ENVIRONMENTAL BEHAVIOUR OF MINERAL FRACTIONS FROM ADVANCED SEPARATION OF INCINERATOR BOTTOM ASH

The present study investigated the properties of eight different samples of incinerator bottom ash, derived from an enhanced separation process aimed at materials recovery, and recycling of the valuable fractions (mainly... [ view full abstract ]

The present study investigated the properties of eight different samples of incinerator bottom ash, derived from an enhanced separation process aimed at materials recovery, and recycling of the valuable fractions (mainly ferrous metals, non-ferrous metals and mineral components). Specifically, five mineral fractions and three metal oxide fractions were tested for physical characteristics, chemical composition and leaching behaviour in order to assess the potential for recycling and predict the associated environmental impacts. While the mineral fractions were found to contain only small amounts of waste glass fragments, the metal oxide fractions turned out to be commingled with a consistent portion of mineral particles, resulting in inhomogeneous materials with limited utilization potential. Their bulk and chemical composition as well as the leaching properties were thus strongly affected by the presence of mineral particles associated with molten magnetic metals. The most critical elements with a view to leaching turned out to be, for both the mineral and the metal oxide fractions, Sb and Cr, which exceeded the quality standards for inert waste disposal in landfills.