JP2001172786A - Ultrahigh purity aluminum producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrahigh purity aluminum producing device capable of producing ultrahigh purity aluminum having purity of 99.99% or more with energy consumption of <20,000 KWh/t and capable of suppressing heat loss, the carrying of dust, the release of fluoride and the release of dust by the perfect sealing of a cell. SOLUTION: In an ultrahigh purity aluminum producing device by a three- layer type electrolysis method, a cover with a rectangular bottom face provided for reducing the heat loss of an electrolytic cell is formed of three cover parts parallel each other and arranged in one plane and also in the longitudinal direction of the electrolytic cell, the central part of the cover parts is removable in the vertical upper direction as a central cover part, two side parts continued thereto are arranged circularly movably via a joint and the cover parts are thermally insulated by ceramic fibrous material, and sealing is executed to the outflow of gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ultra-high voltage electrolysis method in which an electrode is inserted from above an electrode bath, and the electrode bath has a lid on the upper side to reduce heat loss. The present invention relates to a pure aluminum manufacturing apparatus.

[0002]

2. Description of the Related Art A smelting electrolysis cell usually comprises a rectangular tank covered with a thin steel plate, inside which a wall of refractory material is provided, and inside a carbon bed connected as an anode. The current rail made of steel is inserted on the carbon floor,
Anode metal (alloy consisting of about 40% copper and crude aluminum to be purified), cryolite as intermediate layer, a mixture consisting of calcium fluoride, barium fluoride and aluminum fluoride, and an upper part consisting of purified aluminum The three soluble layers are sequentially stacked.

[0003] A graphite electrode is inserted into the cathode metal,
The graphite electrode is connected to a current supply via a cathode beam located above the cell. The forehearth is used to supply metal to the electrolysis cell, and the working temperature for charging the electrolysis cell is such that the cathode current density is 0.3 to 0.5 A / cm ^2.
About 750 ° C.

[0004] Under the technical conditions of purification by known electrolysis cells, only aluminum of 99.99% purity can be produced. Therefore, attempts have been made to improve the purity of aluminum produced as much as possible. In the process, it has been shown that some of the impurities are caused by corrosion of the electrolytic cell lid, and furthermore, the graphitized electrode is fixed to a steel rod, ensuring a reliable contact between the graphite and the steel. It was confirmed that iron was injected into the cathode nails to cause the corrosion, and it was revealed that corrosion products could reach the melt as impurities.
Other substances, such as silicon, can enter the metal by the transport of dust.

[0005] In order to stably perform the refining electrolysis, it is necessary to observe a predetermined cleaning and inspection cycle. The following is a typical operation procedure.

[0006] 1. Cathodic carbon measurement and cleaning To obtain information on the condition of the cathodic carbon / purified aluminum interface, the cathode of each electrolytic cell is measured daily and the voltage at each individual cathode is determined. If the voltage value is lower than, for example, the minimum value of 4.5 mV, the cathode carbon is extracted. That is, the cathode carbon is moved above the furnace lid by about 6 pneumatic pressure (Pneumatikzug).
After being lifted by 00 mm, the copper rod is removed from the current rail and then transferred to the carbon purification tank. For the above operations, the cleaning operator needs direct access to the cathode carbon.

[0007] 2. Removal of Furnace Bubbles As the electrolysis process proceeds, a layer mainly consisting of aluminum oxide and electrolyte particles is formed on the surface of the cathode, here purified aluminum. This layer must be removed regularly to prevent solution movement and electrolyte mixing during removal. Often the foam layer adheres to the longitudinal side of the furnace on the inner wall, so that the foam layer must be removed at this point. Then it needs to be moved to one side, preferably near the furnace end face. Such removal of bubbles lasts about 30 minutes and is performed weekly, with removal of bubbles one after another on all furnace sides. Also, in order to remove bubbles, it is necessary to be able to freely access the furnace surface.

[0008] 3. Furnace removal (Freischlagen) During the electrolysis process, clearly visible deposits form on the furnace walls, in particular in the area where the cathode surface contacts the furnace inner wall. Usually, the deposit is removed only by
The detached debris is removed from the furnace using a defoaming spoon or squeeze. Fishing is performed about two to four times a year and takes about one hour. In order to perform the drop, the workers must be able to freely access each furnace surface.

