Roller kiln provided with a drying tunnel, particularly for ceramic or refractory materials

A roller tunnel kiln for firing a material to be advanced along a longitudinal axis of the kiln, comprising a first tunnel including a prekiln zone, a firing zone, a first forced cooling zone, and a second forced cooling zone and a plurality of refractory rotary rollers positioned transversely to said axis and constituting a progress plane for the material advanced along said rotary rollers;

• means for providing hot gases in said first tunnel, so that hot gases are flowing through said first tunnel;
• a second tunnel for drying the material and extending parallel to said first tunnel along the length thereof and thermally insulated therefrom, said second tunnel including a plurality of transversely positioned rotary rollers constituting a progress plane for the material to be dried and advanced along said rollers;
• means for introducing ambient air into said first tunnel;
• discharging means to withdraw a portion of the hot gases from said first tunnel;
• mixing means for mixing said portion of hot gases received from said first tunnel with a portion of ambient air received from said ambient air introducing means;
• and means for communicating said mixing means with said second tunnel and adapted to form a current of hot gases at drying temperatures passing through said second tunnel in a direction opposite to that of the material to be dried.