Combustion of aluminum powders is studied using a constant volume explosion (CVE) experiment with varied powder mass loads and environment compositions. A simplified model of aerosol combustion in CVE experiment is proposed based on the assumption that the process is adiabatic. The model enables one to extract the information about the burning velocity and particle burn times from the experimental pressure traces. It is observed that at increased oxygen concentrations, the kinetics of Al combustion may be faster than that of gas phase combustion of methane. The burning velocities measured for Al aerosols compare well with those reported earlier for similar size Al powders. The burn times estimated using the proposed model are substantially longer than reported earlier for individual particles and low number density aerosols. The differences may be due to both interaction between burning particles and lack of correction for the difference in the ignition temperatures for particles of different sizes. The data processing also suggests that the flame quenching by the chamber wall results in incomplete combustion explaining the difference between the observed combustion pressures and those predicted by equilibrium thermodynamic calculations. Addition of methane in the oxidizing environment results in increased combustion temperatures and burning velocities for Al aerosol. At nearly stoichiometric Al powder loads, addition of methane also substantially reduces the particle burn time, while at the increased particle mass loads this effect is diminished.