Pre-desiliconization tank overflowing material treatment system and method in aluminum oxide production

Abstract

The invention discloses a pre-desiliconization tank overflowing treatment system in aluminum oxide production, which comprises a first pre-desiliconization tank, a second pre-desiliconization tank, a third discharge tank, a fourth discharge tank and a fifth buffer tank which are sequentially connected through discharge pipes, and further comprises a needle-shaped tank which is arranged in the first pre-desiliconization tank, the second pre-desiliconization tank, the third discharge tank, the fourth discharge tank and the fifth buffer tank, a first overflow pipe is connected between the groove wall above the discharge pipe on the No.1 pre-desiliconization groove and the lower part of the needle-shaped groove, the bottom of the needle-shaped groove is connected with a feeding pipe, a pump is arranged on the feeding pipe, and the discharge end of the feeding pipe is connected with at least one of a No.3 discharge groove, a No.4 discharge groove and a No.5 buffer groove; the system solves the problem of material overflowing of the first pre-desiliconization tank and the second pre-desiliconization tank, and can ensure ore pulp supply at the rear end of the pre-desiliconization system, so that ore pulp balance of the pre-desiliconization system is achieved, the ore pulp of the pre-desiliconization system can be ensured not to be interrupted, and normal operation of two groups of dissolution production is ensured; the invention further discloses a pre-desiliconization tank overflowing treatment method in aluminum oxide production.

Description

Technical Field

[0001] The present invention relates to the field of alumina production by the Bayer process, and particularly to a system and method for treating the overflow of a pre-desilication tank during alumina production. Background Art

[0002] Before the pulp enters the digestion process during the production of alumina by the Bayer process, pre-desilication treatment is required to prevent a large amount of silicon minerals in the pulp from scaling in the digestion process system, which affects the heat exchange efficiency of the system and increases the steam consumption. The existing pre-desilication system includes a No. 1 pre-desilication tank, a No. 2 pre-desilication tank, a No. 3 discharge tank, a No. 4 discharge tank, and a No. 5 buffer tank. The pulp ground by the mill enters the No. 1 pre-desilication tank and after the first pre-desilication treatment, it overflows through the discharge pipe into the No. 2 pre-desilication tank, where the second pre-desilication treatment is carried out. Then, it overflows from the No. 2 pre-desilication tank through the discharge pipe into the No. 3 discharge tank, from the No. 3 discharge tank through the discharge pipe into the No. 4 discharge tank, and from the No. 4 discharge tank through the discharge pipe into the No. 5 buffer tank. Under normal circumstances, the pulp is discharged from the No. 4 discharge tank to the digestion system, and the pulp in the No. 5 buffer tank is pumped into the No. 3 discharge tank by a circulation pump. When the liquid level in the No. 5 buffer tank reaches the lowest level, the pulp is discharged from the No. 3 discharge tank to the digestion system. When multiple mills are under maintenance, it may cause the liquid level in the No. 5 buffer tank to reach the lowest level. At this time, the liquid level in the No. 4 discharge tank cannot meet the production demand, and it is necessary to fully operate the mills for feeding. When the mills are fully operated, a large amount of foam will be generated. The foam enters the No. 1 pre-desilication tank together with the pulp and continuously accumulates on the top of the No. 1 pre-desilication tank, forming a dense layer, resulting in an increase in the internal gas pressure of the No. 1 pre-desilication tank. After reaching the critical pressure, the gas breaks through the foam layer and overflows, causing a large amount of foam to flow out along the observation hole at the top of the No. 1 desilication tank, that is, the overflow phenomenon occurs; due to the influence of the ore, some ores will generate a large amount of non-condensable gas during the pre-desilication process, resulting in more intense foaming in the No. 1 pre-desilication tank. A large amount of foam overflows from the No. 1 pre-desilication tank, causing a large number of fine pulp particles to be carried out of the tank by the foam, resulting in a large fluctuation in the liquid level of the No. 1 pre-desilication tank. Even worse, the foam will also enter the No. 2 pre-desilication tank together with the pulp, causing an overflow phenomenon in the No. 2 pre-desilication tank. This overflow phenomenon will cause the pulp to overflow from the front end to the back end of the pre-desilication system and gradually decrease, resulting in insufficient pulp supply at the back end and unable to maintain the normal operation of two groups of digestion production. Summary of the Invention

[0003] In view of this, one of the objectives of the present invention is to provide a system for treating the overflow of a pre-desilication tank during alumina production to at least solve the technical problems proposed in the background art; the second objective of the present invention is to provide a method for treating the overflow of a pre-desilication tank during alumina production.

