Aluminum electrolysis cell aluminum oxide continuous blanking intelligent crust breaking device and control method

Abstract

The invention discloses an aluminum electrolysis cell aluminum oxide continuous discharging intelligent crust breaking device and a control method. The technical problems that in the prior art, aluminum oxide is prone to being accumulated at a discharging opening, and a crust breaking hammer head is prone to adhering to a bag and being corroded are solved. The crust breaking device comprises a continuous discharging mechanism, a crust breaking mechanism and a control system, the continuous discharging mechanism and the crust breaking mechanism are both controlled by the control system, a laser ranging mechanism is arranged to accurately control the crust breaking stroke, an existing crust breaking pneumatic pipeline structure is improved, and the crust breaking air cylinder stroke control precision is improved; a cooling device is designed to ensure stable operation of the cylinder stroke laser ranging device in a high-temperature environment; on the basis of continuous blanking of aluminum oxide, the aluminum oxide can enter electrolyte more uniformly by improving the crust breaking mode of the electrolytic cell, and the dissolving effect is better. The device has the beneficial technical effects of accelerating electrolyte dissolution, avoiding tank bottom precipitation, improving the current efficiency of the electrolytic tank, effectively prolonging the service life of the crust breaking hammer head and reducing the labor intensity of workers.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum electrolysis, and in particular to an intelligent shelling device for continuous feeding of aluminum oxide in an aluminum electrolysis cell and a control method thereof. Background Art

[0002] The existing aluminum electrolytic cells adopt fixed volume centralized feeding, and the cell control machine uses the under-overfeed control method to feed at the specified intervals, with each feeding amount of about 1.2-1.8 liters. Since the alumina powder is fed into the electrolytic cell in a short time (5-10 seconds), it will cause the normal temperature alumina to enter the electrolyte in a short time, dissolve and absorb more heat, and the electrolyte temperature near the feeding port will drop, and the solubility of alumina will deteriorate, which is easy to form precipitation at the bottom of the electrolytic cell. Over time, scarring will form at the bottom of the cell, causing the horizontal current in the electrolytic cell to increase, affecting the current efficiency and the life of the cell. To this end, the relevant technicians designed a continuous feeding mechanism to continuously and evenly control the feeding amount by controlling the speed of the spiral feeding.

[0003] The existing shelling method is to shell the alumina before unloading, to ensure that the fire eye is open and the alumina can smoothly enter the electrolyte. Each time the shell is broken, the cylinder moves at full stroke. The shelling hammer head is easily worn and corroded by the shell surface and the electrolyte during long-term shelling operations, which eventually leads to the inability of the hammer head to effectively break the shell. The life of the hammer head is generally 4-6 months. In addition, the shelling hammer head goes deep into the electrolyte solution, and the hammer head is in contact with the electrolyte for a long time. The upper part of the hammer head frequently forms sticky bags, which seriously affects the smoothness of alumina entering the electrolyte, causing unstable production and operation of the electrolytic cell, and also greatly increasing the power consumption per ton of aluminum. At the same time, workers need to deal with the sticking of the hammer head on a regular basis, and often open the cover plate. The heat dissipation in the upper part of the tank is large, and the unorganized emission of smoke is large, and the labor intensity of workers is very high.

[0004] The pneumatic pipeline of the shelling cylinder is connected to the air control cabinet next to the electrolytic cell. A large amount of compressed air remains in the pipeline, causing the solenoid valve in the air control cabinet to move when it receives the command, but the cylinder movement has a large lag, making it impossible to accurately control the cylinder stroke, and the purpose of intelligent and precise shelling cannot be achieved. Summary of the invention

