Micro-ultrafiltration system for reducing conductivity of repulping return water

Abstract

The utility model relates to a micro ultrafiltration system for reducing the conductivity of repulping return water, which comprises a storage tank, a repulping return water pump, a micro ultrafiltration unit and a micro ultrafiltration pump, and the micro ultrafiltration unit is used for filtering ions in the repulping return water to reduce the conductivity of the repulping return water. The repulping return water is conveyed to the micro-ultrafiltration unit through the repulping return water pump, and soluble ions such as phosphate ions and hydroxyl ions in the repulping return water liquid can be effectively removed through the micro-ultrafiltration unit, so that the conductivity of a solution is reduced, the quality of the repulping return water is improved, the blocking frequency of a repulping system can be effectively reduced, the stopping frequency is reduced, and the production efficiency is improved. The start-up rate of the whole re-pulping device is improved, the cleaning cost and the environmental protection risk can be effectively reduced, and the economic benefits of enterprises are improved; the micro-ultra-filtration units are arranged between the repulping water return pump and the micro-ultra-filtration water suction pump in a parallel connection mode, and a single micro-ultra-filtration unit or two micro-ultra-filtration units can be selected to operate in parallel so as to adapt to filtration operation under different load working conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical process, in particular to a micro-ultrafiltration system for reducing the conductivity of re-pulp return water. Background Art

[0002] At present, in the phosphoric acid production system of chemical enterprises, the semi-water and dihydrate re-slurry return water is directly returned to the phosphoric acid unit for production through the re-slurry return water pump without pretreatment in the original process design. Due to the high conductivity and high ion concentration in the re-slurry return water, the phosphoric acid unit re-slurry system is seriously blocked (pipelines, equipment, valves, flow meters, etc. frequently occur), and the shutdown is frequent (in serious cases, the entire system is affected for many times). In addition, the cleaning is difficult and expensive, and the environmental protection risk is high, resulting in high operating costs, which has an adverse impact on the economic benefits of the enterprise. Utility Model Content

[0003] In view of the shortcomings of the prior art mentioned above, the purpose of the utility model is to provide a micro-ultrafiltration system for reducing the conductivity of re-pulp return water, which is used to solve the problems that in the production process of the existing phosphoric acid device, the conductivity and ion concentration of the re-pulp return water are high, which easily cause the phosphoric acid device re-pulp system to be blocked and frequently shut down, and the cleaning is difficult and expensive, and the environmental protection risk is high, resulting in high operating costs and serious impact on the economic benefits of the enterprise.

[0004] In order to achieve the above-mentioned purpose and other related purposes, the utility model provides a micro-ultrafiltration system for reducing the conductivity of re-pulp return water, comprising:

[0005] A storage tank, a repulp return water pump, a micro-ultrafiltration unit and a micro-ultrawater pump connected in sequence by pipelines, the storage tank is used to store the repulp return water, the repulp return water pump is used to pump the repulp return water in the storage tank out and pump it to the micro-ultrafiltration unit, the micro-ultrafiltration unit is used to filter ions in the repulp return water to reduce the conductivity of the repulp return water, the micro-ultrafiltration unit includes a first micro-ultrafilter and a second micro-ultrafilter, the first micro-ultrafilter and the second micro-ultrafilter are connected in parallel between the repulp return water pump and the micro-ultrawater pump, and the micro-ultrawater pump is used to pump the filtered repulp return water back to the phosphoric acid production device.

[0006] Optionally, the storage tank is connected to the repulp water pump via a storage tank outlet pipe, and a storage tank valve is provided on the storage tank outlet pipe.

[0007] Optionally, the re-pulp return water pump is connected to the micro-ultrafiltration unit through a re-pulp return water pump outlet pipe, the first micro-ultrafilter is connected to the re-pulp return water pump outlet pipe through a first micro-ultrafilter inlet pipe, the first micro-ultrafilter inlet pipe is provided with a first micro-ultrafilter liquid inlet valve, the second micro-ultrafilter is connected to the re-pulp return water pump outlet pipe through a second micro-ultrafilter inlet pipe, the second micro-ultrafilter inlet pipe is provided with a second micro-ultrafilter liquid inlet valve.

