SLIDE 1
Design of a Hydrometallurgical Treatment System for Aluminium Waste
Thomas J. Robshaw, Keith Bonser, Glyn Coxhill, Dr Robert Dawson & Dr Mark D. Ogden
1
The SNUCER Group
Dr Mark D. Ogden
2
SHEFFIELD
Design of a Hydrometallurgical Treatment System for Aluminium Waste - - PowerPoint PPT Presentation
Design of a Hydrometallurgical Treatment System for Aluminium Waste - - PowerPoint PPT Presentation
Design of a Hydrometallurgical Treatment System for Aluminium Waste Thomas J. Robshaw, Keith Bonser, Glyn Coxhill, Dr Robert Dawson & Dr Mark D. Ogden 1 The SNUCER Group SHEFFIELD Dr Mark D. Ogden 2 Ion-Exchange: What We Do Polymer R -
SLIDE 2
SLIDE 3
Ion-Exchange: What We Do
R- A+ B+ R- B+ A+
Polymer matrix
R+X- Y- R+Y- X- Cation-exchange Anion-exchange
Gold refining Pharmaceutical purification Juice processing Water softening Metal separation Sugar decolourisation
3
SLIDE 4
Hall-Héroult electrolytic cell For aluminium production
REDOX reactions: 2Al2O3 + 3C 4Al + 3CO2 Al2O3 + 3C 2Al + 3CO
Spent Potlining (SPL)
4
Al2O3, Na3AlF6, AlF3
SLIDE 5
~50% carbon ≤10% fluoride ≤1% cyanide
1st-cut 2nd-cut Graphite-based Cement-based TOXIC EXPLOSIVE ENORMOUS SAFE STORAGE CHALLENGE
Characteristics of SPL
5
SLIDE 6
Fluorspar (CaF2) Global reserves: 310 MT “CRITICAL MINERAL”
2nd-cut
Graphite Global reserves: 800 MT
Graphite and Fluorspar
6
50 100 150 200 250 300 350 400 450 Euro tonne-1
SLIDE 7
Hydrometallurgical SPL Treatment
Proposed new system for maximum fluoride recovery
7 Grinding and screening
Caustic leach Solid/liquid separation Acid leach Leachate mixing Solid/liquid separation
Inert carbon/cement product
Solid/liquid separation
Ion-exchange circuit
NaOH Mixed-cut SPL H2SO4
Input Process Output Solid waste-stream Liquid waste-stream
SLIDE 8
SPL Characterisation and Leaching
10 20 30 40 50 60 70 80 50 100 150 200 250 300 350
PXRD spectra
10 20 30 40 50 60 70 80 1000 2000 3000 4000
Intensity (a.u.) 2 theta
Sample A Sample B
NaOH (1M) / H2O2 (3%), 3 hrs H2SO4 (0.5M), 2 hrs Combine leachates
F-
NO3
- Fe
Al Ca Si
500 1000 1500 2000 C o n c e n tra tio n in le a c h a te (m g L -1 )
0.5 M Na 0.25 M SO4
2-
pH ~3
10 30 50 70 500 1000 1500 2000 2500 10 30 50 70 5000 10000 15000 Sample A Sample B
Intensity (a.u.) 2 theta
SLIDE 9
La-MTS9501 Resin
citrate > sulfate > oxalate > iodide > nitrate > cromate > bromide > thiocyanide > chloride > formate > acetate >
fmuoride
F F
- M. Kanesato et al., Chem. Letters, 1988, 207.
9
Puromet MTS9501
Bead diameter = 300 µm
SLIDE 10
*Full coordinate spheres not shown for clarity
Change of recovery strategy (Na3AlF6) ?
Uptake Mechanisms
T.J. Robshaw et al., Chem. Eng. J., 2019, 367, 149.
