Metal Recovery and Recycling by Urban Mining

Prof. Jason LoveEaStCHEM School of Chemistry,

University of Edinburgh

Consumer

Re-use/

repair

recycledesign

manufacture

Urban mining

Secondary sources and resource recovery

Jones et al., J. Clean. Prod., 2013, 55, 45–55. “Enhanced landfill mining in view of multiple resource recovery: a critical review”

Technological requirement• Processing urban mine (WEEE) materials with high metal content• Processing landfill/tailings/legacy materials with low metal content

1 tonne rock

1-5 g gold

1 tonne WEEE, e.g. smartphones

300 g gold

The case for urban mining

• EU-28 12% increase in WEEE 2013-20(note: 98 and 145% in China and India)

• For Cu and Al 85-95% energy saving compared to mining and refining

• 12% of gold consumed by electronics industry

• Gold is the most valuable component of WEEE

• 40% of WEEE in uncontrolled landfill

• WEEE waste sites 100x more contaminated by heavy metals

Focus on Waste Electronic and Electrical Equipment (WEEE)

Hydrometallurgy – energy and resource efficiency

LeachSeparation &

Concentration ReductionMetal ore or other source

Pure Metal

Pregnant Leach Solution

Single Metal Solution

Chemical understanding of metal recovery processes

The Metal Recovery Group @ Edinburgh University

Jason B. Love Professor of Molecular Inorganic ChemistryEmail: jason.love@ed.ac.ukhttps://jasonlovegroup.wordpress.com

Carole A. Morrison Reader in Computational ChemistryEmail: carole.morrison@ed.ac.uk

We aim to:• Understand the chemistry that underpins metal recovery from primary and secondary sources• Identify molecular level solution structure using experiments, spectroscopy, and computation• Develop new reagents for metal recovery by solvent extraction

Solvent extraction

Solution chemistry

For a brief overview see page 154: http://www.paneuropeannetworkspublications.com/GOV20/files/assets/basic-html/page-1.html

Chemical recognition of metals

Chemical knowledge underpins our understanding of metal recovery processese.g. different solution structures are seen depending upon metals, leachate, extractant, and solvents

Chem. Soc. Rev., 2014, 43, 123Cu+

aqueous organic organic

metalate

receptor

−

+

Ion Pairs

metalate

−H2O

H2O

H2O

H2OH2O

H2OH+

receptors

Reverse Micelles

metalcation

L

L L

LLL

Complexes Synergists

metalcation

L

L L

LLL

X

X

X

Cu Cu

2 M hydrochloric acid (HCl)2.37 M copper; 0.61 M iron; 0.57 M aluminium; 0.28 M tin; 0.24 M nickel; 0.11 M zinc; 0.012 M gold

Cu

Fe

Al

SnNi

Zn Au

Leach Extract

Urban mining a smartphone

• Very high metal content: 38% ferrous, 16% non-ferrous• Need highly selective recognition for single metals: 60 elements in a smartphone

0.0

0.5

1.0

1.5

2.0

2.5

Cu Al Zn Ni Fe Sn Au

Meta

l co

ncen

trati

on

/ m

ol

L-1

Metal

Angew. Chem. Int. Ed., 2016

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Sn Au

0.0000

0.0005

0.0010

0.0015

0.0020

Au

Stock NeatMIBK

Neat DBC

Neat 2-EH

0.1 M 1O

Amide

• Other metals in large excess compared with [Au]

• 1o amide gets Au, and a lot less Fe/Sn

MIBK DBC

2-EH

1o Amide

We have discovered a simple amide for the selective recovery of gold from waste electronics

Gold recovery from WEEE

Gold recognition by protonated amide receptor

We have used slope analysis, EXAFS, mass spectrometry, and DFT/MD calculations to identify the mechanism of gold recovery by solvent extraction

Low energy processes to high value products

Au Ag Pt Ir

Bio-leachingHeap leaching

Precious resource

Engineeringsolutions

Chemistrysolutions

Solvent extractionselectivity

stability

speed

safety

synthesis

solubility

system

separation

strength

We believe that chemists, in collaboration with biologists, engineers, and industry can generate more economically and environmentally efficient metal recovery processes

Prof. Michael P. ShaverPolymer synthesisLigand and catalyst design ROP/radical polymerizationUoE Director SOFI

Dr Caroline KirkMaterials chemistryEnergy and environmentFormation of natural materials

1. Recycling of valuable and toxic metals

3. Recycling of plastics• Depolymerisation and regrowth of aromatic and aliphatic polyesters• Challenges: Selectivity; plastic separation; transition of technology

2. New materials from waste materials

• Sustainable cement, waste materials embedded in cement mixes• Challenges: Impact of waste fillers on product; material consistency

Technological solutions for recycling from the urban mine

• Metal recycling from waste electronic and electrical equipment (WEEE)

• Challenges: Leaching; selective separations; economy of scale

Dr Carole. A. Morrison

Prof. Jason B. Love

1. Waste electronic and electrical equipment is a valuable resource

2. Chemistry is integral to metal recovery

3. Dynamic assembly can generate complexity from simple inputs

4. Collaboration between chemists, engineers, economists, and industry is essential

Euan Doidge | Innis Carson | Carole Morrison | Peter Tasker | Ross Ellis | Jamie Hunter

Thanks

Solventextraction

WEEE20 sources

Gold

Conclusions

Further Reading

E. D. Doidge, I. Carson, J. B. Love, C. A. Morrison, P. A. Tasker, “The influence of the Hofmeister bias and the stability and speciation of chloridolanthanates on their extraction from chloride media,” Solvent Extraction Ion Exchange, 2016, 34, 579-593

M. R. Healy, J. W. Roebuck, E. D. Doidge, L. C. Emeleus, P. J. Bailey, J. Campbell, A. J. Fischmann, J. B. Love, C. A. Morrison, T. Sassi, D. J. White, P. A Tasker, “Contributions of inner and outer coordination sphere bonding in determining the strength of substituted phenolic pyrazoles as copper extractants,” Dalton Trans., 2016, 45, 3055-3062

I. Carson, K. J. MacRuary, E. Doidge, R. J. Ellis, R. A. Grant, R. J. Gordon, J. B. Love, C. A. Morrison, G. S. Nichol, P. A. Tasker, A. M. Wilson, “Anion receptor design: exploiting outer-sphere coordination chemistry to obtain high selectivity for chloridometalates over chloride,” Inorg. Chem., 2015, 54, 8685–8692

M. R. Healy, E. Carter, I. A. Fallis, R. S. Forgan, R. J. Gordon, E. Kamenetzky, J. B. Love, C. A. Morrison, D. M. Murphy, P. A. Tasker, “EPR/ENDOR and computational study of outer-sphere interactions in copper complexes of phenolic oximes,” Inorg. Chem., 2015, 54, 8465–8473

J. R. Turkington, P. J. Bailey, J. B. Love, A. M. Wilson, P. A. Tasker, “Exploiting outer-sphere interactions to enhance metal recovery by metal extraction.” Chem. Commun., 2013, 49, 1891-1899.