[0005] The invention provides an intelligent shelling device and a control method for continuous feeding of alumina in an aluminum electrolytic cell, so as to solve the technical problems in the prior art that alumina is easily accumulated at a feeding port and a shelling hammer is easily stuck and corroded.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: An intelligent shelling device for continuous feeding of aluminum oxide in an aluminum electrolytic cell is designed, comprising a continuous feeding mechanism, a shelling mechanism, and a control system, wherein the continuous feeding mechanism and the shelling mechanism are both controlled by the control system, the shelling mechanism comprises a shelling cylinder, a connecting rod, a shelling hammer, a distance measuring mechanism, and a distance measuring target, a shelling reversing solenoid valve is arranged on the top of the shelling cylinder, and an air inlet pipeline and an air outlet pipeline are connected to the shelling reversing solenoid valve to drive the shelling cylinder; The bottom of the shell breaking cylinder is connected to the connecting rod to drive the connecting rod to reciprocate up and down, the shell breaking hammer head is connected to the bottom of the connecting rod, the distance measuring mechanism is connected to the shell breaking cylinder, and the distance measuring target is connected to the connecting rod and is arranged corresponding to the distance measuring mechanism.

[0007] The existing shelling pneumatic pipeline structure was modified, and the shelling control solenoid valve originally located in the air control cabinet next to the electrolytic cell was moved to the top of the shelling cylinder on the upper part of the cell and directly connected to the cylinder. The pneumatic pipeline between the shelling cylinder and the shelling control solenoid valve was shortened, avoiding the lagging effect of compressed air retained in this part of the pipeline on the cylinder stroke control, which greatly improved the stroke control accuracy of the shelling hammer head.

[0008] Furthermore, the distance measuring mechanism is a laser distance measuring module, which is fixed to the top of the shelling cylinder through a bracket. The shelling depth is monitored in real time by laser distance measuring, and the shelling action is adjusted in real time in conjunction with the continuous feeding mechanism.

[0009] Furthermore, a heat-insulating cooling cover is arranged outside the laser ranging module, an air inlet is arranged on the top of the heat-insulating cooling cover, an air outlet is arranged on the bottom, the air inlet is connected to a cooling pipe, and the cooling pipe is connected to a separate cooling fan.

[0010] Furthermore, a guide sleeve is arranged on the outside of the connecting rod, the guide sleeve is fixed on the bottom of the shell breaking cylinder, a guide groove is arranged on the side of the guide sleeve, and the target is arranged in the guide groove and can move up and down along the guide groove.

[0011] The second aspect of the present invention is to design an intelligent shelling control method for continuous feeding of alumina in an aluminum electrolytic cell, which includes the following two shelling methods: (1) Shelling mode commanded by slot control machine: The shelling output signal of the slot control machine is collected. When the signal is converted to a high level, the shelling device is controlled to perform shelling. The shelling action can be performed according to the full stroke of the cylinder or according to the set stroke distance; (2) Determine the shelling method based on the cumulative discharge amount: collect the discharge amount of alumina continuous feeder corresponding to the shelling device, calculate the cumulative alumina discharge amount of the feeder, and when the real-time cumulative value is greater than or equal to the set value of the cumulative discharge amount, control the shelling device to perform shelling according to the set shelling depth, and reset the real-time cumulative value from zero. The depth of the shelling hammer head entering the electrolyte is set to 0-200mm, and the cumulative discharge amount is set to 0-1.8kg.

[0012] Furthermore, after each aluminum discharge operation of the aluminum reduction cell, the shelling depth setting is dynamically adjusted according to the changes in the aluminum discharge amount and the aluminum level. After the aluminum is discharged, the shelling depth of the hammer head decreases by 0.5-2mm per hour.

[0013] Furthermore, when breaking the shell, the hammer head presses the electrolyte shell surface tightly. If the shell surface is broken within the set time, the real-time collected stroke value is greater than the stroke set value, the hammer head returns, and the normal shell breaking process is resumed; if the shell surface cannot be broken after exceeding the set time, an alarm prompts.

[0014] Furthermore, after shelling is completed, if the real-time collected stroke value is greater than the set stroke, the actual control set value is modified, and the control stroke is set to (control set value-compensation amount) for the next shelling.

