Page 40 from: Recycling Technology 2020

40
2020

Technolab

R
ecycling innovations are typically based
on cutting-edge patented processes. But
new research at Michigan Technologi-

cal University (MTU) in the US suggests that
a technology that has been long used in the
mining industry to separate metal from ore
holds the key to the future of battery recyclers.

Cheaper method
The scientists used standard gravity sepa-

rations to separate copper from aluminium,
and froth flotation to recover critical materi-
als, including graphite, lithium, and cobalt.
MTU assistant professor and chemical engi-
neer Lei Pan says this approach is the cheapest
one and does not require new infrastructure.

‘In this study, froth flotation experiments
were carried out with a variety of new and
spent lithium-ion batteries using kerosene as
the collector. The products were characterised
using thermo-gravimetric and chemical anal-
ysis,’ explains Pan, who oversaw the research.

It was found that over 90% of anode materials
were floated in froth layers, while 10–30% of
cathode materials were floated.

High purity obtained
Separating mixed electrode materials us-

ing a modified procedure was evaluated. Re-
sults showed that the froth flotation process
using kerosene as the collector produced a
residual product with cathode materials of
higher purity than those obtained without
kerosene.

‘For spent lithium-ion batteries, a low pu-
rity of cathode materials in tailings might be
improved by fine grinding, at which freshly
liberated hydrophobic surfaces are exposed
and consequently anode materials become
floatable,’ the researchers conclude.

The result confirms that the froth flotation
technique is a viable and versatile technique
for producing ‘high purity’ cathode materials
from lithium-ion batteries.

Future impact
Pan is pleased the cutting-edge research

has recently been published in the journal
Sustainable Materials and Technologies and
the project has received a US$ 15 000 [EUR
13 000] grant from the US Environmental
Protection Agency.

Considering the steady growth in battery-
powered products, the MTU scientists hope
their work may prove helpful. Indeed, new
data by Grand View Research states that the
global lithium-ion battery market will reach
US$ 93.1 billion by 2025. This represents a
compound annual growth rate during the
2018-2025 period of no less than 17%.

A major driver is, of course, strong perfor-
mance in the automotive sector. In the next
four years, the demand for lithium needed
for the production of lithium-ion batteries
for use in electric cars is expected to more
than double from the 26.7kt used in 2018 to
58.3kt in 2022.

For more information, contact Lei Pan at:
[email protected]

Author:
Kirstin Linnenkoper

HigHLigHts

Research:
battery recycling

Pioneer:
Michigan Technological University

Led by:
Lei Pan

Ore mining the answer for
battery recyclers?
Recycling lithium-ion batteries is possible but the practice has yet to be
perfected. What’s missing is a low-energy and low-cost separation system that
selectively recovers electrode materials. The solution, according to Michigan
Technological University, is a mining technique that is more than a century old.

40_technolab-lithium.indd 40 12-09-19 14:22