RU208227U1 - ALUMINUM ELECTROLYSER GAS COLLECTOR - Google Patents

Abstract

The utility model relates to the field of non-ferrous metallurgy, namely to the electrolysis production of aluminum, and can be used to capture gases from Soderberg electrolyzers with a self-baking anode and an upper current lead. The gas collecting bell of the aluminum electrolytic cell is made of hinged sections fastened by means of brackets to the horizontal belt of the anode casing and having inclined walls, while vertical stiffening ribs are placed on the outer surface of the walls of the sections, and the hinged sections with ribs are made of aluminum in the form of monolithic products. The technical result consists in improving the grade of produced raw aluminum by eliminating the ingress of iron and silicon into the electrolyte melt. 5 z.p. f-ly, 3 ill.

Description

Technology area

The utility model relates to the field of metallurgy of non-ferrous metals, namely to the electrolysis production of aluminum, and can be used to capture gases from Soderberg electrolyzers with a self-baking anode and an upper current lead.

State of the art

Electrolyzers of the "Soderberg" type have been known for more than half a century; they produce primary raw aluminum. The main disadvantages of using electrolysers of this type are: outdated design, increased labor intensity and production of low-grade primary aluminum. The impurity of the aluminum produced on this type of electrolyzer depends on the materials and raw materials used, which can transfer Fe, Si and other impurities into the molten electrolyte. The main materials "suppliers" of Fe and Si for the melt in the electrolyzer are articles made of ferrous metals (steel, cast iron), namely, anode pins, anode frame, sections of a gas collecting bell (GSC), tools used for technological processing.

With the development of technical capabilities, the development of materials and the improvement of the design of electrolyzers, new designs of electrolyzer shelters appear in order to improve the sealing of the bell-shaped space, as well as to improve the resistance. Currently, inventions are known (Patent RU2582421, publ. 04/27/2016), where the cover of the electrolytic cell for the production of aluminum, in contact with the vapor-gas phase during its operation, contains central and peripheral sections mounted with the ability to move relative to each other, while the central and peripheral sections are made of corrosion-resistant and erosion-resistant material containing 80.0-99.0 wt. % fluoroflogopite and 20.0-1.0 wt. % refractory filler.

This refractory coating should exclude oxidation of the surface of the sections and the transfer of the material of the sections to the electrolyte. This method has significant drawbacks: the coating is damaged during the installation of the sections on the anode casing, as a result of which the refractory material enters the electrolyte melt, contaminates it and promotes increased foaming in the electrolyzer. A device for aspiration of anode gases on an electrolyzer with an upper current lead is known, containing sections of a gas-collecting bell installed at the anode, while in the bell at the lower part of the anode, plates are installed parallel and at a distance of no more than 5 cm from the side surface of the anode, preventing the ingress of the electrolyte being poured into the sections gas collection bell and into the gas evacuation channel (Patent RU2484184, publ. 10.06.2013). The use of the known device does not have a practical effect, since the corrosive environment in the bell-tower space corrodes the surface of heat-resistant / heat-resistant materials, and these alloys have high fragility, which affects the service life and the cost of using these sections.

The closest to the created gas-collecting bell (prototype) is the gas-collecting bell of an aluminum electrolyzer (patent RU2151825, publ. 06/27/2000), made of hinged sections fastened with brackets to the horizontal belt of the anode casing and having external inclined, middle horizontal and internal walls, with In this case, the inner walls of the sections are made resting on the anode casing, and in the inner space of the sections there are vertical ribs rigidly connected to their walls, while the brackets are rigidly connected to the horizontal walls of the sections in their middle part, and the center of gravity of the sections is displaced relative to their attachment point on the anode the casing towards their outer walls. The prototype has the following disadvantages:

vertical ribs are made in the inner space of the sections, which, under the influence of the corrosive environment and the temperature of the bell space, first of all burn out and give more Fe and Si to the cell melt; additionally, the internal ribs reduce the flow rate of gases into the burners, in this regard, the process of removal and afterburning of the formed gases slows down, which reduces the efficiency of the gas removal system.

the sections are made of cast iron, which increases the load on the anode casing attachment unit and, therefore, when the section warms up, the anode attachment unit deforms and breaks the tightness of the bell space;

The design feature of the sections does not allow the most efficient removal of heat from the outer surface of the sections, as a result of which they overheat and burn out locally.

the design of the sections does not provide for the isolation of the assembly on which the sections are attached from the effects of temperature and corrosion of the gases formed in the belly space, as a result of which the horizontal belt of the anode casing is locally out of order.

In the claimed utility model, in comparison with the prototype, there are the following differences and advantages:

the inner surface of the bell sections does not contain ribs, angles that impede gas flows, but has smooth transitions from the inner side of the horizontal shelf to the main wall, providing a smooth direction of gas flows, which allows not to increase the temperature of the bell space and does not contribute to an increase in gas permeability through the joints between the bell sections ;

the inner surface of the sections contains a horizontal shelf with a thickness of up to 2-4 times greater than the thickness of the anode frame collar in order to reduce the effect of temperature and corrosion and extend the service life of the anode frame collar on which the sections are hung;

the use of ribs on the outer surface of the sections contributes not only to the creation of structural strength, but also to the creation of additional area for the removal of temperature from the surface of the section in order to reduce the risk of overheating and burnout;

The created design of the sections lowers the temperature of the outer surface of the entire gas-collecting bell and increases its service life.

