Method for utilising a phosphorus-containing starting material during cement production in a cement works , comprising the following steps: i. heating a phosphorus-containing ash and/or slag fraction from the phosphorus-containing starting material to at least 1250°C, preferably at least 1300°C, in particular preferably at least 1400°C, in particular substantially 1500°C, to form a phosphorus-containing material flow, in particular a phosphorus-containing gas flow, and substantially phosphorus-free incineration and/or slagging residues; ii. separating the phosphorus-containing material flow, in particular the phosphorus-containing gas flow, and the substantially phosphorus-free incineration and/or slagging residues; iii. recovering elemental phosphorus, phosphorus pentoxide and/or phosphoric acid from the phosphorus-containing material flow; iv. producing an iron fraction from the substantially phosphorus-free incineration and/or slagging residues, wherein the iron fraction has at least 50% by mass iron; v. producing a Si/Ca/Al fraction from the substantially phosphorus-free incineration and/or slagging residues, wherein the elements silicon, calcium and aluminium are present as respective oxides in the Si/Ca/Al-containing fraction , wherein the Si/Ca/Al-containing fraction has a silicon oxide portion of less than 60% by mass, a calcium oxide portion of more than 25% by mass and an aluminium oxide portion of less than 30% by mass, based on the total amount of Si/Ca/Al-containing fraction, wherein the sum of the mass portion of silicon, calcium and aluminium oxide is more than 55% by mass, based on the total amount of the Si/Ca/Al-containing fraction ; vi. using a first portion of the Si/Ca/Al fraction as a first secondary raw material for cement production and vii. using a first portion of the iron fraction as a second secondary raw material for cement production. i. heating a phosphorus-containing ash and/or slag fraction from the phosphorus-containing starting material to at least 1250°C, preferably at least 1300°C, in particular preferably at least 1400°C, in particular substantially 1500°C, to form a phosphorus-containing material flow, in particular a phosphorus-containing gas flow, and substantially phosphorus-free incineration and/or slagging residues; ii. separating the phosphorus-containing material flow, in particular the phosphorus-containing gas flow, and the substantially phosphorus-free incineration and/or slagging residues; iii. recovering elemental phosphorus, phosphorus pentoxide and/or phosphoric acid from the phosphorus-containing material flow; iv. producing an iron fraction from the substantially phosphorus-free incineration and/or slagging residues, wherein the iron fraction has at least 50% by mass iron; v. producing a Si/Ca/Al fraction from the substantially phosphorus-free incineration and/or slagging residues, wherein the elements silicon, calcium and aluminium are present as respective oxides in the Si/Ca/Al-containing fraction , wherein the Si/Ca/Al-containing fraction has a silicon oxide portion of less than 60% by mass, a calcium oxide portion of more than 25% by mass and an aluminium oxide portion of less than 30% by mass, based on the total amount of Si/Ca/Al-containing fraction, wherein the sum of the mass portion of silicon, calcium and aluminium oxide is more than 55% by mass, based on the total amount of the Si/Ca/Al-containing fraction ; vi. using a first portion of the Si/Ca/Al fraction as a first secondary raw material for cement production and vii. using a first portion of the iron fraction as a second secondary raw material for cement production. <EOS>