Solution impurity removal system

Abstract

The utility model provides a solution impurity removal system which comprises an iron remover, a filter, a clear liquid tank, a preheater and an evaporation unit which are sequentially arranged, a solution is subjected to iron removal through the iron remover and then subjected to impurity removal through the filter, and clear liquid obtained after impurity removal enters the clear liquid tank. Clear liquid in the clear liquid tank enters the preheater to be preheated and then is conveyed to the evaporation unit to be evaporated and crystallized. Therefore, high-purity cobalt chloride can be obtained. Meanwhile, the solution impurity removal system further comprises a back flushing unit, when many impurities exist on a filter membrane in the filter, the preheated clear liquid can be conveyed to the filter through the back flushing unit to flush the filter membrane so as to remove the impurities on the filter membrane, so that flow reduction of the filter is avoided, the service life of the filter is prolonged, introduction of the impurities can be avoided, and the service life of the filter is prolonged. And the heated clear liquid is used for flushing, so that the flushing effect can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solution purification, and particularly relates to a solution impurity removal system. BACKGROUND

[0002] In the battery industry, cobalt chloride is a battery precursor material with superior performance, and is used as a raw material in the production process of lithium ion battery positive electrode materials. Cobalt chloride is usually prepared from cobalt-containing raw materials. The cobalt-containing raw materials are subjected to acid leaching to obtain a cobalt chloride solution. In the process, impurities such as oil and solid particles are introduced into the cobalt chloride solution. At the same time, the cobalt chloride solution may also be mixed with iron oxide debris and the like during long-distance pipeline transportation. Therefore, in order to obtain high-purity cobalt chloride, it is necessary to purify and remove impurities from the cobalt chloride solution. CONTENT OF THE UTILITY MODEL

[0003] Based on this, the application provides a solution impurity removal system capable of purifying and removing impurities from a cobalt chloride solution.

[0004] The technical scheme provided by the application is as follows:

[0005] A solution impurity removal system comprises:

[0006] An iron remover;

[0007] A filter arranged downstream of the iron remover;

[0008] A clear liquid tank arranged downstream of the filter;

[0009] A preheater arranged downstream of the filter and used for heating the clear liquid in the clear liquid tank;

[0010] An evaporation unit arranged downstream of the preheater and used for performing evaporation crystallization treatment on the clear liquid in the clear liquid tank;

[0011] A backflushing unit having one end connected to the preheater and the other end connected to the filter, the backflushing unit being capable of obtaining the clear liquid preheated by the preheater and conveying the clear liquid to the filter to flush the filter.

[0012] Further, the solution impurity removal system further comprises a raw liquid tank and a sedimentation tank, the raw liquid tank being arranged upstream of the iron remover and used for storing raw liquid, and the sedimentation tank being arranged downstream of the filter and used for obtaining concentrated liquid in the filter and performing sedimentation, the raw liquid tank being further connected to the sedimentation tank to obtain supernatant in the sedimentation tank.

[0013] Further, the solution impurity removal system further comprises a first conveying pump and a second conveying pump, the first conveying pump is arranged between the raw solution tank and the iron remover, and the second conveying pump is arranged between the sedimentation tank and the raw solution tank.

[0014] Further, the solution impurity removal system further comprises a filter press arranged downstream of the sedimentation tank to obtain and filter the sediment in the sedimentation tank, and the filter press is connected with the raw solution tank to convey the filtrate to the raw solution tank.

[0015] Further, the solution impurity removal system comprises an overflow assembly and a discharge assembly, both of which are arranged between the filter and the sedimentation tank, the overflow assembly is connected with the overflow port of the filter, and the discharge assembly is connected with the discharge port of the filter.

[0016] Further, the solution impurity removal system further comprises a cleaning unit, the liquid outlet of the cleaning unit is connected with the backflushing unit, the backflushing unit can also convey the cleaning liquid provided by the cleaning unit to the filter, and the liquid return end of the cleaning unit is connected with the discharge port of the filter.

