Evaluating the beneficial use of solid waste in clinker production : a multi-criterion decision-making approach

Abstract

Introducing incinerated ashes as raw inputs for eco-cement production is gaining traction. However, the associated reductions in economic and environmental impacts related to clinkering procedures necessitate further verification. In this context, we investigated the production of both ordinary (scenario 1) and eco-friendly clinkers using incinerator bottom ash, incinerated sewage sludge ash, and recycle concrete fines (IBA/RCF-scenario 2; ISSA/RCF-scenario 3) as raw materials, employing Multi-Criteria Decision Analysis (MCDA) to assess different eco-clinker production protocols, including the use of different equipment/plant for processing and calcining, the curing process. IBA/RCF and ISSA/RCF-derived clinkers reduced carbon emissions by 32.45 % and 24.58 %, respectively. However, IBA/RCF-derived clinkers exhibited greater cost reduction (443.93 HKD/t vs. 446.78 HKD/t) and enhanced strength development (113.70 MPa vs. 65.60 MPa) after carbonation compared to ISSA/RCF-derived clinkers, likely due to IBA's unique composition, positioning them as the most sustainable production method measured by VIKOR method. Furthermore, a sensitivity analysis predicted that a variation of 10 % in raw material inputs and coal consumption during clinkering showed consistency in environmental impacts among scenarios. This study motivates cement producers to incorporate incinerated ashes on a large scale to promote sustainability.