WO2025010753A1 - Strip steel pickling system and method - Google Patents

Abstract

The present invention relates to a strip steel pickling system, comprising a decoiling device, a pre-cleaning unit, a multi-stage pickling unit and a final rinsing unit, which are connected in sequence, wherein the pickling unit comprises a pickling tank, an intermediate rinsing tank and a strip steel heating device, which are connected in sequence. In addition, the present invention further relates to a strip steel pickling method implemented on the basis of the strip steel pickling system. In the present invention, the modularized pickling tank-intermediate rinsing tank-strip steel heating device is used, the multi-stage pickling unit peels off oxide scales layer by layer, the oxide scales pickled away in the pickling tank can be rinsed away in the intermediate rinsing tank in time, and the oxide scales at the lower layer are exposed and are continuously pickled; therefore, the pickling efficiency can be greatly improved. The strip steel heating device can increase or maintain the temperature of strip steel and avoid reduction in the temperature of an acid liquor or the strip steel; therefore, the strip steel is continuously kept at a relatively high temperature, and a high pickling rate at the interface of the strip steel is always maintained, thereby guaranteeing pickling efficiency and pickling quality.

Description

Strip steel pickling system and method Technical Field

The invention belongs to the technical field of metallurgical production, and in particular relates to a strip steel pickling system and a strip steel pickling method implemented based on the strip steel pickling system.

Background Art

The market demand for new high-quality steel grades such as high-chromium, high-silicon, and high-manganese steel continues to expand. During the hot rolling and annealing process, a large amount of iron oxide scale is generated on the surface of the strip. In order to reduce the subsequent pickling pressure, a descaling machine and a shot blasting machine are added before pickling to treat the iron oxide scale on the surface of the strip. In the pickling process, a combination of strong hydrochloric acid or sulfuric acid and mixed acid is used. The acid tank adopts a shallow tank design to form a turbulent effect and improve the pickling effect. The above-mentioned steel grades all have the outstanding problem of extremely difficult pickling, and the pickling efficiency is extremely low, which seriously restricts the pickling output.

In view of the current situation that the treatment of surface scale is difficult, mechanical treatment processes such as descaling and shot blasting have become the standard of pickling units. Mechanical treatment processes can remove coarse iron oxide scales on the surface, however, they have significant shortcomings such as high investment cost, large footprint, high operating energy consumption, large maintenance and large environmental pollution. In addition, although conventional mechanical descaling such as shot blasting can remove about 80% of the iron oxide scale on the surface of the strip, for high-silicon, high-manganese and high-chromium steels, due to the presence of elements such as silicon, manganese and chromium, the binding force between the iron oxide scale and the matrix increases exponentially, resulting in high energy consumption for mechanical descaling; in addition, even if the iron oxide scale on the surface of the strip is removed by mechanical descaling (generally mostly high-valent oxides of iron), due to the presence of the above elements, the residual pinning iron oxide scale still needs to be removed by pickling, and the pickling time is still very long. Furthermore, the above-mentioned steel grades have high content of elements that are difficult to pickle and difficult to dissolve, and the amount of acid mud is extremely large. The conventional pickling process uses indirect heat conduction equipment such as graphite heat exchangers, which are very easy to block the heat exchanger heated by acid, resulting in frequent shutdowns.

Summary of the invention

The invention relates to a strip steel pickling system and a strip steel pickling method implemented based on the strip steel pickling system, which can at least solve some defects of the prior art.

The invention relates to a strip steel pickling system, comprising a sequentially connected unwinding device, a pre-cleaning unit, a multi-stage pickling unit and a final rinsing unit, wherein the pickling unit comprises a sequentially connected pickling tank, an intermediate rinsing tank and a strip steel heating device.

As one of the implementation modes, an annealing furnace and/or a pre-heater is arranged between the uncoiling device and the pre-cleaning unit; when the annealing furnace and the pre-heater are arranged, the annealing furnace and the pre-heater are arranged in sequence along the running direction of the strip.

As one of the implementation modes, the pre-heater adopts a flame heating device.

As one of the implementation modes, the strip heating device adopts a flame heating device or a hot air drying device.

As one of the embodiments, each of the pickling tanks is respectively provided with a circulating acid tank.

As one of the implementation modes, the acid solution in each of the circulating acid tanks is overflowed in a step-by-step manner through a connecting pipe, the concentration of the acid solution increases successively, and the total iron content decreases successively.

As one of the embodiments, the strip pickling system further comprises an oxidant generator, which is respectively connected to each of the circulating acid tanks for adding oxidant to each of the circulating acid tanks to adjust the content and ratio of Fe ²⁺ and Fe ³⁺ in the acid tanks.

As one of the implementation modes, an image acquisition module is provided at the strip outlet of each pickling unit for acquiring the surface image of the strip.

The present invention also relates to a strip steel pickling method, which is implemented based on the above-mentioned strip steel pickling system.

The strip steel pickling method comprises:

Passing the steel strip through a pre-cleaning unit for pre-cleaning;

After pre-cleaning, the strip is pickled in a multi-stage pickling unit. In each pickling tank, the high-temperature strip is in contact with the low-temperature acid solution, and a strong physical and chemical reaction can occur on the surface of the strip. Thus, the coarse iron oxide scale on the surface of the strip can be quickly stripped by pickling;

After pickling, the strip enters the final rinsing unit, where it is dried and rolled or sent to downstream processes.

As one of the implementation methods, a strip surface image is collected at the strip outlet of the pickling unit to evaluate the pickling quality; the obtained pickling quality is compared with the preset pickling quality to guide the adjustment of the pickling process.