4. Incorporation of new cathodic carbon The incorporation and commissioning of new cathodic carbon takes place in three stages, first the carbon is fixed by traverse at the lower end approximately 10 cm above the metal layer, each with a waiting time of one day Later, carbon is inserted into the metal solution. During carbon incorporation, the furnace lid remains closed and accessible to the operator.

[0010] 5. Replenishing the electrolyte to the melting layer It is necessary to open the furnace to replenish the electrolyte to the melting layer. Thereafter, the crucible with the refined melt is moved to the furnace, and the spout of the crucible is combined with the collapsible groove. When tilting the crucible, a defoaming spoon is held between the groove outlet and the metal surface to prevent the electrolyte beam from abutting the metal surface. In order to fill the electrolyte, the lid is completely lifted every few weeks, shifted about 1 m in the longitudinal direction, and filled with the electrolyte in about 10 minutes. During the filling of the electrolyte, movement of the solution is not allowed, and even a wave of 1-2 cm on the surface may have an undesirable effect on the cathode metal.

6. Temperature measurement Since temperature control is so important for the performance of the purification process in the electrolytic cell, the measurement is carried out hourly using a manual instrument, during which the furnace is opened for about one minute. The temperature must be kept constant at ± 1 ° C.

7. Measurement of the cathode layer Once a week, during the suction of the furnace, the cathode layer is measured. During the measurement of the cathode layer, the steel rod is inserted vertically into the cathode and pulled out slowly again. This process lasts about 10 minutes until a visible marking is shown on the inserted rod.

8. Melt layer height measurement The melt layer height is measured in each furnace at a 14-day rhythm. The tank opening time is about 10 minutes.

When the apparatus for producing ultra-high purity aluminum is operated as described above, a number of problems occur as described below, but they have not been satisfactorily solved so far.

First, the problem of sealing at high temperatures must be mentioned. The seal in that case is a flat, rounded, seal having a horizontal part and a vertical part on a rigid, moving surface. Due to the crusting (see 3. Furnace Drops), over time, the mounting for sealing becomes uneven. It is believed that a satisfactory seal is only possible by making the seal elastic, since the seal edge moves during each maintenance and also when renewing the inner wall. However, the seal by the seal is
High temperatures have failed due to structural problems.

In addition, for each operation inside the furnace, the lid must be flexible, easily openable and quickly closeable. However, on the other hand, it must have a remarkable stability, in particular in order to make the round graphite cathode suitable for central operation.
Furthermore, the insulating material must be of such a nature that it does not introduce even minimal impurities into the liquid metal.

In German Publication No. 1093997,
A current supply member for connecting to a cathode made of liquid aluminum in a three-layer electrolysis method is described. According to the fourth paragraph, line 59 et seq. Of the publication, a shield is attached above the upper surface of the cathode layer, and the shield is made of an aluminum plate having a thickness of about 7 mm.
The light aluminum plate forms a multi-part lid of the electrolysis cell with other shield parts for the remaining drive time, but is moved together when the electrodes move, for example when changing electrodes.

A disadvantage of this known lid, as shown in DE-A-109 39 997, is that it is not possible to walk into the lid, which is required at regular time intervals for maintenance. Further, the lid has a defect in insulation, and a gap exists between the lid portions, so that a large heat loss occurs,
There is a problem that the heat balance of the device is not desirable.

British Patent Publication GB-PS 583831 describes an apparatus for smelting electrolysis in which a lid made of a ceramic insulating material is used.
"Insulating bricks"). However, since the ceramic block described in the above publication makes the lid extremely heavy, for stability reasons, the lid must be made of strong steel which is broken, which makes it difficult to operate the electrolytic cell during electrolytic driving. (The aforementioned British Patent Publication, page 5,
line).

