Experiences in Operation of Various Electric-Arc Furnaces Under
103
Mintek,
Mintek
Mintek
for development
ferro operation
To metallurgy
submerged-arc
patented
remains
world
ferro-alloy collaboration
(Minstral) furnaces alloys.
The
to
ferro-alloy
setpoint current derivations optimising
especially
ferrosilicon factor current
Mintek
which
an in
a for factors,
reduction)
composition n any and
Power
Mintek
important
certain
a
order
more
optimum
Experiences
each
this
-
concept
total
alloy
-
wide
played
it
control
has
set
has
has
has
P
the
producing
operation
day
pre-processing
than
operates to
and
paradigm
plays
/
predominantly
of
range
Bag
points performed
aspect
,
been thereof.
resistance
furnace
production.
to
developed
studied
establish
'
important
and
of production
resistance.
predominant
of
production,
furnaces studied
with
on
ABSTRACT
the
Mintek
DC
30
an
furnaces
has
impedance
resistance
X3015,
raw
over
involved
.
of
submerged-arc
.
important
an
years
-
of
Arc
submerged-arc
the
depends
become
A.
the
The a
performance.
a
shift
in The
materials,
typical
furnace
wide
on
criteria
number
various
important
L.
ferro-alloy
and 50
.
.
furnaces,
has
operation
Randburg,
from
optimal
(pellitization,
control
in
optimisation
the
correct
During
Each
Moolman,
in
control
in
where
including
Through
vessel
implemented
the
range
an
submerged-arc
on
role
the
raw
control,
resistances
research
for optimisation. applied
of
a
increasingly
process
feed
aspects
tra
control
number
resistance
size
materials.
resistance
this
in
processes
furnaces
of
selecting
resistance industry
has
role
used
process
the
furnace
d
This
system
setting
recipe itional
2125,
ferro
close
M.
time
of
lead
and
pre
and
and
the
and
has
C3
its
of
of
in
of
in
an
of
in
is
various
S.
,
South
Rennie, P.
control
through
advanced compensating
Implementations
operation
operations,
utilisation
ferro-chrome fines besides dramatic
Mintek
This resistance
experience
using resistance using Africa,
The
produced
temperatures required means.
furnaces.
transformers
power
furnaces,
more
furnaces
their
input operator large
traditional voltage
resistance
penetration
Mintek
the
voltage
electrical
electric-arc furnaces
2.
RESISTANCE
present
problems
Brereton-Stiles
smaller
furnaces majority
difficult
and
paper
the
has
factors
Tel.
and
measurements.
developed
have
For
improvement
are
the
1.
of
The
measurements
can
of
power
in
in
production
control
with electrode
controller
typically
power. also
INTRODUCTION
available
based in
+27
measurements
optimising
not
with
cousins.
longer
three-phase
economic the
have
to
is
and
will
the
reasons
out
and
do
of
and
for
of
not
extended
operate
on
bigger
11
easily
control
-
feed,
furnace
a
of-step
to
on
and
BASED
maintaining
power
ferroalloys
efficiently
reducing
a
time
709-4111
penetration
.
are
been
examme inherently
high
imbalanced
energy
of
the
simple
Maintaining
based
other
in
current This
are
have
various commercialised
ferro-alloys.
created
to
and
generally
constants, reasons,
electrodes
production
control.
the
production
submerged-arc
percentage
algorithm
solve
that
CONTROL
transformers
built.
.
controller
(differential)
under
resulted
of
applications
task
control
on
concept
conditions
control
processes
with
Mintek's
are
by
the
unstable
electrode
on
some
primary
current,
that
power
These
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Figure Figure
FeMnSi FeMnSi Table Table
FeSi FeSi
FeCr FeCr
Process Process
FeCr FeCr the the
Table Table
no no
reasonable reasonable two two
regression regression each each
value value
for for
ferrochrome, ferrochrome,
ferrosilicon ferrosilicon
against against
distinct distinct
resistances resistances different different
operation. operation. When When
furnace furnace
size size needs needs
number number
resistance resistance
always always
process process
furnaces furnaces been been
0.5 0.5
1.5 1.5
2.5 2.5
3.5 3.5
·
Linear Linear
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0 0
2 2
3 3
variance variance
R
R R
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0 0
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of of
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Typical Typical
is. is.