The present invention has at least the following beneficial effects:

In the present invention, a modular pickling tank-intermediate rinsing tank-strip heating device is adopted, and the multi-stage pickling unit peels off the iron oxide scale layer by layer. The iron oxide scale removed by pickling in the acid tank can be rinsed off in the intermediate rinsing tank in time, exposing the lower layer of iron oxide scale and continuing pickling, thereby greatly improving the pickling efficiency. The high-temperature strip steel is contacted with the low-temperature acid solution to quickly peel off the coarse iron oxide scale on the surface, eliminating the conventional mechanical descaling devices such as shot blasting and straightening. The strip heating device can increase or maintain the temperature of the strip steel, avoid the temperature of the acid solution or the strip steel to decrease, so that the strip steel can continue to maintain a high temperature, and the strip steel interface always maintains a high pickling rate, thereby ensuring the pickling efficiency and pickling quality; and the heat can directly act on the strip steel, eliminating the acid solution heating devices such as the graphite heat exchanger that is easy to clog and has low heat exchange efficiency; the strip steel temperature rises quickly, and the unit can be directly started and put into production, which takes a short time, avoiding the situation where the conventional indirect heating main acid solution is reheated to the strip steel.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic structural diagram of a strip steel pickling system provided in Embodiment 1 of the present invention;

FIG2 is a schematic diagram of a pickling adjustment framework provided in Embodiment 3 of the present invention;

FIG3 is a schematic diagram of another pickling adjustment framework provided in Embodiment 3 of the present invention;

FIG4 is a schematic diagram of a neural network model provided by Embodiment 3 of the present invention;

FIG5 is a schematic diagram of adjusting and updating weighted coefficients of a neural network model provided in Embodiment 3 of the present invention;

FIG6 is a schematic diagram of the structure of an iron sludge processing subsystem provided in Embodiment 4 of the present invention;

FIG7 is a top view of FIG6;

FIG8 is a schematic diagram of the structure of an iron mud collection box provided in Embodiment 4 of the present invention;

FIG9 is a schematic side view of the structure of an electromagnetic filter provided in Embodiment 5 of the present invention;

FIG10 is a schematic diagram of a top view of the structure of an electromagnetic filter provided in Embodiment 5 of the present invention;

FIG. 11 is a schematic diagram of the front structural view of the electromagnetic filter provided in the fifth embodiment of the present invention.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

Embodiment 1

As shown in Figure 1, an embodiment of the present invention provides a strip pickling system, including a coiling device 1, a pre-cleaning unit, a multi-stage pickling unit 8 and a final rinsing unit connected in sequence, and the pickling unit 8 includes a pickling tank 81, an intermediate rinsing tank 82 and a strip heating device 83 connected in sequence.

In one embodiment, as shown in FIG1 , an annealing furnace 3 is arranged between the uncoiling device 1 and the pre-cleaning unit, and the strip steel can be selectively annealed. A looper 2 can be arranged between the uncoiling device 1 and the annealing furnace 3. Furthermore, a heat preservation chamber 4 is arranged at the outlet of the annealing furnace 3, which can keep the strip steel coming out of the annealing furnace 3 warm, ensuring that the strip steel can enter the pre-cleaning unit at a relatively high temperature.

In one embodiment, as shown in FIG1 , a front portion is arranged between the unwinding device 1 and the pre-cleaning unit. The pre-heater 5 can heat the steel strip so that the steel strip enters the pre-cleaning unit at a relatively high temperature. The pre-heater 5 includes but is not limited to a flame heating device.

Preferably, a temperature measuring instrument 6 is arranged at the strip outlet of the pre-heater 5 to measure the temperature of the outlet strip, which can guide the operation of the pre-heater 5 and save energy when heating the strip to a preset temperature.

It is preferred that an annealing furnace 3 and a preheater 5 are arranged simultaneously, and the annealing furnace 3 and the preheater 5 are arranged in sequence along the running direction of the strip.

It is preferred that the temperature of the steel strip entering the pre-cleaning unit is higher than 100°C, so that a strong physical and chemical reaction can occur on the contact surface between the high-temperature steel strip and the low-temperature acid solution to quickly pickle and peel off the coarse iron oxide scale on the surface.

In one embodiment, as shown in FIG1 , the pre-cleaning unit includes a pre-cleaning tank 7, and a pre-cleaning tank may be further configured to realize the circulation of the pre-cleaning liquid. Preferably, the pickling medium of the pre-pickling tank 81 is HCl, the concentration of HCl is 20-60 g/L, and the pickling medium contains Fe ²⁺ and Fe ³⁺ .

In one embodiment, the pickling medium in the pickling tank 81 is HCl, the concentration of HCl is 20-150 g/L, and the pickling medium contains Fe ²⁺ and Fe ³⁺ .

Preferably, as shown in FIG. 1 , each of the pickling tanks 81 is respectively provided with a circulating acid tank 84 to achieve recycling of the pickling solution and ensure the concentration of the acid solution in the pickling tank 81 .

In one embodiment, the acid solution of each circulating acid tank 84 is overflowed in steps through a connecting pipe, the concentration of the acid solution increases successively (from the first-stage pickling unit 8 to the last-stage pickling unit 8), the total iron content decreases successively, and the oxidizing property of the acid solution of each circulating acid tank 84 is gradually improved. Preferably, the acid solution of the second-stage pickling unit 8 is a reducing system, and the pickling medium of the last-stage pickling unit 8 is a strong oxidizing system, which can ensure the pickling quality of the strip.