[0004] One of the objectives of the present invention is achieved through the following technical solutions: A system for dealing with material overflow in a pre-desilication tank during alumina production, which includes a No. 1 pre-desilication tank, a No. 2 pre-desilication tank, a No. 3 discharge tank, a No. 4 discharge tank and a No. 5 buffer tank. The No. 1 pre-desilication tank, the No. 2 pre-desilication tank, the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank are sequentially connected through a discharge pipe. It further includes a needle-shaped tank. There is a first overflow pipe connecting the tank wall above the discharge pipe of the No. 1 pre-desilication tank and the lower part of the needle-shaped tank. The bottom of the needle-shaped tank is connected with a feeding pipe, and a pump is arranged on the feeding pipe. The discharging end of the feeding pipe is connected with at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank.

[0005] Furthermore, the needle-shaped tank is provided with a defoaming device.

[0006] Furthermore, there is a second overflow pipe connecting the tank wall above the discharge pipe of the No. 2 pre-desilication tank and the lower part of the needle-shaped tank.

[0007] Furthermore, the lower end of the discharge pipe in the No. 1 pre-desilication tank is connected with a first material receiving pipe penetrating through the tank wall of the No. 1 pre-desilication tank. The first material receiving pipe is connected with the feeding pipe, and a valve is arranged on the first material receiving pipe.

[0008] Furthermore, the lower end of the discharge pipe in the No. 2 pre-desilication tank is connected with a second material receiving pipe penetrating through the tank wall of the No. 2 pre-desilication tank. The second material receiving pipe is connected with the feeding pipe, and a valve is arranged on the second material receiving pipe.

[0009] Furthermore, the feeding pipe includes a main pipe, a first branch pipe and a second branch pipe connected to the discharging end of the main pipe. The pump is arranged on the main pipe. A valve is arranged on the first branch pipe and it is connected with at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank through a pipeline. A valve and a standby pump are sequentially arranged on the second branch pipe along the slurry flow direction. The discharging end of the second branch pipe is connected with at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank through a pipeline.

[0010] Furthermore, the needle-shaped tank is a tank with an open top.

[0011] Furthermore, the height of the needle-shaped tank is 26 meters and the diameter is 1.2 meters.

[0012] The second object of the present invention is achieved through the following technical solutions: A method for dealing with material overflow in a pre-desilication tank during alumina production, adopting the above-mentioned system for dealing with material overflow in a pre-desilication tank during alumina production. It uses the first overflow pipe to introduce the slurry above the discharge pipe in the No. 1 pre-desilication tank into the lower part of the needle-shaped tank, uses the second overflow pipe to introduce the slurry above the discharge pipe in the No. 2 pre-desilication tank into the lower part of the needle-shaped tank, uses the defoaming device to eliminate the foam of the slurry in the needle-shaped tank, and uses the feeding pipe and the pump to send the slurry at the bottom of the needle-shaped tank into at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank.

[0013] Furthermore, it also uses the first slurry receiving pipe to introduce a part of the slurry at the lower end of the discharge pipe in the No. 1 pre-desilication tank into the feeding pipe, and uses the second slurry receiving pipe to introduce a part of the slurry at the lower end of the discharge pipe in the No. 2 pre-desilication tank into the feeding pipe, and the slurry is sent into at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank by the feeding pipe and the pump.

