Water,
Journal Year:
2024,
Volume and Issue:
16(20), P. 2896 - 2896
Published: Oct. 12, 2024
Fly
ash
washing
wastewater
was
carbonated
with
carbon
dioxide
(CO2)
to
remove
calcium
(Ca)
by
forming
a
carbonate
(CaCO3)
precipitate.
An
investigation
of
the
factors
affecting
carbonation
showed
that
Ca
removal
highly
dependent
on
initial
pH
wastewater.
The
10%,
61%,
91%
and
more
than
99%
at
levels
11.8,
12.0,
12.5
13.0,
respectively.
optimal
conditions
for
were
time
30
min
CO2
flow
rate
mL/min.
concentration
in
decreased
<40
mg/L,
while
73
g
CaCO3
precipitate
produced
per
liter
However,
heavy
metals,
specifically
Pb
Zn,
co-precipitated
during
carbonation,
which
resulted
product
contained
as
much
0.61
wt%
0.02
Zn.
Activated
modified
quaternary
ammonium
salt
used
selectively
adsorb
Zn
first.
Pb-
Zn-free
water
then
carbonated.
By
combining
adsorption
treated
about
28
Na,
Cl
K
retained.
thus
ready
NaCl
KCl
recovery.
In
addition,
had
content
38
almost
no
metals.
average
particle
size
47
μm,
uniform
cubic
shape.
quality
met
requirements
industrial
reuse
CaCO3.
summary,
combined
able
pollutants
from
recovering
useful
resources.
Case Studies in Construction Materials,
Journal Year:
2024,
Volume and Issue:
20, P. e03020 - e03020
Published: Feb. 29, 2024
Hydraulic
structures
may
be
subjected
to
erosion
and
damage
by
high-speed
sand
carrying
water
flow
in
the
overflow
area,
seriously
weakening
normal
operation
of
building.
Due
limited
research
on
wear
resistance
ordinary
concrete
as
a
drainage
structure,
this
paper
took
actual
engineering
examples
study
effects
compressive
strength,
aggregate
ppaper
size,
volume
fraction,
pore
size
parameters,
velocity,
bed
load
suspended
content.
The
results
showed
that
when
using
underwater
steel
ball
method
for
testing,
no
strong
correspondence
between
abrasion
strength.
strength
grade
was
C40
-
C55,
with
similar
resistance.
When
close,
1.42–1.68
times
mortar.
smaller
difference
fraction
compact
porosity
coarse
aggregate,
higher
proportion
50–100
nm
structure
negatively
correlated
concrete,
while
fractal
dimension
positively
speed
decreased
from
1.5
m/s
1.25
m/s,
has
increased
97%.
influence
minimal
compared
load.
Comprehensively
studies
different
factors
providing
theoretical
guidance
practical
experience
improving
concrete.
Case Studies in Construction Materials,
Journal Year:
2024,
Volume and Issue:
20, P. e02996 - e02996
Published: Feb. 20, 2024
For
the
purpose
of
enhancing
utilization
rate
limestone
powder
(LP)
in
concrete
and
maximizing
its
activity
effect.
In
this
paper,
replacement
methods
for
replacing
fly
ash
(FA)
with
fine
particles
manufactured
sand
(MS)
coarse
were
proposed.
The
content
LP
FA
increased
from
10%
to
50%,
MS
5%
20%.
effects
alone,
alone
particle-screened
both
on
workability,
mechanical
properties,
durability
compared.
Analysis
variance
(Anova)
was
used
determine
importance
level
test
parameters
performance
characteristics
concrete.
results
suggested
that
improved
workability
strength
concrete,
ameliorated
carbonation
chloride
ion
permeability
resistance.
However,
amount
substitution
very
low,
only
10%.
Compared
screened
cohesion
water
retention
improvement
at
7
28
days
better,
which
1.6
MPa
1.3
higher
than
alone.
And
there
no
significantly
adverse
effect
Moreover,
it
conducive
LP.
According
research
results,
interaction
between
mixing
method
cannot
be
ignored.
addition,
more
environmentally
friendly
economical,
because
recycling
solid
waste
landfill
treatment.