In one embodiment, the strip heating device 83 adopts a flame heating device or a hot air drying device, and the heat can directly act on the strip, eliminating the acid-free graphite heat exchanger that is easy to clog and has low heat exchange efficiency. Liquid heating device; the temperature of the strip rises quickly, the unit can be started directly and put into production in a short time, avoiding the situation where the main acid liquid in conventional indirect heating is reheated to the strip.

Preferably, a temperature measuring instrument 6 is arranged at the strip outlet of the strip heating device 83 to measure the temperature of the outlet strip, which can guide the operation of the strip heating device 83 and save energy when heating the strip to a preset temperature.

In one embodiment, the strip heating device 83 is used to heat the strip to 60-170°C.

In one of the embodiments, the temperature of the strip entering the tank of each level of pickling unit 8 is gradually reduced. Preferably, the temperature of the strip entering the tank of the next level of pickling unit 8 is about 10°C lower than that of the previous level of pickling unit 8, so as to ensure that a high pickling rate is always maintained at the interface of the strip, and a better step-by-step pickling effect can be obtained.

Preferably, in each stage of the pickling unit 8, the number of the intermediate rinsing tanks 82 is 1 to 3.

In this embodiment, a modular pickling tank 81-intermediate rinsing tank 82-strip heating device 83 is adopted, and the multi-stage pickling unit 8 peels off the oxidized iron scale layer by layer. The oxidized iron scale removed by pickling in the pickling tank can be rinsed off in the intermediate rinsing tank 82 in time, exposing the lower oxidized iron scale and continuing pickling, thereby greatly improving the pickling efficiency. The strip heating device 83 can increase or maintain the temperature of the strip, avoid the temperature of the acid solution or the strip from decreasing, and keep the strip at a higher temperature continuously, and always keep a high pickling rate at the strip interface, thereby ensuring the pickling efficiency and pickling quality; and the heat can directly act on the strip, eliminating the acid heating devices such as graphite heat exchangers that are easy to clog and have low heat exchange efficiency; the strip temperature rises quickly, and the unit can be directly started and put into production, which takes a short time, avoiding the situation where the conventional indirect heating main acid solution is reheated to the strip.

Among them, the modular pickling unit 8 has high production flexibility, and several pickling units 8 can be selectively opened and closed according to the difficulty of pickling the strip steel. For example, the presence or absence of acid in the pickling tank 81 can be controlled by the tank body vent valve and the acid pump. When there is no acid in the pickling tank 81, the strip steel can pass through empty, that is, the pickling unit 8 is in a closed state/standby state.

FIG1 shows only a two-stage pickling unit 8, but is not limited thereto and may be increased or decreased according to actual working conditions. The number of the pickling units 8 can be reduced, for example, space for arranging the pickling units 8 can be reserved.

In one embodiment, the final rinsing unit comprises a series of multiple final rinsing tanks 9, each of which is equipped with a rinsing tank 91, and the final rinsing tank 9/rinsing tank 91 is equipped with a pH meter and conductivity; preferably, the multiple final rinsing tanks 9 are connected by pumps to achieve cascade utilization of rinsing water. Optionally, the rinsing water pressure of the first few stages is 2-6 kg, and the rinsing water pressure of the last stage is 5-10 kg.

In addition, there are multiple pickling units 8, and the rinsing water of the intermediate rinsing tank 82 of each pickling unit 8 comes from the rinsing water of the intermediate rinsing tank 82 of the subsequent pickling unit 8, and the rinsing water of the intermediate rinsing tank 82 of the final pickling unit 8 preferably comes from the rinsing tank 91 of the final rinsing unit, thereby realizing multi-stage recycling of rinsing water.

In one embodiment, as shown in FIG1 , a drying device 10 is arranged at the outlet of the final rinsing unit to facilitate the strip drying and coiling or sending to the downstream process. The drying device includes but is not limited to a hot air drying device.

In one embodiment, as shown in FIG. 1 , the strip pickling system further includes an oxidant generator 11 , which is respectively connected to each of the circulating acid tanks 84 for adding oxidant to each of the circulating acid tanks 84 to adjust the content and ratio of Fe ²⁺ and Fe ³⁺ in the acid tanks 84 .

Furthermore, each circulating acid tank 84 is respectively equipped with an oxidation potential detection, which determines the redox characteristics of the pickling medium by detecting the redox potential of the acid solution in each pickling tank 81, and thereby controls whether to add an oxidant to the pickling tank 81 and the amount of the oxidant added, so as to realize the redox characteristics of the pickling medium in each pickling tank 81, thereby ensuring the effect and consistency of strip cleaning.

In one embodiment, an image acquisition module is provided at the strip outlet of each pickling unit 8 for acquiring the surface image of the strip to facilitate the pickling quality evaluation, thereby better controlling and optimizing the pickling process.

Embodiment 2

The embodiment of the present invention provides a strip steel pickling method, which is implemented based on the strip steel pickling system provided in the above embodiment 1.

The strip steel pickling method comprises:

Passing the steel strip through a pre-cleaning unit for pre-cleaning;

After the pre-cleaning treatment, the strip steel is sequentially pickled in the multi-stage pickling unit 8. In each stage of the pickling tank 81, the high-temperature strip steel contacts with the low-temperature acid solution, and a strong physical and chemical reaction can occur on the surface of the strip steel, thereby quickly pickling and stripping the coarse iron oxide scale on the surface of the strip steel.

After pickling, the strip enters the final rinsing unit, where it is dried and rolled or sent to downstream processes.

The relevant pickling process has been described in the above embodiment 1 and will not be described again here.

Embodiment 3

The embodiment of the present invention further optimizes the first embodiment.