[0014] The beneficial effects of the present invention are as follows: The pre-desilication tank overflow treatment system in alumina production proposed by the present invention uses the first overflow pipe to introduce a part of the slurry above the discharge pipe in the No. 1 pre-desilication tank into the lower part of the needle-shaped tank, and uses the second overflow pipe to introduce a part of the slurry above the discharge pipe in the No. 2 pre-desilication tank into the lower part of the needle-shaped tank. The defoaming device is used to eliminate the foam of the slurry in the needle-shaped tank, and the slurry at the bottom of the needle-shaped tank is sent into at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank by the feeding pipe and the pump, which solves the problem of overflow in the No. 1 pre-desilication tank or both the No. 1 and No. 2 pre-desilication tanks, and can ensure the slurry supply at the rear end of the pre-desilication system. In this way, the slurry balance of the pre-desilication system is achieved, and the slurry supply of the pre-desilication system can be ensured without interruption, so as to ensure the normal operation of the two groups of digestion production. The needle-shaped tank has a high height and a small diameter and has a defoaming function itself.

[0015] Using the first slurry receiving pipe to introduce a part of the slurry at the lower end of the discharge pipe in the No. 1 pre-desilication tank into the feeding pipe, and using the second slurry receiving pipe to introduce a part of the slurry at the lower end of the discharge pipe in the No. 2 pre-desilication tank into the feeding pipe, and the slurry is sent into at least one of the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank by the feeding pipe and the pump, further solves the problem of overflow in the No. 1 pre-desilication tank or both the No. 1 and No. 2 pre-desilication tanks, and can ensure the slurry supply at the rear end of the pre-desilication system.

[0016] A standby pump is provided to avoid the abnormal operation of the system after the pump is damaged.

[0017] The pre-desilication tank overflow treatment method in alumina production proposed by the present invention is simple and easy to implement.

[0018] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent description, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings, wherein: Figure 1 It is a schematic structural diagram of the present invention.

[0020] In the figure: discharge pipe 1, first overflow pipe 2, second overflow pipe 3, first material receiving pipe 4, second material receiving pipe 5, main pipe 6, first branch pipe 7, second branch pipe 8, pump 9, standby pump 10. Specific embodiments

[0021] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, rather than for limiting the protection scope of the present invention.

[0022] Embodiment 1 As Figure 1 shown in the pre-desilication tank overflow treatment system in alumina production, which includes No. 1 pre-desilication tank, No. 2 pre-desilication tank, No. 3 discharge tank, No. 4 discharge tank and No. 5 buffer tank. The No. 1 pre-desilication tank, No. 2 pre-desilication tank, No. 3 discharge tank, No. 4 discharge tank and No. 5 buffer tank are sequentially connected through the discharge pipe 1. This is the prior art. The improvement lies in that it further includes a needle-shaped tank. The needle-shaped tank is a tank with an open top. The height of the needle-shaped tank is 26 meters and the diameter is 1.2 meters. The needle-shaped tank is provided with a defoaming device, and the defoaming device is a defoaming agent adding device. A first overflow pipe 2 is connected between the tank wall above the discharge pipe 1 on the No. 1 pre-desilication tank and the lower part of the needle-shaped tank. A second overflow pipe 3 is connected between the tank wall above the discharge pipe 1 on the No. 2 pre-desilication tank and the lower part of the needle-shaped tank. The lower end of the discharge pipe 1 in the No. 1 pre-desilication tank is connected with a first material receiving pipe 4 that penetrates through the tank wall of the No. 1 pre-desilication tank. A valve is provided on the first material receiving pipe 4. The lower end of the discharge pipe 1 in the No. 2 pre-desilication tank is connected with a second material receiving pipe 5 that penetrates through the No. 2 pre-desilication tank. A valve is provided on the second material receiving pipe 5. The bottom of the needle-shaped tank is connected with a feeding pipe, and a valve is provided at the feeding end of the feeding pipe. The first material receiving pipe 4 and the second material receiving pipe 5 are connected to the feeding pipe. The feeding pipe includes a main pipe 6 and a first branch pipe 7 and a second branch pipe 8 connected to the discharging end of the main pipe 6. A pump 9 is provided on the main pipe 6. A valve is provided on the first branch pipe 7 and it is connected to two pipes. Valves are respectively provided on the two pipes. One of the pipes is connected to the No. 3 discharge tank and the No. 4 discharge tank, and the other pipe is connected to the No. 5 buffer tank. A valve and a standby pump 10 are sequentially provided on the second branch pipe 8 along the slurry flow direction. The discharging end of the second branch pipe 8 is connected to two other pipes. Valves are respectively provided on these two other pipes. One of the pipes is connected to the No. 3 discharge tank and the No. 4 discharge tank, and the other pipe is connected to the No. 5 buffer tank.