[0015] Furthermore, when the distance measuring mechanism is abnormal, the shelling mode determined by the accumulated material feeding amount is automatically switched to the full-stroke shelling mode commanded by the slot control machine and an alarm is sounded.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are: The present invention can cover the discharge port of the electrolytic cell with a certain thickness of alumina. At this time, when the fluorine-containing hot flue gas discharged from the discharge port passes through the alumina layer above it, the alumina boils and fully contacts with the fluorine-containing hot flue gas. The alumina is heated and absorbs the fluoride therein to form dispersed, boiling, preheated, fluorine-loaded alumina, which can greatly improve the dissolution rate of the alumina after entering the electrolyte; by controlling the alumina discharge amount and the shelling depth of each shelling cycle, the alumina can be properly and evenly entered into the electrolyte, avoiding too much alumina entering the electrolyte at one time and failing to be completely dissolved; when returning after shelling, the hot electrolyte carried on the shelling hammer head automatically falls off into a plurality of small electrolyte blocks of 600-800°C, and the small hot electrolyte blocks are dispersed and fall into the alumina powder below, and the alumina around them can be heated. In the next shelling cycle, the small electrolyte blocks are mixed with the alumina and enter the molten electrolyte, and the small electrolyte blocks wrapped by the alumina are melted by heat, and work together with the molten electrolyte in the tank to accelerate the dissolution rate of the alumina. The above factors can effectively improve the dissolution effect of alumina, improve the uniformity of alumina dissolution, avoid the formation of bottom sediment, and improve the current efficiency of the electrolytic cell; at the same time, accurate shell hammer stroke control is achieved, which can effectively extend the life of the hammer, reduce consumption, and reduce the labor intensity of workers. Effectively extend the life of the hammer and reduce the labor intensity of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is one of the structural schematic diagrams of the intelligent shelling device for continuous feeding of alumina in an aluminum electrolysis cell of the present invention.

[0018] Figure 2 This is the second structural schematic diagram of the intelligent shelling device for continuous feeding of alumina in aluminum electrolysis cell of the present invention.

[0019] Figure 3 This is one of the top schematic diagrams of the intelligent shelling device for continuous feeding of alumina in an aluminum electrolysis cell of the present invention.

[0020] Figure 4 This is the second top schematic diagram of the intelligent shelling device for continuous feeding of alumina in an aluminum electrolytic cell of the present invention.

[0021] Figure 5 This is a schematic diagram of the installation of the ranging target in the present invention.

[0022] In the figure, there are a shelling cylinder 1, a connecting rod 2, a distance measuring mechanism 3, a heat-insulating cooling cover 31, a distance measuring target 4, a shelling reversing solenoid valve 5, a guide sleeve 6, an air inlet pipeline 51, an air outlet pipeline 52, a cooling pipe 53, and a guide groove 7. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are described below in conjunction with the accompanying drawings and examples. However, the following examples are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way.

[0024] Example 1: An intelligent shelling device for continuous feeding of aluminum oxide in an aluminum electrolysis cell, see Figure 1 , including a continuous feeding mechanism, a shelling mechanism, and a control system, wherein the continuous feeding mechanism and the shelling mechanism are both controlled by the control system. The continuous feeding mechanism is a vertically arranged spiral feeding mechanism with a discharge tray at the bottom, which can allow the alumina powder to enter the electrolytic cell slowly and evenly, changing the instantaneous concentrated feeding method of the existing constant volume feeder, which is beneficial to the dissolution of alumina powder. The continuous feeding mechanism and the shelling mechanism are arranged vertically side by side above the electrolytic cell. The electrolyte in the electrolytic cell will form a hard shell on the surface when exposed to the air, and the alumina will not be able to enter the electrolyte. The shell surface needs to be broken regularly with the shelling mechanism so that the alumina can enter the electrolyte smoothly.

