A method and device for preparing a sewage treatment agent using red mud as a raw material

Abstract

The present invention belongs to the technical field of sewage treatment equipment, and specifically relates to a red mud treatment device and a treatment method, which includes an electrodialysis housing, a membrane stack, and electrode plates. It also includes a non-stop reverse mechanism. By setting the non-stop reverse mechanism, during the electrodialysis operation, the inner cavity of the electrodialysis housing is divided into multiple operation tanks, and at least one of the electrodes corresponding to the operation tanks is reversed. At the same time, under the action of the driving member, relative movement is generated between the multiple operation tanks and the two groups of electrodes. Therefore, the part of the membrane stack separated in the multiple operation tanks is successively opposite to the reversed electrode, thereby cleaning the membrane stack. And since the operation tank corresponding to the reversed electrode only accounts for a part of the inner cavity of the electrodialysis housing, the remaining part still normally conducts electrodialysis operation, thereby realizing non-stop reverse scale removal operation.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment equipment, and specifically relates to a red mud treatment device and a treatment method. Background Art

[0002] Red mud is the waste residue produced after alkaline dissolution of bauxite. Since aluminum is both acid-soluble and alkaline-soluble, the Bayer process is generally used for high-pressure and high-temperature alkaline dissolution. The aluminum element enters the alkaline solution in the form of sodium aluminate, and the insoluble solid becomes waste residue. Since a large amount of iron oxide is also associated with bauxite, and iron oxide is insoluble in alkaline solution, the waste residue becomes brown-red sticky mud, and after dehydration, it becomes brown-red powdery waste. At present, the disposal of red mud occupies a large amount of landfills, and at the same time brings great risks to the surrounding environment and groundwater. Therefore, the resource utilization of red mud has become a difficult problem that the alumina industry urgently needs to solve.

[0003] Among the ways to utilize red mud resources, one of the ways to prepare the flocculant aluminum ferric chloride is to react red mud with acid. This method can not only utilize the discarded red mud, but also the generated aluminum ferric chloride flocculant is one of the water treatment agents with better performance. However, since red mud contains more sodium oxide, sodium aluminate and other substances, when red mud is not dealkalized, the preparation of aluminum ferric chloride from red mud not only requires the consumption of more acid, but also due to the strong alkalinity of red mud, it may also affect the properties of the final product.

[0004] In order to dealkalize red mud, a red mud dealkalization and recovery process of electrodialysis coupled with ion exchange resin is disclosed in the related art. The advantages and disadvantages of various red mud dealkalization methods are compared in the scheme, and finally the red mud is dealkalized by electrodialysis coupled with ion exchange resin. However, in actual application, it is found that, on the one hand, since the red mud wash water contains aluminum oxide, iron oxide and other substances, when the red mud wash liquid is electrodialyzed, aluminum oxide will scale on the membrane surface due to the migration of electrolyte, and due to the excessive amount of such substances in the red mud wash liquid, the scaling rate of the membrane surface is too fast. Although the related art can dissolve the scale on the membrane surface by reversing the electrode sheet, on the one hand, frequent reversal of the electrode sheet not only causes great damage to the electrode sheet, but also has poor convenience during operation. On the other hand, during the frequent reversal of the electrode sheet, the electrodialysis operation will be interrupted, which not only affects the smoothness of the eluent treatment, but also reduces the concentration rate of the eluent.

[0005] In view of this, the present invention proposes a red mud treatment device and a treatment method to solve the above technical problems. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art and solve the above-mentioned technical problems, the present invention proposes a red mud treatment device and a treatment method.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0008] An apparatus for treating red mud according to the present invention includes a washing tank for washing red mud, a plate and frame filter press device for filtering the washed slurry to output an eluate and a mud cake, and an electrodialysis device for performing electrodialysis treatment on the eluate; the electrodialysis device includes an electrodialysis housing, a membrane stack, and electrode plates. The electrodialysis housing is a cavity-type structure. Electrode plates are installed at both ends of the inner cavity of the electrodialysis housing. A membrane stack is fixedly installed in the electrodialysis housing. The membrane stack is formed by arranging a plurality of anion and cation exchange membranes at intervals. The anion and cation exchange membranes form alternately arranged concentrated water chambers and fresh water chambers. It further includes a non-stop reverse mechanism. The non-stop reverse mechanism is installed in the electrodialysis housing. The non-stop reverse mechanism includes an installation pipe, a partition member, and a driving member. An installation pipe is rotatably installed in the inner cavity of the electrodialysis housing. The installation pipe is coaxially arranged with the electrodialysis housing. The membrane stack is fixedly installed on the installation pipe. The partition members are designed in plural. The partition members are evenly arranged in the circumferential direction of the installation pipe. The partition members divide the inner cavity of the electrodialysis housing into a plurality of non-connecting working slots in the circumferential direction. A driving member is fixedly installed on the electrodialysis housing. The installation pipe penetrates and extends outside the electrodialysis housing. The driving member is in transmission connection with the installation pipe. The electrode plates at the same end of the electrodialysis housing are divided into two groups, and the polarities of the two groups of electrode plates are opposite. The two groups of electrode plates respectively correspond to different working slots.

