The method involves recovering low granulometry materials i.e. sands on an outlet side of a dryer-mixer type rotary drum (10) during a transitory mode of stopping and draining from the drum in a production cycle. The materials are recycled continuously with controlled flow, in the drum at the time of a transitory mode of starting and filling of the drum in a following cycle so as to adjust granulometry of a mixture. A zone of dry mixture for the materials is determined. A malaxation zone is integrated in the drum between the dry mixture zone and an exit of the drum.