[0025] The shelling mechanism includes a shelling cylinder 1, a connecting rod 2, a distance measuring mechanism 3, and a distance measuring target 4. A shelling reversing solenoid valve 5 is arranged on the top of the shelling cylinder 1, and an air inlet pipeline 51 and an air outlet pipeline 52 are connected to the shelling reversing solenoid valve to drive the shelling cylinder to move. The shelling reversing solenoid valve 5 is installed on the top of the shelling cylinder 1 through a fixing plate. The distance measuring mechanism 3 is a laser distance measuring module, which is fixed to the top of the shelling cylinder through a bracket and is located on the side. The connecting rod 2 is connected to the bottom of the shelling cylinder 1, and the shelling cylinder 1 drives the connecting rod 2 to reciprocate up and down. A shelling hammer head is arranged at the bottom of the connecting rod 2, and the distance measuring target is connected to the connecting rod and is arranged corresponding to the distance measuring mechanism 3.

[0026] The existing shelling pneumatic pipeline structure was modified, and the shelling control solenoid valve originally located in the air control cabinet next to the electrolytic cell was moved to the top of the shelling cylinder on the upper part of the cell and directly connected to the cylinder. The pneumatic pipeline between the shelling cylinder and the shelling control solenoid valve was shortened, avoiding the lagging effect of compressed air retained in this part of the pipeline on the cylinder stroke control, which greatly improved the stroke control accuracy of the shelling hammer head.

[0027] In this embodiment, a guide sleeve 6 is provided on the outside of the connecting rod 2, and the guide sleeve 6 is fixed at the bottom of the shelling cylinder. A guide groove 7 is provided on the side of the guide sleeve 6, and the target 4 is provided in the guide groove 7 and can move up and down along the guide groove 7. A clamping block is provided at the movable end of the shelling cylinder, the top end of the connecting rod 2 is fixed in the clamping block, and the distance measuring target 4 is fixed on the surface of the clamping block. A guide sleeve is installed in the stroke section of the shelling cylinder of the aluminum electrolytic cell, and a target is installed on the connecting rod of the shelling cylinder. The target runs in the guide groove of the guide sleeve, which greatly improves the running stability and stroke detection accuracy of the target.

[0028] Example 2: As a further improvement of Example 1, see Figures 2 to 5Since the temperature at the top of the groove is relatively high, in order to prevent the laser ranging device from overheating, a heat-insulating cooling cover 31 is arranged outside the ranging mechanism 3. The top of the heat-insulating cooling cover 31 is provided with an air inlet, and the bottom is provided with an air outlet. The air inlet is connected to a cooling pipe 53, and the cooling pipe is connected to a cooling fan. The cooling fan is fixed on the top of the shelling cylinder 2.

[0029] Add air cooling device, configure cooling fan and air cooling pipeline, and centrally cool the laser distance measuring device on the top of the slot. Install a heat-insulating cooling cover on the outside of the laser distance measuring device, with an air inlet on the top of the cover and a measurement air outlet on the bottom. On the basis of not affecting the measurement, the cooling air is introduced into the heat-insulating cooling cover through the air inlet and discharged through the exhaust hole at the bottom, thereby cooling the laser distance measuring device.

[0030] Embodiment 3: A method for controlling the continuous feeding of aluminum oxide in an aluminum electrolysis cell by intelligent shelling, comprising the following two shelling methods: (1) Shelling mode commanded by slot control machine: The shelling output signal of the slot control machine is collected. When the signal is converted to a high level, the shelling device is controlled to perform shelling. The shelling action can be performed according to the full stroke of the cylinder or according to the set stroke distance; (2) The shelling method is determined by the cumulative unloading amount: the unloading amount of the alumina continuous feeder corresponding to the shelling device is collected, and the cumulative unloading amount of the alumina feeder is calculated. When the real-time cumulative value is greater than or equal to the cumulative unloading amount setting value, the shelling device is controlled to perform the shelling action, and the real-time cumulative value is reset from zero. The method for collecting the unloading amount of alumina is as follows: the unloading motor of the feeder adopts frequency conversion control, and the unloading amount is related to the motor speed. The corresponding relationship between the speed and the unloading amount is determined. When unloading, the motor speed corresponding to the frequency converter is collected, and the real-time unloading amount can be converted accordingly.