As shown in Figures 2 to 5, the above-mentioned strip pickling system also includes:

Pickling quality quantitative evaluation module, used to obtain the pickling quality and feed it back to PLC;

PLC, used to receive the pickling quality feedback from the pickling quality quantitative evaluation module and calculate the torque of the motor accordingly;

An electric motor, used to adjust the speed of the steel strip according to the torque, for example, to accelerate or decelerate the steel strip according to actual conditions;

PC is used to adjust the relevant parameters of PLC through the neural network model according to the pickling quality fed back by the pickling quality quantitative evaluation module and the preset pickling quality, and send them to PLC to realize pickling adjustment.

Preferably, an image acquisition module is provided at the strip outlet of each pickling unit 8 to acquire the strip surface image; thereby, the pickling quality of each level of pickling unit 8 can be evaluated respectively, so as to facilitate the control of the pickling process of each level of pickling unit 8; in addition, according to the output of the final pickling unit 8, The pickling quality on the mouth side can be used not only to evaluate the final pickling unit 8, but also to evaluate the overall pickling quality of the system.

During the pickling process of the strip steel, the image data of the strip steel is collected by the image data acquisition module (such as a camera) and visualized by the visualization module, and then the strip steel cleaning quality is evaluated and scored by the pickling quality quantitative evaluation module. In addition, the system also has the feedback adjustment function of the neural network self-learning, and after multiple training and learning, the pickling quality of the strip steel can be quantitatively adjusted.

In the embodiment of the present invention, feedback control is performed based on the pickling quality quantitative evaluation module, which has a high degree of digitization and can achieve quantitative adjustment. By adopting the scheme of this embodiment, the response time of strip speed control is shorter than that of traditional PID control, the real-time performance is good, and the overshoot is smaller than that of traditional PID control. At the same time, the PID controller parameters can be adjusted according to the operating conditions, so as to achieve a better control effect.

In addition, in addition to adjusting the motor torque to accelerate or decelerate the strip, the adjustment of the pickling process may also include at least one of the following parameters: strip temperature at the inlet side of the pickling unit, acid concentration, and redox characteristics of the acid.

In one embodiment, the training samples of the neural network model on the PC are collected from the PLC, and the samples include r(k), y(k), _Kp , _KI and _KD , wherein r(k) is the preset pickling quality at the kth iteration, y(k) is the pickling quality fed back by the pickling quality quantitative evaluation module at the kth iteration, and _Kp , _KI and _KD are the adjustable parameters of P, I and D of the PID controller of the PLC, respectively. As shown in Figure 4.

In another embodiment, the PC collects training samples through OPC Client communicating with OPC Server and OPC Server communicating with PLC. After acquiring the samples, they are stored in the database of the PC for training the neural network model.

Furthermore, the neural network model is trained and learned using the BP algorithm, wherein the performance indicator function is:

Among them, r(k) is the preset pickling quality at the kth iteration, and y(k) is the pickling quality fed back by the pickling quality quantitative evaluation module at the kth iteration.

Preferably, the number of neurons in the input layer, hidden layer and output layer of the neural network model is 2, 6 and 3 respectively.

Preferably, the number of neurons in the hidden layer of the neural network model can be adjusted according to actual needs, and the connection relationship between each neuron corresponds to different weighting coefficients that can be continuously adjusted and updated.

On the one hand, the activation function of the hidden layer is:

The hidden layer may also use other activation functions.

On the other hand, the activation function of the output layer is:

The output layer may also use other activation functions.

In one embodiment, the weight coefficients of the neural network model are adjusted and updated using a gradient descent method.

Furthermore, the step of adjusting and updating the weighted coefficients of the neural network model using the gradient descent method specifically includes:

S1. Initialize the initial value of the weight coefficient of each layer of the neural network model, and set the number of iterations of the neural network model k=1;

S2. Calculate the error between the input value and the output value of the input layer. If the error is less than the first threshold, execute S3; otherwise, optimize the input value and the output value of the input layer so that the error is less than the first threshold.

S3. Calculate the input and output of each layer of neurons in the neural network model, wherein the output value of the output layer of the neural network model is an adjustable parameter of the PID controller of the PLC;

S4. The output value of the PID controller calculated according to the adjustable parameters of the PID controller of the PLC;

S5. Perform neural network model learning and adjust weighting coefficients to achieve adaptive adjustment of adjustable parameters of the PID controller;

S6. If the adjustable parameter of the PID controller is greater than the second threshold, the training of the neural network model is completed, otherwise the number of iterations of the neural network model is set to k=k+1, and return to S2.

As shown in Figure 5, the sampling period is set to 1s, that is, the strip pickling system will call the neural network model once every 1s. After the neural network model is trained, the acid quality can be well controlled. When encountering disturbances or parameter changes, the parameter values can be quickly readjusted to achieve better control effects.

Based on the same inventive concept, the embodiment of the present invention is also used to optimize the second embodiment.

The strip pickling method also includes:

The pickling quality quantitative evaluation module evaluates the pickling quality and feeds back to the PLC;

The PLC receives the pickling quality feedback from the pickling quality quantitative evaluation module and calculates the torque of the motor accordingly;

The motor adjusts the speed of the strip according to the torque;

According to the pickling quality feedback from the pickling quality quantitative evaluation module and the preset pickling quality, the PC adjusts the relevant parameters of the PLC through the neural network model and sends them to the PLC to realize the adjustment of the pickling process.

The embodiments of the strip pickling method and the embodiments of the aforementioned pickling system can be implemented one by one, and will not be described in detail here.

The embodiments of the present invention can increase the cleaning speed, reduce energy consumption and acid consumption, and thus obtain a steel strip with high surface cleaning quality.