[0023] When the pulp in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks reaches the first overflow pipe 2 or the first overflow pipe 2 and the second overflow pipe 3, close the valves on the first receiving pipe 4 and the second receiving pipe 5, so that the pulp in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks enters the needle-shaped tank through the first overflow pipe 2 or the first overflow pipe 2 and the second overflow pipe 3. Add defoaming agent to the needle-shaped tank through the defoaming device. After defoaming, start the pump to send the pulp at the bottom of the needle-shaped tank into the No. 5 buffer tank through the main pipe 6, the first branch pipe 7 and the pipeline to replenish the No. 5 buffer tank.

[0024] When the pulp level in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks exceeds the set liquid level above the first overflow pipe 2 or the first overflow pipe 2 and the second overflow pipe 3, open the valve on the first receiving pipe 4 or open the valves on the first receiving pipe 4 and the second receiving pipe 5, so that a part of the pulp at the lower end of the discharge pipe 1 in the No. 1 pre-desilication tank or a part of the pulp at the lower end of the discharge pipe 1 in the No. 1 pre-desilication tank and a part of the pulp at the lower end of the discharge pipe in the No. 2 pre-desilication tank enter the main pipe 6 through the first receiving pipe 4 or the first receiving pipe 4 and the second receiving pipe 5. At the same time, the pulp in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks enters the needle-shaped tank through the first overflow pipe 2 or the first overflow pipe 2 and the second overflow pipe 3. Add defoaming agent to the needle-shaped tank through the defoaming device. After defoaming, the pulp in the needle-shaped tank enters the main pipe 6, the first branch pipe 7 and the pipeline in sequence, so as to send the pulp in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks into the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank to replenish them.

[0025] When the pump 9 is under maintenance, close the valve on the first branch pipe 7, open the valve on the second branch pipe 8 and start the standby pump 10 to send the pulp into the No. 5 buffer tank or the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank to replenish them.

[0026] This system solves the problem of material overflow in the No. 1 pre-desilication tank or the No. 1 and No. 2 pre-desilication tanks, and can ensure the pulp supply at the rear end of the pre-desilication system, so as to achieve the pulp balance of the pre-desilication system, ensure that the pulp in the pre-desilication system does not interrupt, and thus ensure the normal operation of the two groups of digestion production. The needle-shaped tank has a high height and a small diameter and has a defoaming function itself.

[0027] Embodiment 2 A method for treating the overflow of the pre-desilication tank in alumina production, using the above-mentioned system for treating the overflow of the pre-desilication tank in alumina production. It introduces the pulp above the discharge pipe 1 in the No. 1 pre-desilication tank into the lower part of the needle-shaped tank through the first overflow pipe 2, and introduces the pulp above the discharge pipe 1 in the No. 2 pre-desilication tank into the lower part of the needle-shaped tank through the second overflow pipe 3. The defoaming device is used to eliminate the foam in the pulp in the needle-shaped tank, and the pulp at the bottom of the needle-shaped tank is sent into the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank by the main pipe 6, the first branch pipe 7, the pipeline and the pump.

[0028] It also introduces a part of the pulp at the lower end of the discharge pipe 1 in the No. 1 pre-desilication tank into the feed pipe through the first receiving pipe 4, and introduces a part of the pulp at the lower end of the discharge pipe 1 in the No. 2 pre-desilication tank into the main pipe 6 through the second receiving pipe 5, and then sends it into the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank through the main pipe 6, the first branch pipe 7, the pipeline and the pump.

[0029] When the pump 9 is under maintenance, start the standby pump 10 to send the pulp at the lower part of the needle-shaped tank, a part of the pulp at the lower end of the discharge pipe in the No. 1 pre-desilication tank, and a part of the pulp at the lower end of the discharge pipe in the No. 2 pre-desilication tank into the No. 3 discharge tank, the No. 4 discharge tank and the No. 5 buffer tank.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A system for handling overflow in the pre-desilication tank during alumina production, which includes a No. 1 pre-desilication tank, a No. 2 pre-desilication tank, a No. 3 discharge tank, a No. 4 discharge tank, and a No. 5 buffer tank. The No. 1 pre-desilication tank, the No. 2 pre-desilication tank, the No. 3 discharge tank, the No. 4 discharge tank, and the No. 5 buffer tank are sequentially connected through a discharge pipe (1), and it is characterized in that: It also includes a needle-shaped groove. A first overflow pipe (2) is connected between the groove wall above the upper discharge pipe (1) of the No. 1 pre-desilication tank and the lower part of the needle-shaped groove. A feeding pipe is connected to the bottom of the needle-shaped groove. A pump (9) is provided on the feeding pipe. The discharging end of the feeding pipe is connected to at least one of a No. 3 discharging tank, a No. 4 discharging tank, and a No. 5 buffer tank.