[0017] Further, the cleaning unit comprises a liquid storage tank, a first cleaning valve and a second cleaning valve, the liquid storage tank is used to store the cleaning liquid, the first cleaning valve is connected with the liquid storage tank, the backflushing unit is connected with the first cleaning valve, and the second cleaning valve is arranged between the filter and the first cleaning valve.

[0018] Further, the cleaning unit further comprises a liquid discharge valve connected to the end of the second cleaning valve away from the filter.

[0019] Further, the backflushing unit comprises a third conveying pump, one end of the third conveying pump is connected with the preheater and the cleaning unit, and the other end of the third conveying pump is connected with the filter.

[0020] Further, the solution impurity removal system further comprises a first control valve, a second control valve and a third control valve, the first control valve is arranged between the iron remover and the filter, the second control valve is arranged between the preheater and the evaporation unit, and the third control valve is arranged between the preheater and the backflushing unit.

[0021] The solution is first de-ironed by the de-ironer, and then de-impurities by the filter, and the de-impurities clear solution is sent into the clear solution tank. The clear solution in the clear solution tank is preheated by the preheater and then sent to the evaporation unit for evaporation crystallization. In this way, high-purity cobalt chloride can be obtained. At the same time, the preheated clear solution can be sent to the filter through the backflush unit to flush the filter membrane to remove impurities on the filter membrane, thereby avoiding the decrease of the flow rate of the filter, prolonging the service life of the filter, and avoiding the introduction of other impurities. The flushing effect is also improved by using the heated clear solution for flushing. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application, and explain the technical solutions of the present application, and do not constitute a limitation on the present application.

[0023] Figure 1 The structural schematic diagram of the solution de-impurities system provided by an embodiment of the present application is shown.

[0024] Label explanation:

[0025] 11, de-ironer; 12, filter; 13, clear solution tank; 14, preheater; 15, evaporation unit; 16, original solution tank; 17, liquid inlet valve; 18, first conveying pump; 19, first control valve; 20, sedimentation tank; 21, second conveying pump; 22, first on-off valve; 23, filter press; 24, second on-off valve; 25, first connection valve; 26, second connection valve; 27, second control valve; 28, third control valve; 29, third conveying pump; 30, clear solution valve; 31, backflush valve; 32, liquid storage tank; 33, first cleaning valve; 34, second cleaning valve; 35, liquid discharge valve. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0028] An embodiment of the present application provides a solution impurity removal system, which can be applied to purification and impurity removal of cobalt chloride solution to obtain high-purity cobalt chloride. Of course, in other embodiments, the solution impurity removal system can also be applied to other solutions, which are not limited herein. Hereinafter, the cobalt chloride solution is taken as an example for description.

[0029] As shown in Figure 1 The solution impurity removal system comprises an iron remover 11, a filter 12, a clear liquid tank 13, a preheater 14 and an evaporation unit 15.

[0030] The filter 12, the clear liquid tank 13, the preheater 14 and the evaporation unit 15 are sequentially arranged downstream of the iron remover 11. The iron remover 11 is used for removing iron oxides and debris mixed in the solution during transportation. The filter 12 is used for filtering the solution after iron removal to remove oil and solid particle impurities in the solution to generate clear liquid, which is then transported to the clear liquid tank 13. The clear liquid in the clear liquid tank 13 is transported to the preheater 14, the preheater 14 preheats the clear liquid, and then the preheated clear liquid is transported to the evaporation unit 15 for evaporation and crystallization, so as to obtain high-purity cobalt chloride.

[0031] It should be noted that the clear liquid is preheated before evaporation and crystallization, which can shorten the subsequent heating time. Optionally, the component for filtering in the filter 12 adopts an ultrafiltration membrane, and the preheater 14 adopts a heat exchanger.

[0032] Further, the solution impurity removal system further comprises a backflushing unit, one end of the backflushing unit is connected with the preheater 14, the other end is connected with the filter 12, and the backflushing unit can obtain the preheated clear liquid of the preheater 14 and transport it to the filter 12 to flush the filter 12, so as to avoid blockage of the filter 12 and prolong the service life of the filter 12; at the same time, flushing with the clear liquid can also avoid introducing new impurities.