[0031] After each aluminum tapping operation in the aluminum electrolytic cell, the shelling depth setting is dynamically adjusted according to the changes in the aluminum tapping amount and aluminum level. After aluminum tapping, the shelling depth of the hammer head decreases by 0.5-2mm per hour, so that the depth of the shelling hammer head entering the electrolyte remains basically consistent to ensure the shelling effect.

[0032] When breaking the shell, the electrolyte crust blocks the hammer, causing the real-time collected value of the stroke to be less than the lower limit of the stroke setting. The cylinder continues to output, and the hammer presses the electrolyte shell surface. If the shell surface breaks within the set time, the real-time collected value of the stroke is greater than the stroke setting value, and the hammer returns to resume the normal shell breaking process. If the shell surface cannot be broken after the set time, an alarm is triggered. Repeat the above shell breaking process 1-2 times, and it still cannot be broken. The alarm prompts manual processing, and the processing is completed and the shell is reset manually.

[0033] Due to compressed air fluctuations and other reasons, the real-time stroke is greater than the upper limit of the stroke setting. After the shelling is completed, the real-time collected stroke value is greater than the set stroke, and the difference is large. The compensation amount is automatically calculated, the actual control setting value is modified, and the control stroke is set to (control setting value-compensation amount) to perform shelling.

[0034] When the laser rangefinder is abnormal, the shelling mode determined by the cumulative feeding amount is automatically switched to the full-stroke shelling mode commanded by the control system, and an alarm is issued.

[0035] In addition, as a further improvement, the above method utilizes a control system to observe and collect data on various process conditions of the electrolytic cell, thereby optimizing the corresponding relationship between the alumina feed rate and the shelling action.

[0036] The above method is based on the transformation of alumina fixed-volume feeding to continuous feeding. Through intelligent control algorithms, a mathematical model of shelling and feeding is established, and the feeding amount of alumina from a single feeder is counted. When the cumulative feeding amount reaches the set value, intelligent shelling is performed. The shelling depth is set according to the working conditions of the electrolytic cell. When the shelling hammer reaches the set depth, it automatically returns. This method can control the amount of alumina entering the electrolyte in each shelling cycle, avoiding the drawbacks of alumina accumulation and sinking to the bottom in the traditional control method of fixed-volume feeding and shelling. After preheating, alumina can enter the electrolyte in an appropriate and uniform amount, effectively improving the dissolution effect of alumina, improving the uniformity of alumina dissolution, avoiding the formation of sediment at the bottom of the cell, and improving the current efficiency of the electrolytic cell. At the same time, it realizes precise shelling hammer stroke control, which can effectively extend the life of the hammer, reduce consumption, and reduce the labor intensity of workers. Effectively extend the life of the hammer and reduce the labor intensity of workers The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, those skilled in the art will appreciate that, without departing from the spirit of the present invention, the specific parameters in the above embodiments may be changed to form a plurality of specific embodiments, which are all within the common variation range of the present invention and will not be described in detail herein.

Claims

1. An intelligent shelling device for continuous feeding of aluminum oxide in an aluminum electrolytic cell, comprising a continuous feeding mechanism, a shelling mechanism, and a control system, wherein: The continuous feeding mechanism and the shelling mechanism are both controlled by a control system, and are characterized in that the shelling mechanism includes a shelling cylinder, a connecting rod, a shelling hammer, a distance measuring mechanism, and a distance measuring target. A shelling reversing solenoid valve is arranged on the top of the shelling cylinder, and the shelling reversing solenoid valve is connected with an air inlet pipeline and an air outlet pipeline to drive the shelling cylinder; the bottom of the shelling cylinder is connected to the connecting rod to drive the connecting rod to reciprocate up and down, the shelling hammer is connected to the bottom of the connecting rod, the distance measuring mechanism is connected to the shelling cylinder, and the distance measuring target is connected to the connecting rod and is arranged corresponding to the distance measuring mechanism.