Disclosure of a utility model

The technical task of the claimed utility model is to increase the grade of the obtained raw aluminum by eliminating the ingress of iron and silicon into the melt.

The technical task is performed due to the fact that the gas-collecting bell of the aluminum electrolyzer is made of hinged sections, attached by means of brackets to the horizontal band of the anode casing and having inclined walls, according to the claimed utility model, vertical stiffeners are placed on the outer surface of the section walls, while the hinged sections with ribs made in the form of monolithic aluminum products.

The bell additionally contains a horizontally located shelf, fixed on the inner surface of the hinged sections and located under the anode casing band, while the thickness of the horizontal shelf exceeds the thickness of the anode casing band by 2-4 times.

Suspended sections with stiffeners and a horizontal shelf can be made in the form of monolithic or prefabricated aluminum products.

The walls of the sections are connected with side flanges to each other by means of detachable connectors through holes made on the side flanges of the walls of the sections.

The angle of inclination of the main wall of the sections can be 40-70 degrees relative to the horizontal shelves.

The thickness of the walls of the sections between the stiffeners can reach 1.5-2 times the thickness of the walls of the sections between the side flanges and the extreme ribs.

Brief Description of Drawings

The essence of the utility model is illustrated by drawings.

FIG. 1 shows a section of the GSK for an automatic alumina feeding device (APG), as well as sections A-A and B-B of FIG. one; in fig. 2 shows a straight section HSC and section A-A in FIG. 2; in fig. 3 shows a general view of the GSK in section.

The utility model shown in the figures consists of the following structural elements:

1 - wall of the hinged section;

2 - shelf of the hinged section;

3 - side flanges of the hinged section;

4 - stiffeners;

5 - bracket;

6 - holes.

The device works as follows

The gas-collecting bell performs the functions of collecting and afterburning the formed gases in an aluminum electrolyzer during the production of raw aluminum. GSK allows you to concentrate gases in certain places under the bell space, burn them and send combustion products to the gas cleaning system. Each section of the bell has a main wall (1) located at a positive angle (from 45 ° to 70 °) relative to the shelf of the hinged section (2), which helps to isolate the collar of the anode casing of the electrolyzer from corrosion, and also acts as a thermal element that removes the temperature from the collar with the purpose of extending its service life. The sections have vertical side flanges (3), which facilitate a tight fit between the sections to create a hermetically sealed podkolokolny space. The sections contain stiffeners (4) located on the outer surface of the main wall (1) of the hinged section, stiffeners (4) allow maintaining the geometric dimensions of the sections when exposed to sub-bell temperature, and also contribute to the creation of additional planes for cooling by natural or artificial convection and preventing overheating / reflow sections. The sections contain a bracket (5) located in the upper part of the sections for fixing them on the shoulder of the anode casing relative to the anode frame of the aluminum electrolyzer and adjacent sections. The vertical flanges (3) have holes (6) that are necessary to accommodate tightening tools (threaded pins, wedge pins, etc.). The sections are made of primary (grades A5, A7E, A85, etc.) or secondary (grades AB87, AB97, AK5M2) aluminum or an aluminum alloy, for example, with silicon, manganese or magnesium, as a result of which the weight of HSC is less than 75% than that of sections made of ferrous metals. The temperature of the outer surface of aluminum sections is lower (up to 100 ° C) than on sections made of ferrous metals. Aluminum sections allow to withstand the temperature of the bell space up to 600 ° C and can provide a bell-electrolyte distance of ± 4-6 cm, which helps to increase the tightness of the bell space. At the same time, it is not required to insulate the upper surface of the GSK and to process the inner surfaces of the bell space of the GSK with special paints and coatings, and the laboriousness of manufacturing and fixing aluminum sections is up to 60% lower in relation to similar sections made of ferrous metals.

During operation, the aluminum gas-collecting bell is naturally covered in the under-bell space with a protective layer of solidified electrolyte, which creates a coating that prevents the sections from melting and local overheating. The design of the aluminum bell helps to maintain the required technological heat balance of the electrolyzer.

Claims (6)

1. A gas-collecting bell of an aluminum electrolyzer, containing hinged sections attached by means of brackets (5) to the horizontal band of the anode casing and having inclined walls (1), characterized in that vertical stiffeners (4) are placed on the outer surface of the walls (1) of the sections, the hinged sections with ribs are made in the form of monolithic aluminum products. 2. The bell according to claim 1, characterized in that it further comprises a horizontally located shelf (2) fixed on the inner surface of the walls (1) of the hinged sections and located under the belt of the anode casing, while the thickness of the horizontal shelf exceeds the thickness of the anode casing belt by 2 -4 times. 3. The bell according to claim 1, characterized in that the hinged sections with stiffeners (4) and a horizontal shelf (2) are made in the form of monolithic or prefabricated aluminum products. 4. Bell according to claim 1, characterized in that the walls of the sections are connected by side flanges (3) to each other by means of detachable connectors through holes (6) made on the side flanges (3) of the walls of the hinged sections (1). 5. The bell according to claim 1, characterized in that the angle of inclination of the walls of the hinged sections (1) is 40-70 degrees relative to the horizontal shelf (2). 6. The bell according to claim 1, characterized in that the wall thickness of the hinged sections (1) between the stiffeners (4) is 1.5-2 times greater than the wall thickness of the sections between the side flanges (3) and the extreme stiffeners (4).

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