[0009] Preferably, annular installation grooves are provided at both ends of the electrodialysis housing. The electrode plates are all installed in the installation grooves. A partition plate is detachably and fixedly installed in the installation grooves. The partition plate divides the installation grooves into a non-polar chamber, a first electrode chamber, and a second electrode chamber. The non-polar chamber is located between the first electrode chamber and the second electrode chamber. The two groups of electrode plates are respectively installed in the first electrode chamber and the second electrode chamber, and the amplitude of the non-polar chamber is greater than the amplitude of a single working slot.

[0010] Preferably, adjustment grooves are provided at both ends of the electrodialysis housing. Uniformly distributed adjustment holes are provided in the adjustment grooves. The adjustment grooves are communicated with the installation grooves through the adjustment holes. The partition plate extends into the adjustment grooves through the adjustment holes. A sealing plate is detachably and fixedly installed at one end of the adjustment groove away from the installation groove.

[0011] Preferably, one end of the partition plate close to the sealing plate is designed in a T shape. The partition plate is fixedly installed on the sealing plate by bolts.

[0012] Preferably, a connection ring group is commonly installed on the plurality of partition members. The connection ring group is formed by arranging a plurality of connection rings at intervals. The connection ring group corresponds to the membrane stack. Assembly grooves are commonly formed on the partition members and the connection ring group, and an elastic layer is fixedly connected to the inner wall of the assembly groove. The connection ring group and the partition members are elastically and sealingly connected to the membrane stack through the assembly grooves.

[0013] Preferably, slots are formed on the outer wall of the installation pipe. The connection ring is composed of a plurality of arc plates, and the arc plates and the slots correspond to the partition members one by one.

[0014] Preferably, it further includes a conveying mechanism. The conveying mechanism is connected to the electrodialysis housing and is used to control the flow path of the eluent. The conveying mechanism includes a water inlet pipe and a water outlet pipe. The water inlet pipe includes a first water inlet pipe and a second water inlet pipe. The water outlet pipe includes a first concentrated water pipe, a second concentrated water pipe, a first fresh water pipe, and a second fresh water pipe. The first water inlet pipe, the first concentrated water pipe, and the first fresh water pipe all correspond to the first electrode chamber. The second water inlet pipe, the second concentrated water pipe, and the second fresh water pipe all correspond to the second electrode chamber.

[0015] Preferably, the second water inlet pipe, the first concentrated water pipe, and the first fresh water pipe are all fixedly installed on the electrodialysis housing. A flow dividing pipe is rotatably installed in the installation pipe. The first water inlet pipe, the second concentrated water pipe, and the second fresh water pipe are all fixedly installed in the flow dividing pipe and are arranged to be open to the outer ring surface of the flow dividing pipe. Guide through holes are formed on the installation pipe at uniform intervals, and the guide through holes correspond to the working grooves one by one.

[0016] Preferably, a support frame is installed outside the electrodialysis housing, and the flow dividing pipe is fixedly installed on the support frame through a guide plate.

[0017] A red mud treatment method, the method comprising the following steps:

[0018] S1: Introduce red mud into a washing pool to mix with water, and perform aeration washing in the washing pool. After multiple washings, the pH of the slurry is reduced to between 9 and 10. The slurry is output as eluent and filter cake after being filtered by a plate and frame filter press.

[0019] S2: Pump the eluent into the working groove through the first water inlet pipe and the second water inlet pipe, and simultaneously start the non-stop reverse rotation mechanism and the electrode plates. The eluent in the working groove continuously rotates during the electrodialysis process.

[0020] S3: The eluent undergoes electrodialysis in the working groove and outputs fresh water for washing red mud and concentrated water as an acidic waste gas absorbent through the water outlet pipe. At the same time, with the rotation, the polarities of the electrode plates on both sides of the membrane stack are switched.

