Electrolytic cell for graphitized aluminum and furnace wall forming method thereof

Abstract

The invention relates to the technical field of electrolytic cell furnace walls, and provides a graphitized aluminum electrolytic cell which comprises a cell body, an insulating layer, a carbon block layer, a heat exchange assembly and a circulation assembly. The heat exchange assembly comprises a first heat exchange box, a second heat exchange box and a heat exchange pipe. The insulating layer is attached to the inner side wall of the groove body; the carbon block is arranged in one end, close to the insulating layer, of the groove body; the first heat exchange box is clamped between the insulating layer and the carbon block layer; the second heat exchange box is externally arranged on the side, close to the first heat exchange box, of the tank body; the heat exchange pipe is arranged between the first heat exchange box and the second heat exchange box in a reciprocating penetrating mode from the top of the groove body to the bottom of the groove body in the vertical direction. And the heat exchange pipe is communicated with the circulating assembly. The electrolytic cell for graphitized aluminum provided by the invention can promote the formation of a furnace wall which is uniform in thickness, suitable and high in stability, and can also prevent the extending legs from being too long.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic cell furnace walls, and in particular to an electrolytic cell for graphitized aluminum and a method for forming the furnace walls thereof. Background Art

[0002] In the process of electrolytic aluminum production, the furnace wall has an important impact on the operation efficiency, energy consumption and quality of aluminum products of the electrolytic cell. The furnace wall is mainly a circle of solid electrolyte blocks formed by the condensation of molten electrolyte along the inner wall of the tank chamber. Through its continuous and different thicknesses, it constitutes the tank chamber space, and the electrochemical and physicochemical reactions of aluminum electrolysis are carried out in this space to realize the electrolysis process.

[0003] However, the formation process of the furnace side is affected by many factors, such as temperature conditions, potential conditions, and the structure of the electrolytic cell. In the condensation process, the temperature conditions affect the thickness of the furnace side at various positions in the electrolytic cell. In the prior art, condensed water or cold air blowing is usually used to adjust the thickness of the furnace side. For example, the electrolytic cell disclosed in the patent with the announcement number is specifically increased by using the side blowing condensation at the minimum thickness of the furnace side through the addition of cooling air ducts and wind shields.

[0004] However, in the prior art, although the local thickness of the side of the electrolytic cell can be controlled, the thickness and length of the furnace side legs cannot be controlled during the process, and the furnace side legs are too long, which causes the furnace area to be reduced, making the anode current density too large, generating secondary reactions, causing sodium ion discharge and precipitation, and reducing the impact of electrical efficiency;

[0005] Based on the above description, there is an urgent need for an electrolytic cell for graphitized aluminum having high stability and suitable leg length and a method for forming the sidewall thereof. Summary of the invention

[0006] The first object of the present invention is to provide an electrolytic cell for graphitized aluminum, which can promote the formation of a furnace wall with uniform thickness, suitable and high stability, and can also avoid excessive leg extension.

[0007] The embodiments of the present invention are implemented by the following technical solutions:

[0008] An electrolytic cell for graphitized aluminum comprises a cell body, an insulating layer, a carbon block layer, a heat exchange component and a circulation component; the heat exchange component comprises a first heat exchange box, a second heat exchange box and a heat exchange tube; the insulating layer is attached to the inner wall of the cell body; the carbon block is arranged inside the cell body at one end close to the insulating layer; the first heat exchange box is sandwiched between the insulating layer and the carbon block layer; the second heat exchange box is arranged outside the cell body at one side close to the first heat exchange box; the heat exchange tube is reciprocated and penetrates between the first heat exchange box and the second heat exchange box along a vertical direction from the top of the cell body to the bottom of the cell body; the heat exchange tube is connected to the circulation component.

[0009] Preferably, the circulation component includes multiple first circulation pumps and multiple second circulation pumps; the heat exchange tube includes a first pipe section and a second pipe section; the first pipe section is reciprocated between the first heat exchange box and the second heat exchange box along a vertical direction from the top of the tank body to the bottom of the tank body; the second pipe section is arranged in the second heat exchange box; the first circulation pump and the second circulation pump are connected in parallel between the first pipe section and the second pipe section.

