In a method for utilizing phosphorus-containing alternative fuels in the cement clinker production, the alternative fuels are thermolyzed using waste heat from the cement clinker production process in a thermolysis reactor different from a rotary kiln of the cement clinker production process, the energy released thereby is supplied to the cement clinker production process, and the thermolysis residues of the phosphorus-containing alternative fuels are discharged from the thermolysis reactor, so that the thermolysis residues of the phosphorus-containing alternative fuels are mixed in the thermolysis reactor with cement kiln bypass products as halogen carriers and the heavy-metal halides produced are drawn off.