Method and device for preparing sewage treatment agent by using red mud as raw material

Abstract

The invention belongs to the technical field of sewage treatment equipment, and particularly relates to a method and a device for preparing a sewage treatment agent by using red mud as a raw material, the device comprises an electrodialysis shell, a membrane stack and an electrode plate, and further comprises a non-stop reversing mechanism. An inner cavity of an electrodialysis shell is divided into a plurality of operation grooves, an electrode corresponding to at least one operation groove is reversed, and meanwhile, under the action of a driving part, the plurality of operation grooves and two groups of electrodes generate relative motion, so that the parts, separated in the plurality of operation grooves, of a membrane stack are opposite to the reversed electrodes in sequence, and the membrane stack is separated from the electrodes. And the operation groove corresponding to the reverse electrode only occupies one part of the inner cavity of the electrodialysis shell, so that the rest part of the inner cavity of the electrodialysis shell is still normally subjected to electrodialysis operation, and the non-stop reverse descaling operation is further realized.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment equipment, and specifically relates to a method and a device for preparing a sewage treatment agent by using red mud as a raw material. 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 method and device for preparing a sewage treatment agent using red mud as a raw material, in order 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 method and a device for preparing a sewage treatment agent using red mud as a raw material.

[0007] The technical solution adopted by the present invention to solve its technical problem is: The device for preparing sewage treatment agent using red mud as raw material described in the present invention comprises an electrodialysis shell, a membrane stack and electrode sheets, wherein the electrodialysis shell is a cavity structure, and electrode sheets are installed at both ends of the inner cavity of the electrodialysis shell. A membrane stack is fixedly installed in the electrodialysis shell, and the membrane stack is composed of a plurality of anion and cation exchange membranes arranged at intervals, and the anion and cation exchange membranes form concentrated water chambers and fresh water chambers arranged at intervals, and also comprises a non-stop reversing mechanism, which is installed in the electrodialysis shell, and the non-stop reversing mechanism comprises a mounting tube, a separator and a driving member, and the electrodialysis shell is provided with a plurality of anion and cation exchange membranes arranged at intervals. A mounting tube is rotatably installed in the cavity, the mounting tube is coaxially arranged with the electrodialysis shell, the membrane stack is fixedly installed on the mounting tube, the separators are designed in multiple numbers, the separators are evenly arranged in the circumferential direction of the mounting tube, the separators divide the inner cavity of the electrodialysis shell into a plurality of mutually non-conductive working slots along the circumferential direction, a driving member is fixedly installed on the electrodialysis shell, the mounting tube passes through and extends to the outside of the electrodialysis shell, the driving member is transmission-connected with the mounting tube, the electrode sheets located at the same end of the electrodialysis shell are divided into two groups, and the two groups of electrode sheets have opposite polarities, and the two groups of electrode sheets correspond to different working slots respectively.

[0008] Preferably, both ends of the electrodialysis shell are provided with annular mounting grooves, the electrode sheets are installed in the mounting grooves, and a partition is detachably fixed in the mounting groove, the partition divides the mounting groove 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, two groups of electrode sheets 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 operating chamber.

[0009] Preferably, both ends of the electrodialysis shell are provided with adjustment grooves, and evenly distributed adjustment holes are provided in the adjustment grooves. The adjustment grooves are conductively connected to the mounting grooves through the adjustment holes, and the partitions extend into the adjustment grooves through the adjustment holes. A sealing plate is detachably fixedly installed at one end of the adjustment groove away from the mounting groove.

[0010] Preferably, the partition is T-shaped at one end close to the sealing plate, and the partition is fixed on the sealing plate by bolts.

[0011] Preferably, a connecting ring group is commonly installed on the multiple separators, and the connecting ring group is composed of multiple connecting rings arranged at intervals, and the connecting ring group corresponds to the membrane stack. The separators and the connecting ring group are commonly provided with an assembly groove, and an elastic layer is fixedly connected to the inner wall of the assembly groove, and the connecting ring group and the separators are elastically and sealedly connected to the membrane stack via the assembly groove.