[0010] Preferably, the first circulation pump is connected to a first buffer water tank; the second circulation pump is connected to a second buffer water tank.

[0011] Preferably, the first heat exchange box is a stepped box; the carbon block layer is attached to each step surface of the stepped box.

[0012] Preferably, the first heat exchange box is divided into a plurality of heat exchange chambers by a plurality of heat insulation plates.

[0013] Preferably, a third buffer tank is provided in the second heat exchange tank; and the first pipe section and the second pipe section are both connected to the third buffer tank.

[0014] Preferably, the second pipe section is a spiral pipe.

[0015] The second object of the present invention is to provide a method for forming a furnace wall of an electrolytic cell for graphitizing aluminum, comprising the following steps:

[0016] S1: The first stage: start the electrolytic cell, positively adjust the flow direction of the heat exchange medium, and reduce the voltage according to the gradient;

[0017] S2: The second stage: reversely adjust the flow direction of the heat exchange medium, slowly increase the amount of aluminum, control the temperature in the electrolytic cell and adjust the molecular ratio.

[0018] Preferably, in step S1, the period of the first stage is 30 days, and the voltage adjustment range is 3.8-4.4V.

[0019] Preferably, in step S2, the cycle of the second stage is 1-12 weeks, the aluminum level adjustment range is 16-20 cm, the temperature range is 945-985°C, and the molecular ratio is 2.8-3.

[0020] Herein, the molecular ratio is the molar ratio of sodium fluoride to aluminum fluoride.

[0021] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0022] (1) The graphitized aluminum electrolytic cell provided by the present invention adjusts the flow direction of the heat exchange medium by adjusting the circulation component, and utilizes the temperature change of the heat exchange medium in the heat exchange path to first condense at the top of the carbon block layer to form a furnace wall of a certain thickness, while the bottom of the carbon block layer condenses to form a furnace wall thinner than the top. After multiple cycles of condensation, a furnace wall slope that shrinks toward the Chengdu tank wall of the electrolytic cell is formed at the inner top of the electrolytic cell, and the length and thickness of the legs formed by the electrolytic cell can be limited;

[0023] (2) By further observing the contraction angle of the furnace side slope, the water inlet direction of the heat exchange medium is adjusted again, so that the bottom of the carbon block layer further condenses into a furnace side with a certain thickness, and the heat exchange medium is transported from the bottom of the tank body to the top of the tank body. Furthermore, since the furnace side with a certain thickness has been condensed on the top, the furnace side has a certain thermal insulation and heat insulation effect. Further combined with the formed contraction slope, the electrolyte fluidity is increased. Therefore, the furnace side on the top is condensed thinner during this condensation process, thereby forming a furnace side with uniform thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A first structural schematic diagram of an electrolytic cell provided in an embodiment of the present invention;

[0026] Figure 2 for Figure 1 An enlarged schematic diagram of the local structure A;

[0027] Figure 3 A second structural schematic diagram of an electrolytic cell provided in an embodiment of the present invention;

[0028] Figure 4 for Figure 3 An enlarged schematic diagram of the local structure B;

[0029] Figure 5This is the trend chart of furnace side thickness.

[0030] Icons: 1-tank body, 2-insulation layer, 3-carbon block layer, 4-heat exchange component, 41-first heat exchange box, 42-second heat exchange box, 43-heat exchange tube, 431-first pipe section, 432-second pipe section, 5-circulation component, 51-first circulation pump, 52-second circulation pump, 6-first buffer water tank, 7-second buffer water tank, 8-insulation board, 9-third buffer tank. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Example 1

[0037] The following is further described in conjunction with specific embodiments. Figure 1 -Attached Figure 5 As shown, specifically, an electrolytic cell for graphitized aluminum includes a cell body 1, an insulating layer 2, a carbon block layer 3, a heat exchange component 4 and a circulation component 5; the heat exchange component 4 includes a first heat exchange box 41, a second heat exchange box 42 and a heat exchange tube 43; the insulating layer 2 is attached to the inner wall of the cell body 1; the carbon block is arranged in the cell body 1 at one end close to the insulating layer 2; the first heat exchange box 41 is sandwiched between the insulating layer 2 and the carbon block layer 3; the second heat exchange box 42 is externally arranged on one side of the cell body 1 close to the first heat exchange box 41; the heat exchange tube 43 is reciprocated between the first heat exchange box 41 and the second heat exchange box 42 along the vertical direction from the top of the cell body 1 to the bottom of the cell body 1; the heat exchange tube 43 is connected to the circulation component 5.