2. The pre-desilication tank overflow treatment system in alumina production according to claim 1, wherein: The needle-shaped groove is provided with a defoaming device.

3. The pre-desilication tank overflow treatment system in alumina production according to claim 1, wherein: A second overflow pipe (3) is connected between the groove wall above the upper discharge pipe of the No. 2 pre-desilication tank and the lower part of the needle-shaped groove.

4. The pre-desilication tank overflow treatment system in alumina production according to claim 1, characterized in that: The lower end of the inner discharge pipe (1) of the No. 1 pre-desilication tank is connected to a first material receiving pipe (4) passing through the groove wall of the No. 1 pre-desilication tank. The first material receiving pipe (4) is connected to the feeding pipe. A valve is provided on the first material receiving pipe (4).

5. The pre-desilication tank overflow treatment system in alumina production according to any one of claims 1-4, characterized in that: The lower end of the inner discharge pipe (1) of the No. 2 pre-desilication tank is connected to a second material receiving pipe (5) passing through the groove wall of the No. 2 pre-desilication tank. The second material receiving pipe (5) is connected to the feeding pipe. A valve is provided on the second material receiving pipe (5).

6. The pre-desilication tank overflow treatment system in alumina production according to claim 1, characterized in that: The feeding pipe includes a main pipe (6), a first branch pipe (7), and a second branch pipe (8) connected to the discharging end of the main pipe (6). The pump (9) is provided on the main pipe (6). A valve is provided on the first branch pipe (6) and it is connected to at least one of a No. 3 discharging tank, a No. 4 discharging tank, and a No. 5 buffer tank through a pipeline. A valve and a standby pump (10) are sequentially provided on the second branch pipe (8) along the slurry flow direction. The discharging end of the second branch pipe (8) is connected to at least one of a No. 3 discharging tank, a No. 4 discharging tank, and a No. 5 buffer tank through a pipeline.

7. The pre-desilication tank overflow treatment system in alumina production according to claim 1, wherein: The needle-shaped groove is a groove with an open top.

8. The pre-desilication tank overflow treatment system in alumina production according to claim 1, wherein: The height of the needle-shaped groove is 26 meters and the diameter is 1.2 meters.

9. A method for treating the overflow of the pre-desilication tank in alumina production, characterized in that: Adopting the pre-desilication tank overflow treatment system in alumina production according to any one of claims 1-8, it uses the first overflow pipe (2) to introduce part of the slurry above the inner discharge pipe (1) of the No. 1 pre-desilication tank into the lower part of the needle-shaped groove, uses the second overflow pipe (3) to introduce part of the slurry above the inner discharge pipe (1) of the No. 2 pre-desilication tank into the lower part of the needle-shaped groove, uses a defoaming device to eliminate foam from the slurry in the needle-shaped groove, and uses the feeding pipe and the pump (9) to send the slurry at the bottom of the needle-shaped groove into at least one of a No. 3 discharging tank, a No. 4 discharging tank, and a No. 5 buffer tank.

10. The method for treating the overflow of the pre-desilication tank in alumina production according to claim 9, characterized in that: It also uses the first material receiving pipe (4) to introduce part of the slurry at the lower end of the inner discharge pipe (1) of the No. 1 pre-desilication tank into the feeding pipe, uses the second material receiving pipe (5) to introduce part of the slurry at the lower end of the inner discharge pipe (1) of the No. 2 pre-desilication tank into the feeding pipe, and is sent into at least one of a No. 3 discharging tank, a No. 4 discharging tank, and a No. 5 buffer tank by the feeding pipe and the pump.

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