[0008] Optionally, the micro-ultrafiltration pump is connected to the micro-ultrafiltration unit through a micro-ultrafiltration pump inlet pipe, a micro-ultrafiltration pump inlet valve is provided on the micro-ultrafiltration pump inlet pipe, the first micro-ultrafiltration filter is connected to the micro-ultrafiltration pump inlet pipe through a first micro-ultrafiltration filter outlet pipe, a first micro-ultrafiltration filter outlet pipe is provided with a first micro-ultrafiltration filter outlet valve, the second micro-ultrafiltration filter is connected to the micro-ultrafiltration pump inlet pipe through a second micro-ultrafiltration filter outlet pipe, a second micro-ultrafiltration filter outlet pipe is provided with a second micro-ultrafiltration filter outlet valve.

[0009] Optionally, it also includes a re-slurry intermediate tank, a dense phase circulation pump is provided between the re-slurry intermediate tank and the micro-ultrafiltration unit, the dense phase circulation pump is connected to the micro-ultrafiltration unit through a dense phase liquid inlet pipe, and a dense phase circulation pump liquid inlet valve is provided on the dense phase liquid inlet pipe.

[0010] Optionally, the first micro-ultrafilter is connected to the dense phase liquid inlet pipe through a first micro-ultra dense phase tube, and the first micro-ultra dense phase tube is provided with a first micro-ultra dense phase valve; the second micro-ultrafilter is connected to the dense phase liquid inlet pipe through a second micro-ultra dense phase tube, and the second micro-ultra dense phase tube is provided with a second micro-ultra dense phase valve; the dense phase circulation pump is connected to the re-slurry intermediate tank through a dense phase liquid outlet pipe, and the dense phase liquid outlet pipe is provided with a dense phase circulation pump liquid outlet valve.

[0011] Optionally, an air blowing and cleaning pump is further included, wherein the air blowing and cleaning pump is connected to the water outlet pipe of the repulp return water pump through an air inlet pipe, and the air blowing and cleaning pump is used to perform air blowing and cleaning on the first micro-ultrafilter and the second micro-ultrafilter.

[0012] Optionally, a reslurry suction pump and a belt filter are provided between the reslurry intermediate tank and the storage tank, the reslurry suction pump is used to pump out the reslurry in the reslurry intermediate tank and pump it to the belt filter for filtration, and the belt filter is used to dehydrate the reslurry.

[0013] Optionally, a storage tank water inlet pipe is connected between the belt filter and the storage tank, and the repulp return water formed by dehydrating the repulp liquid by the belt filter is transported into the storage tank through the storage tank water inlet pipe for storage.

[0014] Optionally, it also includes a storage area, and the solidified material formed by dehydration of the belt filter is transported to the storage area for storage.

[0015] As described above, the utility model has the following beneficial effects: the repulp return water is sent to the micro-ultrafiltration unit through the repulp return water pump, and the micro-ultrafiltration unit can effectively remove soluble ions such as phosphate ions and hydroxide ions in the repulp return water, thereby reducing the conductivity of the solution, improving the quality of the repulp return water, and can effectively reduce the blockage frequency of the repulp system, reduce the shutdown frequency, and improve the start-up rate of the entire repulp device, and can effectively reduce cleaning costs and environmental risks, which has the beneficial effect of improving the economic benefits of the enterprise; the micro-ultrafiltration unit is arranged in parallel between the repulp return water pump and the micro-ultrafiltration pump, and according to the actual workload, a single set of micro-ultrafilters can be selected to operate or two sets of micro-ultrafilters can be selected to operate in parallel to adapt to filtering operations under different load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a schematic diagram of a micro-ultrafiltration system for reducing the conductivity of repulp return water according to an embodiment of the present application.