[0020]

Accordingly, it is an object of the present invention to make it possible to produce ultra-high-purity aluminum having a purity of more than 99.999%, for example, with an energy consumption of less than 20,000 kWh / t. To provide an ultra-high-purity aluminum manufacturing device that enables good space-time profits and suppresses heat loss, dust carry-in, fluoride release, and dust release by perfect sealing of the electrolytic cell. It is in.

[0021]

That is, the present invention (1)
Is a carbon bed in an electrolytic cell connected as an anode, a graphite cathode inserted from above into the electrolytic cell, connected longitudinally one behind the other, and reduces heat loss in the electrolytic cell. Three-layer electrolysis method comprising: a rectangular lid having an opening through which a graphite cathode is provided, and a forehearth positioned beside the electrolytic cell and supplying metal into the electrolytic cell. In the apparatus for producing ultra-high-purity aluminum from liquid metal according to claim 1, wherein said lids comprise three lids parallel to each other, arranged in one plane and arranged in the longitudinal direction of the electrolytic cell. The central lid located at the center of the lid is vertically detachable upward, and the two side lids located on the left and right sides of the central lid are rotatably arranged via a joint, The lid is made of ceramic fiber. When placed on a peripheral edge of the electrolytic cell, which is lined with a material, the contact surfaces of the three lids are thermally insulated by being brought into close contact with each other so as to be in pressure contact with each other, and against the outflow of gas. To provide sealing properties.
The graphite cathode is surrounded by a ceramic protective bell, and the apparatus provides an ultra-high-purity aluminum manufacturing apparatus in which the protective bell is introduced into a through hole formed in the central lid. .

According to the present invention (2), in the above invention (1), the edge of the lid is cut off at a corner of a thin metal plate frame, and a ceramic fiber material is inserted into the notch in a complementary shape. And an apparatus for producing high-purity aluminum in which the ceramic fiber material protrudes 1 mm to 5 mm beyond the peripheral surface of the metal sheet frame.

Preferred embodiments of the present invention will be listed below. In the present invention (3), in the above inventions (1) and (2), the narrow side of the central lid portion is placed on an end face of an electrolytic cell, and is mounted on a traverse mount whose vertical position can be adjusted. Preferably, a high-purity aluminum manufacturing apparatus is provided, which is formed of a plate-shaped frame provided with an opening through which the graphite cathode is inserted.

The present invention (4) relates to the above inventions (1) to
In (3), a high-purity aluminum manufacturing apparatus is preferable in which a movable slider is disposed in a lateral direction above the opening of the central lid, and the slider is lined with a ceramic fiber material.

The present invention (5) relates to the above inventions (1) to
In (4), each of the sliders is provided with a semicircular opening on a side facing the protection bell-shaped portion, and the radius of the opening matches the outer radius of the protection bell-shaped portion. Apparatus is preferred.

The present invention (6) relates to the above inventions (1) to
In (5), a high-purity aluminum manufacturing apparatus is preferably used in which the center lid is connected to a vertically movable support beam by a driving device mounted on a traverse base via a stay.

Further, the present invention (7) provides the above-mentioned inventions (1) to
In (6), a high-purity aluminum production apparatus in which a hook-shaped joint of a side lid is fixed to the movable support beam is preferable.

The present invention (8) relates to the above inventions (1) to
In (7), the side lid portion includes a pipe frame that makes a circuit, a metal sheet frame fixed to the pipe frame,
An insulating plate composed of a ceramic fiber material lined with the metal sheet frame, wherein the insulating plate is provided with a horizontal insulating plate and a vertical insulating plate,
The horizontal insulation plate is fixed to the underside of the sheet metal frame via a ceramic holder suspended on steel pins, while the vertical insulation plate is made of high-purity aluminum manufactured on the edge of the electrolytic cell. Apparatus is preferred.

The present invention (9) relates to the above inventions (1) to
(8) In the side lid, at least one working opening is arranged, an inner peripheral surface of the working opening is lined with a ceramic fiber material, and the working opening can be closed. The opening lid is preferably a high-purity aluminum production apparatus having a seal ring made of a ceramic fiber material.

Further, the present invention (10) relates to the above-mentioned invention (1).
In (9), a high-purity aluminum manufacturing apparatus in which a foldable and height-adjustable leg member is disposed on an end surface of the side lid portion is preferable.

