Low-power-consumption decomposition tank material passing system for aluminum oxide production

Abstract

The invention discloses an aluminum oxide production low-power-consumption decomposition tank material passing system which comprises one or more air supply devices connected in parallel, a compressed air storage tank and one or more decomposition tanks, the output ends of the air supply devices are communicated with the compressed air storage tank, and the output ends of the compressed air storage tank are respectively communicated to the decomposition tanks through air supply pipelines; the air supply device is a low-pressure air supply device, a discharging pipe is arranged in the decomposing tank, and an arc-shaped flow guide plate is arranged at the lower end of the discharging pipe; the arc-shaped flow guide plate is of a dustpan-shaped special structure with a wide upper part and a narrow upper part and an arc-shaped edge; an inlet of the arc-shaped flow guide plate faces the flowing direction of materials in the decomposing tank; a communicated material lifting air pipe is arranged on the air supply pipeline, and the end of the material lifting air pipe is inserted into the discharging pipe. The operation cost and construction investment of an air compression station and a circulating water system matched with the seed decomposition process can be reduced, scabs at the bottom of the decomposition tank can be effectively reduced, the cleaning difficulty of the decomposition tank is reduced, the cleaning cost is saved, and the system productivity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of seed precipitation in alumina production, and specifically to an overfeeding system for a low-power consumption precipitation tank in alumina production. Background Art

[0002] In the alumina production process, the seed precipitation process is one of the important processes in alumina production. The seed precipitation process consists of a large number of precipitation tanks connected in series. The material flow between the precipitation tanks is realized through the discharge pipe inside the precipitation tank and the overfeeding chute connected outside the tank.

[0003] In order to ensure smooth overfeeding, a certain height difference is set between the precipitation tanks. However, a large amount of high-pressure compressed air still needs to be introduced into the discharge pipe inside the precipitation tank through the lifting air pipe. Using the principle of communicating vessels, the aluminum hydroxide slurry in the discharge pipe is diluted to achieve local negative pressure, so as to promote the material at the bottom of the precipitation tank to overflow into the discharge overfeeding chute at the upper part of the precipitation tank through the discharge pipe, and then flow by gravity into the next precipitation tank through the chute.

[0004] The main problems existing in the current conventional overfeeding system for precipitation tanks are as follows: Due to the large overfeeding volume of the precipitation tank, a large amount of high-pressure compressed air needs to be introduced into the discharge pipe inside the precipitation tank. It is necessary to set up a special high-pressure air compressor station and a supporting circulating water station. The air compressor station usually selects multiple high-pressure screw air compressors, cooling towers, and circulating water pumps. The power consumption of equipment operation is high, and a large amount of water and heat are dissipated in the circulating water system. The equipment maintenance workload is large; Due to the work done by the air compressor, the high-pressure compressed air is heated up, and the heat of the high-temperature compressed air is brought into the precipitation tank, which has an adverse impact on the seed precipitation system.

[0005] The conventional discharge pipe of the precipitation tank inserts the lifting air pipe into the discharge pipe inside the precipitation tank. The insertion depth is 5-10 m from the bottom of the precipitation tank and more than 30 m from the top of the precipitation tank. The bottom of the discharge pipe is cut at a 45° angle.

[0006] Scaling at the bottom of the precipitation tank is serious, and the scaling height on the tank wall exceeds 3 m. The cleaning cycle is short, and cleaning needs to be carried out every 6-10 months. Each cleaning takes about 10-15 days. The cleaning difficulty is large and the cleaning cost is high. Summary of the Invention

[0007] In view of the above-mentioned disadvantages and deficiencies, the present invention provides a low-power feeding system for a decomposition tank in alumina production. By using a low-pressure air supply device as the air source for the lifting air of the decomposition tank and through an improved discharge pipe of the decomposition tank, the operating costs and construction investments of the air compressor station and the circulating water system supporting the seed decomposition process can be effectively reduced. It includes one or more air supply devices connected in parallel, a compressed air storage tank, and one or more decomposition tanks. The output end of the air supply device is connected to the compressed air storage tank, and the output end of the compressed air storage tank is respectively connected to the decomposition tanks through air supply pipelines; the air supply device is a low-pressure air supply device, and a discharge pipe is provided inside the decomposition tank, and an arc-shaped guide plate is provided at the lower end of the discharge pipe; the arc-shaped guide plate is wider at the top and narrower at the bottom, with an arc-shaped edge and a special structure in the shape of a dustpan. The inlet of the arc-shaped guide plate faces the direction of material flow in the decomposition tank; a lifting air pipe is connected to the air supply pipeline, and the end of the lifting air pipe is inserted into the inside of the discharge pipe.