[0017] Description of Reference Numerals

[0018] Storage tank 1, storage tank outlet pipe 101, storage tank valve 102, repulp return water pump 2, repulp return water pump outlet pipe 201, storage tank inlet pipe 202, micro-ultrafiltration unit 3, first micro-ultrafilter 301, second micro-ultrafilter 302, first micro-ultrafilter inlet pipe 303, first micro-ultrafluid inlet valve 304, second micro-ultrafilter inlet pipe 305, second micro-ultrafluid inlet valve 306, first micro-ultrafilter outlet pipe 307, first micro-ultrafluid inlet valve 308, second micro-ultrafilter outlet pipe 309, second micro-ultrafluid inlet valve 31 0, first micro-super dense phase pipe 311, first micro-super dense phase valve 312, second micro-super dense phase pipe 313, second micro-super dense phase valve 314, micro-super water pump 4, micro-super water pump inlet pipe 401, micro-super water pump liquid inlet valve 402, re-slurry intermediate tank 5, dense phase circulation pump 6, dense phase liquid inlet pipe 601, dense phase circulation pump liquid inlet valve 602, dense phase liquid outlet pipe 603, dense phase circulation pump liquid outlet valve 604, air blowing and sweeping pump 7, air inlet pipe 701, air inlet valve 702, re-slurry suction pump 8, belt filter 9, storage area 10. DETAILED DESCRIPTION

[0019] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] See also Figure 1 . It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the utility model in a schematic manner, so the diagram only shows the components related to the utility model rather than being drawn according to the number, shape and size of the components during actual implementation. During actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated. The structure, proportion, size, etc. illustrated in the drawings attached to this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions for the implementation of the utility model, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the utility model without affecting the effect and purpose that can be achieved by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the present utility model. Changes or adjustments to their relative relationships should be regarded as the scope of the implementation of the present utility model without substantially changing the technical content.

[0021] Before describing the embodiments of the utility model in detail, the application environment of the utility model is described first. The technology of the utility model is mainly applied to the field of chemical process technology. The utility model is used to solve the problems that the conductivity and ion concentration of the repulping return water in the production process of the existing phosphoric acid device are high, which easily causes the phosphoric acid device repulping system to be blocked and frequently stopped, and the cleaning is difficult, expensive, and has a high environmental risk, resulting in high operating costs and serious impact on the economic benefits of the enterprise.

[0022] Please combine Figure 1 As shown, the utility model provides a micro-ultrafiltration system for reducing the conductivity of repulp return water, comprising:

[0023] In an exemplary embodiment of the present application, a storage tank 1, a repulp return water pump 2, a micro-ultrafiltration unit 3 and a micro-ultrawater pump 4 are connected in sequence by pipelines. The storage tank 1 is used to store the repulp return water. The repulp return water pump 2 is used to pump the repulp return water in the storage tank 1 out and pump it to the micro-ultrafiltration unit 3. The micro-ultrafiltration unit 3 is used to filter ions in the repulp return water to reduce the conductivity of the repulp return water. The micro-ultrafiltration unit 3 includes a first micro-ultrafilter 301 and a second micro-ultrafilter 302. The first micro-ultrafilter 301 and the second micro-ultrafilter 302 are connected in parallel between the repulp return water pump 2 and the micro-ultrawater pump 4. The micro-ultrawater pump 4 is used to pump the filtered repulp return water back to the phosphoric acid production device.

