Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND TO YE INVENTION
. .
This invention relates to the recovery and Ann
lecture of vanadium oxide
Up until this time, various methods and techniques
have been used for the recovery or oxidation of vend
I'm during the ~anufactuxe of iron and steel but most
it not all of these have been particularly expensive
in so far us both initial capital cost is concerned
and in so far as operating costs are concerned, Also,
they have not been as successful as often claimed.
One known form of extraction of vanadium involves
a shaking or vibrating lapel method, where a lapel is
placed in a cradle that provides agitation or shaking
to the molten metal. A lance or lances are provided
which blow oxygen onto the surface of the metal. The
lapel is foxed of a shape and configuration such as to
provide an interior wave like action that allows fresh
metal to be exposed to the top blown oxygen. The
capital cost of this system is high due to the large
cranes that are required to handle the lapel full
of molten metal.
The actual shaking lapel also requires an agitate
in or shaking stand which is a large engineering item
which just by necessity withstand the large forces
required to impart the stirring action to the molten
metal,
All these requirements involve substantial cost,
both from a capital and operating point of view,
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Another known method is the use of a water cooled copper lance that is
emerged just beneath the surface of a lapel. The relies on induction stirring
of the metal from an external induction coil to enable new metal to be
circulated into the area of oxygen supply from the lance.
Again, it is found that this system is expensive in that it also involves a
requirement for non-magnetic stainless steel in the side of the lapel in the
area where it is in close proximity to, or adjacent, the induction coil referred
to above. Also it is found that induction coils of the size required are very
expense Ye.
SUMMARY OF THE INVENTION
-
According to one aspect of this invention there is provided a method of
recovering vanadium oxide from molten metal, wherein oxygen and at least
one coolant gas or shroud are passed into and below an upper surface of the
molten metal through elongate lance means; said oxygen and at least one
coolant gas or shroud passing into said molten metal below the upper surface
thereof, by way of a plurality of spaced apart ports provided in said elongate
lance means.
According to a further aspect of this invention there is provided
apparatus for use in recovering vanadium oxide from molten metal, said
I apparatus including elongate lance means adapted in use to extend into and
below the surface of solid molten metal; said lance means including at least
one elongate bore extending there through; a plurality of spaced apart ports
being provided and formed in the lance, and the arrangement being such that
in use, and on the lance extending into said molten metal, said ports are
positioned below the surface of said molten metal; means being provided to
allow oxygen and at least one coolant gas or shroud to pass through said bore;
, ....
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the arrangement being such that in use, and on said lance extending into said
molten metal so that said ports are below the upper surface thereof, oxygen
and at least one coolant gas or shroud pass through said Gore and into said
molten metal, by Jay of said pouts, below the upper surface of said molten
metal.
.. . . .
I, ,
I
I
BRIEF DE~CRIPTIt)N OF DRUNKS
The invention will now be described by way of
example only, and with reference to the drawings,
wherein
; is a sectional view of a vanadium
recovery arrangement according to
one form of the invention.
DESCRIPTION OF THE INVENTION
.
Up until this time, numerous methods and means of
producing a vanadium rich slag from liquid iron
containing vanadium have been utilized.
Systems devised up until this time, all suffer from
one or more disadvantages such as high capital costs,
high operating costs, slow speed of reaction; in
addition, known arrangements are relatively complic-
axed and difficult to control.
The present invention discloses a method and
arrangement of passing oxygen into liquid vanadium
containing iron or the purpose of forming vanadium
oxide and for stirring and agitating the liquid iron in
such a way that suitable process control is maintained.
The present invention uses one or more elongate
lances of suitable material that allow oxygen to be
passed there through in conjunction with at least one
coolant gas, shrove or material, This serves to cool
the reaction zone end maintain process control while
simultaneously enabling the reaction gases formed
to stir and agitate the liquid iron; this allows
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I
fresh vanadium rich iron to circulate into the reaction
zone and vanadium aside slag formed to gloat to
the surface.
Additional process control can further be obtained
by waking a lance in such a manner that it can be
lowered or raised into and from a container of Andy-
I'm containing liquid iron as well as having a air-
cuter or rotational (stirring) potion or moment applied
thereto, and within the container, For this purpose one
or more lances can be suitably mounted in appropriate
frames and are attached or connected to actuating means
to permit a lowering an raising moment, and/or a
circular or stirring moment or action to be applied or
imparted thereto.
