Disclosed is a method for treating fly ash containing an initial carbon concentration to obtain ash containing a predetermined final carbon concentration less than the initial concentration, the method including: —a step of granulometric separation of the ash into at least two fractions, a coarse traction and a fine fraction, the coarse fraction having a granulometry greater than the fine fraction; —a step of extracting carbon from the ash; a method wherein the extraction step is subsequent to the separation step, the extraction step being implemented solely on the coarse fraction, by electrostatic separation, the method including a step of drying the ash during which the temperature of the ash is above 60° C.