The article reveals the spontaneous ignition characteristic of activated carbon(AC)as well as its key influencing factors in order to avoid or reduce the spontaneous ignition risk of AC in the process of storage and transportation.The AC samples were successfully prepared with cottonwood powder as carbon precursor and zinc chloride as activated agent at temperature from 300℃ to 700℃

and the variation of spontaneous ignition temperature with the activation temperature was also investigated.The microstructure and surface functional groups of AC samples were characterized by X-ray diffraction(XRD)and Fourier transform infrared(FT-IR)spectra and the thermostability was studied by simultaneous thermal analyzer(STA).The results show that activation temperature has a great influence on the spontaneous ignition temperature of AC samples.Spontaneous ignition becomes easier if decreasing the activation temperature

which is attributed to the gradual increase of the quantities or varieties of surface functional groups of AC.It is also confirmed that the DSC and TG curves of the AC samples tend to shift to the high-temperature region with the activation temperature increasing.In other words

a higher activation temperature in the preparation process is beneficial to reduce the spontaneous ignition risk of AC.