2. The intelligent shelling device for continuous feeding of aluminum oxide in aluminum electrolysis cell according to claim 1 is characterized in that: The distance measuring mechanism is a laser distance measuring module, which is fixed to the top of the shell breaking cylinder through a bracket.

3. The intelligent shelling device for continuous feeding of aluminum oxide in aluminum electrolysis cell according to claim 2 is characterized in that: A heat-insulating cooling cover is arranged outside the laser ranging module.

4. The intelligent shelling device for continuous feeding of aluminum oxide in aluminum electrolysis cell according to claim 3 is characterized in that: The top of the heat-insulating cooling cover is provided with an air inlet, and the bottom is provided with an air outlet. The air inlet is connected to a cooling pipeline, and the cooling pipeline is connected to a cooling fan.

5. The intelligent shelling device for continuous feeding of aluminum oxide in aluminum electrolysis cell according to claim 1 is characterized in that: A guide sleeve is arranged outside the connecting rod, the guide sleeve is fixed at the bottom of the shell-breaking cylinder, a guide groove is arranged on the wall of the guide sleeve, and the target is arranged in the guide groove and can flexibly move up and down along the guide groove.

6. A method for controlling the continuous feeding and intelligent shelling of aluminum oxide in an aluminum electrolysis cell, characterized in that: There are two shelling methods: (1) Shelling mode commanded by slot control machine: The shelling output signal of the slot control machine is collected. When the signal is converted to a high level, the shelling device is controlled to perform shelling. The shelling action can be performed according to the full stroke of the cylinder or according to the set stroke distance; (2) Determine the shelling method based on the cumulative discharge amount: collect the discharge amount of alumina continuous feeder corresponding to the shelling device, calculate the cumulative alumina discharge amount of the feeder, and when the real-time cumulative value is greater than or equal to the set value of the cumulative discharge amount, control the shelling device to perform shelling according to the set shelling depth, and reset the real-time cumulative value from zero. The depth of the shelling hammer head entering the electrolyte is set to 0-200mm, and the cumulative discharge amount is set to 0-1.8kg.

7. The method for controlling the continuous feeding and intelligent shelling of aluminum oxide in an aluminum electrolysis cell according to claim 6, characterized in that: After each aluminum tapping operation in the aluminum electrolytic cell, the shelling depth setting is dynamically adjusted according to the changes in the aluminum tapping amount and aluminum level. After aluminum tapping, the shelling depth of the hammer head decreases by 0.5-2mm per hour.

8. The method for controlling the continuous feeding and intelligent shelling of aluminum oxide in an aluminum electrolysis cell according to claim 6, characterized in that: When breaking the shell, the hammer head presses the electrolyte shell surface tightly. If the shell surface is broken within the set time, the real-time collected stroke value is greater than the stroke set value, the hammer head returns, and the normal shell breaking process is restored; if the shell surface cannot be broken within the set time, an alarm prompts.

9. The method for controlling the continuous feeding and intelligent shelling of aluminum oxide in an aluminum electrolysis cell according to claim 6, characterized in that: After shelling is completed, if the real-time collected stroke value is greater than the set stroke, the actual control set value will be automatically modified, and the control stroke will be set to (control set value - compensation amount) for the next shelling.

10. The method for controlling the continuous feeding and intelligent shelling of aluminum oxide in an aluminum electrolysis cell according to claim 6, characterized in that: When the distance measuring mechanism is abnormal, the shelling mode determined by the accumulated material feeding amount is automatically switched to the full-stroke shelling mode commanded by the slot control machine and an alarm is issued.

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