[0008] When there are multiple decomposition tanks, each decomposition tank is connected in sequence and has a height difference.

[0009] The insertion depth of the lifting air pipe inserted into the discharge pipe of the decomposition tank is 10 - 20 meters from the top of the decomposition tank.

[0010] The air supply device includes an efficient liquid-cooled air suspension blower, an air-cooled air suspension blower, a magnetic suspension blower, a Roots blower, or a single-stage high-speed centrifugal blower that does not require a large amount of supporting circulating water and cooling tower systems.

[0011] The air supply device provides a set pressure range of compressed air between 0.1 - 0.3 MPa.

[0012] A blower outlet valve and a flow meter are sequentially provided at the outlet of the air supply device. An inlet valve is provided at the inlet end of the compressed air storage tank, an outlet valve is provided at the outlet end, a safety valve is provided at the top, a drain valve is provided at the bottom, and a pressure gauge is connected to the compressed air storage tank.

[0013] The beneficial effects of the present invention are as follows: The present invention is a low-power feeding system for a decomposition tank in alumina production. By using a low-pressure air supply device as the air source for the lifting air of the decomposition tank and through the setting positions of the arc-shaped guide plate, the discharge pipe of the decomposition tank, and the lifting air pipe, the operating costs and construction investments of the air compressor station and the circulating water system supporting the seed decomposition process can be effectively reduced, the power consumption of the seed decomposition feeding system can be reduced, the floor area of the seed decomposition process and supporting facilities can be reduced. The present invention can effectively reduce the scale formation at the bottom of the decomposition tank, reduce the cleaning difficulty of the decomposition tank, save cleaning costs, effectively improve the equipment operation rate, and increase the system production capacity; The decomposition tank of the present invention can be replaced with a pre-desilication tank or a causticization tank in the alumina production technology field and used in its feeding system to achieve the same technical effects. Description of the Drawings

[0014] Figure 1 This is a schematic flow diagram of a low-power feeding system for an alumina production decomposition tank according to the present invention.

[0015] In the figure: 1 is a low-air-pressure air supply device, 2 is a compressed air storage tank, 3 is an air supply pipeline, 4 is a material lifting air pipe, 5 is a decomposition tank, 6 is a discharge pipe, 7 is an arc-shaped guide plate, 8 is a first valve, 9 is a second valve, 10 is a third valve, 11 is a fourth valve, 12 is a flow meter, and 13 is a pressure gauge. Specific embodiments

[0016] The present invention will be further described below with reference to the accompanying drawings of the specification. As Figure 1 shown, a low-power feeding system for an alumina production decomposition tank according to the present invention includes two low-air-pressure air supply devices 1 connected in parallel, a compressed air storage tank 1, and three decomposition tanks 5. Each decomposition tank 5 is connected in sequence and has a height difference.

[0017] The low-air-pressure air supply device 1 can select high-efficiency liquid-cooled air suspension blowers, air-cooled air suspension blowers, magnetic suspension blowers, Roots blowers, or single-stage high-speed centrifugal blowers, etc. that do not require a large amount of circulating water and a cooling tower system. The pressure range of the compressed air provided by the low-air-pressure air supply device 1 is set between 0.1 - 0.3 MPa.

[0018] The decomposition tank can select a pre-desilication tank or a causticization tank in the technical field of alumina production.

[0019] The output end of the low-air-pressure air supply device 1 is connected to the compressed air storage tank 1, and the output end of the compressed air storage tank 1 is respectively connected to the decomposition tank 5 through the air supply pipeline 3; A first valve 8 and a flow meter 12 are sequentially provided at the outlet of the low-air-pressure air supply device 1. A second valve 9 is provided at the inlet end of the compressed air storage tank 2, a third valve 10 is provided at the outlet end, a safety valve is provided at the top, a drain valve is provided at the bottom, and the compressed air storage tank 2 is connected with a pressure gauge 13.

[0020] A discharge pipe 6 is provided in the decomposition tank 5, and an arc-shaped guide plate 7 is provided at the lower end of the discharge pipe 6; the arc-shaped guide plate 7 is wider at the top and narrower at the bottom, with an arc-shaped edge and a special structure of a dustpan type. The inlet of the arc-shaped guide plate 7 faces the direction of material flow in the decomposition tank; a connected material lifting air pipe 4 is provided on the air supply pipeline 3, and the end of the material lifting air pipe 4 is inserted into the discharge pipe 6; the insertion depth of the material lifting air pipe 4 into the discharge pipe 6 is 10 - 20 meters from the top of the decomposition tank 5.