[0024] In this embodiment, the repulp return water is pumped to the micro-ultrafiltration unit 3 through the repulp return water pump 2. The micro-ultrafiltration unit 3 can effectively remove soluble ions such as phosphate ions and hydroxide ions in the repulp return water, thereby reducing the conductivity of the solution and improving the quality of the repulp return water. It can effectively reduce the blockage frequency of the repulping system, reduce the shutdown frequency, and improve the start-up rate of the entire repulping device. It can also effectively reduce cleaning costs and environmental risks, and has the beneficial effect of improving the economic benefits of the enterprise. The micro-ultrafiltration unit 3 is arranged in parallel between the repulp return water pump 2 and the micro-ultrafiltration pump 4. According to the actual workload, a single set of micro-ultrafilters can be selected to operate or two sets of micro-ultrafilters can be selected to operate in parallel to adapt to filtering operations under different load conditions.

[0025] In an exemplary embodiment of the present application, the storage tank 1 is connected to the repulp water pump 2 via a storage tank outlet pipe 101 , and a storage tank valve 102 is provided on the storage tank outlet pipe 101 .

[0026] In this embodiment, the repulp return water pump 2 is connected to the storage tank 1 through the storage tank outlet pipe 101. When the repulp return water temporarily stored in the storage tank 1 reaches a preset value, the storage tank valve 102 is opened, and the repulp return water in the storage tank 1 is pumped out through the repulp return water pump 2 and pumped to the micro-ultrafiltration unit 3 for filtration operation.

[0027] In an exemplary embodiment of the present application, the repulp return water pump 2 is connected to the micro-ultrafiltration unit 3 through the repulp return water pump outlet pipe 201, the first micro-ultrafilter 301 is connected to the repulp return water pump outlet pipe 201 through the first micro-ultrafilter inlet pipe 303, and the first micro-ultrafilter inlet pipe 303 is provided with a first micro-ultrafiltration liquid inlet valve 304, the second micro-ultrafilter 302 is connected to the repulp return water pump outlet pipe 201 through the second micro-ultrafilter inlet pipe 305, and the second micro-ultrafilter inlet pipe 305 is provided with a second micro-ultrafiltration liquid inlet valve 306.

[0028] In this embodiment, the first micro-ultrafilter 301 and the second micro-ultrafilter 302 are connected to the repulp return water pump outlet pipe 201 through the first micro-ultrafilter water inlet pipe 303 and the second micro-ultrafilter water inlet pipe 305, respectively, so as to realize that the first micro-ultrafilter 301 and the second micro-ultrafilter 302 are connected in parallel in the pipeline, and the first micro-ultrafilter liquid inlet valve 304 and the second micro-ultrafilter liquid inlet valve 306 are correspondingly arranged on the first micro-ultrafilter water inlet pipe 303 and the second micro-ultrafilter water inlet pipe 305. When the filtering load is small, the first micro-ultrafilter liquid inlet valve 304 or the second micro-ultrafilter liquid inlet valve 306 can be closed to perform the filtering operation of the repulp return water through a single set of micro-ultrafilters. When the filtering load is large, the first micro-ultrafilter liquid inlet valve 304 and the second micro-ultrafilter liquid inlet valve 306 are opened to enable two sets of micro-ultrafilters to perform the filtering operation to adapt to the large filtering load condition. The parallel connection of the first micro-ultrafilter 301 and the second micro-ultrafilter 302 effectively improves the compatibility of the system.

[0029] In an exemplary embodiment of the present application, the micro-ultrafiltration pump 4 is connected to the micro-ultrafiltration unit 3 through a micro-ultrafiltration pump inlet pipe 401, a micro-ultrafiltration pump inlet valve 402 is provided on the micro-ultrafiltration pump inlet pipe 401, the first micro-ultrafiltration filter 301 is connected to the micro-ultrafiltration pump inlet pipe 401 through a first micro-ultrafiltration filter outlet pipe 307, a first micro-ultrafiltration filter outlet pipe 307 is provided with a first micro-ultrafiltration filter outlet valve 308, the second micro-ultrafiltration filter 302 is connected to the micro-ultrafiltration pump inlet pipe 401 through a second micro-ultrafiltration filter outlet pipe 309, a second micro-ultrafiltration filter outlet pipe 309 is provided with a second micro-ultrafiltration filter outlet valve 310.