[0021] S4: At the same time, react the filter cake with acid, react at 90 - 110 °C for 1 - 10 h, and prepare ferric aluminum chloride sewage treatment agent after filtration, concentration, and drying.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. For a red mud treatment device and method according to the present invention, by providing a non-stop reverse mechanism, during the electrodialysis operation, the inner cavity of the electrodialysis housing is divided into multiple operation tanks, and at least one of the electrodes corresponding to the operation tanks is reversed. At the same time, under the action of the driving member, a relative movement is generated between the multiple operation tanks and the two groups of electrodes. Therefore, the parts of the membrane stack separated in the multiple operation tanks are successively opposite to the reversed electrodes, thereby cleaning the membrane stack. And since the operation tank corresponding to the reversed electrode only occupies a part of the inner cavity of the electrodialysis housing, the remaining parts still carry out the electrodialysis operation normally, thereby realizing the non-stop reverse scale removal operation.

[0024] 2. For a red mud treatment device and method according to the present invention, in one rotation cycle, the water flow in the same operation tank flows in two opposite directions respectively, thereby respectively flushing the anion and cation exchange membranes in different directions. By using the multi-directional flushing and cooperating with the electrode reversal, the probability of scale layer shedding can be effectively enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 is a perspective view of the present invention;

[0027] Figure 2 is a perspective view of the present invention from another perspective;

[0028] Figure 3 is an assembled perspective view of the installation pipe, the membrane stack and the partition member;

[0029] Figure 4 is an exploded view of the installation pipe, the membrane stack and the partition member;

[0030] Figure 5 is an exploded view of the electrodialysis housing and the sealing plate;

[0031] Figure 6 is a perspective view of the sealing plate;

[0032] Figure 7 is a perspective view of the installation groove and the partition plate;

[0033] Figure 8 is a schematic diagram of the partition of the installation groove;

[0034] Figure 9 is an exploded view of the shunt pipe and the installation pipe;

[0035] Figure 10 is a flowchart of the method of the present invention;

[0036] In the figure: 1. electrodialysis shell; 11. electrode sheet; 12. anion and cation exchange membrane; 2. mounting tube; 21. separator; 22. working tank; 23. driving member; 24. mounting tank; 25. partition; 26. non-polar chamber; 27. first electrode chamber; 28. second electrode chamber; 3. adjusting tank; 31. adjusting hole; 32. sealing plate; 4. connecting ring; 41. assembly tank; 42. slot; 5. first water inlet pipe; 51. second water inlet pipe; 52. first concentrated water pipe; 53. second concentrated water pipe; 54. first fresh water pipe; 55. second fresh water pipe; 6. shunt pipe; 61. conduction hole; 7. support frame. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0038] like Figures 1 to 9 As shown, a red mud treatment device described in the present invention comprises a washing tank for washing red mud, a plate and frame filter press device for filtering the washed mud and then outputting eluent and mud cake, and an electrodialysis device for electrodialyzing the eluent; the electrodialysis device comprises an electrodialysis housing 1, a membrane stack and an electrode sheet 11, the electrodialysis housing 1 is a cavity structure, both ends of the inner cavity of the electrodialysis housing 1 are equipped with electrode sheets 11, a membrane stack is fixedly installed in the electrodialysis housing 1, the membrane stack is composed of a plurality of anion and cation exchange membranes 12 arranged at intervals, and the anion and cation exchange membranes 12 form concentrated water chambers and fresh water chambers arranged at intervals, and also comprises a non-stop reversal mechanism, the non-stop reversal mechanism is installed in the electrodialysis housing 1, and the non-stop reversal mechanism includes an installation pipe 2. A separator 21 and a driving member 23. A mounting tube 2 is rotatably installed in the inner cavity of the electrodialysis shell 1. The mounting tube 2 is coaxially arranged with the electrodialysis shell 1. The membrane stack is fixedly installed on the mounting tube 2. The separators 21 are designed in multiple numbers. The separators 21 are evenly arranged in the circumferential direction of the mounting tube 2. The separators 21 divide the inner cavity of the electrodialysis shell 1 into a plurality of mutually non-conductive working slots 22 along the circumferential direction. A driving member 23 is fixedly installed on the electrodialysis shell 1. The mounting tube 2 penetrates and extends to the outside of the electrodialysis shell 1. The driving member 23 is transmission-connected with the mounting tube 2. The electrode sheets 11 located at the same end of the electrodialysis shell 1 are divided into two groups, and the two groups of electrode sheets 11 have opposite polarities. The two groups of electrode sheets 11 correspond to different working slots 22, respectively.