Embodiment 4

This embodiment optimizes the above embodiment 1. Specifically, the acid tank 84 is equipped with an iron mud processing subsystem for online cleaning of iron mud impurities in the acid tank 84, which can improve the operating stability and reliability of the pickling system and reduce the downtime and frequency of desilting.

As shown in Figures 6 and 7, the iron mud processing subsystem includes an intermediate medium circulation mechanism and an iron mud recovery mechanism. The intermediate medium circulation mechanism includes a plurality of intermediate media 330 capable of extracting iron mud from the bottom of the acid tank 84, and a medium conveying unit 331, a medium transfer unit 332 and a medium reflux unit 333 connected in sequence. The medium conveying unit 331 is connected to the intermediate medium outlet of the acid tank 84, and the medium reflux unit 333 is connected to the intermediate medium inlet of the acid tank 84; the iron mud recovery mechanism includes a flushing unit arranged above the medium transfer unit 332 and an iron mud collection box 321 arranged below the medium transfer unit 332.

In one embodiment, the intermediate medium 330 includes medium steel balls for entraining iron mud, which can conveniently bring out the iron mud at the bottom of the acid tank 84. For the iron mud at the bottom of the acid tank 84, they will be entrained by the steel balls flowing in layers and brought out of the acid tank 84 through the medium conveying unit 331; wherein, when the surface of the medium steel balls is designed to have a certain roughness, the iron mud entrainment effect can be improved. In one embodiment, the surface roughness of the medium steel balls Ra ≥ 0.8 μm, and more preferably controlled to Ra ≤ 12 μm.

In one embodiment, as shown in FIG6 , a slope is provided at the bottom of the acid tank 84 , and the slope slopes from the intermediate medium inlet to the intermediate medium outlet, so as to facilitate the circulation of the intermediate medium 330 in the acid tank 84 . For example, the medium steel balls can run from the intermediate medium inlet to the intermediate medium outlet by gravity, and the medium steel balls at a high position exert an extrusion and driving effect on the medium steel balls at a low position and the iron mud on the slope. Based on the circulation of the medium steel balls, the bottom of the acid tank 84 is ensured to be in motion at all times, which can reduce the siltation of the iron mud, thereby saving the intervention of power equipment. At the same time, the design of the slope is also conducive to the deposition of the iron mud at the intermediate medium outlet, thereby facilitating the intermediate medium 330 to bring the iron mud out.

In one embodiment, the medium conveying unit 331 is a screw pump or a screw conveyor. According to the relative position relationship between the intermediate medium outlet and the medium transfer unit 332, the screw pump or the screw conveyor can be arranged obliquely or horizontally.

In one embodiment, as shown in FIG6 and FIG7 , the medium transfer unit 332 is a chain conveying unit, for example, a chain plate conveyor or a drag chain conveyor. Accordingly, the medium transfer unit 332 includes an upper chain layer 3321 and a lower chain layer 3322 .

The gap between the chain plates of the chain conveying unit is smaller than the size of the intermediate medium 330, for example, smaller than the diameter of the medium steel ball.

Among them, the medium conveying unit 331 is connected with the upper chain layer 3321. For example, the medium output port of the medium conveying unit 331 is located directly above the upper chain layer 3321, and the intermediate medium 330 can be conveyed to the upper chain layer 3321; optionally, a hopper is arranged above the upper chain layer 3321, and the intermediate medium 330 output by the medium conveying unit 331 is received by the hopper and transferred to the upper chain layer 3321, which can avoid the intermediate medium 330 from being ejected outside the upper chain layer 3321 due to excessive falling distance.

The medium reflux unit 333 is arranged at the outlet side of the chain conveying unit. Optionally, the medium reflux unit 333 adopts a conveying roller to convey the cleaned intermediate medium 330 back to the acid tank 84 .

The flushing unit is used to flush the intermediate medium 330 on the medium transfer unit 332, so as to separate the iron mud from the intermediate medium 330. In one embodiment, as shown in FIG7 , the flushing unit includes a flushing pipe 351, and at least one group of spray structures can be arranged at the bottom of the flushing pipe 351. When there are multiple groups of spray structures, each spray structure is arranged in sequence along the conveying direction of the intermediate medium 330; each group of spray structures includes at least one nozzle. When there are multiple nozzles in the spray structure, each nozzle in the spray structure is preferably arranged in sequence along the width direction of the medium transfer unit 332.

7 , the flushing unit further comprises a flushing liquid supply pipe 352, which is connected to the flushing pipe 351 and is used to supply flushing liquid. Preferably, the surface water of the acid tank 84 is used as the flushing liquid, and accordingly, the flushing liquid supply pipe 352 is connected to the upper part of the acid tank 84.

The flushing liquid can leave through both sides of the medium transfer unit 332, and/or the medium transfer unit 332 is a hollow conveying device, for example, it can leave through the gap between the chain plates of the above-mentioned chain conveying unit. In one embodiment, as shown in Figures 6 and 8, the iron sludge recovery mechanism also includes a drainage unit 322, and the drainage unit 322 is arranged between the upper chain layer 3321 and the lower chain layer 3322 of the medium transfer unit 332, the top inlet of the drainage unit 322 is located directly below the flushing unit, and the bottom outlet of the drainage unit 322 is located directly above the iron sludge collection box 321. Based on this design, the flushing liquid can be reliably drained into the iron sludge collection box 321, and the on-site environment is cleaner; at the same time, it is prevented that the flushing water carrying iron sludge contaminates the lower chain layer 3322, and the working reliability of the medium transfer unit 332 is correspondingly improved and its maintenance frequency is reduced.