[0033] The solution is first deironed by the deironer 11, and then decontaminated by the filter 12. The decontaminated clear solution is then stored in the clear solution tank 13. The clear solution in the clear solution tank 13 is preheated by the preheater 14, and then sent to the evaporation unit 15 for evaporation and crystallization. In this way, high-purity cobalt chloride can be obtained. At the same time, the preheated clear solution can be sent to the filter 12 through the backflush unit to flush the filter membrane in the filter 12, so as to remove the impurities on the filter membrane, thereby avoiding the decrease of the flow rate of the filter 12, prolonging the service life of the filter 12, and avoiding the introduction of other impurities. In addition, the flushing effect can be improved by using the heated clear solution for flushing.

[0034] In one embodiment, the solution decontamination system further comprises a raw solution tank 16, which is arranged upstream of the deironer 11 and is used to store raw solution, i.e. cobalt chloride solution containing impurities. Further, the solution decontamination system further comprises a liquid inlet valve 17, which is connected to the raw solution tank 16 and is used to control the input of the raw solution.

[0035] In one embodiment, the solution decontamination system further comprises a first conveying pump 18, which is arranged between the raw solution tank 16 and the deironer 11 and is used to pump the raw solution in the raw solution tank 16 to the deironer 11 and other downstream structures. Further, the solution decontamination system further comprises a first control valve 19, which is arranged between the deironer 11 and the filter 12. In the case that the first conveying pump 18 stops operating, the first control valve 19 is closed to avoid the backflow of liquid in the filter 12. Of course, the first control valve 19 can also be a one-way valve to avoid the backflow of liquid.

[0036] In one embodiment, the solution decontamination system further comprises a sedimentation tank 20, which is arranged downstream of the filter 12 and is used to obtain concentrated solution in the filter 12 and perform sedimentation. At the same time, the sedimentation tank 20 is also connected to the raw solution tank 16 to send the supernatant to the raw solution tank 16 after sedimentation is completed, thereby improving resource utilization and avoiding resource waste. It should be noted that the liquid after flushing the filter 12 can also be sent to the sedimentation tank 20.

[0037] Further, the solution decontamination system further comprises a second conveying pump 21, which is arranged between the sedimentation tank 20 and the raw solution tank 16 to pump the supernatant in the sedimentation tank 20 to the raw solution tank 16.

[0038] As Figure 1As shown, the liquid inlet valve 17 and the second delivery pump 21 are both connected to the stock solution tank 16 through a liquid inlet pipe. In order to avoid the stock solution from being delivered to the second delivery pump 21, a first on-off valve 22 is arranged between the liquid inlet pipe and the second delivery pump 21. During the process of replenishing the stock solution into the stock solution tank 16, the liquid inlet valve 17 is opened and the first on-off valve 22 is closed. During the process of delivering the supernatant in the sedimentation tank 20 to the stock solution tank 16, the liquid inlet valve 17 is closed, the second delivery pump 21 and the first on-off valve 22 are opened. In other embodiments, if the liquid inlet valve 17 and the second delivery pump 21 are connected to the stock solution tank 16 through different pipes, and the second delivery pump 21 is connected to the top of the stock solution tank 16, no valve can be arranged between the second delivery pump 21 and the stock solution tank 16.

[0039] In an embodiment, the solution impurity removal system further comprises a filter press 23, which is arranged downstream of the sedimentation tank 20 to obtain the precipitate in the sedimentation tank 20 and perform pressure filtration. Further, the filter press 23 is connected to the stock solution tank 16 to deliver the filtrate generated by pressure filtration to the stock solution tank 16.

