RU2240382C2 - Anode casing of aluminum cell - Google Patents

Abstract

FIELD: non-ferrous metallurgy, possibly designs of aluminum cells.

SUBSTANCE: casing includes shell in the form of rectangular cross section box without bottom and cross beams. Casing is provided with upper and lower rigidity bands secured to upper part of shell along its sides and mutually joined by means of metallic sheet and also with additional rigidity band arranged in mean part of shell. Width of upper rigidity band exceeds that of lower rigidity band. Relation of width values of upper band to lower band along lengthwise sides of shell is in range 1 - 3. Additional rigidity band adjoins to lower one or it is spaced by distance 100 mm from lower rigidity band and from shell. Cross beams have steps on their end portions and they are placed onto upper rigidity band. Height of said steps consists 15 - 50% of height of mean portion of beam.

EFFECT: enhanced quality of anode, improved technical and economic factors of cell with self-fired anode.

4 cl, 1 dwg

Description

The invention relates to non-ferrous metallurgy and can be used in electrolyzers to produce aluminum by electrolytic method.

Known is the anode casing of the electrolyzer with a self-burning anode and an upper current lead of the S-8BM type, containing a shell, U-shaped buttresses cut into the upper part of the shell along the height of the transverse buttress beam, a stiffening belt along the longitudinal sides at the level of the lower edge of the buttress beam and the gas collector belt in the lower parts of [1, 2].

During operation, the anode casing is constantly supported upward. The result is the loosening of the anode mass in the area of the buttress beams and the formation of cavities under them, which leads to a decrease in the quality of the anode, especially “dry” (with a low binder content).

The closest in technical essence is the anode casing of an aluminum electrolyzer containing a shell in the form of a box without a bottom with a rectangular cross-section and transverse buttresses, consisting of stiffeners and transverse beams connected to the walls of the casing, installed relative to the lower edge of the casing at a distance of 0.825 - 0.995 of its longitudinal height walls [3].

The disadvantages of this anode casing: increased deformation of the walls of the anode shell during operation, leading to a decrease in the quality of the anode, and a decrease in the constriction of the anode frame due to the removal of buttresses from the body of the anode. As a result, the technical and economic indicators of the electrolyzer are reduced.

Constant loads act on the anode casing: the mass of the anode, the hydraulic pressure of the “liquid phase”. During operation, there are periodic loads associated with servicing the lateral parts of the anode and hauling the frame. Under the influence of these loads, as well as thermal effects, the anode casing is deformed both in the vertical plane - deflection, and in the horizontal - barrel-shaped casing. When the longitudinal walls are deflected, the probability of the formation of transverse cracks in the anode increases, the anode is partially “exposed” - the oxidation surface increases. With horizontal deformation, the largest of which is in the lower part of the shell, the likelihood of breakthrough of the pitch increases when the casing is supported and the cell is depressurized. And, as a consequence of this, the consumption of the anode mass increases, intense pricing and a violation of the normal course of the cell arise.

The anode casing in the cell occupies a middle position between the cathode and the anode frame. The binding of the cathode and the anode frame to the building structures eliminates the possibility of changing the height of the anode casing without compromising performance. Removal of buttresses from the anode, i.e. installation on the shell leads to a decrease in the distance between the buttress and the anode frame. This may cause a decrease in the anode frame constriction, since the constriction beam is mounted on buttresses, the size increases from the surface of the anode to the beam clamps, as a result of which the clamp cannot cover the lower pin head. There is a need to reduce the height of the waist.

The listed disadvantages that reduce the quality of the anode and the technical and economic indicators of the electrolyzer were identified when testing such casings at the Krasnoyarsk aluminum smelter.

The objective of the present invention is to improve the quality of the anode and the technical and economic indicators of the electrolytic cell with a self-baking anode when using the anode mass with a reduced content of binder, "dry" and "dry", by reducing the deformation of the anode casing and eliminating the influence of the transverse beams on the size of the waist.

To solve this problem, the known anode casing of the electrolyzer for aluminum production, containing a shell in the form of a box without a bottom with a rectangular cross section and transverse beams, according to the invention is equipped with upper and lower stiffness belts, fixed in the upper part of the shell along its sides and interconnected by a metal sheet moreover, the width of the upper stiffening belt is greater than the width of the lower, as well as an additional stiffening belt located in the middle part of the shell.

The proposed design is complemented by private distinctive features aimed at solving the problem.

