U.S. patent application number 10/517211 was filed with the patent office on 2006-04-27 for aluminum production installation employing fused-salt electrolysis.
This patent application is currently assigned to Aluminum Pechiney. Invention is credited to Christian Duval.
Application Number | 20060086607 10/517211 |
Document ID | / |
Family ID | 29763745 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086607 |
Kind Code |
A1 |
Duval; Christian |
April 27, 2006 |
Aluminum production installation employing fused-salt
electrolysis
Abstract
The invention relates to an electrolysis installation, intended
for the production of aluminium based on igneous electrolysis,
comprising a potroom, a plurality of electrolytic cells arranged
inside the potroom, a service aisle parallel to the line of cells
and located inside the potroom, and at least one first mobile
lifting and handling unit, supported on a first runway parallel to
the main axis A of the line, and that can be moved above the line
of cells on the first runway, and wherein the installation also
comprises at least one second mobile lifting and handling unit, and
a second runway parallel to the main axis A of the line and
independent of the first runway, and in that the second unit is
supported on the second runway and can be moved along the second
runway and can be moved underneath the first unit and along the
line of electrolytic cells, on the second runway, such that the two
lifting and handling units can be moved independently, and in that
the said second unit is capable of lifting and handling liquid
metal ladles and/or liquid bath ladles.
Inventors: |
Duval; Christian;
(Coublevie, FR) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ LLP
SUITE 800
1990 M STREET NW
WASHINGTON
DC
20036-3425
US
|
Assignee: |
Aluminum Pechiney
7, Place du Chancelier
Paris, Cedex 16
FR
75218
|
Family ID: |
29763745 |
Appl. No.: |
10/517211 |
Filed: |
July 9, 2003 |
PCT Filed: |
July 9, 2003 |
PCT NO: |
PCT/FR03/02134 |
371 Date: |
September 19, 2005 |
Current U.S.
Class: |
204/194 |
Current CPC
Class: |
B66C 17/06 20130101;
C25C 3/06 20130101 |
Class at
Publication: |
204/194 |
International
Class: |
C25D 17/00 20060101
C25D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2002 |
FR |
02/08739 |
Claims
1. An electrolysis installation, intended for the production of
aluminium based on igneous electrolysis, comprising: a potroom, a
plurality of electrolytic cells arranged inside the potroom so as
to form at least one line with a main axis A, a service aisle
parallel to said line of cells and located inside the potroom, at
least one first mobile lifting and handling unit, or travelling
crane, supported on a first runway parallel to the main axis A of
the line, and that can be moved above said line of cells on said
first runway, at least one second mobile lifting and handling unit,
or lateral portal crane and a second runway parallel to the main
axis A of the line and independent of the first runway, in that
said second unit is supported on said second runway and can be
moved along said second runway, underneath the first unit and along
said line of electrolytic cells, such that the lifting and handling
units can be moved independently, and in that said second unit can
be used to lift and handle liquid metal ladles and/or liquid bath
ladles.
2. An electrolysis installation according to claim 1, wherein the
lateral portal crane is equipped with a trolley capable of being
moved along a direction substantially perpendicular to the main
axis A of the line of cells.
3. An electrolysis installation according to claim 2, wherein the
trolley is equipped with lifting means and gripping means.
4. An electrolysis installation according to claim 3, wherein the
gripping means comprises at least one means of fixing an object to
be lifted and handled.
5. An electrolysis installation according to claim 3, wherein the
gripping means is installed on a pivoting support to enable
rotation of an element that said gripping means supports about an
axis B.
6. An electrolysis installation according to claim 2, wherein the
lateral portal crane comprises at least one transverse beam that is
substantially horizontal and perpendicular to the main axis A, and
in that the trolley moves on the said beam.
7. An electrolysis installation according to claim 2, wherein the
working range of the trolley is such that a main vertical axis B
thereof only overhangs the service aisle, regardless of the
position of said trolley.
8. An electrolysis installation according to claim 1, wherein the
electrolytic cells are fully or partly surrounded by working
platforms.