[0039] When the red mud eluate is subjected to electrodialysis treatment, the method of reversing the electrode sheet 11 can effectively alleviate the degree of membrane scaling. In the related art, when reversing the electrode sheet 11, the method of switching the electrode sheet 11 or directly replacing the electrode sheet 11 is usually adopted to adjust the polarity of the electrode sheets 11 at both ends. This operation will cause the direction of ion migration in the entire electrodialysis equipment to change. Therefore, when changing the reversed electrode sheet 11, it is necessary to discharge the sewage in the electrodialysis equipment, which affects the sewage treatment rate. In order to enhance the convenience of reversing the electrode sheet 11, the present invention provides a non-stop reversing mechanism. Through the change of the relative position of the electrode sheet 11 and the working tank 22, the polarity of the electrode sheets 11 at both ends of the working tank 22 can be quickly switched while the sewage treatment continues.

[0040] Specifically, the red mud eluate is filled into the electrodialysis housing 1, and the staff turns on the electrodialysis equipment. At this time, driven by the external DC electric field, the anion and cation exchange membrane 12 is selectively permeable, and the anions and cations move to the anode and cathode respectively, thereby realizing the concentration of the red mud eluate (here is the electrodialysis technology well known to those skilled in the art, and no further summary is given here). During the continuous electrodialysis operation, the reversing mechanism is started synchronously without stopping the machine, wherein the driving member 23 is connected to the mounting tube 2 in a transmission manner. In the present invention, the driving member 23 is preferably an electric motor, which is mounted on the electrodialysis housing 1 and connected to the mounting tube 2 through a reducer and a coupling mounted at the end. Under the action of the driving member 23, the mounting tube 2 rotates at a uniform speed in the electrodialysis housing 1. Since the membrane stack and the separator 21 are both mounted on the mounting tube 2, the mounting tube 2 rotates at a uniform speed. During the rotation, the membrane stack and separator 21 are synchronously driven to rotate, wherein the separator 21 is evenly distributed in the circumferential direction of the mounting tube 2, and cooperates with the mounting tube 2 to divide the electrodialysis shell 1 into multiple working slots 22, and the multiple working slots 22 are not connected to each other, while the electrode sheets 11 are installed at both ends of the electrodialysis shell 1, and the electrode sheets 11 are divided into two groups, and the two groups of electrode sheets 11 have opposite polarities. It should be noted that in the present invention, the number of electrode sheets 11 in a group is at least two, and must be a multiple of two. The same group of electrode sheets 11 is evenly divided at both ends of the electrodialysis shell 1. During the rotational movement of the working slot 22, and therefore during the uniform rotation of the mounting tube 2, the position of the working slot 22 changes, and then the working slot 22 is connected to different electrode sheets 11 respectively. Therefore, during the rotation, the electrode continues to work to concentrate the eluent in the working slot 22.

[0041] The present invention realizes scale removal during operation without shutdown by setting up a non-stop reverse mechanism. During the electrodialysis operation, the inner cavity of the electrodialysis housing 1 is divided into multiple operation slots 22, and at least one of the electrodes corresponding to the operation slots 22 is reversed. Meanwhile, under the action of the driving member 23, relative movement is generated between the multiple operation slots 22 and the two sets of electrodes. Therefore, the part of the membrane stack separated in the multiple operation slots 22 is successively opposite to the reversed electrode, thereby cleaning the membrane stack. Since the operation slot 22 corresponding to the reversed electrode only occupies a part of the inner cavity of the electrodialysis housing 1, the remaining part still normally conducts electrodialysis operation, thus realizing scale removal by reverse rotation without shutdown.

[0042] As a preferred embodiment of the present invention, annular installation grooves 24 are provided at both ends of the electrodialysis housing 1. The electrode plates 11 are all installed in the installation grooves 24. A partition plate 25 is detachably and fixedly installed in the installation grooves 24. The partition plate 25 divides the installation grooves 24 into a non-polar chamber 26, a first electrode chamber 27, and a second electrode chamber 28. The non-polar chamber 26 is located between the first electrode chamber 27 and the second electrode chamber 28. The two sets of electrode plates 11 are respectively installed in the first electrode chamber 27 and the second electrode chamber 28, and the amplitude of the non-polar chamber 26 is greater than the amplitude of a single operation slot 22.