The ratio of the width of the stiffening belts of the upper to the lower along the longitudinal sides of the shell is 1.0-3.0.

An additional stiffening belt is adjacent to the lower stiffening belt or is located at a distance of up to 100 mm from the lower stiffening belt and from the shell.

The transverse beams are made with ledges at the ends and are mounted on the upper stiffening belt, and the height of the ledges of the transverse beams is from 15 to 50% of the height of the beam in its middle part.

Replacing buttresses with transverse beams with ledges at the ends with a height of 15 to 50% of the height of the beam in its middle part and installing them on the upper stiffening belt under the devices for anode frame hauling allows the removal of transverse beams from the anode body with installation on the upper stiffening belt without reduction the size of the banner.

The implementation of the upper stiffening belt with a width greater than 1.0-3.0 times relative to the lower, as well as the installation of an additional stiffening belt in the middle part of the shell, increase the bearing capacity and stiffness of the walls of the anode casing without reducing the service area of the cell. As a result, deformation of the anode casing is reduced.

The drawing shows a cross section of the anode casing.

The anode casing of the electrolyzer for producing aluminum consists of a shell 1, stiffening belts of the upper 2 and lower 3, an inclined wall 4, transverse beams 5, an additional stiffening belt 6, a gas collector belt 7 and ribs 8. The shell 1 is made of sheet material and is a box without bottom having a rectangle in cross section. To it, along the sides, the upper 2 and lower 3 stiffeners are attached. The width of the upper stiffener 2 is greater than the width of the lower 3 by 1.0-3.0 times. Fulfillment of the ratio less than 1.0 times is ineffective, since an increase in the bearing capacity and gain stiffness is negligible, and with an increase in the ratio more than three times the service area of the cell decreases and the material consumption for the manufacture of the casing increases. An inclined wall 4 is attached to the stiffening belts 2, 3. An additional stiffening belt 6 is attached to the lower stiffening belt 3 and to the shell 1, which, in turn, is connected to the gassing band 7 with ribs 8. The additional stiffening belt 6 can be separated from the stiffening belt 3, and from the shell 1 at a distance of 100 mm and be installed on the stiffening ribs 8. At a greater distance from the shell, the gain cross section should be reduced to provide access to the processing equipment, which will lead to a decrease in the bearing capacity of additional gain .

On the upper stiffening belt 2, transverse beams 5 are installed, which are performed with ledges at both ends under the beam for constricting the anode frame. The height of the ledges is from 15 to 50% of the height of the beam in its middle part. Reducing the height of the beam in the area of the sites by less than 15% of its height in the middle part does not exclude the height of the waist, and a decrease of more than 50% leads to a decrease in the strength of the beam.

An increase in the bearing capacity and rigidity of the walls of the casing allows the transverse beams made with ledges to be removed from the anode body without reducing the anode constriction, and reduces the anode deformation. Reducing deformation allows you to get a better anode by reducing oxidation of the side surface, sticking to the casing due to leakage of the binder, reducing the formation of cracks in it and reducing the consumption of the anode mass. This, in turn, allows to reduce the negative impact of the anode on the process and improve the technical and economic performance of the cell.

The anode casing of this design is being tested at the KrAZ OJSC (Krasnoyarsk Aluminum Plant).

Sources of information

1. Handbook of mechanics of non-ferrous metallurgy. M.: Metallurgy, 1981, pp. 399-402.

2. Damn. YOU 70668. The casing is anode.

3. RF patent 2078855, cl. C 25 C 3/12, BI No. 13, 1997.

Claims (4)

1. The casing of the anode electrolyzer for the production of aluminum, containing a shell in the form of a box without a bottom with a rectangular cross section and transverse beams, characterized in that it is equipped with upper and lower stiffness belts, mounted in the upper part of the shell along its sides and interconnected by a metal sheet, moreover, the width of the upper stiffening belt is greater than the width of the lower, and an additional stiffening belt located in the middle part of the shell. 2. The casing according to claim 1, characterized in that the ratio of the width of the stiffening belts of the upper to the lower along the longitudinal sides of the shell is 1.0-3.0. 3. The casing according to claim 1, characterized in that the additional stiffening belt is adjacent to the lower stiffening belt or is located at a distance of up to 100 mm from the lower stiffening belt and from the shell. 4. The casing according to claim 1, characterized in that the transverse beams are made with ledges at the ends and are mounted on the upper stiffening belt, the height of the ledges of the transverse beams being from 15 to 50% of the height of the beam in its middle part.