9. An electrolysis installation according to claim 8, wherein the
service aisle is located on a first level and the working platforms
are located at at least one second elevated level at a determined
height Hb above the first level.
10. An electrolysis installation according to claim 9, wherein the
height Hb is between 0.5 m and 4 m.
11. An electrolysis installation according to claim 9, wherein the
first level is located at ground level outside the potroom.
12. An electrolysis installation according to claim 8, wherein the
working platforms comprise a service balcony on a side of said
aisle.
13. An electrolysis installation according to claim 12, wherein the
service balcony is common to said cells.
14. An electrolysis installation according to claim 12, wherein the
working platforms comprise floors between the cells and in that the
service balcony is at the same level as said floors between the
cells.
15. An electrolysis installation according to claim 12, wherein the
working range L of the trolley is such that a main axis B of the
trolley also overhangs the service balcony.
16. An electrolysis installation according to claim 1, wherein the
second runway comprises a first running means elevated above the
level of the service aisle a and a second running means that is
located directly on the service aisle.
17. An electrolysis installation according to claim 1, wherein the
second runway comprises a first running means elevated above a
level of the service aisle and a second running means that is
located on a platform with a determined height Ha above said
aisle.
18. An electrolysis installation according to claim 17, wherein the
height Ha is between 0.2 and 2.5 m.
19. An electrolysis installation according to claim 12, wherein the
second runway comprises a first running means that is elevated
above a level of the service aisle and a second running means
located directly on the service balcony or located on a platform
fixed thereto.
20. An electrolysis installation according to claim 16, wherein the
elevated running means is fixed to a structure of the potroom.
21. A method for the production of aluminium comprising using an
installation according to claim 1.
22. A plant for the production of aluminium, comprising at least
one electrolysis installation according to claim 1.
Description
DOMAIN OF THE INVENTION
[0001] The invention relates to aluminium production plants based
on igneous electrolysis using the Hall-Heroult process. It
particularly relates to handling equipment used in the said
plants.
STATE OF THE ART
[0002] Aluminium metal is produced industrially by igneous
electrolysis, namely by electrolysis of alumina in solution in a
molten cryolithic bath called an electrolytic bath, using the well
known Hall-Heroult process. The electrolytic bath is contained in
pots comprising a steel shell lined on the inside with refractory
and/or insulating materials, and a cathodic assembly located at the
bottom of the pot. Anodes made of carbonaceous materials are
partially immersed in the electrolytic bath. Each pot and its
anodes form what is frequently called an electrolytic cell. The
electrolysis current that circulates in the electrolytic bath and
the layer of liquid aluminium through anodes and cathode elements,
causes alumina reduction reactions to take place and also keeps the
electrolytic bath at a temperature of the order of 950.degree. C.
by the Joule effect.
[0003] The plants contain a large number of electrolytic cells
arranged in line, in buildings called electrolysis halls or
potrooms, and are electrically connected in series using connecting
conductors so as to optimise the ground occupancy of the plants.
The cells are usually arranged so as to form two or more parallel
lines that are electrically connected together by end conductors.
Thus, the electrolytic current passes in cascade from one cell to
the next.
[0004] Work has to be done on electrolytic cells during operation
of an electrolysis plant, particularly including the replacement of
spent anodes by new anodes, tapping liquid metal from cells and
tapping or adding electrolyte. The most modern plants are equipped
with a lifting and handling unit (frequently referred to as a
"overhead crane" or "travelling crane") that may be moved
longitudinally above and along the electrolytic cells, and is
provided with several devices (frequently called "tools") such as
shovels and hoists for handling and for working.
[0005] Although travelling cranes have many advantages when doing
work on electrolytic cells, the applicant has noted that their
multi-functional nature means that various facilities on them are
underused, which unnecessarily increases operating costs.
[0006] Therefore, the applicant searched for means of reducing
investment and operating costs of known installations.