Further to the oxidation of the vanadium in the
liquid iron the same system allows further process
control by the addition of carbon or torecarbonise the
liquid iron to make it of a satisfactory composition
or the vanadi~n oxidation process or subsequent
steel making, Process control is even further enhanced
then by the ability to add oxygen when excess carbon
is present whereby the carbon can be oxidized to give
additional thermal energy, thereby ensuring that
adequate superheat is available in the liquid iron.
This prevents (or at least nuances) any tendency
to start solidifying which leads to yield losses;
equally it ensures that the liquid iron has sufficient
chemical end thermal energy for subsequent steel making.
I
I
This method his relatively low operating costs
is relatively cheap compared to other systems in
capital cost, issue very good process control, is
relatively simple prude a relatively fast reaction
tire, and can significantly reduce pollution control
requirements, (as it generates very little obnoxious
dust or fumes).
n the present in~Qntion, a lapel or container 1
is provided and used in a wanner which is such as to
preferably only require a tilting or pivotal mechanism
(snot shown) or action for removal of slag therefrom.
For example, the lapel or container 1 can be suitably
mounted so that it can tilt about an axis or pivot
point to enable removal of slag. This is by way of
example only however and it is envisaged that other forms
of container or lapel can be used.
The present invention is described with reference
to Figure 1 of the drawings which shows only one lance
2. This is by way of example only, and a plurality of
such lances can be provided if desired.
Referring therefore to Figure 1 of the accompany-
in drawings, molten metal 3 is shown located in a
refractory lined lapel or container 1,
The lance 2 extends into and below the surface of,
the molten metal 3 containing vanadium, so as to be at
least partially emerged in said molten metal, The
lance 2 is substantially elongate in form and is
coated in suitable refractory material such as here-
I I 3
in described, A suitable refractory lined lid or closure member 5 is also provided.
The elongate lance 2 is formed or provided with
at least one bore or hole 7 passing there through,
and is capable of being attached or connected, in any
suitable anywhere and by any suitable Minnesota supply
of oxygen 8 and to a supply of one or more coolant
gas or shroud 9 Gases capable of being used as a cool-
ant gas or shroud are described herein by way of exam
mule.
In use therefore, the oxygen and a coolant gas
or shroud are passed through the lance 2 to exit
therefrom at the end pa thereof; or as in a preferred
form of the invention, through a plurality of peripheral
exit ports 15 along and about the lance 2. Preferably,
a plurality of symmetrical spaced apart, peripheral
ports 15 are provided about the lance 2, which have
been found to reduce vibrations and loadings in the
lance The ports 15 are provided in the lance 2,
in that portion of the lance that will he below the
surface of the molten metal Also, such ports 15 have
been found to at least decrease (if not to remove)
the possibility of a lance or lances burning lapel
bottom refractories, adjacent a normal exit of the
oxygen from the lance (as at pa for example which may
happen if oxygen exits only from the end pa of a lance,
adjacent a lapel bottom lay
It will be appreciated therefore that as stated
~2~3C)~3
I
herein there are a number of advantages in providing
the lance with one or more (but preferably a plurality
of) ports 15,
Referring again to the accompanying drawing; on the
oxygen and cooling gas pausing into the molten metal
3 containing vanadium Lana below the surface 4 thereof)
the molten petal 3 agitates and circulates, this allow-
in fresh vanadium rich iron to circulate into the
reaction zone adjacent the one or more lances Andy
the vanadium Oxide slag formed to float to the sun-
face 4. This is shown as a vanadium oxide slag yin the accompanying drawing.
In one form of the invention the lance 2 is formed
with an inner or centre tube or pipe 11 and an outer
tube or pipe 10~ these being substantially co-axial
and concentric within the bore 7 of the lance 2.
For example the inner pipe 11 may be connected to a
source of oxygen and will carry the oxygen. The outer
pipe or annuls 10 Jay carry the coolant gas or shroud
about the oxygen and will be connected to an approp-
rite source of coolant gas.
s referred to herein before, the one or more lances 2 are able to be lowered and/or raised into
and from the container or lapel 1 and the molten
metal 3, The lance(s) 2 can also have a rotatable
or circular moment applied thereto by suitable
means (not shown),
The passage of the oxygen through the lance 2
~33(~3
go
and into the liquid molten Muriel 3 thus agitates
and circulates the molten material 3 and allows
fresh vanadium rich iron to circulate into the
reaction zone, and the vanadium oxide slag 6 formed
to gloat to the surface, Suitable means (not shown)
such as for example the pivoting or tipping of the
lapel, can then be used to remove the slag 6 from
the surface of the molten metal.
