Abstract: Isothermal and non-isothermal C80 micro-calorimetry experiments and Semenov and Frank-Kamenetskii spontaneous combustion theory have been applied to study the critical temperature for spontaneous combustion of the polished aluminum powder induced by water and the induction time of each reaction stage. The results show that both Al₂O₃-H₂O and Al-H₂O reactions follow the Arrhenius kinetic mechanism， with the activation energy being equal to 61.7 and 138.6kJ·mol^-1， respectively. The induction time of aluminum powder consists of two stages. The first stage is the time for alumina film hydrolysis， and the second stage is the time for the aluminum-water exothermic reaction system to reach the non-return temperature T_NR from the ambient temperature， depending on the accumulation state and the deposit mass of the aluminum powder. When the ambient temperature is 25℃， the induction time of the first stage is 155.6h. When aluminum powder of 25kg is deposited in a cylindrical dust collecting drum， the induction time of the second stage is 0.7h with the same ambient temperature， and the critical temperature for spontaneous combustion is 24.9℃. The aluminum powder has the risk of spontaneous combustion， and the induction time increases as the deposit mass increases.

Key words: polished aluminum powder; water; spontaneous combustion; induction time; C80 micro-calorimetry