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Seminar

Seminar. Chemical Methods for Electronic Wastes Recovery Supervisor: Professor H. S. Ghaziaskar Department of Chemistry. Gholamhossein Paniri. Isfahan University of Technology. Content. What is electronic wastes Why E-Wastes are recycling E-waste recycling steps

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Seminar

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  1. Seminar Chemical Methods for Electronic Wastes Recovery Supervisor: Professor H. S. Ghaziaskar Department of Chemistry Gholamhossein Paniri Isfahan University of Technology

  2. Content • What is electronic wastes • Why E-Wastes are recycling • E-waste recycling steps • Methods of materials chemical recovery • Conclusions • References

  3. What is Electronic Waste? Electronic Waste E- Waste

  4. Why E-Waste Recycling??? Others 6% CRT 12% Plastics 33% Metals 49% H.-Y. Kang, J.M. Schoenung / Resources, Conservation and Recycling 45 (2005)

  5. Types material of E-Waste • precious metals • hazardous material

  6. Weight Percent of Metals in different Electronic Wastes J. Cui, L. Zhang / Journal of Hazardous Materials 158 (2008) 228–256

  7. 100 WtiPri Vi= ∑ WtiPri Vi= Value distribution Wti= Weight precent of metal i in the electronic scrap sample Pri= the current price of metal i

  8. Value-Share (%) a The metal price data are from London Metal Exchange (LME) official prices for cash seller and settlement on the 24th October, 2007.

  9. Toxic Content of E-waste

  10. E-waste hazards Average pc of approx. 31.5 kgTwo million obsolete Wt. contains Pcs world mean www.toxicslink.org

  11. Scope of the problem Rapidly growing E-waste stream 2002 4.5 2005 3 2009 2 H.-Y. Kang, J.M. Schoenung / Resources, Conservation and Recycling 45 (2008) 368–400

  12. Why recycling E-waste? 1.E-Waste large amount of preciousmetals 2.E-Waste contain hazardous material 3.E-Waste is a huge secondaryresourceabove (mine ground) should notwasted

  13. E-waste recycling content 1.Ban export and disposal as well as incineration landfilling 2.Advertisement for recycling 3.Collection and transportation 4.Market for reuse 5.Materials recovery facility (MRF) Resources, Conservation and Recycling 45 (2005) 368–400

  14. Ban export and disposal The Basel convention Disposal = reuse + recycling The amount of secondhand personal computer exported from Japan in 2005 The amount of seconhand television exported from Japan in 2005

  15. Advertisement and sorting Advertisement Sorting

  16. Collection and transportation

  17. Market for reuse MRF Materials Recovery Facility

  18. Electronic Waste in IRAN

  19. Materials recovery of chemical methods 1. percious metals Recovery 2. hazardous materials Recovery

  20. Precious metals recovery 1.Pyrometallurgical 2.Hydrometallurgical

  21. Recovery of precios metals from E- waste by pyrometallurgical processing 1.Incineration 2.Smelting in a blast furnace 3.Drossing 4.Sintering 5.Reaction in a gas phase at high tempertures

  22. A summary of typical pyrometallurgical methods for recovery of metals from electronic waste

  23. Advantages pyrometallurgical processing 1.High efficiency recovery precious metals from E-waste 2.Recovery of energy from PC waste gives an example for using of plastic in E-waste

  24. Disavantages pyrometallurgicalprocessing 1.Integrated smelters cannot recoveraluminum andiron as metals 2.Ceramic componets and glass in theE-waste increase the amount of slag from Blast furnaces 3.Precious metals stay for a long time inthepyrometallurgical processing

  25. Disavantages pyrometallurgicalprocessing 4.Energy recovery and utilizing of organic constituents as a reducing agent are only on its beginning 5.Thermal processing of e-waste provides a feasible approach for recovery of energy from e-waste if a comprehensive emissioncontrol system isinstalled

  26. Recovery of precious metals fromE-Waste by hydrometallurgicalprocessing The main steps in hydrometallurgical Separation and purification Processing consist of a series of acid Or caustic leaches of solid material Precipitation of impurities Solvent extraction Adsorption Cementation…..