[0030] In this embodiment, the micro-super pump 4 is connected to the micro-super filtration unit 3 through the micro-super pump inlet pipe 401, and the first micro-super liquid discharge valve 308 or the second micro-super liquid discharge valve 310 is opened according to the filtration load, or the first micro-super liquid discharge valve 308 and the second micro-super liquid discharge valve 310 are opened at the same time. By opening the micro-super pump inlet valve 402, the micro-super pump 4 can pump the re-pulped return water filtered in the first micro-super filter 301 / the second micro-super filter 302, or the first micro-super filter 301 and the second micro-super filter 302 back to the phosphoric acid production device through the micro-super pump inlet pipe 401.

[0031] In an exemplary embodiment of the present application, it also includes a re-slurry intermediate tank 5, a dense phase circulation pump 6 is provided between the re-slurry intermediate tank 5 and the micro-ultrafiltration unit 3, the dense phase circulation pump 6 is connected to the micro-ultrafiltration unit 3 through a dense phase liquid inlet pipe 601, and a dense phase circulation pump liquid inlet valve 602 is provided on the dense phase liquid inlet pipe 601.

[0032] In this embodiment, when the dense phase circulation pump 6 needs to be activated, the first micro-excess liquid valve 308, the second micro-excess liquid valve 310 and the micro-ultrafiltration pump inlet valve 402 are closed, and the dense phase circulation pump inlet valve 602 is opened. The dense phase circulation pump 6 extracts the concentrated slurry or precipitated material in the micro-ultrafiltration unit 3 through the dense phase inlet pipe 601.

[0033] In an exemplary embodiment of the present application, the first micro-ultrafilter 301 is connected to the dense phase liquid inlet pipe 601 through the first micro-ultra dense phase pipe 311, and the first micro-ultra dense phase pipe 311 is provided with a first micro-ultra dense phase valve 312; the second micro-ultrafilter 302 is connected to the dense phase liquid inlet pipe 601 through the second micro-ultra dense phase pipe 313, and the second micro-ultra dense phase pipe 313 is provided with a second micro-ultra dense phase valve 314; the dense phase circulation pump 6 is connected to the re-slurry intermediate tank 5 through the dense phase liquid outlet pipe 603, and the dense phase liquid outlet pipe 603 is provided with a dense phase circulation pump liquid outlet valve 604.

[0034] In this embodiment, by opening the first micro-ultra-dense phase valve 312 or the second micro-ultra-dense phase valve 314, or opening the first micro-ultra-dense phase valve 312 or the second micro-ultra-dense phase valve 314 at the same time, and opening the dense phase circulation pump inlet valve 602 and the dense phase circulation pump outlet valve 604, the concentrated slurry or precipitate in the first micro-ultra-filter 301 or the second micro-ultra-filter 302 is extracted by the dense phase circulation pump 6, and the concentrated slurry or precipitate is pumped back to the re-slurry intermediate tank 5 through the dense phase outlet pipe 603, and the concentrated slurry or precipitate pumped back is dehydrated again through the belt filter 9 to form solid-liquid separation, the solid is transported to the storage area, and the liquid is sent to the storage tank 1, and enters the micro-ultra-filtration system again, so as to further improve the quality of the re-slurry return water, reduce the blockage and shutdown frequency of the phosphoric acid production device, and thus improve the economic benefits of the enterprise.

[0035] In an exemplary embodiment of the present application, an air blowing and cleaning pump 7 is also included. The air blowing and cleaning pump 7 is connected to the repulp return water pump outlet pipe 201 through an air inlet pipe 701. The air blowing and cleaning pump 7 is used to blow and clean the first micro-ultrafilter 301 and the second micro-ultrafilter 302. An air inlet valve 702 is provided on the air inlet pipe 701.

