Installation for the thermal treatment of dispersible raw material, and method for operating such an installation

A method for thermal treatment of free-floating raw material including at least one of cement raw meal or mineral products, the method comprising:

• introducing, through a fuel inlet, fuel into a riser line for guiding hot gases;
• introducing, through a raw meal inlet, raw meal into the riser line, wherein the raw meal is introduced into the riser line upstream of the fuel inlet in a flow direction of gas;
• and
• introducing, through an inert gas inlet, inert gas into the riser line;
• wherein the riser line includes at least two treatment regions that are arranged in succession in the flow direction, wherein each of the at least two treatment regions has a different diameter, wherein the raw meal is introduced into an upstream treatment region of the at least two treatment regions in the flow direction;
• wherein each of the two treatment regions includes a section of the riser line including at least one inlet for introducing raw meal, fuel, and/or inert gas;
• wherein each of the two treatment regions includes a middle region having a constant diameter, an upstream region arranged upstream of the middle region having an increasing diameter, and a downstream region arranged downstream of the middle region having a decreasing diameter.