A device for thermal treatment comprises at least a preheater, a calciner, and a materials cooler, wherein a solids stream is guided into the preheater, from the preheater into the calciner, from the calciner into the materials cooler, and out of the materials cooler, wherein a gas stream is guided into the materials cooler, from the materials cooler into the calciner, from the calciner into the preheater, and out of the preheater, wherein the device comprises a combustion chamber, wherein the gas stream from the materials cooler is guided at least partially through the combustion chamber into the calciner, wherein a residence time device is arranged between the combustion chamber and the calciner.