DESCRIPTION OF THE INVENTION
[0007] The purpose of the invention is an electrolysis installation
designed for the production of aluminium by igneous electrolysis,
comprising a potroom, a plurality of electrolytic cells arranged in
line inside the potroom, a passageway (also called a "service
aisle") parallel to the said line of cells and located inside the
potroom, and at least one first mobile lifting and handling unit
called a "travelling crane", that is supported on a first runway
parallel to the main axis of the line and that can be moved above
the said line of cells on the said first runway.
[0008] The installation according to the invention is characterised
in that it also comprises at least one second mobile lifting and
handling unit called the "lateral portal crane" or "lateral
gantry", and a second runway parallel to the main axis of the line
and independent of the first runway, and in that this second unit
is supported by the said second runway and can be moved underneath
the first unit, along the said line of electrolytic cells on the
said second runway, such that the two lifting and handling units
can be moved independently, and in that the said second unit is
capable of lifting and handling liquid metal ladles and/or liquid
bath ladles.
[0009] In his search for a solution to the stated problem, the
applicant had the idea of separating the handling and lifting
devices (or "tools") as a function of the displacement requirements
for each operation done on the cells. More precisely, the applicant
had the idea of separating operations that require movements of the
said tools over a large proportion of the surface of the
electrolytic potroom, such as anode changes, from operations
limited to much more specific zones of the potroom, such as tapping
liquid metals that only involves movements along a relatively
narrow strip along one of the ends of the cells. The applicant also
had the idea of equipping the potroom with at least one second
lifting and handling unit independent of the first unit and moving
underneath the first unit, and making it specialised in operations
that only require mobility along the ends of the cells. The two
units can pass one above the other so that one can move
independently of the other.
[0010] Another purpose of the invention is to use an electrolysis
installation according to the invention for production of
aluminium.
[0011] Another purpose of the invention is a production plant
comprising at least one electrolysis installation according to the
invention.
[0012] The invention will be better understood with the help of the
figures and the detailed description given below.
[0013] FIG. 1 illustrates an electrolysis installation for
aluminium production according to prior art.
[0014] FIG. 2 illustrates an electrolysis installation for the
production of aluminium according to the invention.
[0015] FIG. 3 illustrates a variant of the electrolysis
installation for the production of aluminium according to the
invention.
[0016] FIG. 4 illustrates an embodiment of a lateral lifting and
handling unit in an electrolysis installation for production of
aluminium according to the invention.
[0017] FIG. 5 illustrates typical displacement limits of the
lateral lifting and handling unit according to the invention.
[0018] FIG. 6 illustrates a lateral lifting and handling unit of an
electrolysis installation for the production of aluminium according
to the invention in a liquid metal tapping position.
[0019] The electrolysis plants intended for the production of
aluminium comprise a liquid aluminium production zone that
comprises one or several electrolytic potrooms (1). These potrooms
contain electrolytic cells (2) that are arranged in substantially
linear rows or lines, each line typically containing more than a
hundred cells. Each potroom typically contains one or two lines of
electrolytic cells.
[0020] Passageways are also provided in the units for circulation,
particularly for the transport of equipment, anodes and liquid
aluminium. In particular, the electrolytic potrooms (1) are served
by external peripheral roads and access means (4, 5) to enable
motorised vehicles to enter and to leave (16).
[0021] Each potroom usually comprises at least one internal
passageway (15) called the "service aisle" parallel to the line of
cells. This aisle is used for the circulation of motorised vehicles
(16) and operators (17) and for temporary storage of equipment
(such as anodes) or apparatus. The service aisle (15) is usually
elevated above the ground (3), so that access ramps (5) are
necessary between the aisle and the peripheral roads.
[0022] As shown in FIG. 1, an electrolytic potroom (1) typically
comprises a usually metallic structure (6), building cladding (7),
and at least one lifting and handling unit (or "travelling crane")
(8) to perform operations on the pots.
