RECOVERY OF PRECIOUS METALS FROM INCINERATION BOTTOM ASH

Incineration bottom ash (IBA), the final solid residues from Energy of Waste Facilities (EfW), holds a huge potential for recovery of valuable metals and a complete reuse of the residual mineral matter. Modern treatment technologies allow for a recovery of lumpy metals to the greatest possible extend and the production of a homogeneous secondary construction material. Over the last two years, LAB Geodur has developed a new approach for IBA treatment: Based on its existing dry treatment process for wet-discharged and matured IBA, known under the name of RecuLAB® NF, a wet processing for fresh IBA has been developed, which allows to directly treat wet-discharged IBA. This process, called RecuLAB® AU, is designed to treat IBA without any upfront storage or maturation. RecuLAB® AU is a modular concept, which can be installed on the premises of an EfW plant or at an existing IBA treatment site. Given the wet processing, both the metal recovery yield as well as the metal qualities are importantly improved. Besides further value creation from additionally recovered metals down to 0.03 mm, a sand-like secondary aggregate is produced, opening up new application possibilities. The mineral fraction additionally benefits from an improved visual appearance and from further reduced contamination. Process water is kept in a closed loop, enabling a residue-free treatment technology. Due to the wet processing, typical dust issues from IBA treatment can be completely solved. With this, not only the mode of operation is simplified, the environmental and working conditions are massively improved, too.