End of life
   
 

Figure 3 illustrates the LED-products in the focus of the CycLED project and their principal pre-treatment.

 
  Figure 3: LED-products for recycling of CycLED target metals
 

Figure 4 shows the concentration of rare earth metals as average across 50 retrofit LED lamps.

 
  Figure 4: Estimated concentrations of target metals in retrofit LED lamps
 

These low concentrations of target metals (TM) potentially does not support the technical and economic requirements of recycling and end-processing in existing smelting technologies. Pre-treatment is therefore required to:

  • concentrate the TM in the pre-processing fractions technically and economically facilitating the recycling of these metals from these fractions
  • separate all TM from LED-products which require the same end-processing into the same fractions, or vice versa avoid mixing of TM in one fraction that require different final processing.

In conventional shredding and mechanical separation (SMS) processes, the target metals will be distributed over all output fractions thus further decreasing the already low TM concentrations. The LEDs must therefore be removed for separate treatment prior to the mechanical pre-treatment.
In lighting products, the LEDs are assembled on printed circuit boards (PCBs). The extraction of the PCBs prior to SMS of the rest of the devices therefore is an option for a first concentrating step in the pre-processing. Displays must be opened in order to extract the LEDs used for backlighting. Figure 5 gives an overview on the various pre-treatment options for LED products.

 

  Figure 5: Overview on pre-treatment of LED products (ELPRO)
 

Methods for the mechanical treatment of displays including mercury containing cold cathode fluorescent lamps, the alternative to LED backlights, are currently very expensive or only available in an experimental stage. The LEDs containing the TM must therefore be extracted manually, given current product design and recovery systems. Table 1 displays the average time and cost for this.

 

 

Product

Time to extract LEDs [sec]

Arising labour costs [€]*

Laptops/Notebooks

203

1,86

Monitors / TV-sets

402

3,70

  Table 1: Dismantling times and cost for extraction of LED-parts   *Assumed labour costs: 33 €/h
 

Due to the high cost of manual treatment in the EU, the project consortium investigates mechanical pre-treatment processes and is currently assessing one process that might enable the mechanical concentration of the target rare earth metals in one fraction.

If the LEDs must be manually removed from LED-products in the pre-treatment phase, to avoid additional sorting costs,LED-products should be collected separately. In the case of the investigated mechanical treatment process actually providing the necessary concentration and allocation of TMs into fractions (from which they can be recycled) such a separate collection may not be required.

  For more information please contact: Otmar Deubzer (Otmar dot deubzer at izm dot fraunhofer dot de)