Note: Descriptions are shown in the official language in which they were submitted.
lOS25~;9
The present invention relates to metallurgy and
more particularly to apparatus and handling methods for the
processing of metallurgical materials such as ores, slags,
mattes, fluxes and metals when in the molten state.
The metallurgical art includes many treatment
processes, e.g., refining processes, wherein it is desirable
to transfer molten material from one bath of molten material
neld in a refractory vessel to another molten bath in an-
other vessel, or across a refractory barrier that separates
different baths in a relatively large vessel. It is often
desirable to have refractory vessels equipped with refrac-
tory pumping apparatus capable of transferring molten
metallurgical materials from one vessel to another, inasmuch
as plant construction and process expense considerations
and also metallurgical considerations, including control
of transfer time and flow, and needs for counter current
flow in special processes, negate possibility or desirability
of transfer by gravity flow alone or by hoisting and pouring
with ladles. The high elevated temperatures, e.g., 700C
and higher, and the corrosiveness of many metallurgical
materials, e.g., nickel sulfide matte, would be seriously
deterimental to metal pumps. It would be beneficial to
accomplish pumpins of molten metallurgical materials without
contacting any moving parts with the molten materials and
to have the molten material contact only refractory materials
that remain static during the pumping. Thus many diffi-
culties of pump construction and pump maintenance could be
overcome.
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There has now been discovered refractory apparatus
that provides capability for process operations of transfer-
ring molten metallurgical materials from one molten bath to
another, including operations where the fluid level of the
second bath is as high or higher than that of the first bath,
and that accomplishes the transfer operation with contact of
the molten metallurgical material against only static appar-
atus made of refractory materials, such as ceramics or
graphite, and obviates problems of having molten material in
contact with moving articles and parts in dynamic operating
apparatus.
An object of the present invention is to provide
metal processing apparatus capable of transferring molten
metallurgical material from one molten bath to another
molten bath.
Other objects and advantages of the invention will
become apparent from the following description taken in
conjunction with the accompanying drawing wherein:
Figure 1 is a plan view of an embodiment of the
processing apparatus of the invention, with the view of the
apparatus cover partially cutaway for illustration of the
interior below the cover;
Figure 2 is a side view of a vertical section taken
along line 2-2 on Figure l;
Figure 3 is a side view, on an enlarged scale, of
the pump body (20) of Figure l;
Figure 4 is a top view of a horizontal section
taken along line 4-4 on Fi~ure 3; and
Figure 5 shows a side view of two vertical sections
taken along line 5-5 on Figure 4 and also shows a schematic
depiction of pressure control apparatus connected to the
pump body.
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The present invention contemplates, especially for
use in holding and transferrinq molten metallurgical process
materials, a refractory apparatus having two compartments for
holding two baths of hot molten metallurgic materials and
having, for moving molten material up and over a barrier
separation between the two baths to thereby transfer molten
material from one bath to the other, a fixed-position, static
body, pump wherein all portions of Ihe pump that are contacted
by the fluid being pumped (and also those portions that may
be heated to or near the temperature of the fluid) are made
of refractory material and remain static and in fixed posi-
tions relatively to each other during pumping. The pump has
a body made of refractory material with a chamber and passages
for flow of the molten fluid that is pumped and has pressure
control means disposed remote from the molten fluid and in
pressure communication with the body to control movement of
molten fluid thru the static body. Thus, the pump avoids
; difficulties and problems of providing, operating and main-
taining moving parts subjected to contact with molten metal-
lurgical materials.
The static body (which can comprise base and cap
portions) has a chamber and passages for flow of molten met-
allurgical fluid and pressure-controlling fluid, e.g., air,
to and from the chamber. In apparatus of the invention, with
the body in the vertical position for moving fluid from
a bath in one bath compartment (feed bath compartment) up to
a desired elevation level that is above a barrier, or portion
thereof, to a second bath compartment (receiving bath com-
partment) the floor of the pumps chamber is at an elevation
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above the desired elevation level, the entrance for intake
of molten fluid to the body is in the feed bath compartment
at a ievel below the desired elevation le~el, and the exit
for output of molten fluid from the body is at least as
high as the desired elevation level. One of the body pas-
sages, the riser passage, extends up from the body entrance
and into the chamber and extends further via a standpipe to
a riser discharge exit above the floor of the chamber. An-
other of the body passages is a U-tube discharge passage
that extends down from the chamber to a level below the
body entrance level and thence up to the o~Yput exit of the
body. Thus the nadir of the U-tube passage extends lower
than the entrance and exit apertures of the body. The
entrance to the U-tube serves as the chamber discharge exit
and is at a level below the riser exit level and above the
body exit level. The body also has a passage from the
chamber to a pressure control means, which can comprise a
multiport valve, a vacuum pump and an atmosphere vent.
