Chemical and mineralogical characterization of processing residues from oxygen-enhanced municipal solid waste incineration bottom ashes

• O 2 -enhanced incineration bottom ash shows higher heavy metal levels than literature • Higher temperature and O 2 supply do not significantly alter bottom ash mineralogy • Single-particle analysis identified pure metals, alloys, sulfides and silicates This study provides a comprehensive characterization of municipal solid waste incineration bottom ash (MSWI-BA) produced by an O 2 -enhanced grate incineration process. Unlike conventional MSWI bottom ash, the ash exhibits notable enrichment of potentially hazardous elements, including Pb, Sb, Cd, Mo, Cr, and Cu, across most particle sizes, reflecting the combined effects of input waste composition and the unique operational conditions of O 2 -enhanced combustion. Bulk mineralogical analysis using X-ray diffraction (XRD) reveals distinct variations across size fractions, with minor crystalline phases such as ettringite more prominent in the finest fraction. The ash composition is dominated by silicates and oxides and includes substantial amorphous glass and minor metallic and sulfide phases. In addition to XRD-based phase identification, this study introduces a novel application of cosine similarity-based phase matching for electron probe microanalysis data. Despite differences in chemical composition, the overall mineralogical assemblage and amorphous content remain comparable to conventional bottom ash. This dataset offers detailed insights into elemental distributions and mineralogy of O 2 -enriched bottom ash, providing a valuable reference for environmental assessments, resource recovery strategies, and comparative studies across incineration technologies.