[0038] In this embodiment, in the first stage of the process of forming the furnace sidewall by electrolysis, the heat exchange medium (heat transfer oil or condensed water) is positively transported from the top to the bottom of the electrolytic cell body 1 by adjusting the circulation component 5. By utilizing the temperature change of the heat exchange medium in the heat exchange path, the top of the carbon block layer 3 is first condensed to form a furnace sidewall of a certain thickness, while the bottom of the carbon block layer 3 is condensed to form a furnace sidewall thinner than the top. After multiple cycles of condensation, a furnace sidewall slope that shrinks toward the Chengdu tank wall of the electrolytic cell is formed at the inner top of the electrolytic cell, and the length and thickness of the legs formed by the electrolytic cell can also be limited.

[0039] In the second stage, the contraction angle of the furnace side slope is observed (the inclination angle is 30-60°), and the water inlet mode of the heat exchange medium is adjusted, that is, it is transported from the bottom to the top of the electrolytic cell, so that the bottom of the carbon block layer 3 is further condensed into a furnace side with a certain thickness, and the heat exchange medium is transported from the bottom to the top of the cell body 1. Furthermore, since the top has condensed a furnace side with a certain thickness, and the furnace side has a certain thermal insulation and heat insulation effect, further combined with the formed contraction slope, the electrolyte fluidity is increased, so that the furnace side at the top is condensed thinner during this condensation process, thereby forming a furnace side with uniform thickness.

[0040] In this embodiment, the second heat exchange box 42 can use a heat exchanger for heat exchange and cooling. Specifically, a plate heat exchanger can be used as the heat exchanger to exchange heat for the heat exchange medium in the inner cavity of the second heat exchange box 42, thereby exchanging heat for the heat exchange tubes in the second heat exchange box 41; or a shell-and-tube heat exchanger can be directly used as the second heat exchange box 42.

[0041] Specifically, as attached Figure 2As shown, the circulation component 5 includes multiple first circulation pumps 51 and multiple second circulation pumps 52; the heat exchange tube 43 includes a first pipe section 431 and a second pipe section 432; the first pipe section 431 is reciprocated between the first heat exchange box 41 and the second heat exchange box 42 along the vertical direction from the top of the tank body 1 to the bottom of the tank body 1; the second pipe section 432 is arranged in the second heat exchange box 42; the first circulation pump 51 and the second circulation pump 52 are connected in parallel between the first pipe section 431 and the second pipe section 432.

[0042] In this embodiment, the first circulating pump 51 is connected to the first buffer water tank 6; the second circulating pump 52 is connected to the second buffer water tank 7. The branch pipes where the first circulating pump 51 and the second circulating pump 52 are located are both provided with pipe valves to adjust the direction of the heat exchange medium; in order to prevent scalding, the buffer water tank and the circulating pump are built into the heat insulation cover, and a heat exchanger can be further arranged in the heat insulation cover for cooling, which can also reduce the workload of the circulating pump.

[0043] Specifically, as attached Figure 2 As shown, the first heat exchange box 41 is a stepped box; the carbon block layer 3 is attached to each stepped surface of the stepped box. The first heat exchange box 41 is divided into a plurality of heat exchange chambers by a plurality of heat insulation plates 8.

[0044] In this embodiment, the stepped box body is used to facilitate supporting the carbon block layer 3 and ensure the stability of the carbon block layer 3 during the furnace side formation process, and can also fully contact the carbon block layer 3 to facilitate efficient heat exchange and form a furnace side with appropriate thickness.

