"Joint recovery of lithium metal oxides and graphite particles from spent lithium-ion batteries using froth flotation" talk at Advanced Automotive Battery Conference AABC2022 conference in Mainz (Germany)

Abstract

Recycling symposium

This talk presents how we can separate the fine active particles (lithium metal oxides and graphite) from the black mass by using froth flotation.
This research demonstrates that graphite can be recovered from spent lithium ion batteries and recycled into new anodes

Full text

Anna Vanderbruggen, Kai Bachmann, Mayokun Olutogun, Dominic Bresser, Martin Rudolph, Rodrigo Serna
Joint recovery of lithium metal oxides and graphite particles from
spent lithium-ion batteries using froth flotation

AABC 2022 Anna Vanderbruggen2
Motivations
Spent lithium ion batteries –A complex secondary material
Vanderbruggen et al., 2021

AABC 2022 Anna Vanderbruggen3
Motivations
Spent lithium ion batteries –A complex secondary material
Why recycle Graphite?
Critical Raw Material
Monopole anode supply
New EU Battery
regulation: 70 wt.% by
2030
Anode Graphite
represents 15-19 wt.%
Vanderbruggen et al., 2021

Motivations
4
Spent lithium ion batteries –A complex secondary material
Schematic of a binder coating
the active particles
Binder
•Ensure electrical contact
•Counter volumetric changes
•Coat and bond active
particles
•Ensure adhesion to foils
Recycling challenging!
Ex: Polyvinylidene Fluoride (PVDF)
Styrene-Butadiene Rubber (SBR)
Carboxymethyl Cellulose (CMC)
SEM image with imposed colours
cathode electrode with LCO ad PVDF
AABC 2022 Anna Vanderbruggen

5
Active particles liberation
Objective
Left: SEM images of non-liberated Al foil from cathode active material
Right: Electrode foil liberation
Active
particles
Foil
Liberation
Evaluate the influence of pre-treatment recycling
processes on electrode liberation
AABC 2022 Anna Vanderbruggen

Automated mineralogy
6
Particle based analysis
Particle based characterization:
•Elemental and phase composition
(Volume or mass fraction)
•Particles size and shape
•Phase association
•Liberation degree
Process efficiency evaluation
Phases grouping according to LIB
components
AABC 2022 Anna Vanderbruggen

Material and methods
7
Black mass production: mechanical and thermo mechanical routes
Cylindrical batteries Pyrolyzed batteries Crushed batteries
> 1 mm Crushed batteries
< 63 µm
AABC 2022 Anna Vanderbruggen

Material and methods
8
Froth flotation: joint recovery of active particles
AABC 2022 Anna Vanderbruggen
Froth flotation:
separation technique based on
physico-chemistry surface properties
Liberated particles
+
Surface wettability difference Froth flotation diagram (Kupka, 2020)
SEM image with imposed colors:
blue for heavy elements (cathode active particles)
and black for light elements (graphite)

9
Characterization results
LIB components distribution with automated mineralogy
0%
25%
50%
75%
100%
<63 µm
(21.9 wt.%)
63-125 µm
(5.3 wt.%)
125-500 µm
(19.8 wt.%)
500-1000 µm
(4.4 wt.%)
Lithium metal oxides Carbon materials Al foils Cu foils Casing Others
0%
25%
50%
75%
100%
<63 µm
(5.1 wt.%)
63-125 µm
(5.2 wt.%)
125-500 µm
(22.6 wt.%)
500-1000 µm
(3.4 wt.%)
Lithium metal oxides Carbon materials Al foils Cu foils Casing Others
0
25
50
75
100
Mechanical pre-treatment Thermo-mechanical pre-
treatment
Mass composition
(wt.%)
Mechanical Black mass Thermo-mechanical Black mass
350µm
50 µm 350µm
50 µm
Processed images by automated mineralogy
AABC 2022 Anna Vanderbruggen

Flotation results: pre-treatment influence
10
63.2 66.6
94.4 89.4
0
25
50
75
100
Graphite recovery in overflow product LMOs recovery in underflow product
Mechanical process Thermo-mechanical process
AABC 2022 Anna Vanderbruggen
Thermo-mechanical black mass presents the
best flotation selectivity
binder removal
SEM images in false color of flotation products.
Rougher flotation of
pyrolyzed industrial black mass
Feed
Graphite product
Metals product

Graphite product purification
11 AABC 2022 Anna Vanderbruggen
85% C
+ 99.5% C
Construction of EcoGraf HFfree™ Facility in Australia
for Battery Anode Material (https://www.ecograf.com.au/)
For more information please contact:
Andrew Spinks aspinks@ecograf.com.au
Purification process
to remove fine impurities
(Patent pending: AU2020901589A0)

Recycled graphite performance
12 AABC 2022 Anna Vanderbruggen
Recycled graphite very
comparable performance to
pristine graphite
Recycled graphite would diversify
the raw material supply chain in
Europe
010 20 30 40 50
0
100
200
300
400
500
600
700
Delithiation
Lithiation
Specific Capacity / mAh g-1
Cycle Number
Graphite 2
Graphite 3
Graphite 4
Recycled Graphite
Graphite 1
1CC/2
C/5
1C = 350 mA g-1
20
30
40
50
60
70
80
90
100
Coulombic Efficiency / %
Comparison recycled graphite with pristine graphite
(Graphite 1 –SLP30, Graphite 2- Actilition,
Graphite 3 –SFG 15L, Graphite 4 –Showa Denko)
For more information please contact:
Dominic Bresser dominic.bresser@kit.edu

Summary and Outlook
13 AABC 2022 Anna Vanderbruggen
If you want to read more about black mass characterization
or black mass flotation, have a look here:
Difference of wettability needed for froth flotation:
highest efficiency with thermo mechanical
black mass due to binder removal and full graphite
liberation
Join recovery of the active particles by using
froth flotation
•Graphite with 85% C and a recovery higher than 90%
•Lithium metal oxides product with less than 5% C
Increase the efficiency of the following
hydrometallurgy process
2 valuable products instead of 1 !

Thank you for
your attention!
a.vanderbruggen@hzdr.de