The invention relates to the production of cement clinker from cement raw material, wherein preheated raw material is calcined in a calcination zone, then finally burnt to cement clinker in a sintering combustion zone of a kiln supplied with fuel, and the hot cement is cooled in a cooler, and wherein fuel is generated from waste-derived fuels in a gasification reactor to which at least one gas conveying pipe for a reagent is connected and which is connected via at least one fuel gas pipe to at least one combustion zone. In order to increase the reaction rate of the lumpy waste-derived fuels and thus to achieve optimum fuel gas generation in the gasification reactor, a reagent introduction zone is constructed in the gasification reactor in the region above a solids bed made up of the waste-derived fuels, and reagent introduction connections uniformly distributed over the circumference of the reactor open into the reagent introduction zone in such a way that in the region of this introduction zone the reagent can be introduced with a high pulsation to create a pre-selected flow form.