[0012] Preferably, a slot is provided on the outer wall of the mounting tube, the connecting ring is composed of a plurality of arc plates, and the arc plates and the slot correspond to the separators one by one.

[0013] Preferably, it also includes a conveying mechanism, which is connected to the electrodialysis shell, and is used to control the flow path of the elution water. 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 cavity, and the second water inlet pipe, the second concentrated water pipe and the second fresh water pipe all correspond to the second electrode cavity.

[0014] Preferably, the second water inlet pipe, the first concentrated water pipe and the first fresh water pipe are all fixedly mounted on the electrodialysis shell, a shunt pipe is rotatably mounted in the mounting pipe, the first water inlet pipe, the second concentrated water pipe and the second fresh water pipe are all fixedly mounted in the shunt pipe and are arranged with an opening on the outer annular surface of the shunt pipe, and the mounting pipe is provided with evenly distributed conducting holes, which correspond one-to-one to the working slots.

[0015] Preferably, a support frame is installed outside the electrodialysis housing, and the shunt tube is fixedly mounted on the support frame via a guide plate.

[0016] A method for preparing a sewage treatment agent using red mud as a raw material, the method comprising 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: The eluent is pumped into the working tank through the first water inlet pipe and the second water inlet pipe, and the non-stop reversing mechanism and the electrode sheet are started synchronously, so that the eluent in the working tank rotates continuously during the electrodialysis process; S3: The eluent undergoes electrodialysis in the operating tank, and fresh water for washing red mud and concentrated water as an absorbent for acidic waste gas are output through the outlet pipe. At the same time, the polarity of the electrode sheets on both sides of the membrane stack is switched as it 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.

[0017] The beneficial effects of the present invention are as follows: 1. The method and device for preparing a sewage treatment agent using red mud as a raw material described in the present invention, by setting a non-stop reversal mechanism, during the electrodialysis operation, the inner cavity of the electrodialysis shell is divided into a plurality of working slots, and the electrodes corresponding to at least one of the working slots are reversed, and at the same time, under the action of a driving member, relative movement is generated between the plurality of working slots and the two groups of electrodes, so that the parts of the membrane stack separated in the plurality of working slots are successively opposite to the reversed electrodes, thereby cleaning the membrane stack, and since the working slots corresponding to the reversed electrodes only occupy a part of the inner cavity of the electrodialysis shell, the remaining part still performs the electrodialysis operation normally, thereby realizing the non-stop reversal descaling operation.

[0018] 2. The method and device for preparing a sewage treatment agent using red mud as a raw material described in the present invention, in which water flows in two opposite directions in the same working tank during a rotation cycle, thereby flushing the anion and cation exchange membranes in different directions respectively. The multi-directional flushing combined with electrode reversal can effectively enhance the probability of scale layer shedding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] Figure 1 is a stereogram of the present invention; Figure 2 It is a stereogram of another viewing angle of the present invention; Figure 3 It is a stereoscopic diagram of the assembly of the installation tube, membrane stack and separator; Figure 4 It is an exploded view of the installation pipe, membrane stack and separator; Figure 5 It is a disassembled diagram of the electrodialysis housing and the sealing plate; Figure 6 is a three-dimensional view of the sealing plate; Figure 7 It is a three-dimensional diagram of the mounting slot and the partition; Figure 8 It is a schematic diagram of the partition of the installation slot; Fig. 9 This is a disassembled diagram of the shunt pipe and the installation pipe; Fig.10 is a flow chart of the method of the present invention; 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

[0021] 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.