Preferably, as shown in Figures 6 and 8, the drainage unit 322 is in an inverted Y-shaped structure, forming one drainage inlet tube and two drainage outlet tubes; the two drainage outlet tubes can ensure the drainage efficiency and effect of the flushing liquid on the one hand, and on the other hand, it is also convenient for the arrangement of the lower chain layer 3322, for example, the lower chain layer 3322 is located between the two drainage outlet tubes.

The upper chain layer 3321 may be arranged in the drainage inlet pipe, so that the intermediate medium 330 and iron mud splashed by the high-pressure jet can be better captured.

Preferably, as shown in Figure 8, the drainage unit 322 is connected to the iron mud collection box 321 to form an integrated structure. For example, for the drainage unit 322 with the inverted Y-shaped structure, its outer frame 3221 is integrally formed with the iron mud collection box 321 to form a top-closed box body, and an inverted V-shaped mudguard 3222 is arranged in the box body, which correspondingly constitutes the inner frame of the drainage unit 322.

In one embodiment, a protective net 323 is arranged around the upper chain layer 3321 of the medium transfer unit 332, and the protective area of the protective net 323 at least covers the flushing area of the upper chain layer 3321. By providing the protective net 323, the high-pressure jet can be prevented from spraying the intermediate medium 330 out of the medium transfer unit 332.

The protection net 323 can be used for lateral protection. Optionally, the protection net 323 includes two side enclosure net panels 3231, which are arranged on both sides of the conveying channel of the medium transfer unit 332; The mesh plate 3231 preferably does not move together with the medium transfer unit 332 , for example, it is installed through a mesh plate bracket. For the above-mentioned solution with a drainage unit 322 , the side enclosure mesh plate 3231 can also be installed on the outer frame 3221 of the drainage unit 322 .

And/or, the protective net 323 can perform upper protection. Optionally, the protective net 323 includes a top mesh panel 3232, which is installed above the medium transfer unit 332; the top mesh panel 3232 preferably does not move together with the medium transfer unit 332, and its installation method can refer to the installation method of the side enclosure mesh panel 3231.

The iron mud processing subsystem is further optimized. As shown in FIG. 6 and FIG. 7 , the iron mud recovery mechanism further includes a filtering unit, and the iron mud collection box 321 is provided with a flushing liquid recovery pipe connected to the filtering unit.

Optionally, the filtrate produced by the filter unit can be used as a flushing liquid again, for example, the filtrate outlet pipe of the filter unit is connected to a flushing liquid storage tank, and the flushing liquid supply pipe 352 is also connected to the flushing liquid storage tank. When the flushing liquid adopts the surface water of the acid tank 84, the filtrate produced by the filter unit can flow back into the acid tank 84, and accordingly, the filtrate outlet pipe of the filter unit is connected to the acid tank 84.

The iron mud collection box 321 can control the direction of the flushing liquid by overflow, and the flushing liquid recovery pipe is connected to the overflow level of the iron mud collection box 321. Heavier impurities are deposited at the bottom of the iron mud collection box 321, which can be cleaned regularly or irregularly.

In one embodiment, the filtering unit includes an electromagnetic filter 100 for removing ferromagnetic impurities in the flushing liquid, which can reliably adsorb and remove the ferromagnetic impurities suspended in the flushing liquid.

Embodiment 5

This embodiment provides an electromagnetic filter 100, which can be used in the above-mentioned fourth embodiment.

As shown in Figures 9 to 11, the electromagnetic filter 100 includes a filter tank 101, a filter plate 102 and an impurity collector 103. The filter plate 102 includes an annular bracket 1021, a plurality of electromagnetic suction cups 1022 and an electric control unit for controlling the power supply of each electromagnetic suction cup 1022. Each electromagnetic suction cup 1022 is installed in the The annular bracket 1021 is arranged in a circular pattern along the circumference of the annular bracket 1021, and the annular bracket 1021 is provided with a rotating driving mechanism 105 for driving the rotation thereof; the annular bracket 1021 is partially located in the filter tank 101, and the impurity collector 103 is arranged outside the filter tank 101 and includes an impurity removal portion for driving impurities away from the electromagnetic suction cup 1022.

In one embodiment, the annular bracket 1021 includes an inner ring frame and an outer ring frame, and the inner ring frame and the outer ring frame are connected by a plurality of spokes, and each spoke divides the annular area between the inner ring frame and the outer ring frame into a plurality of suction cup mounting positions, and each suction cup mounting position is installed with an electromagnetic suction cup 1022.

Among them, optionally, as shown in FIG9 , the spokes are distributed along the radial direction of the annular support 1021 , and the inner ring frame-spokes-outer ring frame are connected to form a hub shape.

The electromagnetic suction cup 1022 is preferably detachably mounted on the annular bracket 1021, including but not limited to being fixed by screws.

The disk surface of the electromagnetic suction cup 1022 is preferably coplanar with the corresponding side surface of the annular bracket 1021, which not only facilitates the removal of impurities on the electromagnetic suction cup 1022, but also prevents the formation of some corners between the electromagnetic suction cup 1022 and the annular bracket 1021 to cause dirt to accumulate.

Preferably, the annular bracket 1021 is connected to the rotation drive mechanism 105 via the bracket shaft 104 , and the rotation drive mechanism 105 drives the bracket shaft 104 to rotate, thereby driving the annular bracket 1021 and the electromagnetic suction cup 1022 on the annular bracket 1021 to rotate.

In one embodiment, the above-mentioned rotation drive mechanism 105 adopts a motor + transmission component structure, and the transmission component can be a sprocket drive, a pulley drive, etc.; the motor is preferably a variable frequency motor, which can control the rotation speed of the annular bracket 1021.