[0043] In practical applications, since the installation pipe 2 drives the partition member 21 to rotate in the electrodialysis housing 1, in order to avoid the mutual influence of the two sets of electrodes with opposite polarities, in the present invention, the partition plate 25 is used to divide the installation groove 24 into a non-polar chamber 26, a first electrode chamber 27, and a second electrode chamber 28. Among them, the number of non-polar chambers 26 is two, which are used to separate the first electrode chamber 27 and the second electrode chamber 28, and the two sets of electrodes are respectively installed in the first electrode chamber 27 and the second electrode chamber 28. Since the installation grooves 24 are located at both ends of the electrodialysis housing 1, the first electrode chamber 27 and the second electrode chamber 28 are respectively communicated with different operation slots 22, so that electrodialysis operations in opposite directions are simultaneously carried out in the inner cavity of the same electrodialysis housing 1. At the same time, it should be noted that since the amplitude of the non-polar chamber 26 is greater than the amplitude of the operation slot 22, when the operation slot 22 rotates relative to the installation groove 24, the existence of the non-polar chamber 26 can effectively prevent the same operation slot 22 from being simultaneously communicated with the first electrode chamber 27 and the second electrode chamber 28, thereby avoiding mutual interference between the two sets of electrodes.

[0044] As a preferred embodiment of the present invention, adjustment grooves 3 are provided at both ends of the electrodialysis housing 1. Uniformly distributed adjustment holes 31 are provided in the adjustment grooves 3. The adjustment grooves 3 are connected to the installation grooves 24 through the adjustment holes 31. The partition plate 25 extends into the adjustment grooves 3 through the adjustment holes 31. A sealing plate 32 is detachably and fixedly installed at one end of the adjustment groove 3 away from the installation groove 24.

[0045] One end of the partition plate 25 close to the sealing plate 32 is designed in a T shape, and the partition plate 25 is fixedly installed on the sealing plate 32 by bolts.

[0046] In actual application, in order to further enhance the flexibility of the electrode reversal scale removal operation, the present invention is provided with an adjustment groove 3 and an adjustment hole 31 at both ends of the electrodialysis housing 1. Under the communication action of the adjustment hole 31, the adjustment groove 3 is communicated with the installation groove 24. When adjusting the ratio of the first electrode chamber 27 to the second electrode chamber 28 in the electrodialysis device, the staff, with the cooperation of tools, disassembles the sealing plate 32 detachably fixed in the adjustment groove 3. During the process of pulling out the sealing plate 32 from the adjustment groove 3, the partition plate 25 fixedly connected to the sealing plate 32 by bolts is taken out synchronously. Subsequently, the staff removes the partition plate 25 from the sealing plate 32, and at the same time, according to the new ratio, fixes the partition plate 25 at the position corresponding to the new ratio on the sealing plate 32. Then, the sealing plate 32 and the partition plate 25 are reset. The partition plate 25 divides the adjustment groove 3 and the installation groove 24 into non-communicating chambers, so as to adjust the proportion of the first electrode chamber 27, the second electrode chamber 28, and the non-polar chamber 26. It should be noted that when adjusting the position of the partition plate 25 on the sealing plate 32, the position of the adjustment hole 31 needs to be referred to. Therefore, in actual application, in the circumferential direction of the installation groove 24, the greater the opening density of the adjustment hole 31, the higher the adjustable precision of the first electrode chamber 27, the second electrode chamber 28, and the non-polar chamber 26, and the stronger the adjustable flexibility of the electrodialysis device.

[0047] As a preferred embodiment of the present invention, a set of connecting rings 4 is commonly installed on a plurality of the partition members 21. The set of connecting rings 4 is formed by arranging a plurality of connecting rings 4 at intervals. The set of connecting rings 4 corresponds to the membrane stack. An assembly groove 41 is commonly opened on the partition member 21 and the set of connecting rings 4, and an elastic layer is fixedly connected to the inner wall of the assembly groove 41. The set of connecting rings 4 and the partition member 21 are elastically and hermetically connected to the membrane stack through the assembly groove 41.

[0048] When the electrodialysis device is in use, the partition member 21 and the membrane stack rotate in the electrodialysis housing 1. In order to enhance the protection of the membrane stack, in the present invention, a set of connecting rings 4 is fixedly installed on the partition member 21. Through the assembly groove 41 commonly opened on the set of connecting rings 4 and the partition member 21, the membrane stack is clamped and fixed, thereby enhancing the mechanical properties of the membrane stack and reducing the probability of bending and deformation of the membrane stack during rotation. At the same time, the set of connecting rings 4 is slidably and hermetically connected to the inner wall of the electrodialysis housing 1, which can effectively reduce the frictional damage of the membrane stack during rotation, thereby prolonging the service life of the cation and anion exchange membranes 12 that make up the membrane stack.

