Treatment of municipal solid waste incineration bottom ash using cement for integrated recovery of hydrogen and production of supplementary cementitious material

Municipal solid waste incineration (MSWI) bottom ash (MBA) represents both a disposal challenge and a potential resource for sustainable construction materials, especially as a supplementary cementitious material (SCM). However, the conventional use of MBA in cement-based materials is hindered by its high metallic aluminum content, which reacts in alkaline environments to release hydrogen gas and causes volumetric instability (e.g., expansion and cracking). This study introduces an innovative, simple, and low-cost alkali pretreatment method that uses a dilute cement suspension to stabilize metallic aluminum while upgrading MBA into a high-quality SCM. Compared to conventional chemical alkali treatments, this cement-based approach is safer to handle, more scalable, and economically advantageous. Experimental results have shown that treated MBA, after generating around 2.5 kg of hydrogen per metric ton, can replace 20% cement while retaining over 75% of the reference mixture’s strength. Lifecycle and economic assessments indicate reduced CO2 emissions and more than 25% cost savings compared to the plain Portland cement alternative. These findings demonstrate a practical, environmentally beneficial pathway for integrating MSWI ash into industrial sustainability and the circular economy.