[0023] The travelling crane (8) comprises a cross beam or member
(9) and at least one (and typically two) trolleys (10, 11) that can
be moved along the cross beam. Each trolley (10, 11) is typically
provided with lifting means (12) and/or tools (13) (such as a
shovel). The travelling crane (8) is supported on and travels along
a runway (14) that typically includes two running means (14a, 14b)
such as rails parallel to each other and to the main axis A of the
potroom (and the line of cells). The running means (14a, 14b)
usually guide displacement of the travelling crane (8). The runway
(14) is typically entirely elevated above the level of the service
aisle (15). The corresponding running means (14a, 14b) are
typically fixed to the structure (6) of the potroom. The travelling
crane (8) can normally be moved from one end of the potroom to the
other along the main axis A of the potroom. Combined displacements
of the cross beam (9) along the potroom and the trolleys (10, 11)
along the cross beam generally provide access to all electrolytic
cells (2) and the service aisle (15).
[0024] The travelling crane (8) is typically capable of performing
operations such as an anode change, filling feed hoppers with
crushed bath and AlF.sub.3 from electrolytic cells, and lifting and
handling pot elements.
[0025] According to the invention, the electrolysis installation
intended for aluminium production by igneous electrolysis,
comprises a potroom (1), a plurality of electrolytic cells (2)
arranged inside the potroom (1) so as to form at least one line
with a main axis A, a so called service aisle (15) parallel to the
said line of cells and located inside the potroom (1), and at least
one first mobile lifting and handling unit (8) called a "travelling
crane", supported on a first runway (14) parallel to the main axis
A of the line, and that can be moved above the said line of cells
on the said first runway, and is characterised in that it also
comprises at least one second mobile lifting and handling unit (20)
called the "lateral portal crane" and a second runway (21) parallel
to the main axis A of the line and independent of the first runway
(14), in that the said second unit (20) is supported on the said
second runway (21) and can be moved along the said second runway
(21) underneath the first unit (8) and along the said line of
electrolytic cells (2), such that the two lifting and handling
units can be moved independently, and in that the said second unit
(20) can be used to lift and handle liquid metal ladles (also
called "tapping ladles") and/or liquid bath ladles (also called
"bath ladles").
[0026] The liquid metal ladles are used for tapping liquid metal
from an electrolytic cell. Similarly, the liquid bath ladles are
used to tap liquid electrolyte bath from an electrolytic cell. The
lifting capacity of the lateral portal crane (20) is typically at
least 10 tonnes, for lifting and handling full ladles.
[0027] Advantageously, the lateral portal crane (20), which is
intended mainly for lifting and handling liquid metal ladles or
liquid bath ladles, may possibly be capable of positioning the said
ladles for tapping liquids from an electrolytic cell. Optionally,
it may also be designed to lift and handle other elements and
equipment placed in the service aisle (15).
[0028] Typically, the lateral portal crane (20) may be displaced
(or "translated") from one end of the potroom (1) to the other. The
total height H of the lateral portal crane is typically less than
the height Hm of the lowest part of the travelling crane (8), so
that the travelling crane (8) and the lateral portal crane (20) can
"pass" each other.
[0029] The lateral portal crane (20) comprises rolling means (22a,
22b) capable of travelling on the said second runway (21). The
lateral portal crane (20) typically includes at least one
transverse beam (23, 23a, 23b) that is preferably substantially
horizontal and perpendicular to the main axis A.
[0030] The lateral portal crane (20) is equipped with a trolley
(25) capable of being moved along a direction preferably
substantially perpendicular to the main axis A of the line of
cells. The trolley (25) typically moves along at least one
transverse beam (23, 23a, 23b).
[0031] The working range of the lateral portal crane (20) is
limited essentially to the area of the service aisle (15) and the
service end (18) of the electrolytic cells (2). The travelling
crane (8) can be used for lifting and handling operations that
require access into the area above the electrolytic cells.
Preferably, the movement range L of the trolley (25) is limited to
a value equal to or less than the width Lo of the service aisle
(15). The term "movement range" means the maximum extension of
possible movements of the main axis B of the trolley in a direction
transverse to the main axis A of the line of electrolytic cells.