[0021] In use, fill the decomposition tank with slurry, start the low-air-pressure air supply device 1, and open the first valve 8. When the pressure gauge value is between 0.1 - 0.3 MPa within the set pressure range, open the fourth valve. The slurry in the decomposition tank is stirred. Under the action of the material lifting air pipe 4 and the arc-shaped guide plate 7, the initial kinetic energy of the material entering the discharge pipe 6 can be effectively utilized to ensure smooth discharge. The slurry is smoothly transported to the next decomposition tank through the discharge pipe.

[0022] Observe the discharge condition of the material in the discharge pipe of the decomposition tank. By adjusting the opening degree of the fourth valve, ensure that the discharge flow rate of the discharge pipe is in a stable state; observe the air supply flow rate of the low-pressure air supply device 1 through the flow meter 12. The rotation speed of the low-pressure air supply device is adjusted according to the value of the compressed air pressure gauge to ensure that the compressed air pressure is between the set pressure range of 0.1 - 0.3 MPa.

[0023] The present invention uses a low-pressure air supply device as the air source for the material lifting air in the decomposition tank. By setting the positions of the arc-shaped guide plate, the decomposition tank discharge pipe, and the material lifting air pipe, the operating costs and construction investments of the air compressor station and the circulating water system supporting the seed decomposition process can be effectively reduced, the power consumption of the seed decomposition material passing system can be reduced, and the floor area occupied by the seed decomposition process and its supporting facilities can be reduced; moreover, the scarring at the bottom of the decomposition tank can be effectively reduced, the cleaning difficulty of the decomposition tank can be reduced, the cleaning cost can be saved, the equipment operation rate can be effectively improved, and the system production capacity can be increased.

[0024] The decomposition tank of the present invention can be replaced with a pre-desilication tank or a causticization tank in the field of alumina production technology. When used in its filtration system, the same technical effects can be achieved.

[0025] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications after learning the basic creative concepts; therefore, the claims should be interpreted to include the preferred embodiments as well as various modifications and variations that fall within the spirit and scope of the invention without departing from the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies.

Claims

1. A low-power consumption decomposition tank feeding system for alumina production, characterized in that: It comprises one or more air supply devices, compressed air storage tanks and one or more decomposition tanks connected in parallel, wherein the output end of the air supply device is connected with the compressed air storage tank, and the output end of the compressed air storage tank is connected to the decomposition tank through an air supply pipeline; the air supply device is a low-pressure air supply device, a discharge pipe is arranged in the decomposition tank, and an arc-shaped guide plate is arranged at the lower end of the discharge pipe; the arc-shaped guide plate is wide at the top and narrow at the top, has an arc-shaped edge, and has a special dustpan-shaped structure, and the inlet of the arc-shaped guide plate faces the material flow direction in the decomposition tank; a connected material lifting air duct is arranged on the air supply pipeline, and the end of the material lifting air duct is inserted into the discharge pipe.

2. A low power consumption decomposition tank feeding system for aluminum oxide production according to claim 1, characterized in that: When there are multiple decomposition grooves, each decomposition groove is connected in sequence and has a height difference.

3. The low power consumption decomposition tank feeding system for aluminum oxide production according to claim 1 is characterized in that: The insertion depth of the material lifting air duct into the discharging pipe of the decomposition tank is 10-20 meters from the top of the decomposition tank.

4. The low power consumption decomposition tank feeding system for aluminum oxide production according to claim 1 is characterized in that: The air supply device includes a high-efficiency liquid-cooled air suspension blower, an air-cooled air suspension blower, a magnetic suspension blower, a Roots blower or a single-stage high-speed centrifugal blower that does not require a large amount of circulating water and a cooling tower system.

5. The low power consumption decomposition tank feeding system for aluminum oxide production according to claim 1 is characterized in that: The air supply device provides compressed air with a set pressure range of 0.1-0.3MPa.

6. A low power consumption decomposition tank feeding system for aluminum oxide production according to claim 1, characterized in that: The outlet of the air supply device is provided with a fan outlet valve and a flow meter in sequence, the air inlet end of the compressed air storage tank is provided with an inlet valve, the air outlet end is provided with an outlet valve, the top is provided with a safety valve, the bottom is provided with a drain valve, and the compressed air storage tank is connected to a pressure gauge.

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