1. PORTLAND
CEMENT
REPLACEMENT
AND
CO2
SEQUESTRATION
THROUGH
CARBONATION
OF
MECHANICALLY-­‐ACTIVATED
WOLLASTONITE
Nancy
Fujikado,
Chemical
Engineering
Mentor:
Hamdallah
Bearat,
Senior
Research
Scien?st
School
for
Engineering
of
MaAer,
Transport
&
Energy
The
purpose
of
finding
a
Portland
cement
replacement
is
to
decrease
the
levels
of
CO2
emissions
in
our
atmosphere,
while;
crea?ng
a
more
sustainable
form
of
cement
that
can
withstand
environmental
obstacles.
In
this
case,
the
mineral
wollastonite
(CaSiCO3)
is
the
key
ingredient
u?lized
to
obtain
the
perfect
recipe.
The
first
step
involves
mechanically
ac?va?ng
the
wollastonite
and
achieving
an
ideal
amorphous
structure.
Mechanically-­‐ac?va?ng
CaSiCO3
prior
to
carbona?on
favors
the
forma?on
of
calcite.
Following
is
the
carbona?on
of
these
samples.
By
evalua?ng
these
final
samples,
we
can
designate
which
samples
will
bear
the
condi?ons
we
predict
will
encompass
it.
AUerwards,
through
XRD
analysis
we
can
determine
which
is
more
suitable
and
applicable
as
a
concrete
subs?tute.
Abstract
Expected
Results/
Future
Research
Process
&
Methods
Why
Concrete?
In
2009
the
United
States
was
the
second
greatest
producer
of
atmospheric
CO2
,
having
produced
1,445,204
thousand
metric
tons
of
atmospheric
carbon
alone.
The
release
of
this
gas
into
the
atmosphere
is
the
result
of
fossil-­‐fuel
burning,
cement
produc?on,
and
gas
flaring
Purpose
Scien?sts
and
engineers
have
been
working
together
in
proposing
and
tes?ng
ways
of
sequestra?ng
CO2
from
our
atmosphere
by
means
of
mineral
carbona?on.
This
method
of
sequestra?on
provides
an
advantage
to
other
means
of
sequestra?on
because
the
final
products
are
geologically
stable
and
harmless
to
humans
and
the
environment
Step
1:
Mechanically
ac?vate
wollastonite
in
ball
mill
Mimicking
Nature
Step
2:
Analyze
samples
for
amorphicity
and
possible
contamina?on
by
means
of
XRF
and
SEM
analyses
Figure
1:
X-­‐ray
powder
diffrac/on
pa1erns
of
feedstock
and
mechanically-­‐ac/vated
NYCO
wollastonite
materials.
CondiCons
for
wollastonite
carbonaCon:
• Room
Temperature;
21.5
°C
• Low
CO2
pressure;
913
psi
• Deionized
water
Step
3:
React
wollastonite
with
CO2
By
characterizing
the
final
products
of
CaSiO3
carbona?on,
we
can
determine
which
is
more
suitable
and
applicable
as
a
concrete
subs?tute.
XRD
(x-­‐ray
powder
diffrac?on)
and
SEM
analyses
will
both
play
major
roles
in
discerning
the
extent
of
carbona?on
taking
place,
characteris?cs
and
disposi?on
of
newly
formed
products,
and
the
microstructure
of
the
final
product.
Addi?onal
research,
via
mechanical
tes?ng,
will
help
determine
if
the
product
can
func?on
as
a
sustainable
Portland
cement
subs?tute.
Cement
produc?on
has
contributed
a
large
percentage
of
CO2
emissions
all
across
the
world,
primarily
the
United
States.
In
contrast,
the
Portland
cement
"green"
subs?tute
would
sequestrate
CO2
from
our
atmosphere
and
u?lize
it
in
its
produc?on
process.
However
presence
of
undesired
products
can
impede
the
ability
of
carbonated
CaSiO3
as
subs?tute
for
cement.
Further
tests
and
analysis
must
ensue
in
order
to
acquire
ideal
standards
for
a
concrete
replacement.
Plants
and
Ocean
• A
carbon
sink
is
anything
that
removes
carbon
dioxide
(CO2)
from
the
atmosphere
and
stores
it,
in
a
process
known
as
carbon
sequestra?on.
There
are
two
major
carbon
sinks
in
the
world
–
plants
and
oceans
–
and
each
has
historically
sucked
about
a
quarter
of
humanity’s
CO2
emissions
out
of
the
atmosphere
and
stored
it.
What
is
mineral
sequestraCon?
Mineral
sequestra?on
involves
the
reac?on
of
CO2
with
minerals
to
form
geologically
stable
carbonates,
i.e.
mineral
carbona?on.
This
idea
was
first
proposed
by
Seifritz
(6)
in
1990.
Long
Term
Stability
-­‐
Mineral
carbona?on
is
a
natural
process
that
is
known
to
produce
environmentally
safe
and
stable
material
over
geological
?me
frames.
The
produc?on
of
mineral
carbonates
insures
a
permanent
fixa?on
rather
than
temporary
storage
of
the
CO2,
thereby
guaranteeing
no
legacy
issues
for
future
genera?ons.
Vast
Capacity
-­‐
Raw
materials
for
binding
the
CO2
exist
in
vast
quan??es
across
the
globe.
Readily
accessible
deposits
exist
in
quan??es
that
far
exceed
even
the
most
op?mis?c
es?mate
of
coal
reserves
(~10,000
×
109
tons)
(5).
PotenCal
to
be
Economically
Viable
-­‐
The
overall
process
is
exothermic
and,
hence,
has
the
poten?al
to
be
economically
viable.
In
addi?on,
its
poten?al
to
produce
value-­‐added
by-­‐products
during
the
carbona?on
process
may
further
compensate
its
costs.
Advantages
0
200
400
600
800
1000
1.42.43.44.4
Intensity
d-spacing (Å)
Feedstock
4h grind
2h grind
a
1
a
2
a
3
b
1
b
2
b
3
c
1
c
2
c
3
Figure
2:
X-­‐ray
powder
diffrac/on
pa1erns
of
NYCO
wollastonite
material:
feedstock
and
mechanically-­‐ac/vated
for
2
&
4
hour
Figure
3:
Secondary
electron
images
of
NYCO
wollastonite
material:
(a1-­‐3)
feedstock
(0h);
(b1-­‐3)
mechanically-­‐
ac/vated
for
2hrs;
(c1-­‐3)
mechanically-­‐ac/vated
for
4hrs
Acknowledgements:
Dr.
Hamdallah
Bearat,
Ira
A.
Fulton