[0049] As a preferred embodiment of the present invention, a slot 42 is opened on the outer wall of the installation pipe 2. The connecting ring 4 is composed of a plurality of arc plates, and the arc plates and the slot 42 correspond to the partition member 21 one by one.

[0050] By providing slots 42 on the installation pipe 2 and using multiple arc plates to form the connection ring 4, and multiple connection rings 4 constituting a set of connection rings 4, the set of connection rings 4, the membrane stack, the installation pipe 2 and the partition 21 can be detachably combined. Therefore, when maintaining or repairing the equipment, it is convenient to disassemble and combine the installation pipe 2, the membrane stack, the partition 21 and the set of connection rings 4, reducing the difficulty of replacing or maintaining the equipment components.

[0051] As a preferred embodiment of the present invention, it further includes a conveying mechanism. The conveying mechanism is connected to the electrodialysis housing 1. The conveying mechanism is used to control the flow path of the eluent. The conveying mechanism includes a water inlet pipe and a water outlet pipe. The water inlet pipe includes a first water inlet pipe 5 and a second water inlet pipe 51. The water outlet pipe includes a first concentrated water pipe 52, a second concentrated water pipe 53, a first fresh water pipe 54 and a second fresh water pipe 55. The first water inlet pipe 5, the first concentrated water pipe 52 and the first fresh water pipe 54 all correspond to the first electrode chamber 27. The second water inlet pipe 51, the second concentrated water pipe 53 and the second fresh water pipe 55 all correspond to the second electrode chamber 28.

[0052] In order to further enhance the convenience of sewage treatment in the electrodialysis housing 1, a water inlet pipe and a water outlet pipe are provided in the present invention. According to the corresponding relationship with the first electrode chamber 27 and the second electrode chamber 28, the water inlet pipe and the water outlet pipe are both divided into two groups and are respectively named the first water inlet pipe 5, the first concentrated water pipe 52, the first fresh water pipe 54, the second water inlet pipe 51, the second concentrated water pipe 53 and the second fresh water pipe 55. In actual application, under the pumping of a water pump, sewage enters the working tanks 22 corresponding to the first electrode chamber 27 and the second electrode chamber 28 through the first water inlet pipe 5 and the second water inlet pipe 51 respectively. As the working tank 22 continues to rotate and the electrodialysis operation proceeds, when the working tank 22 rotates and aligns with the first fresh water pipe 54, the first concentrated water pipe 52, the second fresh water pipe 55 and the second concentrated water pipe 53 respectively, concentrated water and fresh water are output. It should be noted that the first fresh water pipe 54 and the first concentrated water pipe 52 respectively correspond to adjacent concentrated water chambers and fresh water chambers in the same working tank 22. In the circumferential direction of the electrodialysis housing 1, the first fresh water pipe 54 and the first concentrated water pipe 52 are in the same position, while in the axial direction of the electrodialysis housing 1, the first fresh water pipe 54 and the first concentrated water pipe 52 are arranged in a staggered manner. Similarly, the second fresh water pipe 55 and the second concentrated water pipe 53 are also arranged in this way. Since the water inlet pipe and the water outlet pipe are in a fixed position relative to the electrodialysis housing 1, during the rotation of the working tank 22, the working tank 22 successively experiences the processes of water inlet, water outlet, re-water inlet and re-water outlet. When the two sets of electrode components are switched, the sewage that has undergone electrodialysis in the working tank 22 can be discharged by itself, and untreated sewage can be pumped in. Therefore, during the continuous rotation process, it can not only maintain the continuous progress of sewage treatment, but also avoid the problem of re-mixing of the separated ions.

[0053] As a preferred embodiment of the present invention, the second water inlet pipe 51, the first concentrated water pipe 52 and the first fresh water pipe 54 are all fixedly installed on the electrodialysis housing 1. A flow dividing pipe 6 is rotatably installed in the installation pipe 2. The first water inlet pipe 5, the second concentrated water pipe 53 and the second fresh water pipe 55 are all fixedly installed in the flow dividing pipe 6 and are arranged to be open to the outer ring surface of the flow dividing pipe 6. The installation pipe 2 is provided with uniformly distributed guide through holes 61, and the guide through holes 61 correspond to the working grooves 22 one by one.

[0054] A support frame 7 is installed outside the electrodialysis housing 1, and the flow dividing pipe 6 is fixedly installed on the support frame 7 through a guide plate.

