The gasification of coal can produce large amounts of fly ash, which still contains untapped charcoal. Fly ash was demineralized by flotation and activated carbons(ACs) were prepared by activation using KOH. The effect of preparation conditions on the performance of ACs was analyzed. The results show that: ① Total pore volume and micropore volume increased with the alkali-carbon ratio, while the content of mesopores decreased; ②The capacitance increased with the alkali-carbon ratio, but become stable after ...