A high metal yield is achieved. At the same time, the quality of the mineral content that is still deposited is improved. The mid-term goal is to be able to assign these residuals to a lower hazard class.
When planning the ZAV Recycling AG treatment plant, from the beginning the focus was on a high degree of efficiency in the separation of recyclable materials. This is achieved either by connecting identical separation machines in series or by recirculating the material during separation processing. Both principles were implemented in the plant. The circulation concept is applied to bottom ash fractions larger than 15 mm. For bottom ash fractions smaller than 15 mm, the separation machines are linked one behind the other in processing chains.
Due to the consistent screening and selective crushing of the bottom ash, the metal parts of a fraction size can be separated directly or recirculated until they are definitively separated out. In this way, almost complete recovery of the metal fractions is achieved.
In order to guarantee a constantly high metal yield, further important operational conditions are observed:
- Thanks to the sequential crushing process in three stages, the metals enclosed in bottom ash agglomerates are almost completely exposed and thus made accessible for recovery.
- Five processing lines guarantee optimum matching of the fraction size ranges to the separation machines.
- The bottom ash flows constantly at an optimum level through the individual separation machines in order to guarantee the best possible process reliability.
- The plant's 24-hour operation enables optimum capacity utilization on relatively small, easily controllable sorting machines.3
- The system is closed and operates under a slight vacuum to avoid dust emissions. High health and safety standards ensure optimum working conditions and safe operation.
Quelle: 3 THERMO-RECYCLING, Efficient recovery of recyclable materials from dry bottom ash, D. Böni, Managing Director, Stiftung ZAR, 2018