Spontaneous ignition of low-concentration nano-sized Al-water slurry

Spontaneous ignition of a nano-sized aluminum (Al) particles-water slurry using a hot plate was investigated. The aluminum weight fractions were 17% and 27%. The hot plate temperatures ranged from 303 to 343K. For all experimental conditions used, ignition was observed to occur at about 321K and it was followed by a rapid temperature increase to above the boiling temperature of the water. Although the thermal runaway condition did not occur until the slurry reached a temperature of 321K, it was able to react at a temperature as low as 303K and develops sufficient heat for the slurry to reach the ignition condition. The ignition kinetic data were determined showing that E/R=28619.66 (K) and k=1.2644×1037K/s for the slurry containing 17% aluminum and, the value of k was about 2.398×10m37K/s for those having 27% aluminum by weight.