Chemical Engineering May 2022 - 5

Chementator
Applying capacitive deionization for
critical-metals recovery
R
esearchers at Argonne National
Laboratory (Lemont, Ill.; www.
anl.gov) are investigating an electrochemical
separation process
known as capacitive deionization (CDI;
diagram) to extract and recover ions from
liquid streams in wide-ranging applications,
including battery recycling and biomanufacturing.
CDI holds several advantages
over traditional separations techniques,
such as distillation and liquid-liquid extraction,
because it requires no chemical solvents
or phase change. It is currently used
in large-scale desalination processes, but
it also shows promise in product and resource-recovery
applications.
Following dismantling, various components
from end-of-life batteries are usually
present in a complex, multicomponent liquid
mixture, where it can be difficult to efficiently
separate critical metals, such as lithium
and cobalt, using traditional methods.
" CDI gives the ability to target and remove
a minority component in a single step. By
applying functionalized materials and finetuning
operational parameters, such as cell
voltage, flowrates and the time voltage is
applied, we can control ionic separation, "
explains Lauren Valentino, an environmental
engineer at Argonne. CDI cells employ
specialized sorbent materials as their electrodes,
which can be chemically functionalized
to interact with specific ions of interest.
" We are looking for materials that have very
Reduced fouling when
pneumatically conveying lactose products
T
o ensure product safety and quality,
products containing lactose (at
dairy plants, for example) are processed
under hygienic conditions.
These strict hygiene conditions require frequent
cleaning of pneumatic transport systems
- typically every eight weeks. This
procedure is both labor-intensive and timeconsuming,
because various components
of the conveyor system must be dismantled
for cleaning with hot water, and then
dried before reassembly to prevent bacterial
growth. The entire cleaning process can
take several days.
To reduce this effort, Dinnissen Process
Technology BV (Sevenum, the Netherlands;
www.dinnissen.nl) introduced its new, patented
Aeolus pneumatic lactose transport
system, which it developed in cooperation
with FrieslandCampina (Amersfoort, the
Netherlands; www.frieslandcampina.com) -
one of the world's largest dairy companies.
In this conveying system, no coatings
are used. Instead, the design of the various
components, such as curves and switches,
has been optimized. Friction, turbulence
and wear are minimized by the shape and
construction of bends and corners. Because
materials scour less around corners,
fouling is prevented, says Dinnissen. As a
result, production has to be stopped up
to 12 times less often for cleaning, which
can lead to 8-12% more production days
per year, the company says. The savings
on labor costs are said to be " enormous. "
Product quality is also said to be improved,
because there is no more accumulation of
lactose, and the orifice diameter of the piping
remains open during transport.
The Aeolus transport concept is also
suitable for conveying other (lactose-free)
substances that may be prone to fouling.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM MAY 2022
Argonne
Edited by:
Gerald Ondrey
high surface areas with many sites for adsorption.
Our goal is to add specific chemical
functionality to the material surface that
invokes some selective interaction between
the material and the component we are trying
to extract, " adds Valentino.
For battery recycling, the CDI cells incorporate
patented high-capacity sorbents
developed by NuMix Materials,
Inc. (Chicago, Ill.; www.numixmaterials.
com) to adsorb critical metals. Currently,
Argonne operates a laboratory-scale cell,
which, if operated continuously, has an
operating capacity of around 10 L/d. For
scaling up the technology, the team will
continue to fine-tune the operating parameters,
as well as investigate methods
to separate the deionized and ion-rich
streams in the cell.
NITROGEN UTILIZATION
Late March, the first nitrogen
fertilizer produced from a
wastewater-treatment plant
sidestream was delivered to a
farm in Sweden. The fertilizer
was produced at a pilot plant
that began operation last December
at Ragn-Sells Högbytorp's
(www.ragensells.se)
wastewater-treatment and
recycling facility in UpplandsBo,
near Stockholm, Sweden.
The pilot plant is part of
the E.U.'s LIFE RE-Fertilizer
project, which includes partner
companies EasyMining
AB (Uppsala, Sweden; www.
easymining.se), Biofos (Copenhagen,
Denmark; biofos.
dk), Lantmännen (Stockholm,
Sweden; www.lantmannen.
com) and Sagn-Sells.
The pilot plant features two
mobile units and has a capacity
to process 4 m3/h of
water. It is the first industrialscale
demonstration of a patented
process, developed
by EasyMining, that recovers
resources from wastewater
with high concentrations of
ammonium nitrogen.
According to project manager
Anna Lundbom, head
of marketing at EasyMining,
the currently used biological-based
processes just
release the nitrogen into the
atmosphere after removing
it. Instead, the process applied
by the nitrogen pilot
plant captures it for use in, for
example, fertilizers, she said.
The new process also would
replace conventional denitrification
methods that produce
emissions of nitrous oxide, a
powerful greenhouse gas.
After completing tests last
month, the pilot plant was
moved to Denmark, where
it will operate on reject water
from the sewage-sludge
dewatering stage of Biofos'
Lynetten wastewater-treatment
facility.
MINING WASTEWATER
In a related project, several
pilot plants were deployed
at BBEU (Bio Base Europe
Pilot Plant; www.bbeu.org)
(Continues on p. 6)
5
http://www.anl.gov http://www.anl.gov http://www.ragnsells.se http://www.easymining.se http://www.easymining.se http://www.lantmannen.com http://www.lantmannen.com http://www.numixmaterials.com http://www.numixmaterials.com http://www.dinnissen.nl http://www.bbeu.org http://www.frieslandcampina.com http://WWW.CHEMENGONLINE.COM
Chemical Engineering May 2022

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