Preferably, the electric control unit comprises a plurality of electric control cables and an electric control module, the number of the electric control cables is the same as the number of the electromagnetic suction cups 1022 and they are connected one-to-one, and each of the electric control cables is electrically connected to the electric control module.

In one embodiment, the support shaft 104 is a hollow shaft, and each of the electric control cables is wired through the hollow cavity of the support shaft 104. This method can facilitate the layout of the electric control cables, and has high safety and reliability. Preferably, a wiring hole is provided on the annular support 1021 (such as an inner ring frame) to facilitate the electric control cables to enter the support shaft 104; a wiring channel is also provided in the electromagnetic suction cup 1022 to connect the electric control cables to the coil in the electromagnetic suction cup 1022.

Preferably, the annular bracket 1021 is detachably mounted on the bracket shaft 104. In one embodiment, the bracket shaft 104 is designed in sections, and the annular bracket 1021 is clamped between two shaft segments 1041 of the bracket shaft 104 (generally, the inner ring frame is clamped between two shaft segments 1041 of the bracket shaft 104); optionally, a shaft shoulder is machined on the shaft segment 1041, and both ends of the inner hole of the inner ring frame respectively adopt a stepped hole structure, and the shaft neck at the end of the shaft segment 1041 is inserted into the large diameter hole segment in the corresponding side stepped hole structure, and the shaft shoulder of the shaft segment 1041 is abutted against the corresponding side end face of the inner ring frame and the two are fixed by screws.

Furthermore, when the rotating shaft segment 1041 and the inner ring frame are assembled, the electromagnetic suction cup 1022 can be further clamped between the two. For example, the outer ring wall of the inner ring frame adopts a stepped shaft structure, and a clamping groove is formed between the shoulder of one rotating shaft segment 1041 and the large diameter wall of the stepped shaft outer ring wall, and the corresponding side end of the electromagnetic suction cup 1022 is clamped in the clamping groove. This method can improve the stability and reliability of the installation of the electromagnetic suction cup 1022, especially when the electric control cable needs to enter the electromagnetic suction cup 1022 through the bracket rotating shaft 104, the above structure can ensure the alignment accuracy between the wiring hole on the annular bracket 1021 and the wiring channel in the electromagnetic suction cup 1022, thereby avoiding damage to the electric control cable and other faults.

In one embodiment, the electric control module includes a central controller and a conductive slip ring, each of the electric control cables is connected to the rotor part of the conductive slip ring, and the central controller is connected to the stator part of the conductive slip ring. The rotor part of the conductive slip ring is preferably installed on the bracket shaft 104. Based on this structure, when the electromagnetic chuck 1022 rotates normally, the reliability of the gain and loss of electricity of each electromagnetic chuck 1022 can be guaranteed. control.

The above-mentioned central controller includes but is not limited to a PLC controller.

When the annular bracket 1021 drives each electromagnetic suction cup 1022 to rotate, some of the electromagnetic suction cups 1022 are immersed in the filter tank 101 from outside the filter tank 101, and some of the electromagnetic suction cups 1022 leave the filter tank 101 and swing upward; for the electromagnetic suction cups 1022 that swing upward, ferromagnetic impurities are adsorbed on their surfaces, and the liquid that is carried up and the liquid in the adsorbed impurities can leave the electromagnetic suction cups 1022 under the action of gravity, thereby achieving the effect of gravity dehydration. The impurities collected in the impurity collector 103 have a low water content, which is not only convenient for subsequent treatment of the impurities, but also can reduce the loss of liquid in the filter tank 101.

In one embodiment, as shown in Fig. 10 and Fig. 11, the filter disc 102 further comprises a water retaining ring 1023, which is coaxially mounted on the support shaft 104 and abuts against the disc surface of each electromagnetic suction cup 1022. An annular water retaining edge is protruded on the outer ring wall of the water retaining ring 1023, and the annular water retaining edge and each electromagnetic suction cup 1022 are enclosed to form a water retaining groove. By providing the water retaining ring 1023, the liquid can be better guided to prevent the liquid from entering the support shaft 104 and other places to affect the normal operation of the electronic control unit.

Preferably, there are two water retaining rings 1023 , which are arranged on both sides of the annular support 1021 .

Preferably, a sealing gasket may be sandwiched between the water retaining ring 1023 and the electromagnetic suction cup 1022 to improve the water retaining effect.

At the impurity collection station, impurities on the surface of the electromagnetic chuck 1022 may be scraped off, or the surface of the electromagnetic chuck 1022 may be flushed with high-pressure water or high-pressure gas.

In one embodiment, as shown in FIGS. 9 to 11 , the impurity removal unit includes a scraper 1031, the working end of which is in contact with the surface of the electromagnetic suction cup 1022 at the impurity collection position; the impurity collector 103 also includes an impurity collection groove 1032, which is connected to the scraper The bottom of the board 1031. This method has low energy consumption and high working reliability.

Generally, both sides of the electromagnetic suction cup 1022 can absorb impurities. Therefore, it is preferred to respectively set a scraper 1031 and an impurity collection groove 1032 on both sides of the annular bracket 1021; the distance between the working ends of the scrapers 1031 on both sides is preferably the same as the thickness of the electromagnetic suction cup 1022.

Preferably, as shown in FIG. 10 and FIG. 11 , the scraper blade 1031 is arranged at an angle to facilitate the scraped impurities to fall into the impurity collecting groove 1032 .

