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Recovery of Precious Metals from dISCARDED cellphones

ESCUELA POLITÉCNICA NACIONAL Quito - Ecuador. Faculty of Chemical Engineering and Agroindustry Department of Extractive Metallurgy. Recovery of Precious Metals from dISCARDED cellphones. E. de la Torre , S. Espinoza, A. Guevara. Pb Co Ni Cd Cr. ceramics. Au, Ag, Pd, Nb, Rh.

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Recovery of Precious Metals from dISCARDED cellphones

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  1. ESCUELA POLITÉCNICA NACIONAL Quito - Ecuador Faculty of Chemical Engineering and Agroindustry Department of Extractive Metallurgy Recovery of Precious Metals from dISCARDEDcellphones E. de la Torre , S. Espinoza, A. Guevara

  2. Pb • Co • Ni • Cd • Cr

  3. ceramics Au, Ag, Pd, Nb, Rh • Epoxy Resins • Glass fiber • Cu, Pb, Co, Ni, Fe, Cd, Cr • Flame Retardant PVC/PC/ABS

  4. Cyanidation • Low cost and effectiveness to dissolve noble metals. 4Au + 8(CN)- → 4Au(CN)2- • Au > Ag > Pd > Rh • [CN]-, dp, t • Cyanicide (Cu)

  5. Acid Leaching The elements from the group of Platinum (Pd, Rh) are soluble in mineral acids Pd + 2HNO3 → Pd(NO3)2 + 2H- Pd + H2SO4 → Pd(SO4) + 2H- With HNO3 andH2SO4 the dissolution is slow. Nd y Rh are dissolved with difficulty Presence of Cl- ion benefits the dissolution ofPd

  6. Samples Characterization 1000 ºC 1h Ta – 850ºC 3 h 0,72 atm 21% O2 960 ºC 1h 0,5 g 30 ml Aqua Regia

  7. Electronic Microscope MEB-EDX

  8. Chemical Characterization

  9. Size reduction Cyanidation • Preliminary • Treatments • Parameter Definition ([NaCN], t) • Roasting • Leaching NH3 / HNO3 • Size reduction AcidLeaching • Preliminary • Treatments • Parameter Definition (Concentration, t) • Roasting

  10. Size reduction, roasting and cyanidation 4x4 cm 1x1 cm 7x7 mm 5x5 mm 1000 m 136 m

  11. Influence of roasting and size reduction in the gold and silver cyanidation [NaCN] 2 g/L; solids 2,5-5%, time24 hours

  12. Influence of the concentration of cyanide in gold and silver recovery Roasted sample; d80 136 m; solids 2,5-5%, time 24 hours

  13. Influence of cyanidation time in the gold and silver recovery Roasted sample; d80 136 m; solids 2,5-5%, [NaCN] 4 g/L

  14. Preliminary treantments: Leaching NH3 / HNO3 14 % Solids 2 h 500 rpm

  15. Influence of pretreatments with NH3 and HNO3 Roasted sample d80 136 m; Pretreatment time 2h

  16. Acid Leaching

  17. Kinetics of paladium leaching Roasted sample; d80 136 m; solids 2,5-5%, [acid] 50 g/L

  18. Effects of chloride ions in the leaching of paladium with sulfuric acid Roasted sample; d80 136 m

  19. DiscardedCellphones Cases, keyboards, Screens Dismantling Printedcircuitboard Gases toatmosphere Scrubber Gases Roasting Milling Leachinf NH3 Ammonialiquor Filtering Cyanidation ChargedCarbon Cyanideliquor CIP Filering Elution Leaching HNO3 Electrowinning Electrowinning Acidliquor Filtering Au, Ag SolidWaste Ag, Pd

  20. Conclusions • It is factible to recover 85% Au , 80% Ag, 80% Pd y 80% Cu byinstalling a treatment plant of 195 kg/month for the printed circuit boards of discarted cellphones • Nb y Rh couldn`t be recovered

  21. Economic criteria

  22. ESCUELA POLITÉCNICA NACIONAL Quito - Ecuador Faculty of Chemical Engineering and Agroindustry Department of Extractive Metallurgy Recovery of Precious Metals from descarted cellphones E. de la Torre , S. Espinosa, A. Guevara

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