[0040] Figure 1 The liquid inlet valve 17, the second delivery pump 21 and the filter press 23 are all connected to the stock solution tank 16 through a liquid inlet pipe. In order to avoid the stock solution from flowing into the filter press 23, a second on-off valve 24 is arranged between the filter press 23 and the liquid inlet pipe. During the process of replenishing the stock solution into the stock solution tank 16, the liquid inlet valve 17 is opened, and the first on-off valve 22 and the second on-off valve 24 are closed. During the process of delivering the supernatant in the sedimentation tank 20 to the stock solution tank 16, the liquid inlet valve 17 and the second on-off valve 24 are closed, the second delivery pump 21 and the first on-off valve 22 are opened. During the process of pressure filtration, the liquid inlet valve 17 and the first on-off valve 22 are closed, the filter press 23 is started, and the second on-off valve 24 is opened. In addition, it can be understood that the filter press 23 can also be connected to the stock solution tank 16 alone, and no on-off valve can be arranged between the filter press 23 and the stock solution tank 16.

[0041] In an embodiment, the solution impurity removal system further comprises an overflow assembly and a discharge assembly, both of which are arranged in the filter 12 and the sedimentation tank 20 assembly. The overflow assembly is connected to the overflow port of the filter 12 to deliver the concentrated solution overflowing from the overflow port of the filter 12 to the sedimentation tank 20. The discharge assembly is connected to the discharge port of the filter 12 to empty the liquid in the filter 12 into the sedimentation tank 20.

[0042] It should be explained that the filter 12 comprises an inlet, an outlet, an overflow port and a discharge port. The inlet is used to input the stock solution, the outlet can output the clear solution, and the overflow port and the discharge port can discharge the concentrated solution. The discharge port is located at the bottom of the filter 12 and can empty the liquid in the filter 12.

[0043] As an example, the overflow assembly includes a first connecting pipe and a first connecting valve 25, and the discharge assembly includes a second connecting pipe and a second connecting valve 26. The first connecting pipe is connected to the overflow port of the filter 12 at one end and to the sedimentation tank 20 at the other end. The second connecting pipe is connected to the discharge port of the filter 12 at one end and to the sedimentation tank 20 at the other end. The first connecting valve 25 and the second connecting valve 26 are respectively arranged in the first connecting pipe and the second connecting pipe to control the opening and closing of the first connecting pipe and the second connecting pipe. During the purification of the raw solution, the first connecting valve 25 is opened, and the second connecting valve 26 is closed. The concentrated solution flows into the sedimentation tank 20 through the first connecting pipe. When the filter 12 is flushed with the clear solution, the second connecting valve 26 is also kept closed. The concentrated solution generated by the flushing also flows into the sedimentation tank 20 through the first connecting pipe. After the flushing is completed, in order to discharge the liquid in the filter 12, the second connecting valve 26 can be opened. The liquid in the filter 12 is discharged into the sedimentation tank 20 through the second connecting pipe.

[0044] In one embodiment, the solution impurity removal system further includes a second control valve 27 and a third control valve 28. The second control valve 27 is arranged between the preheater 14 and the evaporation unit 15, and the third control valve 28 is arranged between the preheater 14 and the backflushing unit. In this way, when it is necessary to deliver the clear solution to the evaporation unit 15, the second control valve 27 is opened, and the third control valve 28 is closed. When it is necessary to deliver the clear solution to the backflushing unit, the third control valve 28 is opened, and the second control valve 27 is closed.

[0045] In one embodiment, the backflushing unit includes a third delivery pump 29. One end of the third delivery pump 29 is connected to the preheater 14, and the other end is connected to the filter 12, so as to guide the clear solution in the clear solution tank 13 to pass through the preheater 14 and the third delivery pump 29 in sequence and then be delivered into the filter 12. Similarly, the evaporation unit 15 also has a pumping structure to draw the clear solution in the clear solution tank 13 into the evaporation unit 15. As an example, in the embodiment shown in Figure 1 In the embodiment shown in FIG. 1, the third delivery pump 29 is connected to the third control valve 28.