[0036] In this embodiment, when the air blowing and cleaning process is carried out, the storage tank valve 102, the first micro-ultrafiltration liquid outlet valve 308, and the second micro-ultrafiltration liquid outlet valve 310 are closed, the air inlet valve 702, the first micro-ultrafiltration liquid inlet valve 304, and the second micro-ultrafiltration liquid inlet valve 306 are opened, the first micro-ultrafiltration dense phase valve 312, the second micro-ultrafiltration dense phase valve 314, the dense phase circulation pump liquid inlet valve 602, and the dense phase circulation pump liquid outlet valve 604 are opened, and the air blowing and cleaning pump 7 purges the micro-ultrafiltration unit 3 through the air inlet pipe 701, and purges the impurities on the filter membrane to make them deposited and concentrated at the bottom of the first micro-ultrafiltration filter 301 and the second micro-ultrafiltration filter 302, and the deposited and concentrated products are pumped back to the re-slurry intermediate tank 5 through the dense phase circulation pump 6. After the purge is completed, the flux of the micro-ultrafiltration unit 3 can be restored, and the long-term and effective operation of the micro-ultrafiltration unit 3 can be achieved.

[0037] In an exemplary embodiment of the present application, a reslurry suction pump 8 and a belt filter 9 are further provided between the reslurry intermediate tank 5 and the storage tank 1. The reslurry suction pump 8 is used to pump out the reslurry in the reslurry intermediate tank 5 and pump it to the belt filter 9 for filtration. The belt filter 9 is used to dehydrate the reslurry.

[0038] In this embodiment, the reslurry suction pump 8 pumps the reslurry in the reslurry intermediate tank 5 to the belt filter 9, and the belt filter 9 separates the solid and liquid of the reslurry. The solid is transported to the storage area 10 for storage and treatment through the belt filter 9, and the liquid (i.e., the reslurry return water) is sent to the storage tank 1 through a pipeline for temporary storage.

[0039] In an exemplary embodiment of the present application, a storage tank water inlet pipe 202 is connected between the belt filter 9 and the storage tank 1 , and the repulp return water formed by dehydrating the repulp liquid by the belt filter 9 is transported into the storage tank 1 through the storage tank water inlet pipe 202 for storage.

[0040] In an exemplary embodiment of the present application, a storage area 10 is further included, and the solidified material formed by dehydration of the belt filter 9 is transported to the storage area 10 for storage.

[0041] Working principle: according to the actual filtering load, a single set of micro-ultrafilter or two sets of micro-ultrafilters are selected to be turned on. The re-pulp return water pump 2 pumps the re-pulp return water in the storage tank 1 into the micro-ultrafiltration unit 3. The filtered re-pulp return water is pumped back to the phosphoric acid production device through the micro-ultrafiltration pump 4. When the micro-ultrafiltration unit 3 is blocked, the air blowing and cleaning process is started. During the air blowing and cleaning process, the storage tank valve 102, the first micro-ultrafiltration liquid inlet valve 308, and the second micro-ultrafiltration liquid inlet valve 310 are closed, and the air inlet valve 702, the first micro-ultrafiltration liquid inlet valve 304, and the second micro-ultrafiltration liquid inlet valve 306 are opened. , open the first micro-ultra dense phase valve 312, the second micro-ultra dense phase valve 314, the dense phase circulation pump inlet valve 602 and the dense phase circulation pump outlet valve 604, and the air purge pump 7 purges the micro-ultrafiltration unit 3 through the air inlet pipe 701, and purges the impurities on the filter membrane to make them deposit and concentrate at the bottom of the first micro-ultrafilter 301 and the second micro-ultrafilter 302, and the deposited and concentrated materials are pumped back to the re-slurry intermediate tank 5 through the dense phase circulation pump 6. After the purge is completed, the flux of the micro-ultrafiltration unit 3 can be restored, so that the long-term and effective operation of the micro-ultrafiltration unit 3 can be realized. The repulp return water is sent to the micro-ultrafiltration unit 3 through the repulp return water pump. The micro-ultrafiltration unit 3 can effectively remove soluble ions such as phosphate ions and hydroxide ions in the repulp return water, thereby reducing the conductivity of the solution and improving the quality of the repulp return water. It can effectively reduce the blockage frequency of the repulping system, reduce the shutdown frequency, improve the start-up rate of the entire repulping device, and effectively reduce the cleaning costs and environmental risks, which has the beneficial effect of improving the economic benefits of the enterprise; by arranging the first micro-ultrafilter 301 and the second micro-ultrafilter 302 in parallel between the repulp return water pump 2 and the micro-ultrawater pump 4, a single set of micro-ultrafilters or two sets of micro-ultrafilters in parallel can be selected according to the actual workload to adapt to filtering operations under different load conditions.