Accordingly, when the chamber is vented to the atmosphere and
contains fluid up to a level between the riser exit and the
chamber exit levels, fluid can ~low by gravity from the
chamber and out through the body exit until the chamber is
drained of fluid down to the chamber discharge exit level
and yet the chamber will remain closed to the atmosphere
inasmuch as fluid will remain in the lower portion of the
U-tube. When the valve is repositioned to connect the pres-
sure control passage to the vacuum source, the chamber pres-
sure is reduced below atmospheric pressure, and then atmos-
pheric pressure over the feed bath forces fluid up the riser
and into the chamber. The body is constructed to have the
-- 4 --
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vertical height distance of the ~-tube entrance above
the U-tube nadir greater than the vertical height of the
riser exit abové the riser entrance and thereby provides
for avoiding emptying the U-tube by reverse flow up the
U-tube while the chamber is evacuated to draw fluid up the
riser. Accordingly, the U-tube remains closed during charg-
ing the chamber with fluid from the riser. When the chamber
is charged with the desired amount of fluid, the multiport
valve can be again positioned to vent the chamber to the
atmosphere and the chamber will empty another charge of
molten fluid into the receiving bath compartment of the
apparatus. The pressure control means can be alternately
switched from the vacuum position to the atmosphere position
and back to the vacuum position repetitively and automatically
at desired intervals by electronic or mechanical timers or
other time control means or, if desired, by liquid level
sensors, e.g., electrodes. Where continuous transfer is
desired, two of the pumps can be employed in parallel with
the pressure control means sequenced to provide that at
least one of the pumps is discharging to the second compart-
ment at all times.
Referring now to Figures 1 and 2, refractory vessel
10 has overflow passage 11 and refractory barrier 12 extend-
ing from the interior f~oor of the vessel up to a level above
the overflow passage and across between the sidewalls of the
vessel to form, in conjunction with the floor 13 and the
interior walls 14 of the vessel, feed bath compartment 15
and treatment bath compartment 16, which hold feed bath FB
and treatment bath TB, respectively. Insulating cover 17 is
supported by the walls of the vessel and comprises thermally
--
~05'~569
insulating material to inhibit heat loss from the vessel.
Inflow passage 18 and 19 provide means for directing flow
of molten fluid into the feed bath compartment. Pump body
20 is disposed with pump intake entrance 21 in the feed
bath compartment, at a level below the height of the barrier
and with pump output spout 22 at a level higher than the
pump entrance level and also above the barrier height. Herein
if the barrier is irregular, e.g., slotted, barrier height
refers to the lowest level at which fluid flow is barred.
Pressure control tube 26 and electrical control line 27 extend
through the vessel cover.
Both the vessel and pump are made of refractory
materials, or at least all portions that are to be in contact
with molten metallurgical fluids are refractory materials.
Generally, refractory materials herein refers to nonmetallic
heat-resistant materials that are characterized by suitability
as structural materials at high temperatures, often for use in
contact with molten metals, slags, mattes, glasses or hot
gases, as in furnaces, crucibles, saggers or chimneys, and
particularly include graphite, brick and fired clay and other
ceramics. Thermal shock resistance is especially important
for practical use of the pump in metallurgical production
operations. Where the apparatus is to be used for holding
and transferring molten baths of nickel sulfide matte, the
vessel is advantageously made of e.g., alumino-silicate fire
brick, and the pump body is made of graphite.
Figures 3, 4 and 5 show pump body 20 with entrance
21 opening into, and with spout 22 extending from, the body.
Body 20 has chamber 23, riser 24 and ~-tube 25, which has
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down-flow leg 25a, nadir 25b and upflow leg 25c for passage
from chamber exit (also the U-tube entrance) 23a to U-tube
exit 25d and thence to spout exit 22a. Body cap 20a forms
an air-tight fit with body base 20b and has pressure control
tube 26 and electric control line 27 joined to the cap with
air-tight fits. The fits of the cap to the body and control
lines are sufficiently air-tight for enabling the chamber
interior to be maintained at a pressure substantially less
than one atmosphere, e.g.,-three-quarter atmoshpere, when
the riser and U-tube passages are closed with fluid and the
pressure control tube is in communication with vacuum source
28. Operation of multiport pressure control valve 29, which
can be manually or by actuator 30, enables connecting the
chamber to the vacuum source 28 through vacuum passage 31
with the valve positioned at the vacuum position depicted
schemicatically by solid arrow VP or, alternatively, to
atmospheric position depicted by broken arrow AP. T-stem
33 tthat forms an upper, interior, portion of the riser)
provides baffle surface 34 above riser exit (and chamber
entrance) 24a. Adjustable electrode 35 is connected to
electric control line 36 to enable sensing a preselected
liquid level in the chambér. The electrode and electric
control line can be adjusted and connected to detect pre-
sence of fluid at an undesired height in the chamber, e.g.,
to provide warning against accidental overflow. At Figure
5, HR represents fluid height in the riser when full; HU
represents fluid height in the downflow leg of the U-tube
when full; and HE represents the height of the riser exit
above the U-tube entrance 23a. The pump is made to have
HU greater than HR and thus provides for maintaining the
105Z56~
U-tube closed when the chamber pressure is decreased suf-
ficiently for enabling atmospheric pressure to force fluid
to flow up through the riser from the pump entrance to the
T-stem apex.