[0022] like Figures 1 to 9 As shown, a device for preparing a sewage treatment agent using red mud as a raw material according to the present invention 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. The anion and cation exchange membranes 12 form concentrated water chambers and fresh water chambers arranged at intervals. The device also comprises a non-stop reversing mechanism, which is installed in the electrodialysis housing 1. The non-stop reversing mechanism comprises a mounting tube 2, a separator 21 and a driving member 23. The rotating device 21 in the inner cavity of the electrodialysis housing 1 rotates. A mounting tube 2 is provided, the mounting tube 2 is coaxially arranged with the electrodialysis shell 1, the membrane stack is fixedly mounted on the mounting tube 2, the separators 21 are designed in plural 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 mounted on the electrodialysis shell 1, the mounting tube 2 passes through 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, and the two groups of electrode sheets 11 correspond to different working slots 22, respectively.

[0023] 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.

[0024] 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.

[0025] The present invention is provided with a non-stop reversal mechanism. During the electrodialysis operation, the inner cavity of the electrodialysis shell 1 is divided into a plurality of working slots 22, and the electrode corresponding to at least one of the working slots 22 is reversed. At the same time, under the action of the driving member 23, relative movement is generated between the plurality of working slots 22 and the two groups of electrodes. Therefore, the parts of the membrane stack separated in the plurality of working slots 22 are successively opposite to the reversed electrodes, thereby cleaning the membrane stack. Moreover, since the working slots 22 corresponding to the reversed electrodes only occupy a part of the inner cavity of the electrodialysis shell 1, the remaining part still performs the electrodialysis operation normally, thereby realizing the non-stop reversal descaling operation.

[0026] As a preferred embodiment of the present invention, both ends of the electrodialysis shell 1 are provided with annular mounting grooves 24, and the electrode sheets 11 are installed in the mounting grooves 24. A partition 25 is detachably fixedly installed in the mounting grooves 24, and the partition 25 divides the mounting 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. Two groups of the electrode sheets 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 operating groove 22.

[0027] In actual application, since the mounting tube 2 drives the separator 21 to rotate in the electrodialysis shell 1, in order to avoid mutual influence between the two groups of electrodes with opposite polarities, the present invention uses a partition 25 to separate the mounting groove 24 into a non-polar cavity 26 and a first electrode cavity 27 and a second electrode cavity 28, wherein the number of non-polar cavities 26 is two, which are used to separate the first electrode cavity 27 and the second electrode cavity 28, and the two groups of electrodes are respectively installed in the first electrode cavity 27 and the second electrode cavity 28. Since the mounting groove 24 is located at both ends of the electrodialysis shell 1, the first electrode cavity 27 and the second electrode cavity 28 are respectively connected to different working grooves 22, and then electrodialysis operations in opposite directions are simultaneously performed in the inner cavity of the same electrodialysis shell 1. At the same time, it should be noted that since the amplitude of the non-polar cavity 26 is greater than the amplitude of the working groove 22, when the working groove 22 and the mounting groove 24 rotate relative to each other, the existence of the non-polar cavity 26 can effectively avoid the same working groove 22 from being connected to the first electrode cavity 27 and the second electrode cavity 28 at the same time, thereby avoiding mutual interference between the two groups of electrodes.

[0028] As a preferred embodiment of the present invention, both ends of the electrodialysis shell 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 partition 25 extends into the adjustment grooves 3 through the adjustment holes 31. A sealing plate 32 is detachably fixedly installed at one end of the adjustment groove 3 away from the mounting groove 24.

[0029] The partition plate 25 has a T-shaped design at one end close to the sealing plate 32 , and the partition plate 25 is fixed on the sealing plate 32 by bolts.