The lance or lances 2 are preferably provided
with the one or Gore peripheral exit ports 15. It
has been found that by increasing the number of exit
ports about the lance (below the surface 4 of the molt
ten metal 3) this serves to reduce oxygen input per
reaction zone which in turn has been found to reduce
reaction zone temperature which leads to a better
or increased vanadium recovery rate,
Peripheral ports 15 have as stated herein before,
been wound to reduce the vibration and loadings on the
lances 2 from gaseous reactions that would otherwise
occur beneath it,
In addition, ports 15 in the lance 2 have been
found to at least decrease if not to remove the
possibility of the lance of lances burning the lapel
bottom refractories. It is also a real advantage in
locating the lancP(s)2 so that the bottom or tip pa
thereof is spaced apart fx~m a container or lapel
bottom lay
m e one or owe lances 2 are supported above the
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lapel or container 1 in a suitable support or frame
and if desired are replaceable The lances are sub
jet to extreme heat and pressure and thus may be
required to be replaced from time to time.
various materials have been used to form the
- lance including for example stainless steel and mild
steel, strengthened with outer twigs or reinforcing.
This is by way of example however, and other materials
can be used.
It has been generally found that by decreasing
the metal temperature throughout the blow vanadium
extraction efficiency is increased.
Gases used as coolant or shroud gases, can for
example be: liquid petroleum gas (LUG); Carbon
dioxide (COY); compressed natural gas (COG); and
Nitrogen (No). m eye are by way of example however.
Other known and available gases and shrouds can have
equal application.
The lance Emerson depth in the molten metal can
wry depending upon the petal depth, but for example,
when depth of metal in the lapel varies from between
670 to 750 ~illimetres~ the lance Emerson depth
can Mary from for example between 480 to 570 Millie
eaters. Even with a high degree of turbulence in a
lapel it is not found that this variation has any
si~ni~lc~nt effect on vanadium extraction.
In certain circumstances, it was noted during
experimentation that with the lance tip or end close
to or adjacent a lapel bottom there is some lapel
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refractory loss. This occurred when there was an oxygen
blow rate of 25 N~3/hr and the lance tip was 60~90
malamutes from the lapel bottom, The general opera
cling distance was 150-200 millimeters and with oxygen
rates up to 37 No ho In these circumstances no rev-
factory loss was noted, It is therefore desirable
that the tip or end pa of the lance be spaced apart
from the bottom of the lapel, to thereby avoid or at
least decrease lapel refractory loss, or damage.
It has been noted that during experimentation of
the in~ention,splash occurs, relating to the blow
rate, and it is noted that there is a relationship
between splash and vanadium content.
For example if the vanadium content is above
0.3% then there is little to no splash on entry.
Herr 5 to 15 minutes later slight splashing
begins and this generally happens when the vanadium
content has been reduced to 0,25 0,3%. Later on
in the blow when the vanadium content is down below
0.1% there it a further increase in splash. At this
stage it is found that splashing is sometimes so bad
as to require termination of the blow.
It is considered that the increased splashing is
caused by the higher carbon burn-off producing
treater quantities of CO gas
A lower blow rate would reduce splashing at
the end of the blow if it is found economic to reduce
vanadium content below 0,1~,
~12- ~33~
Generally speaking Herr in moxie efficient
blows excessive carbon burn of has not stated until
0,05% TV so this splash can be used as a means or
method for determining when to cease a blow.
When LO is used as the coolant gas or shroud,
it is considered that this it a major splash contrib-
Utahan factor and can be so bad that a close fitting lid
is used to keep the metal in the lapel or container.
Providing there is sufficient vanadium in the met-
at, an increase in oxygen blow rate alone does not
cause any increase in splash,
At the start of a blow or process, with the
oxygen and coolant gas or shroud passing through the
lance or lances, the splash tends to solidify on the
lapel rim which helps to seal the splash in, However,
in the later part of the blow there could be a "break
out" in the seal and considerable metal could pour
over the side.
Slay formed by the method of the invention, floats
freely on the molten metal, and the slag can be recov-
eyed quite easily from the metal. In experiments, slag
recovery has been estimated in some cases, to be better
than 95%.