Further, the present invention (11) provides the above-mentioned invention (1)
In (10), the insulating plate is made of aluminum silicate, the plate facing the outside of the furnace has an Al ₂ O ₃ content of at least 44%, and the plate facing the inside of the furnace has a content of at least 73%. An apparatus for producing high-purity aluminum having an Al ₂ O ₃ content is preferred.

According to the present invention, for example, 20,000 kW
99.999% at energy consumption less than h / t
Enables production of ultra-high-purity aluminum with above purity, easy access for workers, etc., enables good space-time profit, and complete sealing of electrolytic cell, heat loss and dust carry-in , Fluoride release and dust release can be suppressed.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-purity aluminum manufacturing apparatus according to an embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a plan view of a high-purity aluminum manufacturing apparatus of the present embodiment (hereinafter, simply referred to as “the present embodiment”), and shows a part of a lid formed of a multi-member lid. FIG. 2 is a partial cross-sectional view showing an edge region of a side lid portion among lid portions forming a lid used in the present embodiment. FIG. 3 is a partial cross-sectional view of a lid portion in a movable support beam region having a side lid portion rotatably linked among lid portions forming a lid used in the present embodiment. FIG. 4 is a side view as a partial cross section in the longitudinal direction of the present embodiment. FIG. 5 is a side view as a partial cross section in the narrow direction of the present embodiment. FIG.
FIG. 3 is a cross-sectional view of a side lid portion of a lid used in the present embodiment. FIG. 7 is a cross-sectional view of the center lid of the lid used in the present embodiment. 8 and 9 are side views of the closing plate used in the present embodiment. FIG.
FIG. 2 is a side view of the electrolytic cell according to the present embodiment.

The lid consists of a central lid 1 and two side lids 7, 8 adjacent to the left and right of the central lid 1, which are parallel to each other and arranged in one plane. And a three-part structure arranged in the longitudinal direction of the electrolytic cell (FIG. 1). Further, both the central lid 1 and the side lids 7 and 8 are made of metal sheet frames 15 and 16 and ceramic fiber material is lined. The central lid 1 is mounted on traverse racks 19 and 20 arranged on the end face of the electrolytic cell on the narrow side, and the side lids 7 and 8 are disposed above the central lid 1 in the longitudinal direction. The supporting beams 31 and 32 are mounted on the supporting beams 31 and 32, and the supporting beams 31 and 32 are connected to the traverse racks 19 and 20 (FIGS. 3 and 4). Hook-shaped joints 2, 3 are provided on the center side of the side lids 7, 8, and the joints 2, 3 are mounted in the corresponding multiple suspensions 17, 18 (FIGS. 3, 5 and 5). (Fig. 6). The side lids 7, 8 can be pivotally opened via the joints 2, 3 independently of the central lid 1.

Openings are formed in both the central lid 1 and the side lids 7 and 8. The opening of the central lid 1 can be closed via sliders 11, 12 which move laterally (FIG. 1). The slider is made of a heat-resistant steel sheet having a ceramic lining, and preferably has a semicircular terminal edge on the side facing the protective bell-shaped portion, and has a radius outside the protective bell-shaped portion. Match the radius.

A protective bell-shaped part made of a ceramic material is
When used in combination with an elastic ceramic seal formed on the inner peripheral surface of the opening, it is preferable in that the gap between the graphite cathode and the lid can be further significantly reduced. In addition, the ceramic seal and the protective bell-shaped portion,
Using similar ceramic materials with similar coefficients of thermal expansion, the movement of the graphite cathode is maintained with small tolerance values over the entire operating temperature range, and the gap between the protective bell and the ceramic sealing material is reduced. This is advantageous in that the temperature difference is kept within preset limits and the lid can be removed at any time without any problem.

