temperature under isothermal conditions. ZrCl4 sublimation was confirmed to be a zero-order process under isothermal conditions, whereas it was first-order kinetics under non-isothermal conditions. The activation energy of ZrCl4 sublimation under isothermal conditions was 21.7 kJ mol-1. The activation energy for non-isothermal sublimation was 101.4 kJ mol-1 and 108.1 kJ mol -1 with the Kissinger method and Flynn-Wall-Ozawa method, respectively. These non-isothermal activation energies were very close to the heat of sublimation (103.3 kJ mol-1). Sublimation occurs by two elementary steps: surface reaction and desorption. Therefore, the overall activation energy of ZrCl4 sublimation is 104.8 (±3.4) kJ mol-1. The activation energy of the surface reaction and desorption steps are proposed to be 83.1 kJ mol-1 and 21.7 kJ mol-1, respectively.
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U2 - 10.1016/j.matchemphys.2013.11.007
DO - 10.1016/j.matchemphys.2013.11.007
M3 - Article
AN - SCOPUS:84891629176
VL - 143
SP - 1075
EP - 1081
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
SN - 0254-0584
IS - 3
ER -