Effects of phosphorus and iron on the composition and property of Portland cement clinker utilized incinerated sewage sludge ash

Recently, a large amount of incinerated sewage sludge ash (ISSA) has been produced with the popularization of sludge incineration technology. And it needs to be disposed of properly to reduce the environmental impact. In this work, the ISSA is used as a partial substitution of raw materials in the production of Portland cement clinker. Moreover, the influence of phosphorus and iron on the mineral composition and hydration property of Portland cement clinker utilized ISSA is studied. In the experiment, 0 ~ 3 wt% of Fe2O3 and P2O5 are respectively added into the raw material incorporated 3.6 wt% of ISSA. The results show that the C3A in the clinker increases and the hydration heat rate grows in the pre-induction period with the incorporation of P2O5. In addition, the formation of C3S is blocked and the general hydration process of produced clinker is delayed. With the addition of 0.5 wt% P2O5 the compressive strength of clinker could achieve 96.7% of the reference clinker, however, when P2O5 achieves 3 wt%, there is no C3S forming in the clinker and the compressive strength is reduced by 83.3% at 28d. Furthermore, little influence on the mineral composition and hydration property of produced clinkers has been observed with the addition of Fe2O3. The results provide supports for the utilization of ISSA in the production of industrial cement clinker.

Automated summary

This study investigates the feasibility of utilizing ISSA in the production of Portland cement clinker and examines the influence of phosphorus and iron on the clinker. The results show that the addition of P2O5 increases the C3A in the clinker but inhibits the formation of C3S and delays the general hydration process. However, the addition of Fe2O3 has little influence on the clinker.