The central lid 1 and the side lids 7 and 8 are both lined with a ceramic fiber material, and when placed on the peripheral edge of the electrolytic cell, contact surfaces of the three lids are provided. Are thermally insulated by being brought into close contact with each other so as to be in contact with each other, and provide sealing properties against outflow of gas. In particular,
The form of insulation of the side lids 7, 8 consists of horizontal and vertical insulating plates 23a, 23b (FIG. 2). The horizontal insulating plate 23b is fixed via a ceramic holder 43 suspended on a steel pin 6 to the lower side of the side parts 7, 8 formed as sheet metal frames 15, 16 (FIG. 7). . The vertical insulating plates 23a are elastically connected to each other and rest on the edge of the electrolytic cell. Also,
The insulating plates 23a, 23b are made of aluminum silicate, furthermore the plate facing the furnace outside has an Al ₂ O ₃ content of at least 44% and the plate facing the inside space has at least 73%. % Al ₂ O ₃
Has content.

For short-term inspection and measurement, the side lids 7 and 8 are provided with a closing plate 3 in addition to the working opening 13.
5 are provided and are similarly sealed with a ceramic insulating material (FIG. 10). The pressure required for the sealing function can be obtained in the closing plate 35 by forming the closing plane in the direction of gravity in the form of an arrow. The lid 28 and the working opening 13 in the side lids 7, 8 are provided with conical ceramic seal rings in order to likewise increase the pressing pressure.

As shown in FIG. 1, the center cover 1 has a number of openings 9, 10 corresponding to the number of electrodes, and each of the openings 9, 10 has a semicircular notch. Sealing can be performed via the sliders 11 and 12 provided. Working openings 13 are formed in one of the side lids 7, 8 of the lid for performing measurements and inspections during the operation of the three-layer electrolysis. This working opening 13 can also be closed via a separately arranged lid, as described above.

The cross section shown in FIG. 2 again shows the structure of the edge region of the lid and the arrangement of cryolite-filled water cups as seals 14 in the region of the electrolytic cell. The lid is usually a reinforced box-shaped sheet metal frame 15,
16 is a structure in which the inside of the metal sheet is lined with a ceramic fiber material, and a notch 5 is provided in a region of the metal sheet bent from the upper side of the thin sheet to the side of the thin sheet. Are inserted in a complementary manner, and the ceramic fiber material 27 projects from 1 mm to 5 mm beyond the peripheral surface of the sheet metal frame (FIG. 7). Thereby, each lid is insulated both on the mounting surface and in the side region. Also, in the gap between the lid portions 1, 7, 8
By further inserting a squashed seal made of insulating mats arranged in multiple layers, the insulating properties are further enhanced in the side regions of each lid.

The structure of insulation between the side lids 7, 8 and the edge of the electrolytic cell is shown in FIG. An insulating plate 23a stands upright on the edge of the lid.
3a absorbs the pressure of the lid applied to the edge of the tank of the electrolytic cell 29. In the central cover 1, the insulating action is important here, but the pressure absorption is not important.
3b are horizontally stacked. The advantages of a lid formed in accordance with the present invention include high insulation with a perfect seal, use of inert materials with reduced gas permeability, and space-time with flexible access to the furnace interior during operation. Income improvement.

The center cover 1 is attached to the stay 30 by multiple suspensions 17,
With 18 and multiple support, this central part can be formed very firmly even if its own weight is small, so to lift or lower the lid,
It is sufficient to apply a slight driving force on the front side of the furnace.
Further, the side lid is movable during electrolysis.
The side lids do not show any deformation, cracking or damage even during a short temperature shock. They therefore represent an optimization based on various requirements of insulation, space-time revenue and environmental protection incidents.

According to a preferred embodiment, the central lid 1
Is mounted on traverse mounts 19 and 20 shown in FIGS. 4 and 5. The traverse mounts 19 and 20 are respectively arranged on the front side of the furnace. The traverse rack 19, 2
At 0, an adjusting device 21 (cathode beam) for raising and lowering the electrode is arranged.

FIG. 6 shows a joint formed in the shape of a hook, by which the side lid of the lid can be turned around the central lid, or the hook can be removed. After that, it can be completely removed from the tank surface.