F F F F O F H H
+
F O H H
2+
O H H
Al Al Al
CaF2 €370 per Tonne Na3AlF6 €750 per Tonne
SLIDE 11
Proposed Ion-Exchange Circuit
SPL leachate streams Carousel Lead column Breakthrough column Fluoride
- loaded
column Pump
NaOH(aq)
Fluoride- selective electrode Pump pH electrode Pump pH adjust
Na3AlF6(aq)
Defluoridated leachate To precipitation stage Fluoride- selective electrode
11
T.J. Robshaw et al., J.
- Hazard. Mater., 2019, 361,
200. La- MTS9501 La- MTS9501 La- MTS9501
SLIDE 12
100 150 200 250 300 350 400 450 500 0,5 1 1,5
Experimental Dose-Response model Effluent volume (mL)
Breakthrough (a.u.) 20 30 40 50 60 70 80 90 100 110 120 0,2 0,4 0,6 0,8 1 1,2 Breakthrough (a.u.) 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500
Effluent volume (mL) Fluoride effluent concentration (mg L-1)
q0 = 37 mg g-1
SPL leachate
Pump
Fluoride- selective electrode
12
Dynamic Resin Performance
SLIDE 13
Contaminants
Recovery
100 200 300 400 500 600 700 200 400 600 800 1000 1200 1400 1600 1800 Fluoride Aluminium mL eluent
- Conc. in eluent (mg L-1)
Elution with water 1M NaOH
€ € € € € € € € €
13
SLIDE 14
Conclusions
La-MTS9501 resin is highly suitable for purpose Al in SPL leachate produces synergistic uptake mechanism Recovery of synthetic cryolite may be possible
14
SLIDE 15
Acknowledgements
Dr Mark Ogden & the SNUCER group Dr Robert Dawson & research group Polymer Centre CDT Engineering & Physical Sciences Research Council Bawtry Carbon International Trimet Aluminium Royal Society of Chemistry (Environment Sustainability & Energy Division) You for listening
15
See poster 123 for more fluoride work! Tjrobshaw1@Sheffield.ac.uk
SLIDE 16
Supporting Information
16
Al Metal Productio n
SLIDE 17
Pyrometallurgical SPL Treatment
D.G. Brooks et al., Light Metals, 1992, 283-287.
✦ Produces 2.5 T waste per T SPL processed ✦ In operation today
17
SLIDE 18
Proposed Leaching Treatment
Caustic leachate T
- IX
circui t
Solid/liquid separation
Na3AlF6 and Al2O3 solublised
Solid/liquid separation
CaF2 and NaAl4O17 solublised Purifjed graphite Leachate mixing?
Slurry Impello r
CN- destruction
H2O2 NaOH(aq)
Ground & screened SPL
HNO3(aq)
Acidic leachate
18
SLIDE 19
Cryolite Precipitation
PXRD spectrum of cryolite precipitated from leachate before IX treatment
19
10 20 30 40 50 60 70 80 100 200 300 400 500 600 700 800 900 1000 10 20 30 40 50 60 70 80 100 200 300 400 500 600 700 2 theta Intensity (a.u.)
Literature spectrum for comparison
SLIDE 20
XPS Analysis of Resin Beads
La environments Al environments O environments
65 67 69 71 73 75 77 79 81 83 85 100 200 300 400 500 Binding energy (eV) Counts (s-1) 522 527 532 537 542 1000 2000 3000 4000 5000 6000 7000 Binding energy (eV) Counts (s-1) 820 830 840 850 860 870 1800 2000 2200 2400 2600 2800 3000 Binding energy (eV) Counts (s-1) 522 527 532 537 542 1500 2000 2500 3000 3500 4000 4500 5000 Counts (s-1) 820 830 840 850 860 870 2000 2500 3000 3500 4000 4500 5000 Counts (s-1)
(none)
NaF solution Leachate
- C. Stosiek et al., Chem. Mater., 2010, 22, 2347.
- S. Selvasekarapandian et al., Physica B., 2003, 337, 52.
Aluminium hydroxyfluoride (AHF) 20
SLIDE 21
Resin Regeneration Study
Equilibrium fluoride uptake of La-MTS9501 over 5 adsorption/desorption cycles
21
10 20 30 40 50 60 70 qe (mg g-1)