[0055] By providing the flow dividing pipe 6 and fixedly installing the flow dividing pipe 6 on the support frame 7, during the circumferential rotation of the working groove 22, when the working groove 22 is within the range of the first electrode chamber 27, at this time the first water inlet pipe 5 is communicated with the working groove 22 through the guide through hole 61 on the installation pipe 2, and the sewage flows in along the direction away from the center of the cation and anion exchange membrane 12. When the working groove 22 rotates to the range of the second electrode chamber 28, at this time the second water inlet pipe 51 is communicated with the working groove 22, and the sewage flows in along the direction towards the center of the cation and anion exchange membrane 12. Similarly, when the working groove 22 corresponds to the first fresh water pipe 54 and the first concentrated water pipe 52, the treated water flows out along the direction away from the center of the cation and anion exchange membrane 12. When the working groove 22 corresponds to the second fresh water pipe 55 and the second concentrated water pipe 53, the treated water flows out along the direction towards the center of the cation and anion exchange membrane 12. In one rotation cycle, the water flow in the same working groove 22 flows in two opposite directions respectively, and then flushes the cation and anion exchange membrane 12 in different directions respectively. By using multi-directional flushing and cooperating with the electrode reversal, the probability of scale layer shedding can be effectively enhanced.

[0056] As Figure 10 shown, a red mud treatment method includes the following steps:

[0057] S1: Introduce red mud into a washing pool and mix it with water, and perform aeration washing in the washing pool. After multiple washings, the pH of the slurry is reduced to between 9 and 10. The slurry is filtered through a plate and frame filter press to output an eluate and a filter cake.

[0058] S2: Pump the eluate into the working groove 22 through the first water inlet pipe 5 and the second water inlet pipe 51, and simultaneously start the non-stop reverse rotation mechanism and the electrode plate 11. The eluate in the working groove 22 continuously rotates during the electrodialysis process.

[0059] S3: The eluate performs electrodialysis in the working groove 22, and fresh water for washing red mud and concentrated water as an acidic waste gas absorbent are output through the water outlet pipe. At the same time, with the rotation, the polarities of the electrode plates 11 on both sides of the membrane stack are switched.

[0060] S4: React the mud cake with acid simultaneously, react at 90 - 110 °C for 1 - 10 h, and prepare the polyaluminum ferric chloride sewage treatment agent after pressure filtration, concentration and drying.

[0061] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A red mud treatment device, comprising a washing tank for washing red mud, a plate-frame filter press device for filtering washed mud to output eluent and mud cake, and an electrodialysis device for electrodialyzing the eluent; The electrodialysis device comprises an electrodialysis housing (1), a membrane stack and an electrode sheet (11); The electrodialysis housing (1) is a hollow structure, and electrode sheets (11) are installed at both ends of the inner cavity of the electrodialysis housing (1); A membrane stack is fixedly installed in the electrodialysis housing (1), wherein the membrane stack is composed of a plurality of anion and cation exchange membranes (12) arranged at intervals, and concentrated water chambers and fresh water chambers arranged at intervals are formed between the anion and cation exchange membranes (12); Features: It also includes a non-stop reversing mechanism, which is installed in the electrodialysis housing (1), and includes a mounting tube (2), a separator (21) and a driving member (23); A mounting tube (2) is rotatably mounted in the inner cavity of the electrodialysis housing (1), the mounting tube (2) being coaxially arranged with the electrodialysis housing (1), and the membrane stack being fixedly mounted on the mounting tube (2); The separators (21) are designed in plural numbers, and the separators (21) are evenly arranged in the circumferential direction of the mounting tube (2). The separators (21) evenly divide the inner cavity of the electrodialysis housing (1) into a plurality of mutually non-conductive operating slots (22) along the circumferential direction. A driving member (23) is fixedly mounted on the electrodialysis housing (1), the mounting tube (2) penetrates through and extends to the outside of the electrodialysis housing (1), and the driving member (23) is drivingly connected to the mounting tube (2); The electrode sheets (11) located at the same end of the electrodialysis housing (1) are divided into two groups, and the two groups of electrode sheets (11) have opposite polarities. The two groups of electrode sheets (11) correspond to different operating tanks (22), respectively.

2. A red mud treatment device according to claim 1, characterized in that: Both ends of the electrodialysis housing (1) are provided with annular mounting grooves (24), the electrode sheets (11) are mounted in the mounting grooves (24), a partition (25) is detachably fixedly mounted in the mounting grooves (24), the partition (25) divides the mounting groove (24) into a non-polar chamber (26), a first electrode chamber (27) and a second electrode chamber (28), the non-polar chamber (26) is located between the first electrode chamber (27) and the second electrode chamber (28), two groups of the electrode sheets (11) are respectively mounted in the first electrode chamber (27) and the second electrode chamber (28), and the amplitude of the non-polar chamber (26) is greater than the amplitude of a single operating tank (22).