[0045] Specifically, as attached Figure 2 As shown, the third buffer tank 9 is arranged in the second heat exchange tank 42; the first pipe section 431 and the second pipe section 432 are both connected to the third buffer tank 9. The second pipe section 432 is a spiral tube.

[0046] In this embodiment, the third buffer box 9 and the spiral tube are used to facilitate sufficient heat exchange and improve the condensation efficiency.

[0047] In this embodiment, the voltage adjustment gradient in the electrolytic cell in the first stage is shown in Table 1:

[0048] Table 1

[0049]

[0050] In this embodiment, the aluminum level control parameters of the second stage are shown in Table 2:

[0051] Table 2

[0052]

[0053]

[0054] In this embodiment, the second stage tank temperature and the corresponding molecular ratio control parameters are shown in Table 3:

[0055]

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electrolytic cell for graphitized aluminum, characterized in that: The invention comprises a tank body (1), an insulating layer (2), a carbon block layer (3), a heat exchange component (4) and a circulation component (5); the heat exchange component (4) comprises a first heat exchange box (41), a second heat exchange box (42) and a heat exchange pipe (43); the insulating layer (2) is attached to the inner wall of the tank body (1); the carbon block is arranged inside the tank body (1) at one end close to the insulating layer (2); the first heat exchange box (41) is sandwiched between the insulating layer (2) and the carbon block layer (3); the second heat exchange box (42) is arranged outside the tank body (1) at one side close to the first heat exchange box (41); the heat exchange pipe (43) is reciprocatedly penetrated between the first heat exchange box (41) and the second heat exchange box (42) along a vertical direction from the top of the tank body (1) to the bottom of the tank body (1); the heat exchange pipe (43) is connected to the circulation component (5).

2. The electrolytic cell for graphitized aluminum according to claim 1, characterized in that: The circulation component (5) comprises a plurality of first circulation pumps (51) and a plurality of second circulation pumps (52); the heat exchange tube (43) comprises a first tube section (431) and a second tube section (432); the first tube section (431) is reciprocated between the first heat exchange box (41) and the second heat exchange box (42) along a vertical direction from the top of the tank body (1) to the bottom of the tank body (1); the second tube section (432) is arranged inside the second heat exchange box (42); the first circulation pump (51) and the second circulation pump (52) are connected in parallel between the first tube section (431) and the second tube section (432).

3. The electrolytic cell for graphitized aluminum according to claim 2, characterized in that: The first circulation pump (51) is connected to a first buffer water tank (6); and the second circulation pump (52) is connected to a second buffer water tank (7).

4. The electrolytic cell for graphitized aluminum according to claim 2 or 3, characterized in that: The first heat exchange box (41) is a stepped box body; the carbon block layer (3) is attached to each stepped surface of the stepped box body.

5. The electrolytic cell for graphitized aluminum according to claim 4, characterized in that: The first heat exchange box (41) is divided into a plurality of heat exchange chambers by a plurality of heat insulation plates (8).

6. The electrolytic cell for graphitized aluminum according to claim 2, characterized in that: A third buffer tank (9) is provided in the second heat exchange tank (42); the first pipe section (431) and the second pipe section (432) are both in communication with the third buffer tank (9).

7. The electrolytic cell for graphitized aluminum according to claim 6, characterized in that: The second pipe section (432) is a spiral pipe.

8. A method for forming a furnace ridge using the electrolytic cell for graphitized aluminum according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: The first stage: start the electrolytic cell, positively adjust the flow direction of the heat exchange medium, and reduce the voltage according to the gradient; S2: The second stage: reversely adjust the flow direction of the heat exchange medium, slowly increase the amount of aluminum, control the temperature in the electrolytic cell and adjust the molecular ratio.

9. The method for forming a furnace ridge in an electrolytic cell for graphitized aluminum according to claim 8, characterized in that: In step S1, the cycle of the first stage is 30 days, and the voltage regulation range is 3.8-4.4V.

10. The method for forming a furnace ridge in an electrolytic cell for graphitized aluminum according to claim 8, characterized in that: In step S2, the cycle of the second stage is 1-12 weeks, the aluminum level adjustment range is 16-20 cm, the temperature range is 945-985°C, and the molecular ratio is 2.8-3.

Images