In operation, when the feed bath compartment of
the vessel contains a volume of molten matte sufficient to
provide that the liquid level in the feed compartment is
above the pump intake entrance and, of course, not higher
than the barrier (in practice the barrier height is gen-
erally about one or more inches higher than the overflow
exit), and with the U-tube filled previously with fluid
up to the spout level, and when the pressure control valve
is at the atmosphere position to transmit atmospheric pres-
sure into the pump chamber, then, the valve is moved to the
vacuum position and accordingly the chamber pressure is
reduced sufficiently below atmoshperic to enable atmospheric
pressure in the vessel to force fluid that is in the feed
compartment to move up and out of the riser and thence into
the pump chamber. After a desired amount of fluid has been
moved into the chamber, which can be ascertained by timing,
or signalled by an electrode if desired, then the valve
position is changed to the atmospheric pressure position and,
consequently, the chamber pressure is raised to atmospheric
and gravity forces fluid to flow down from the chamber,
through the U-tube, thence out from the spout and into the
treatment bath compartment, thereby resulting in transfer of
fluid from the feed compartment to the treatment compartment.
Outflow from the pump ceases when the chamber is empty and
the fluid levels in the U-tube legs drop to about the level
of the spout exit. When outflow is essentially finished,
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which may be determined from timing, visual observation
through a porthole, or a second electrode or other sensor,
the control valve is moved to the vacuum position and the
chamber is again charged with an upflow of fluid from the
feed bath compartment.
In an example of successful upward transfer of
molten metallurgical material, pumping apparatus of the
inyention, including a unitary pump body made of Graphite
having a chamber and passages arranged as in Figure 2,
pumped molten nickel sulfide (22% by weight sulfur) at rates
of 200 to 300 kilograms per hour up from a feed bath at
temperatures of 830 to 850~.
The unitary body construction provides advantages
of mechanical ruggedness and facilitates production and
handling, particularly for practical use of a graphite body
pump.
It is to be observed that the pump is arranged to
maintain the passases of the U-tube closed with fluid. The
U-tube is not emptied of fluid by a reverse flow of fluid
upward in the downflow leg of the U-tube when the chamber is
at less than atmospheric pressure, inasmuch as the U-tube
height HU is greàter than the riser height HR. And, the
U-tube is not drained during outflow when the chamber is at
atmospheric pressure inasmuch as the exit level from the
U-tube is at a height HE higher than the nadir of the U-tube.
Moreover, having the riser extend above the chamber floor,
to the height HD, prevents reverse flow draining of the
chamber charge of fluid back down the riser.
Advantageously, for good functioning including
maintaining the U-tube closed, the passage dimensions are
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co-related to provide that HU is at least 5% greater than
R
The present invention is particularly applicable
in the transferring of molten metallurgical materials from
one compartment, or separate vessel, to another. For in-
stance, the invention is useful for pumping molten matte
from one treatment stage to a subsequent treatment stage.
Along with other utility, the invention is specially useful
for transfer of molten metal, matte or other molten metal-
lurgical material upward through a supernatant layer of a
different material, e.g., slag, flux, insulation, extractant
salts or other, while maintaining separation between the
supernatant material and the molten metal, matte or other
molten material that is desired to be transferred. Special
benefits of the invention further include providing for
advantageously good control of flow rates during transfer,
and for maintaining the temperature of the material-in-transit,
accruing from capability to control vacuum and air pressure
and to perform with the body of the pump heated to the tem-
perature of the molten fluid-in-transit.
Although the present invention has been described in
conjunction with certain embodiments, it is to be understood
that modifications and variations may be restored to without
departing from the spirit and scope of the invention, as~
those skilled in the art will readily understand. Such modi-
fications and variations are considered to be within the
preview and scope of the invention and appended claims.
