The object of the invention is a chemical-looping combustion device utilizing a solid fuel generating unburnt particles and using oxygen-carrying particles such as metallic oxides, and comprising at least one combustion zone and a separator for the particles contained in a gaseous mixture coming from the combustion zone, wherein the separator comprises at least one enclosure (1) with an intake line (4) for said mixture, a discharge line (5) arranged in the lower part of the enclosure and an outlet line (6) arranged in the upper part of the device, the intake and discharge/outlet parameters being so selected as to create in the enclosure a dense phase in the lower part and a dilute phase in the upper part, and wherein said intake line opens into the dilute phase.The invention also relates to a combustion method implementing the device according to the invention.