As shown in FIG. 6, a pipe frame 22 is provided around the side lid, and a thin metal sheet coating 16b for accommodating an insulating plate in the pipe frame.
Is attached. In order to be able to maintain the side lid at a predetermined distance from the top edge of the tank after opening, at least the front side of the side lid has foldable legs 2.
4 and 25 are provided. These legs are adjustable in height, so that the various opening angles of the side lids are adjustable.

As shown in FIG. 6, a hook-shaped extension in the form of a claw 26 is provided on the central lid 1 of the lid to open the side lid. Due to the large opening angle of the claw 26, the side lids 7, 8 can be easily lifted off the swinging area. If a crane is used for this purpose, this step can be limited to lifting, since the legs 24, 25 allow fixing in the open position.

FIGS. 8 and 9 show side views of the closing plate 35. FIG. The drawing shows, in addition to the closing plate 35, a holding grip 36 for the closing plate 35 and a holding plate holder 37, for example a sheet metal part, which is bolted by a bolt, a clip device or the like. It is tightly bound to the silicate molding. Calcium silicate materials are extremely temperature-resistant and have high breaking strength, so that high mechanical loads can be applied.

FIG. 10 shows a side view of an electrolytic cell 29 according to the present invention. The arrangement of the closure plate 35 is evident from the figure. The closing plate covers the overflow section 38, in particular, so that the contents cannot escape, even when the closing plate 35 is in the open state.

The electrolytic cell 29 has a wall (furnace edge 40) which, in the arrangement shown in FIG. 10, extends horizontally up to the closing plate 35, from which it extends in a V-shape. I have. On the wall (furnace edge 40), a V-shaped calcium silicate block is provided, and the mounting surfaces 35a, 3
5b covers the horizontal seal and the V-shaped point covers the open area.

At the side of the outer region of the electrolytic cell 29, the electrolytic cell 2
A ladder 34 for accessing the lid 9 is provided. Furthermore, a grid 41 is arranged on the side parts 7, 8 and is mounted in the region of the pipe frame 22 (FIG. 6). From here, the operator can open the lid 28 over the working opening 13 (FIG. 1) or open the sliders 11, 12 to manage the electrodes 42 (FIG. 4).

The closing plate 35 of the overflow section 38
Opening allows accurate temperature guidance of the furnace of ± 1 ° C. For this purpose, the closing plate 35 is
7, the closing plate grip 36 is fixed to the holder. The closing plate 35 is made of a material made of calcium silicate, and therefore has a high heat resistance, and at the same time is rigid enough to withstand the mechanical load of opening and closing the overflow 38 without damage.

The closing plate 35 is preferably fixed to the side of the electrolytic cell 29. As a result, the outflow of the furnace gas is substantially prevented, so that the emissions when operating the furnace according to the invention are very low. Furthermore, it is particularly preferred that the closing plate 35 is mounted on the side of the end face of the furnace. This is because the heat-raising winds there prevent the outflow of gaseous impurities. As an additional measure, the closure plate 35 is pointed in a V-shape towards the overflow section 38, thereby forming a relatively long gap opening through which fine temperature adjustment can be made. And the release rate is minimized at the same time.

The calcium silicate block of the closing plate 35 is formed in a T shape, and the roof surface 35a of the T roof,
It is particularly preferred that 35b be mounted on 39 built inside furnace edge 40 (wall). Thereby, the closing plate 35 can more reliably close the electrolytic cell 29.

A ladder 34 is fixed to the side of the furnace edge 40 (wall), and the ladder allows an operator to go to the furnace lid. Since the ladder 34 is fixed in the vicinity of the work opening 13, it is preferable because all handling can be performed at a short distance. Since the grid 41 is fixed in the area of the pipe frame 22 above the side parts 7, 8, the operator can easily go to the work opening. Thus, the side lids provide a working platform for cleaning and replacing the electrode or cathode carbon.