[0030] In practical application, in order to further enhance the flexibility of electrode reversal and descaling operations, the present invention is provided with adjustment slots 3 and adjustment holes 31 at both ends of the electrodialysis housing 1. Under the connecting effect of the adjustment hole 31, the adjustment slot 3 is connected to the mounting slot 24. When adjusting the ratio of the first electrode chamber 27 to the second electrode chamber 28 in the electrodialysis equipment, the staff removes the sealing plate 32 detachably fixed in the adjustment slot 3 with the help of tools. In the process of pulling the sealing plate 32 out of the adjustment slot 3, the partition 25 fixedly connected to the sealing plate 32 by bolts is taken out synchronously. Then the staff removes the partition 25 from the sealing plate 32, and at the same time, according to the new ratio, Fix the partition 25 on the sealing plate 32 according to the position corresponding to the new ratio, and then reset the sealing plate 32 and the partition 25. The partition 25 divides the adjustment groove 3 and the installation groove 24 into mutually non-conductive chambers, so that the proportions of the first electrode chamber 27, the second electrode chamber 28, and the non-polar chamber 26 can be adjusted. It should be noted that when adjusting the position of the partition 25 on the sealing plate 32, it is necessary to refer to the position of the adjustment hole 31. Therefore, in actual application, the greater the density of the adjustment holes 31 in the circumferential direction of the installation groove 24, the higher the adjustable accuracy 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 equipment.

[0031] As a preferred embodiment of the present invention, 4 groups of connecting rings are commonly installed on the multiple separators 21, and the 4 groups of connecting rings are composed of multiple connecting rings 4 arranged at intervals, and the 4 groups of connecting rings correspond to the membrane stack. An assembly groove 41 is commonly opened on the separator 21 and the 4 groups of connecting rings, and an elastic layer is fixedly connected to the inner wall of the assembly groove 41. The 4 groups of connecting rings and the separator 21 are elastically sealed and connected to the membrane stack through the assembly groove 41.

[0032] When the electrodialysis equipment is in use, the separator 21 and the membrane stack rotate in the electrodialysis housing 1. In order to enhance the protection of the membrane stack, four groups of connecting rings are fixedly installed on the separator 21 in the present invention. The membrane stack is clamped and fixed by the assembly groove 41 jointly provided on the four groups of connecting rings and the separator 21, 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 four groups of connecting rings are connected to the inner wall of the electrodialysis housing 1 in a sliding and sealing manner, which can effectively reduce the friction damage of the membrane stack during rotation, thereby extending the service life of the anion and cation exchange membranes 12 constituting the membrane stack.

[0033] As a preferred embodiment of the present invention, 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, and the arc plates and the slot 42 correspond to the partitions 21 one by one.

[0034] By opening a slot 42 on the mounting tube 2 and using a plurality of arc plates to form a connecting ring 4, a plurality of connecting rings 4 constitute 4 groups of connecting rings, so that the 4 groups of connecting rings, the membrane stack, the mounting tube 2 and the separator 21 can be detachably combined. Therefore, when the equipment is maintained or repaired, the mounting tube 2, the membrane stack, the separator 21 and the 4 groups of connecting rings can be easily disassembled and combined, thereby reducing the difficulty of replacing or maintaining equipment components.

[0035] As a preferred embodiment of the present invention, it also includes a conveying mechanism, which is connected to the electrodialysis shell 1, and is used to control the flow path of the elution water. The conveying mechanism includes an inlet pipe and an outlet pipe, the inlet pipe includes a first inlet pipe 5 and a second inlet pipe 51, and the 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 inlet pipe 5, the first concentrated water pipe 52 and the first fresh water pipe 54 all correspond to the first electrode cavity 27, and the second inlet pipe 51, the second concentrated water pipe 53 and the second fresh water pipe 55 all correspond to the second electrode cavity 28.

