Finding the best way to recover more metals and improve the environmental quality of the residue fraction from bottom ash (BA) are hot topics in BA recycling. In the last decade, many companies have tried to find a method to recover most of the metals (aluminium scrap, ferrous scrap, copper/copper alloy scrap, precious metals) and residue fractions (aggregates, sand) for building purposes without incurring any extra costs related to environmental safety regulations.
The first step in achieving this is to begin with the right strategy and treatment concept. The following aspects should be considered:
- Local legal regulations (utilisation of residue or landfilling)
- Leaching limits (or other environmental criteria)
- Metal recovery goal
- Metals content, quality of metals, size of metals
- Moisture content of bottom ash
- Size of the plant/size limitations