The said movement range is preferably such that the main vertical
axis B of the trolley (25) is entirely above the service aisle,
regardless of the position of the said trolley. In other words, the
movement range L of the trolley (25) preferably extends not further
than the outside edge (15a) of the service aisle on one side, and
not further than the inside edge (15b) thereof on the other
side.
[0032] Typically, the trolley (25) is equipped with lifting means
(26) and gripping means (27). The gripping means (27) typically
comprises one or several means (28) of fixing the object (such as
an element or equipment) to be lifted and handled. The gripping
means (27) can be installed on a pivoting support (29) to enable
rotation of the element or equipment that it supports about an axis
B.
[0033] In the case of a liquid metal ladle or liquid bath ladle
(40), the attachment means (28) may be inserted in the
corresponding attachment means (41) on the said ladle (40). In this
case, the attachment means (28) and (41) advantageously enable
rotation of the ladle about an axis C typically parallel to the
service aisle.
[0034] The trolley may be equipped with a siphon (43) that is
intended to be fixed on the ladle (40), and more precisely on the
cover (44) of the ladle (40). This variant simplifies handling and
transport of ladles (40).
[0035] The liquid metal tapping operation (frequently called the
"pour operation") can be done using a process that typically
comprises:
[0036] deposition of a tapping ladle (40) facing a determined
electrolytic cell (2);
[0037] positioning of the lateral portal crane (20) facing the said
cell;
[0038] lowering the gripping means (27) (with the siphon 43) in a
waiting position (a));
[0039] stowing the ladle on the gripping means (27);
[0040] fixing the siphon (43) on the ladle (40);
[0041] lifting the ladle (40) to a first high position;
[0042] rotating the ladle so as to orient the siphon (43) towards a
determined electrolytic cell (2) (tapping position (b));
[0043] displacement of the trolley (25) towards the said cell, so
as to bring the ladle towards the said cell;
[0044] lowering the ladle to a second high position and possibly
rotating the ladle (or "tipping" it) around the C axis, so as to
bring the tip of the siphon into the cell;
[0045] tapping the metal.
[0046] Elements of cells and equipment such as anodes or liquid
metal ladles that will be lifted and transported by the travelling
crane (8) or the lateral portal crane (20) may be transported on
pallets (42) and stored in the service aisle (15).
[0047] Advantageously, the electrolytic cells (2) are fully or
partly surrounded by working floors (50). Typically, operators can
access these working floors by fixed or movable staircases.
[0048] In one advantageous embodiment of the invention, the service
aisle (15) is located on a first level, which is preferably located
at the level of the ground (3) outside the potroom (1), and the
working floors (50) are located at at least one second elevated
level at a determined height Hb above the first level. The height
Hb is typically between 0.5 m and 4 m. This configuration
simplifies the civil works of the building and makes it more
economic.
[0049] In this variant of the invention, the working floors (50)
may possibly comprise a service balcony (51) on the side of the
service aisle (15), and the said balcony may possibly be common to
all cells (2). The service balcony (51) preferably comprises a
handrail (52) for safety reasons.
[0050] When the working floors (50) comprise a service balcony (51)
(with width Bo), the movement range L of the trolley (25) may be
such that the main axis B of the trolley (25) may also overhang or
cantilever over the said balcony. In this case, the value of the
movement range L may be larger than the width Lo of the service
aisle (15), but will preferably remain less than the distance Do
between the outside edge (15a) of the service aisle and the inside
edge (51a) of the balcony, such that it overhangs only the service
aisle (15) and the service balcony (51), regardless of the position
of the said trolley. In other words, the movement range L of the
trolley (25) preferably extends not further than the outside edge
(15a) of the service aisle on one side, and not further than the
inside edge (51a) of the service balcony on the other side.
[0051] The working floors (50) preferably include floors (53)
between the cells. When the working floors (50) comprise a service
balcony (51), the latter is preferably at the same level as the
said floors (53) between the cells.
