Automotive Engineering - May 2022 - BET10

Recycling Batteries
Cobalt Concentrate
Cobalt Sulfate
Impurities
Al, Fe, Zn, Mn
Clean Energy
+ e-
Ni2+Mn2+
O2
OHFe3+
Fe2+
Cu0
Lithium-Ion
Battery
Black Mass
Cu2+
Co2+
Li+
Ni/Co
separation
SX or IX
The electrochemical boost to the
leaching process is an important component
in achieving the goal of a greener
Li-ion batteries recycling solution.
" Electrochemistry is the transformation
Leachate
Electroplated
copper
Graphite/
Carbon
Nickel Concentrate
Lithium carbonate
Nickel Sulfate
of electrical energy into chemical bonds
or chemical bonds into electrical energy, "
said Luis Diaz-Aldana, an INL electrochemical
scientist and team member.
" The vision that we had is that we can
use this electricity as a green reagent. So
that it can substitute for a significant
amount of chemicals. "
He added that the electricity could
Li-ion battery black mass is fed to the EC-Leach system producing a leachate solution containing
critical metals, which are separated downstream to produce cobalt, nickel, and lithium
products for use in new batteries. Biproducts such as copper and graphite can be reused.
ium, " said Tedd Lister, an INL staff scientist.
He is also a member of a research
team that developed a new Li-ion battery
material recycling technology that is
more efficient and environmentally
friendly than current methods.
Tighter Recycling Loop
Battery recycling is vital because one
solution to the looming supply issue would
be a closed-loop setup, with batteries processed
at end-of-life to recover cobalt,
lithium, and other critical materials that
can then be used to make new batteries.
Significant recycling already takes place.
In 2018, 20 companies worldwide recycled
just under 100,000 metric tons of Li-ion
batteries, about half of the global volume
of batteries disposed that year. Recovering
materials can involve direct recycling, pyrometallurgy,
and/or hydrometallurgy.
Direct recycling attempts to employ a
tighter recycling loop and retain more manufacturing
value. A major target is the rejuvenation
of the cathode material, so that it
can be directly reused in a battery of the
same type. In practice, however, because
battery formulations change rapidly and Liion
batteries are designed to last a decade
or longer, the value of this approach is limited.
Another challenge is the need to segregate
collected batteries by manufacturer
and production time, since every manufacturer
uses unique cathode material.
Pyrometallurgical processes can accept
different kinds of batteries, using high
temperatures (above 700 °C) in a furnace
to smelt the battery
10
into an alloy.
Hydrometallurgical refining using acids
and other chemicals then separates and
recovers cobalt, nickel, and copper from the
alloy, while the lithium is extracted from
the waste slag. Because of the temperatures
required, the recycling process can
have a significant carbon footprint if fossil
fuels provide the energy for the smelting.
One way to reduce the greenhouse gas
emissions from Li-ion battery recycling is
to use hydrometallurgy alone to leach
out materials. Often this involves use of
sulfuric acid and hydrogen peroxide because
the combination is very effective;
reported yields for the target metals are
over 90 percent when the leaching is
conducted at temperatures above 40 °C.
Making the chemicals, though, has significant
negative environmental impacts
and presents safety risks, as does transporting
and storing them.
An Electrochemical Boost
As described in the peer-reviewed scientific
journal, Resources, Conservation and
Recycling, an INL team investigated a different
approach employing an electrically
driven hydrometallurgical process. INL researchers
developed an electrochemical-assisted
leaching method that continuously
regenerates Fe2+ in small concentrations.
The Fe2+ reacts with the Li-ion battery cathode
metals to promote their extraction into
the aqueous phase. The team achieved near
complete metal leaching from Li-ion battery
" black mass, " material recovered from shredded
Li-ion batteries that contains the active
battery components.
come from a carbon-free source, such as
a solar panel array, a wind farm, a hydroelectric
dam, or a nuclear power plant.
This would reduce total emissions associated
with the new recycling process as
compared to competing processes to an
even greater degree.
The process has been scaled from the
initial proof-of-principle demonstration
to a system that can process over 0.5 kg/
day. From an industrial battery recycler,
the team obtained metal oxide black
mass composed of the anode and cathode
powder recovered from a mixture of different
Li-ion batteries.
The black mass contained lithium, cobalt,
manganese, nickel, and aluminum in
observed formulations, such as LiCoO2
LiMnxCoy
O2
LiNixCox
, LiNixMnyCoz
AlzO2
O2
, LiCuX
MnO2
. Along with these lithium-containing
materials, more than 30
percent of the weight in the black mass
was nonmetallic, including graphite from
the anode and elsewhere, carbon material
and polymeric bits of battery separators.
,
, and
Nickel and cobalt salts isolated from Li-ion
batteries.
Battery & Electrification Technology, May 2022
Crystallization

Automotive Engineering - May 2022

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