[0046] Further, the third delivery pump 29 and the clear liquid tank 13 are both connected with the outlet of the filter 12, so the solution impurity removal system further comprises a clear liquid valve 30 and a backflush valve 31, the clear liquid valve 30 and the backflush valve 31 are respectively arranged on two pipelines, and the clear liquid valve 30 is arranged between the filter 12 and the clear liquid tank 13, and the backflush valve 31 is arranged between the filter 12 and the third delivery pump 29. In other words, one end of the clear liquid valve 30 and the backflush valve 31 is respectively connected with the clear liquid tank 13 and the third delivery pump 29, and the other end is connected with each other and connected with the outlet of the filter 12. In this way, during the process of purifying the raw liquid, the clear liquid valve 30 is opened, the backflush valve 31 is closed, and the clear liquid generated by the filter 12 flows into the clear liquid tank 13; during the process of flushing the filter 12, the clear liquid valve 30 is closed, the backflush valve 31 is opened, and the third delivery pump 29 is started to pump the clear liquid to the outlet of the filter 12 to flush the ultrafiltration membrane in the filter 12.

[0047] In one embodiment, the solution impurity removal system further comprises a cleaning unit, the liquid outlet of the cleaning unit is connected with the outlet of the filter 12, and the liquid return of the cleaning unit is connected with the discharge port of the filter 12, and the cleaning unit is used for chemical cleaning of the filter 12. Optionally, the cleaning unit is used for pickling of the filter 12. For example, after other valves connected with the filter 12 are closed, the cleaning unit is started, the cleaning unit inputs hydrochloric acid into the filter 12, and the filter 12 is soaked, circulated and pickled, and after pickling, the hydrochloric acid is discharged through the cleaning unit. By using hydrochloric acid for pickling, other impurities can also be avoided.

[0048] Preferably, the end of the third delivery pump 29 away from the filter 12 is further connected with the liquid outlet of the cleaning unit, that is, the cleaning liquid in the cleaning unit is delivered to the filter 12 through the backflush unit. In this way, the cleaning liquid does not need to be pumped by an additional pumping structure, which reduces the cost of the equipment. It should be noted that the liquid return of the cleaning unit is also connected with the second connecting pipe, and the liquid return is located between the filter 12 and the second connecting valve 26.

[0049] In one embodiment, the cleaning unit comprises a liquid storage tank 32, a first cleaning valve 33 and a second cleaning valve 34, the liquid storage tank 32 is used for storing cleaning liquid, the first cleaning valve 33 is connected with the liquid storage tank 32, the backflush unit is connected with the end of the first cleaning valve 33 away from the liquid storage tank 32, and the second cleaning valve 34 is arranged between the filter 12 and the first cleaning valve 33, that is, one end of the second cleaning valve 34 is connected with the discharge port of the filter 12, and this end is a liquid return end and is connected with the second connecting pipe, and the other end is connected with the end of the first cleaning valve 33 away from the liquid storage tank 32.

[0050] When the filter 12 is cleaned by the cleaning unit, the backflush valve 31, the first cleaning valve 33 and the second cleaning valve 34 are opened, and other valves are closed. The third delivery pump 29 pumps the cleaning solution in the storage tank 32 into the filter 12. When soaking cleaning is performed, the second cleaning valve 34 can be closed. When circulating cleaning is performed, the first cleaning valve 33 can be closed and the second cleaning valve 34 can be opened.

[0051] In one embodiment, the cleaning unit further comprises a drainage valve 35 connected to the second cleaning valve 34 away from the filter 12, for draining the cleaning solution. When the cleaning solution needs to be drained, the first cleaning valve 33 and the second connecting valve 26 are closed, and the second cleaning valve 34 and the drainage valve 35 are opened.

