Pilot-scale cement production using treated waste incineration bottom ash: physical and environmental performance

Abstract The use of washed municipal solid waste incineration (MSWI) bottom ash as a kiln-feed material for cement production provides an opportunity to recycle materials which are traditionally landfilled. The impact of MSWI bottom ash as a kiln feed material on cement performance is still poorly understand and industry feedback suggests that robust pilot-scale data sets are needed to address operator concerns prior to widespread implementation. This work contributes to the knowledge based as it reports the results from three discrete pilot-scale trials where washed MSWI bottom ash was used to replace typical kiln feed material at 0%, 1% and 2% by mass to manufacture portland cement. The resultant elemental and mineralogical composition were equivalent for each of the three cements. A detailed analysis of mechanical performance parameters indicate no significant differences in grindability, workability, hydration kinetics, or strength properties of the three cements. A screening assessment of direct exposure and leaching risk indicate no meaningful differences in constituents of potential concern. Air emissions monitored during each trial indicate no differences in concentration for monitored pollutants. The results support that modest incorporation of washed MSWI bottom ash into full-scale portland cement production is a safe and feasible means of replacing traditional raw materials.