[0036] In order to further enhance the convenience of sewage treatment in the electrodialysis housing 1, an inlet pipe and an outlet pipe are provided in the present invention, and the inlet pipe and the outlet pipe are divided into two groups according to the corresponding relationship with the first electrode cavity 27 and the second electrode cavity 28, and are respectively named as the first inlet pipe 5, the first concentrated water pipe 52, the first fresh water pipe 54, the second inlet pipe 51, the second concentrated water pipe 53 and the second fresh water pipe 55. In actual application, the sewage enters the working tank 22 corresponding to the first electrode cavity 27 and the second electrode cavity 28 through the first inlet pipe 5 and the second inlet pipe 51 under the pumping of the water pump. With the continuous rotation of the working tank 22 and the progress of the electrodialysis operation, when the working tank 22 is in the process of rotation, it is aligned 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, and then the concentrated water and fresh water are output. It should be known that The first fresh water pipe 54 and the first concentrated water pipe 52 correspond to adjacent concentrated water chambers and fresh water chambers in the same working tank 22 respectively. In the circumferential direction of the electrodialysis shell 1, the first fresh water pipe 54 and the first concentrated water pipe 52 are in the same position, and in the axial direction of the electrodialysis shell 1, the first fresh water pipe 54 and the first concentrated water pipe 52 are staggered. Similarly, the second fresh water pipe 55 and the second concentrated water pipe 53 are also arranged. Since the water inlet pipe and the water outlet pipe are in fixed positions compared to the electrodialysis shell 1, during the rotation of the working tank 22, the working tank 22 successively undergoes the process of water inlet, water outlet, re-inlet, and re-outlet. When the two sets of electrode components are switched, the sewage that has been electrodialyzed in the working tank 22 can be discharged automatically and untreated sewage can be pumped in. Therefore, during the continuous rotation process, it can not only maintain the continuous sewage treatment, but also avoid the problem of re-mixing of the separated ions.

[0037] 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 shell 1, and a diverter pipe 6 is rotatably installed 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 installed in the diverter pipe 6 and are arranged with an opening on the outer annular surface of the diverter 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 working tanks 22.

[0038] A support frame 7 is installed outside the electrodialysis housing 1 , and the shunt tube 6 is fixedly installed on the support frame 7 through a guide plate.

[0039] By setting the shunt pipe 6 and fixing the shunt pipe 6 on the support frame 7, during the circumferential rotation of the working tank 22, when the working tank 22 is located in the range of the first electrode cavity 27, the first water inlet pipe 5 is connected to the working tank 22 through the conducting hole 61 on the mounting pipe 2, and the sewage flows in the direction away from the center of the anion and cation exchange membrane 12. When the working tank 22 rotates to the range of the second electrode cavity 28, the second water inlet pipe 51 is connected to the working tank 22, and the sewage flows in the direction toward the center of the anion and cation exchange membrane 12. Similarly, in the working tank 2 When the working tank 22 corresponds to the first fresh water pipe 54 and the first concentrated water pipe 52, the treated water flows out in a direction away from the center of the anion and cation exchange membrane 12. When the working tank 22 corresponds to the second fresh water pipe 55 and the second concentrated water pipe 53, the treated water flows out in a direction toward the center of the anion and cation exchange membrane 12. In one rotation cycle, the water flows in two opposite directions in the same working tank 22, respectively, and then flushes the anion and cation exchange membrane 12 in different directions. The multi-directional flushing, combined with the electrode reversal, can effectively enhance the probability of scale shedding.

[0040] like Fig.10 As shown, a method for preparing a sewage treatment agent using red mud as a raw material 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: The eluent is pumped into the working tank 22 through the first water inlet pipe 5 and the second water inlet pipe 51, and the non-stop reversing mechanism and the electrode sheet 11 are started synchronously, so that the eluent in the working tank 22 rotates continuously during the electrodialysis process; S3: The eluent is subjected to electrodialysis in the working tank 22, and fresh water for washing red mud and concentrated water as an absorbent for acidic 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.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A device for preparing a sewage treatment agent using red mud as a raw material, comprising 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material according to claim 6, characterized in that: It also comprises a conveying mechanism, which is connected to the electrodialysis housing (1) and is used to control the flow path of the elution water; 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. The device for preparing a sewage treatment agent using red mud as a raw material 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. The device for preparing a sewage treatment agent using red mud as a raw material 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 preparing a sewage treatment agent using red mud as a raw material, characterized in that: The method uses the device for preparing a sewage treatment agent using red mud as a raw material as claimed 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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