Abstract: The invention relates to a clay calcination plant for activating clay as feed material, which has a proportion of at least 40% of thermally activatable layered silicates. The plant comprises a rotary kiln with a kiln inlet and a kiln outlet, wherein feed material is thermally treated while being conveyed through the rotary kiln. In addition, a gas infeed is provided at the kiln outlet and a gas outfeed at the kiln inlet. Furthermore, the clay calcination plant has a mixing chamber for generating a temperature-homogeneous flow of calcination gas, with a burner for generating flue gas and a process gas infeed for the infeed of warm process gas being provided.