3. A red mud treatment device according to claim 2, characterized in that: Both ends of the electrodialysis housing (1) are provided with adjustment grooves (3), and evenly distributed adjustment holes (31) are provided in the adjustment grooves (3). The adjustment grooves (3) are conductively connected to the mounting grooves (24) through the adjustment holes (31), and the partitions (25) extend into the adjustment grooves (3) through the adjustment holes (31). A sealing plate (32) is detachably fixedly mounted on one end of the adjustment grooves (3) away from the mounting grooves (24).

4. A red mud treatment device according to claim 3, characterized in that: The partition plate (25) is designed in a T-shape at one end close to the sealing plate (32), and the partition plate (25) is fixedly mounted on the sealing plate (32) by means of bolts.

5. A red mud treatment device according to claim 4, characterized in that: A connecting ring (4) group is commonly installed on the plurality of the separators (21), the connecting ring (4) group is composed of a plurality of connecting rings (4) arranged at intervals, the connecting ring (4) group corresponds to the membrane stack, an assembly groove (41) is commonly provided on the separators (21) and the connecting ring (4) group, and an elastic layer is fixedly connected to the inner wall of the assembly groove (41), and the connecting ring (4) group and the separators (21) are elastically sealed and connected to the membrane stack via the assembly groove (41).

6. A red mud treatment device according to claim 5, characterized in that: A slot (42) is provided on the outer wall of the mounting tube (2), and the connecting ring (4) is composed of a plurality of arc plates, wherein the arc plates and the slot (42) correspond to the separators (21) one by one.

7. A red mud treatment device according to claim 6, characterized in that: It also includes a conveying mechanism, which is connected to the electrodialysis housing (1) and is used to control the flow path of the eluent; The conveying mechanism comprises a water inlet pipe and a water outlet pipe; The water inlet pipe comprises a first water inlet pipe (5) and a second water inlet pipe (51); The water outlet pipe comprises a first concentrated water pipe (52), a second concentrated water pipe (53), a first fresh water pipe (54) and a second fresh water pipe (55); The first water inlet pipe (5), the first concentrated water pipe (52) and the first fresh water pipe (54) all correspond to the first electrode chamber (27), and the second water inlet pipe (51), the second concentrated water pipe (53) and the second fresh water pipe (55) all correspond to the second electrode chamber (28).

8. A red mud treatment device according to claim 7, characterized in that: The second water inlet pipe (51), the first concentrated water pipe (52) and the first fresh water pipe (54) are all fixedly mounted on the electrodialysis housing (1); a shunt pipe (6) is rotatably mounted in the mounting pipe (2); the first water inlet pipe (5), the second concentrated water pipe (53) and the second fresh water pipe (55) are all fixedly mounted in the shunt pipe (6) and are arranged with an opening on the outer annular surface of the shunt pipe (6); the mounting pipe (2) is provided with evenly distributed conducting holes (61), and the conducting holes (61) correspond one-to-one to the operating tanks (22).

9. A red mud treatment device according to claim 8, characterized in that: A support frame (7) is installed outside the electrodialysis housing (1), and the shunt pipe (6) is fixedly mounted on the support frame (7) via a guide plate.

10. A method for treating red mud, characterized in that: The method uses a red mud treatment device as described in claim 9, and the method comprises the following steps: S1: Red mud is passed into a washing tank and mixed with water, and washed by aeration in the washing tank. After multiple washings, the pH of the mud is reduced to between 9 and 10. The mud is filtered through a plate and frame filter and then the eluent and mud cake are output; S2: pumping the eluent into the working tank (22) through the first water inlet pipe (5) and the second water inlet pipe (51), and synchronously starting the non-stop reversing mechanism and the electrode sheet (11), so that the eluent in the working tank (22) continuously rotates during the electrodialysis process; S3: The eluent is subjected to electrodialysis in the operation tank (22), and fresh water for washing red mud and concentrated water as an absorbent for acid waste gas are output through the outlet pipe. At the same time, the polarity of the electrode sheets (11) on both sides of the membrane stack is switched as the membrane stack rotates; S4: The mud cake is reacted with acid at 90-110°C for 1-10h, and aluminum ferric chloride sewage treatment agent is obtained after filter pressing, concentration and drying.

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