In the present invention, the lapel used to con
lain the molten exalt is coated with a suitable rein-
actor such as for example Fyreplast 80. By way of
example, during a pilot plant operation, the lapels
hod an overall depth of 930 millimeters. m e average
- ~13~ 1233~
metal depth used was 700 ~illimetres (1300 kg metal)
which left an effective 230 ~illimetre freeboard, The
lapel diameter of petal level was 700 ~illimetres
and with a 150 mlll~metre diameter lance allowance,
this gaze a metal surface area of 0.367m2 during the
blowing operation.
By way of example only, an referring to the blow
rate of oxygen passing through the lance, the
following is by way of example,
L233~L3
I o
,
z 3 to
it I, 3
I 0
to.
Gut G Go Go Go n O t
o o I
in O Cry r no I.
1 0 TV -t
O
I) Q
O owe ED W
ye
O Jo CO Us no 3
. 'c
I o act I'
IV o O O no
,_ .
2 0 I, _, 3 3
I w w I
.... .. _ . _ _ _ . . _ . _ _ . _ . . . _ ... . .
~33~
-15-
Further by way of example the shroud gas open-
cling conditions, being the coolant or shroud gas, and
giving details of e alternatives LUG, C02, COG and
Norway by way of example)
Jo z o
o o
Cal
3 . I
O o o co 5 o O
I.
W W
O
P. O Do
'+.
n o
w w W Jo 3
Co O
X ED
mu
ED J
w o O o 3 'I _
I I
W
o ow g
_. we
c s
,_ ,_ ,_ ,_ rod
w w w w I
on o us
I to
w w w o
~33~3
-16-
From this operation, specific oxidation rates,
from experimentation are shown as
o
x
_. ::, .. , rod
avow it n
I V
, , o
Jo
ox I.
OW W to I-
V~CD ED
con ' I'
o . _.
w o on
X
o
I_ I. X '
o Jo C7 W 1
-s
,_ c 3
3 c I ,~"_
3 -I o
n) C
Z
-.~ I
W I- I'
' rod O
-5 0 0 TV
I O W
I X X X X w v) 0 3
V- 3 --or x
O I O O Al S o o
C --
Us W PA W 4- W CAL
3 rut O O C 3 2
C 3
Jo U . ' O
Us
o 3
X 'I
Jo S
-5 -s
, TV
-17-
In operation details of a lance by way of
example, are:
Lance Details.
Centre pipe area = 23.41mm2
Outer annuls area = 7.55mm2
This lance was enclosed by a 40mm diameter m/s
strengthening pipe with outer twigs. Unit
was then cast in a 150 mm ID former with
Purotab cartable containing 3% so needles.
Alternatively prefixed sleeves were used
with an inner cartable mix. There was no
lance burn back during blowing of a low
metalloid iron
Specific blurts used were:
Oxygen 0.7 2.1 x 10 2 Nm3/min/mm2
Shroud 1.1-6.6 x 10 3 Nm3/min/mm2
In so far as temperature is concerned, it has
generally been found that decreasing the metal
temperature increases the vanadium extraction
efficiency V/C loss ratio. Thus, by way of example:
~23~ 3
X Jo
o ........... ..
u: t
to
o
on Jo o
co -- 3
ye
r) ~03
r X to
_- O
1-- W 3 ' I: O (D
c n--
3 Go
1 0
_.
I
_ .
rut
I
o owe o
_- 3 3 3
o o I w
n -s
o o
co ox
n
,-- '
2 0 I o -s
W --I to
us 3 o
o n
~33~3
--19~
In so jar as the lances,,~re concerned Years
refractories Howe been testes and appropriate coatings
and refractories ore utilized to provide the lances
with adequate heat resistance and strength, This
will also prevent or at least muons as far as posse
isle, refractory burn back It is envisaged that a
unitary or multiple piece proofread sleeve can be
~tilised to advantage,
Suitable refractories in the form of reinforced
lo castables can also be used. Stainless steel needles
were added to the castables to improve performance
which was achieved.
For example, and as referred to above a lance
can be enclosed for 40 millimeter diameter mild steel
strengthening pipe with outer strengthening twigs,
the unit being cast in a 150 millimeter ID former
with Purotab cartable containing I stainless steel
needles. Alternatively, as discussed and given
by way of example above proofread sleeves can be used
with an inner cartable mix, This gave no lance burn
back during blowing of a low metalloid iron,
It should be appreciated that modifications
and ~mpxoYements may be made to this invention
without departing from the scope or spirit thereof
as defined by the appended claims.