[0052] As described above, the composition of the solution impurity removal system provided by the present application has been described, and how these compositions work together to complete a specific action process is an important part of further interpreting the value of the present application. The following will be combined with the above description to illustrate the action process of the solution impurity removal system in the above embodiment: Figure 1 The action process of the solution impurity removal system in the above embodiment is described as follows:

[0053] The purification and impurity removal process of the stock solution: the liquid inlet valve 17, the first control valve 19, the first connecting valve 25, the clear liquid valve 30 and the second control valve 27 are opened, and other valves are closed. The cobalt chloride solution with a mass concentration of 10% to 20% and a temperature of 20 to 40°C enters the stock solution tank 16. The stock solution is subjected to iron removal by the iron remover 11 under the action of the first delivery pump 18, and then enters the filter 12. The clear liquid produced by the filter 12 flows into the clear liquid tank 13. The clear liquid in the clear liquid tank 13 flows into the preheater 14 under the action of the evaporation unit 15, is preheated in the preheater 14, and then flows into the evaporation unit 15 for evaporation and crystallization, thereby obtaining high-purity cobalt chloride. At the same time, the concentrated liquid produced by the filter 12 overflows into the sedimentation tank 20 through the first connecting pipe for sedimentation.

[0054] The sedimentation treatment process: first, the first on-off valve 22 is opened, and other valves are closed. The supernatant in the sedimentation tank 20 is sent to the stock solution tank 16 by the second delivery pump 21. After the supernatant treatment is completed, the sediment in the sedimentation tank 20 is delivered to the filter press 23, the second on-off valve 24 is opened, and other valves are closed. The filter press 23 performs pressure filtration on the sediment, and the filtrate is delivered to the stock solution tank 16, and the filter residue is subjected to other treatment.

[0055] Physical rinsing process of filter 12: open third control valve 28, backflush valve 31 and first connection valve 25, and close other valves. Third delivery pump 29 pumps the cleaning solution in cleaning solution tank 13 out, and the cleaning solution is heated by preheater 14 to a temperature of 60-80℃, and then is input into filter 12 from the outlet of filter 12 to rinse the ultrafiltration membrane in filter 12. The concentrated solution produced by rinsing is first flowed into sedimentation tank 20 through first connection pipe. After rinsing is completed, third delivery pump 29 is closed, and second connection valve 26 is opened to empty the liquid in filter 12 into sedimentation tank 20.

[0056] Chemical cleaning process of filter 12: first open first cleaning valve 33 and backflush valve 31, and close other valves. Third delivery pump 29 pumps the hydrochloric acid with a concentration of 5000-10000ppm in liquid storage tank 32 into filter 12 to soak the ultrafiltration membrane in filter 12, and the soaking time is 1-2h, and third delivery pump 29 can be closed during soaking. Then close first cleaning valve 33, open second cleaning valve 34, and start third delivery pump 29 to perform circulation cleaning of the ultrafiltration membrane, and the circulation time is 10min. After cleaning is completed, third delivery pump 29 is closed, and drain valve 35 is opened to drain the hydrochloric acid. Next, the concentration of the hydrochloric acid in liquid storage tank 32 is adjusted to 500ppm, first cleaning valve 33 is opened, second cleaning valve 34 and drain valve 35 are closed, third delivery pump 29 is started to pump the hydrochloric acid into filter 12, then first cleaning valve 33 is closed, second cleaning valve 34 is opened, and the hydrochloric acid is circulated to clean the ultrafiltration membrane again under the action of third delivery pump 29, and the circulation time is 5min. After cleaning is completed, third delivery pump 29 is closed, and drain valve 35 is opened to drain the hydrochloric acid.

[0057] It needs to be noted that the normal process of the solution impurity removal system is to perform the purification and impurity removal process first, and then perform the sedimentation treatment process. The physical rinsing process can be performed once every preset time, and the chemical cleaning process is started when the transmembrane pressure difference of the ultrafiltration membrane in filter 12 increases by 10%-20%, or when the cleaning solution flow rate of filter 12 decreases by 10%-20%. As can be seen, a pressure detector and a flow rate detector are also arranged in filter 12, and this means is conventional and will not be described here.