  27. Leaching of precious metals Cyanide leaching Halide leaching Thiourea leaching Thiosulfate leaching

  28. Halide leaching Exceptions of flurine and astatine Gold forms both Au(I) and Au(III) complexes with all halogens Low pH High halogen level Icreased temperature High surface area

  29. Aqua regia Advantage 2HNO3 + 6HCl 2NO + 4H2O +3Cl2 2Au + 11HCl + 3HNO3 2HAuCl4 + 3NOCl + 6H2O Halide leaching The process generally fast Low reagent consumption disavantage Highly corrosive acid Highly poisonous

  30. Recovery of precious metale from leachate Cementation Zinc cementation Crowe 1890 2Au(CN)2- +2e 2Au+4CN- Zn+ 4CN- Zn(CN)4-2 + 2e PH 8-11

  31. Crushed matter (0.3 mm) Sulfuric acid leaching of copper L Precipitation (NaCl) of Ag filtration S L Cu Recovery filtration Chloride leaching of palladium S AgCl L L filtration Cementation ( Al ) filtration Recycling S S Cyanide leaching of gold and silver Pd,Ag,Au L L filtration Activeted Carbon Adsorption Recycling S S Solid waste treatment Ag,Au,Cu

  32. Comparing withthe pyrometallurgical processing hydrometallurgical methode is More exact More predictable More easily controlled

  33. Recovery of hazardious metalsfrom E-Waste Cathod Ray Tube R T C 0.5 – 5 kg pb

  34. Cathode Ray Tube Recycling CRT components 1.Glass Funel glass, panel glass,solder glass,neck Sio2,Nao,Cao for coloring and Zno,Bao,Pbo for proctecting from X-Rays 2.Non glass Plastic,steel,copper,electron gun ,phosphor coating

  35. Cathode Ray Tube Recycling 1.Glass-to-glass recycling 2.Glass-to-lead recycling

  36. Glass-to-lead recycling collection sorting Vibratin scrren Magnetic separation Ferrous metals Eddy current separation Nonferrous metals

  37. Eddy current σ:electrical conductivity ρ :density σ/ρ:ratio of electrical conductivity to density H.-Y. Kang, J.M. Schoenung / Resources, Conservation and Recycling 45 (2005) 368–400

  38. pretreatment reductant reverberatory furnace disposal PbO + C → Pb + CO slage landfillsd Soft Pb 99.98% H.-Y. Kang, J.M. Schoenung / Resources, Conservation and Recycling 45 (2005) 368–400

  39. Conclusion 1.Recycling of electronic waste is an important subject 2. E-Waste is a huge secondary resource (maine above ground) Shouh not wasted 3.The major economic driver for recycling of electronic waste is from the recovery of precious metals

  40. References J.Cui,E.Fotssberg,Mechanical recycling of waste electronic and electric equipment : a reveiew , j.Hazard .mater.99 (3) (2003) 243-263 EPCEU,:Directive 2002 / 96/EC of the European parliament and of the council of 27 January 2003 on waste electronic and electrical equipment (WEEE) ,off.j.Eur.Union (2003) 24-38 T. Maruyama, H. Matsushita, Y. Shimada, et al., Proteins and protein-rich biomass as environmentally friendly adsorbents selective for precious metal ions, Environ. Sci. Technol. 41 (4) (2007) 1359–1364, Feb 15 A.N. Mabbett, D. Sanyahumbi, P. Yong, et al., Biorecovered precious metals from industrial wastes: Single-step conversion of a mixed metal liquid waste to a bioinorganic catalyst with environmental application, Environ. Sci. Technol. 40 (3) (2006) 1015–1021, Feb 1 J. Shibata, S. Matsumoto, Development of Environmentally Friendly Leaching and Recovery Process of Gold and Silver from Wasted Electronic Parts, 2007-10-29, 2007 D. Morin, A. Lips, T. Pinches, et al., BioMinE – Integrated project for the development of biotechnology for metal-bearing materials in Europe, Hydrometallurgy 83 (1–4) (2006) 69–76.

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