Optionally, the working end of the scraper 1031 is its top end, and the working end is preferably parallel to the horizontal plane, that is, the contact line between the scraper 1031 and the electromagnetic suction cup 1022 is parallel to the horizontal plane. This method can facilitate the arrangement of the scraper 1031, the impurity collection trough 1032, etc. and facilitate the collection of impurities.

Preferably, the scraper plate 1031 is a grooved plate, and the length direction of the scraper plate 1031 is defined as the direction from its working end to the impurity collecting groove 1032. Wing plates are respectively extended at the two lateral ends of the scraper plate 1031 to better restrain and guide the scraped impurities.

As a preferred solution of this embodiment, as shown in Figures 10 and 11, the filter discs 102 are provided in multiple groups, and the annular brackets 1021 are sequentially mounted on the same bracket shaft 104, and the bracket shaft 104 is connected to the rotary drive mechanism 105. Providing multiple groups of filter discs 102 can improve filtering efficiency and filtering effect.

As shown in FIG. 10 , two adjacent filter discs 102 may share a common impurity collection groove 1032 .

Preferably, as shown in FIG. 10 , a plurality of partitions are provided in the filter tank 101 , each partition dividing the filter tank 101 into a plurality of liquid storage tanks 1011 , preferably each liquid storage tank 1011 is respectively provided with a filter disc 102 ; wherein the number of filter discs 102 and liquid storage tanks 1011 is preferably the same and they are arranged one-to-one.

In one embodiment, upstream sewage can be allowed to enter each liquid storage tank 1011 at the same time.

In another embodiment, the liquid storage tanks 1011 can be connected in series in sequence, with the upstream sewage first entering the first liquid storage tank 1011, and the sewage flowing between the upstream and downstream liquid storage tanks 1011 in the form of overflow. In this way, the sewage can be processed in an assembly line manner, and continuous processing can be achieved to ensure the processing effect and efficiency. As shown in Figure 10, in the first-stage liquid storage tank 1011, the filter disc 102 is preferably arranged close to the sewage inlet, which can capture ferromagnetic impurities in the sewage at the first time and improve the electromagnetic filtration effect; in the tail-stage liquid storage tank 1011, the filter disc 102 is preferably arranged close to the filtrate outlet, which can improve the cleanliness of the discharged filtrate.

In particular, based on the above-mentioned segmented design of the bracket shaft 104, the installation and arrangement of each filter disc 102 can be facilitated; the number of filter discs 102 can be increased or decreased as needed, so the flexibility is very high; and it can facilitate equipment maintenance, for example, the filter disc 102 at the corresponding liquid storage tank 1011 can be disassembled and assembled without affecting the filtration process in other liquid storage tanks 1011.

The method of using the electromagnetic filter 100 includes:

The annular bracket 1021 drives each electromagnetic chuck 1022 to rotate, so that the electromagnetic chuck 1022 can move cyclically between the working position, the dehydration position and the impurity removal position.

In the working position, the electromagnetic suction cup 1022 is powered and at least partially immersed in the filter tank 101 to absorb ferromagnetic impurities in the filter tank 101;

In the dehydration position, the electromagnetic chuck 1022 remains powered;

In the impurity removal position, the electromagnetic chuck 1022 loses power, and the impurities are driven off the electromagnetic chuck 1022 and collected by the impurity removal unit.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

A strip steel pickling system comprises a coiling device, a pre-cleaning unit, a multi-stage pickling unit and a final rinsing unit connected in sequence, characterized in that the pickling unit comprises a pickling tank, an intermediate rinsing tank and a strip steel heating device connected in sequence. The strip pickling system as described in claim 1 is characterized in that an annealing furnace and/or a pre-heater are arranged between the uncoiling device and the pre-cleaning unit; when the annealing furnace and the pre-heater are arranged, the annealing furnace and the pre-heater are arranged in sequence along the running direction of the strip. The strip pickling system as described in claim 2 is characterized in that the pre-heater adopts a flame heating device. The strip steel pickling system as described in claim 1 is characterized in that the strip steel heating device adopts a flame heating device or a hot air drying device. The strip steel pickling system as described in claim 1 is characterized in that each of the pickling tanks is respectively equipped with a circulating acid tank. The strip pickling system as described in claim 5 is characterized in that the acid solution in each of the circulating acid tanks is overflowed in a step-by-step manner through a connecting pipe, the concentration of the acid solution increases successively, and the total iron content decreases successively. The strip pickling system according to claim 5 is characterized in that it also includes an oxidant generator, which is connected to each of the circulating acid tanks respectively and is used to add oxidant to each of the circulating acid tanks to regulate the content and ratio of Fe2 ⁺ and Fe3 ⁺ in the acid tank. The strip steel pickling system as described in claim 1 is characterized in that an image acquisition module is provided at the strip steel outlet of each pickling unit for acquiring the strip steel surface image. A strip steel pickling method, characterized in that it is implemented based on the strip steel pickling system described in any one of claims 1 to 8. The strip steel pickling method comprises: Passing the steel strip through a pre-cleaning unit for pre-cleaning; After the pre-cleaning treatment, the strip steel is successively pickled in a multi-stage pickling unit. In each pickling tank, the high-temperature strip steel contacts with the low-temperature acid solution, and a strong physical and chemical reaction can occur on the surface of the strip steel, thereby quickly pickling and stripping the coarse iron oxide scale on the surface of the strip steel; After pickling, the strip enters the final rinsing unit, where it is dried and rolled or sent to downstream processes. The strip pickling method as described in claim 9 is characterized in that a strip surface image is collected at the strip outlet of the pickling unit to evaluate the pickling quality; the obtained pickling quality is compared with the preset pickling quality to guide the adjustment of the pickling process.