Characterisation of rotary kiln residues from the pyrolysis of shredder wastes

1. Characterisation of rotary kiln residues from the pyrolysis of shredder wastes Osric Tening Forton Marie K. Harder Norman R. Moles Waste & Energy Research Group. Faculty of Science and Engineering. University of Brighton, UK

2. Presentation Outline • UK shredder waste volumes – landfill disposal is unsustainable • Key Drivers ~ ELV Directive (2000/53/EC): maximum recovery! • Aims and objectives of this work: • -Maximize materials recovery from the inerts • -Which metals present and at what levels? • -Identify contribution of automotive feed • Results & Discussions • Major conclusions

3. Waste characteristics & recovery options MIDDLES (15 – 130mm) OVERSIZE (>130mm) • Complex & heterogeneous waste stream • -Depends on several factors • Plastics - highest proportion by mass • Waste is amenable to : • Mechanical treatment e.g. SiCoN process • Thermo chemical treatment e.g. pyrolysis Fines (<15mm)

4. Characterise of solid residues from the pyrolysis of ASR & SR Presence of residual metals and contaminants - Cu, Zn and Fe – potential for further recovery from residues? Pb – major contaminant and limiting factor for reuse options Evaluate/Use the performance of a mechanical roll crushing process to fractionate metals for recovery and disposal +GASEOUS PRODUCTS Widely studied GENERAL PYROLYSIS +LIQUID PRODUCTS +SOLID RESIDUES Limited attention Aims and Objectives

5. Flue Gas Exhaust Thermocouple Chain drive Combustion chamber Gas fired furnace and Bag Filters Feed S.R. plug Char and metals 600°C 700°C Condenser BURNER Experimental Design & feed characteristics • Residence time - 12min • Liquids condensed • Exhaust gases passed through bag • filters • Solid residues collected and processed Kiln type – MRP Rotary Kiln Unit • Feedstock, ASR & SR fines (<15mm) • Feed rate- ~1kg/min • Temperature - 600oC

6. Magnetic Separation Screening Mechanical roll crushing Screening & sieving Chemical Analyses Screening, roll crushing schematic 1 SR SR ASR ASR

7. Analytical Techniques and Sample preparation • Heterogeneous nature of solid residues (particle size, composition) • 4 analytical techniques used • Each have their specificities • Fitness For Purpose approach

8. Magnetic Separation Screening Mechanical roll crushing Screening & sieving Chemical Analyses Screening, roll crushing schematic 2 SR SR ASR ASR

9. Results – particle size distribution & Carbon Content • 50 - 60% solid residues -Average Carbon Content (LOI @ 550oC) - ASR – 17% - SR – 23% • Screening & Roll crushing concentrates residues in different particle sizes -largest proportion of residues in <500µm • Does this have an effect on metal partitioning & segregation? -changes in aspect ratio

10. Pb fractionation by particle size

11. Cu fractionation by particle size

12. Zn fractionation by particle size

13. Fe fractionation by particle size

14. Summary

15. Pyrolysis is useful in the characterisation of shredder wastes Pyrolysis (commercial) is useful for material recovery towards ELV Directive targets Inerts contain useful metals (Cu, Zn, Fe) and contaminants (Pb) Lead levels in SR residues are ~double ASR residues Implications for sustainable waste management? Implications for automotive industry? Mechanical roll crushing and separation concentrates metals and contaminants into some fractions. leaves most of the inerts less contaminated – reusable? Pb concentration for re use or disposal Possible Fe, Zn and Cu recovery for secondary markets Value from shredder wastes pyrolytic solid residues Suitable markets with product specifications must be identified Collation of larger datasets for more rigorous statistical analyses Conclusions