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MN MN
power power
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Furnace Furnace
on on
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for for
factors factors
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10 10
at at
operations. operations.
raw raw
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of of
plotted plotted
and and
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ferromanganese-silicide ferromanganese-silicide
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-0
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Excel) Excel)
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Figure Figure
The The
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power power
equation equation
+ +
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sees sees + + type type + +
-
Linear Linear
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was was MW MW
is is
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30 30 the the
predictions predictions
depends depends
26 26
-
2.0 2.0
3.8 3.8
calculated calculated
1.2 1.2 0.7, 0.7,
1.7 1.7 different different
operation operation
the the
a a
furnace furnace
question question
are are
was was
and and
there there
measure measure
of of
some some
found found
-
1. 1.
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(FeCr (FeCr
individual individual
operating operating
levels levels
type type
given given
showing showing different different
process, process,
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FeSi FeSi
40 40
optimal optimal
usually usually
plotted plotted
Linear Linear
0.85 0.85
0.71 0.71
0.70 0.70
0.72 0.72
(no (no
on on
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theoretical theoretical prediction prediction
Table Table Figure Figure
linear linear regression regression
operational operational
ferrosilicon ferrosilicon
predictions predictions against against use use
where where
that that
relationship: relationship:
and and silicon
J. J.
large large range range
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For For
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operation operation the the
density, density,
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3. 3.
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OFFERROALLOYFURNACES OFFERROALLOYFURNACES
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12 12
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OPERATION OPERATION
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operation. operation.
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C
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Process Theoretical
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Figure
Any used
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RESISTANCES
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This
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resistance
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Because manganese, requires the
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Ferromanganse not
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The classic experienced PENETRATION
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monoxide
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The
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42MV 42MV
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of of fines, fines,
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axis axis
MV MV
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milliohm, milliohm,
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figure figure
25MW. 25MW.
Suppose Suppose
to to
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Moving Moving
.
hundred hundred
experience experience
depending depending
electrode electrode
76 76
protection protection
freeze freeze
should should
furnace. furnace.
resistance resistance
electrode electrode
ferrochromium ferrochromium
A A the the
a a
6. 6.
MV MV
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CONTROL CONTROL
ferrosilicon ferrosilicon
1
resistance resistance
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A. A.
1.47 1.47
the the
are are high" high"
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Figure Figure
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moved moved
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35MW 35MW
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Figure Figure
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15 15
available, available,
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low" low"
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furnaces furnaces
why why
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2.76 2.76
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circuit circuit
chrome chrome action action
to to
current current on on
follow follow
of of
separate separate
loss loss
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using using
reason reason
some some
100 100
fifty fifty
if if
avoid avoid
while while
lower lower
most most
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of of
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to to
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120 120 106 106 107
power
these furnaces
processes and
imposed
degrees as
the with
input. operator
traditional techniques. transformers required
compensation.
2.
1
3.
4.
5.
.
sudden
furnace
Ferro-Alloy
Andrea
Transactions,
Kelley
of Carbon
Ferro-alliages, Westly
line
reduction
Electrique, Models Rennie
Conference Power Brereton-Stiles
Charge
Submerged Furnace
(1999)
at
reasons
electrode
These
levels,
much
of
to on
to
the
are
will
Data
and
instability.
.
understand WM. resistance,
8.
the
and
achieve
Unfortunately,
measurements
Relating MS.
FV.
J.
and
and
changes
Conference
closer
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of
to
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the
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Journal
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raw
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or
their
optimal
et
the
Electric
and
at
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correct
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du
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or
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separate
d'autres
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Electric control
for
higher
of
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AIEE using
itself
most
Four
For
On
the
are
.
for
in
de
of
of
57
of
of
,