An apparatus serves for the treatment of particulate material and comprises a process chamber for the reception and treatment of the particulate material. The process chamber has a bottom provided with a passage orifice through which the process air can be introduced into said process chamber and an outlet for the discharge of said process air from said process chamber. A device for conditioning said process air and for circulating said process air in a circuit through said process chamber said outlet and back to said bottom has at least one fan for circulating said process air at least one condenser and at least one process air heater. A filter arrangement is provided for removing solids from said process air flowing out of said process chamber. A second chamber is arranged around said process chamber within said second chamber at least parts of said filter arrangement at least parts of said device for conditioning the process air are received.