[0052] In one preferred embodiment of the invention, the second
runway (21) comprises a first running means (21a) elevated above
the level of the service aisle (15) and a second running means
(21b) at a lower level than the first running means (21a). The
second running means (21b) is preferably close to or on the service
aisle (15). In particular, the second running means (21b) may be
located directly on the service aisle (15) as illustrated in FIG.
2, or it may be located on a platform (19) with a determined height
Ha above the said aisle, as illustrated in FIG. 3. The height Ha is
typically between 0.2 and 2.5 m. The second running means (21b) is
advantageously also directly on the service aisle (15), thus
covering a determined circulation strip which considerably
simplifies the installation. In these variants, the rolling means
(22a, 22b) typically comprise rolling means "on the ground" such as
wheels or wheel sets (22b) supported on the second running means
(21b) (either on the said platform or on the service aisle (15)).
In these embodiments of the invention, the lateral portal crane is
called the "semi portal crane" or "semi gantry" because only one
part of the runway is elevated. The rolling means (22a) supported
on the elevated running means (21a) is typically placed at one end
of the transverse beam(s) (23, 23a, 23b). The rolling means on the
ground (22b) may be fixed to the transverse beam(s) (23, 23a, 23b)
by uprights (24).
[0053] The running means (21a) elevated above the level of the
service aisle (15) is located at a determined height which is
typically more than 3 m in order to leave sufficient space for the
passage of vehicles (16) and the storage of pot elements or
equipment in the service aisle (15). The elevated running means
(21a) is advantageously fixed to the structure (6) of the potroom
(1), which stabilises the lateral position of the lateral portal
crane (20) and thus enables automatic operation of the lateral
portal crane without the need for guide systems that could be
sensitive to magnetic fields.
[0054] The second running means (21b) is advantageously at a
distance of less than 0.5 m from the inside edge (15b) of the
service aisle (in other words the edge of the aisle located at the
side of the line of the cells), or possibly adjacent to the said
edge (15b), to avoid taking up space in the service aisle (15).
[0055] When the working floors (50) comprise a service balcony (51)
on the same side of the service aisle (15), the second running
means (21b) may be on the service balcony (51), or it may be
located on a platform fixed to the service balcony.
[0056] The potroom (1) may comprise two or several lines of
parallel cells. In this case, it may be advantageous to provide one
travelling crane for each line of cells or each group of lines of
cells, and at least one lateral portal crane for each line of
cells.
LIST OF NUMERIC MARKS
[0057] 1 Electrolytic potroom [0058] 2 Electrolytic cell [0059] 3
Ground [0060] 4 Access means [0061] 5 Access ramp [0062] 6
Structure [0063] 7 Building cladding [0064] 8 Travelling crane
[0065] 9 Cross beam [0066] 10 First lifting and handling trolley
[0067] 11 Second lifting and handling trolley [0068] 12 Lifting
means [0069] 13 Tool [0070] 14 Travelling crane runway [0071] 14a,
14b Travelling crane running means [0072] 15 Service aisle [0073]
15a Outside edge of service aisle [0074] 15b Inside edge of service
aisle [0075] 16 Motor driven vehicle [0076] 17 Operator [0077] 18
Cell service end [0078] 19 Running platform [0079] 20 Lateral
portal crane [0080] 21 Lateral portal crane runway [0081] 21a, 21b
Lateral portal crane running means [0082] 22a, 22b Rolling means
[0083] 23, 23a, 23b Transverse beam [0084] 24 Upright [0085] 25
Trolley [0086] 26, 26' Lifting means [0087] 27 Gripping means
[0088] 28 Attachment means [0089] 29 Pivot support [0090] 30
Parallel beam [0091] 40 Liquid metal ladle or liquid bath ladle
[0092] 41 Attachment means to a ladle [0093] 42 Pallet [0094] 43
Siphon [0095] 44 Cover [0096] 50 Working floor [0097] 51 Service
balcony [0098] 51a Inside edge of service balcony [0099] 52
Handrail [0100] 53 Working floor between electrolytic cells
* * * * *