[0058] In summary, the solution impurity removal system provided by the application has at least the following advantages:

[0059] 1. The cobalt chloride solution can be purified and impurity-removed to realize preparation of high-purity cobalt chloride;

[0060] 2. The ultrafiltration membrane in filter 12 is rinsed by the cleaning solution after being heated, the cleaning effect is improved, the service life of the ultrafiltration membrane is prolonged, and no other impurities are introduced;

[0061] 3. The concentrated liquid produced by filtration and physical rinsing flows into the sedimentation tank 20. The supernatant produced by sedimentation and the filtrate after sedimentation and filtration are sent back to the original liquid tank 16 to improve the utilization rate of cobalt chloride and avoid resource waste.

[0062] 4. After long-term operation, hydrochloric acid can be used for chemical cleaning to further prevent ultrafiltration membrane clogging, extend the service life of the ultrafiltration membrane, and also prevent the introduction of other impurities.

[0063] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solution impurity removal system characterized by, The solution impurity removal system comprises: an iron remover; a filter arranged downstream of the iron remover; a clear liquid tank arranged downstream of the filter; a preheater arranged downstream of the filter, for heating the clear liquid in the clear liquid tank; an evaporation unit arranged downstream of the preheater, for performing evaporation crystallization treatment on the clear liquid in the clear liquid tank; a backflushing unit having one end connected to the preheater and the other end connected to the filter, the backflushing unit being capable of obtaining the clear liquid preheated by the preheater and delivering the clear liquid to the filter to flush the filter.

2. The solution impurity removal system of claim 1, wherein, The solution impurity removal system further comprises a raw liquid tank and a sedimentation tank, the raw liquid tank being arranged upstream of the iron remover and used for storing raw liquid, and the sedimentation tank being arranged downstream of the filter and used for obtaining concentrated liquid in the filter and performing sedimentation, the raw liquid tank being further connected to the sedimentation tank to obtain supernatant in the sedimentation tank.

3. The solution impurity removal system of claim 2, wherein, The solution impurity removal system further comprises a first delivery pump and a second delivery pump, the first delivery pump being arranged between the raw liquid tank and the iron remover, and the second delivery pump being arranged between the sedimentation tank and the raw liquid tank.

4. The solution impurity removal system of claim 2, wherein, The solution impurity removal system further comprises a filter press arranged downstream of the sedimentation tank to obtain sediment in the sedimentation tank and perform pressure filtration, the filter press being further connected to the raw liquid tank to deliver filtrate to the raw liquid tank.

5. The solution impurity removal system of claim 2, wherein, The solution impurity removal system comprises an overflow assembly and a discharge assembly, both of which are arranged between the filter and the sedimentation tank, the overflow assembly being connected to an overflow port of the filter, and the discharge assembly being connected to a discharge port of the filter.

6. The solution impurity removal system of claim 1, wherein, The solution impurity removal system further comprises a cleaning unit, an outlet of the cleaning unit being connected to the backflushing unit, the backflushing unit being further capable of delivering cleaning liquid provided by the cleaning unit to the filter, and a return of the cleaning unit being connected to the discharge port of the filter.

7. The solution impurity removal system of claim 6, wherein, The cleaning unit comprises a liquid storage tank, a first cleaning valve and a second cleaning valve, the liquid storage tank being used for storing cleaning liquid, the first cleaning valve being connected to the liquid storage tank, the backflushing unit being connected to the first cleaning valve, and the second cleaning valve being arranged between the filter and the first cleaning valve.

8. The solution impurity removal system of claim 7, wherein, The cleaning unit further comprises a liquid discharge valve connected to one end of the second cleaning valve away from the filter.

9. The solution impurity removal system of claim 6, wherein, The backflushing unit comprises a third delivery pump, one end of the third delivery pump being connected to the preheater and the cleaning unit, and the other end of the third delivery pump being connected to the filter.

10. The solution impurity removal system of claim 1, wherein, The solution impurity removal system further comprises a first control valve, a second control valve and a third control valve, the first control valve being arranged between the iron remover and the filter, the second control valve being arranged between the preheater and the evaporation unit, and the third control valve being arranged between the preheater and the backflushing unit.

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