Metal Recovery from Incinerator Bottom Ash: The Role of Modern Sorting Equipment
Incinerator bottom ash (IBA) contains recoverable metals mixed with mineral residues. For recycling operators, the challenge is separating valuable materials while preparing the remaining ash for further treatment.
A 2026 study published in Waste Management & Research examined metallic aluminum recovery at an industrial-scale treatment facility in Austria. Researchers investigated bottom ash from two different incineration technologies and demonstrated how multi-stage processing can recover aluminum from challenging material streams.
The findings are particularly relevant to recycling equipment such as trommel screens, magnetic separators and eddy current separators.
Why Particle Size Matters in IBA Recycling
Bottom ash contains materials with widely varying particle sizes, from fine mineral particles to larger pieces of metal.
This variation affects separation performance. Small aluminum particles behave differently from larger fragments, making particle size classification an important part of material preparation.
A trommel screen can divide mixed ash into more controlled size fractions. Depending on the material characteristics, different fractions can then be directed toward suitable downstream recovery equipment.
Proper screening helps operators maintain more consistent feeding conditions and reduces the difficulty of separating valuable metals from mineral residues.
Magnetic Separation Removes Ferrous Metals
After material preparation, magnetic separation can recover iron and steel from bottom ash.
Removing ferrous metals before downstream non-ferrous recovery helps reduce contamination and produces a more suitable feed for subsequent separation stages.
Both permanent-magnet and electromagnetic systems can be considered, depending on installation requirements and material conditions.
For IBA processing facilities, magnetic separation therefore serves two purposes: recovering usable ferrous material and preparing the remaining fraction for non-ferrous metal separation.
Eddy Current Separation Recovers Aluminum
Once ferrous metals have been removed, eddy current separators can recover conductive non-ferrous metals, particularly aluminum.
The equipment uses a rapidly changing magnetic field to induce electrical currents in conductive particles. The resulting electromagnetic force changes their discharge trajectory, separating them from much of the non-conductive mineral material.
The 2026 Austrian study reported aluminum extraction into metal concentrates of 97% for fluidized-bed ash and 78% for grate-incinerator ash across two full-scale experiments. These results describe the entire treatment process at the studied facility, not the performance of an individual separator or CurrenTek equipment.
The difference illustrates why feed characteristics and processing conditions must be considered when evaluating metal recovery opportunities.
Building an Effective IBA Sorting Process
Successful metal recovery depends on more than installing a single separator.
Important factors include particle size distribution, moisture content, metal concentration, material liberation and processing capacity.
CurrenTek offers trommel screens, magnetic separators and eddy current separators suitable for integration into metal recovery processes. Its published equipment information emphasizes selecting configurations according to actual material conditions and downstream requirements.
For a typical project, screening can prepare different size fractions, magnetic separation can remove ferrous metals, and eddy current separation can recover conductive non-ferrous materials.
However, the exact sequence and settings should be determined through feed analysis and, where appropriate, material testing.
Turning Bottom Ash into Recoverable Value
Research continues to show that incinerator bottom ash is more than a disposal residue. It contains recoverable metallic resources that can be separated through appropriately designed processing systems.
For recycling operators, effective screening and metal separation can create additional recovery opportunities while reducing the amount of metal remaining in the mineral fraction.
As interest in resource recovery from municipal waste increases, well-matched magnetic and eddy current separation technologies will remain important components of IBA treatment systems.