[0055]

According to the high-purity aluminum manufacturing apparatus of the present invention, since the tank / cell can be sealed, heat loss and dust carry-in can be suppressed, and the emission of fluoride and dust can be reduced by about 50%. % Can be reduced. Also, the side lid can provide a working platform for collaborators when cleaning and replacing the cathode carbon. Since the lid used in the high-purity aluminum manufacturing apparatus of the present invention has a continuous structure without a central support, an operator can easily access the work on the upper surface of the tank, and the opening time can be reduced. Also, the side lids 7, 8 can be connected via hook profiles / joints.
Can be rotatably supported. Further, since the refractory coating on the inside of the lid is inactive, it is possible to suppress the reaction product of the lid support material from reaching the inside of the tank as metal impurities. Also, the fire-resistant coating can have a double structure. In addition, the work opening provided with the closing lid 28 formed in the side lid can prevent an increase in the number of opening steps at the time of cell suction. The side lid can be moved completely and can be removed, especially during the on-off process and the electrolyte supply. In addition, heat-resistant steel can be used in places where heat is received. Also,
The minimum opening can be formed by the cathode carbon lids or sliders 11, 12 and the closing plate 35 of the overflow section 38, and accurate temperature guidance of the furnace (maintaining the operating temperature) must be performed within ± 1 ° C. Can be.

[Brief description of the drawings]

FIG. 1 is a top view showing a part of a lid formed from a multi-member lid used in an ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 2 is a partial cross-sectional view showing an edge region of a side lid used in the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 3 shows a partial cross section of a lid used in the ultra-high-purity aluminum production apparatus according to the invention in the region of a movable support beam 31 having a side part 7 which is pivotally linked. FIG.

FIG. 4 is a side view (as a partial cross section) of the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 5 is a side view (as a partial cross section) of the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 6 is a cross-sectional view of a side lid used in the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 7 is a cross-sectional view of a central lid used in the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 8 is a side view of a closing plate used in the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 9 is a side view of a closing plate used in the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

FIG. 10 is a side view of an electrolytic cell of the ultrahigh-purity aluminum manufacturing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Central lid part 2, 3 Joint 5 Notch 6 Steel pin 7, 8 Side lid part 9, 10 Opening part 11, 12 Slider 13 Working opening part 14 Seal 15, 16 Metal sheet frame, metal sheet, 17, 18 Multiple Suspension 19, 20 Traverse stand 21 Adjusting device (cathode beam) 22 Pipe frame 23a, b Insulating plate 24, 25 Leg 26 Claw 27 Ceramic fiber material 28 Lid, closing lid 29 Electrolyzer, electrolytic cell 30 Stay 31, 32 Support beam Reference Signs List 33 drive device 34 ladder, stairs 35 closing plate 35a, b mounting surface 36 closing plate grip 37 closing plate holder 38 overflow part 39 wall built inside 40 furnace edge (wall) 41 grid 42 electrode 43 ceramic holder

Claims (2)

[Claims] 1. A carbon bed in an electrolytic cell connected as an anode, a graphite cathode inserted from above into the electrolytic cell and connected one after the other in the longitudinal direction, and heat loss of the electrolytic cell A three-layer system including a rectangular lid having an opening through which a graphite cathode provided to reduce the size of the lid is located, and a forehearth located on the side of the electrolytic cell and supplying metal into the electrolytic cell. An apparatus for producing ultra-high purity aluminum from liquid metal according to an electrolysis method, wherein the lids are parallel to each other, arranged in one plane, and arranged in a longitudinal direction of the electrolytic cell. A central lid portion located at the center of the lid is vertically detachable, and two side lid portions located on the left and right sides of the central lid portion are rotatably arranged via joints. And the lid is When placed on an edge around the electrolytic cell, which is lined with a mic fiber material, the contact surfaces of the three lids are insulated so as to be in pressure contact with each other to thermally insulate the gas and allow gas to flow out. The graphite cathode is surrounded by a ceramic protective bell-shaped part, and the protective bell-shaped part is introduced into a through hole formed in the central lid part. An ultra-high-purity aluminum production apparatus. 2. An edge portion of the lid portion is formed by cutting a corner of a sheet metal frame, a ceramic fiber material is inserted into the notch in a complementary shape, and the ceramic fiber material is provided around the periphery of the sheet metal frame. 2. The high-purity aluminum production apparatus according to claim 1, wherein the apparatus projects from 1 mm to 5 mm beyond the surface.