Dataset for article: Biomass ash: A study of its leachability

The dataset was created to document the leachability behaviour of biomass ash. Its primary purpose is to provide raw experimental data characterizing the release of potentially harmful substances from ash materials in the context of waste classification and their potential utilization in the construction industry. The dataset includes raw results obtained from leaching tests performed according to EN 12457‑4, including pH, electrical conductivity, total dissolved solids, soluble inorganic salts, dissolved organic carbon, and concentrations of selected trace elements and anions measured in the leachates. The ash samples originate from multiple combustion technologies and fuel types, representing both fly ash and bottom ash fractions.