[0042] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A micro-ultrafiltration system for reducing the conductivity of repulp return water, characterized in that: include: A storage tank, a repulp return water pump, a micro-ultrafiltration unit and a micro-ultrawater pump connected in sequence by pipelines, the storage tank is used to store the repulp return water, the repulp return water pump is used to pump the repulp return water in the storage tank out and pump it to the micro-ultrafiltration unit, the micro-ultrafiltration unit is used to filter ions in the repulp return water to reduce the conductivity of the repulp return water, the micro-ultrafiltration unit includes a first micro-ultrafilter and a second micro-ultrafilter, the first micro-ultrafilter and the second micro-ultrafilter are connected in parallel between the repulp return water pump and the micro-ultrawater pump, and the micro-ultrawater pump is used to pump the filtered repulp return water back to the phosphoric acid production device.

2. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 1, characterized in that: The storage tank is connected to the repulp return water pump through a storage tank outlet pipe, and a storage tank valve is provided on the storage tank outlet pipe.

3. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 2, characterized in that: The repulp return water pump is connected to the micro-ultrafiltration unit through a repulp return water pump outlet pipe, the first micro-ultrafilter is connected to the repulp return water pump outlet pipe through a first micro-ultrafilter inlet pipe, the first micro-ultrafilter inlet pipe is provided with a first micro-ultrafluid inlet valve, the second micro-ultrafilter is connected to the repulp return water pump outlet pipe through a second micro-ultrafilter inlet pipe, the second micro-ultrafilter inlet pipe is provided with a second micro-ultrafluid inlet valve.

4. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 3, characterized in that: The micro-super pump is connected to the micro-super filtration unit through a micro-super pump inlet pipe, a micro-super pump inlet valve is provided on the micro-super pump inlet pipe, the first micro-super filter is connected to the micro-super pump inlet pipe through a first micro-super filter outlet pipe, a first micro-super filter outlet pipe is provided with a first micro-super liquid valve, the second micro-super filter is connected to the micro-super pump inlet pipe through a second micro-super filter outlet pipe, and a second micro-super filter outlet pipe is provided with a second micro-super liquid valve.

5. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 4, characterized in that: It also includes a re-slurry intermediate tank, a dense phase circulation pump is provided between the re-slurry intermediate tank and the micro-ultrafiltration unit, the dense phase circulation pump is connected to the micro-ultrafiltration unit through a dense phase liquid inlet pipe, and a dense phase circulation pump liquid inlet valve is provided on the dense phase liquid inlet pipe.

6. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 5, characterized in that: The first micro-ultrafilter is connected to the dense phase liquid inlet pipe through a first micro-ultra dense phase pipe, and a first micro-ultra dense phase valve is provided on the first micro-ultra dense phase pipe. The second micro-ultrafilter is connected to the dense phase liquid inlet pipe through a second micro-ultra dense phase pipe, and a second micro-ultra dense phase valve is provided on the second micro-ultra dense phase pipe. The dense phase circulation pump is connected to the re-slurry intermediate tank through a dense phase liquid outlet pipe, and a dense phase circulation pump liquid outlet valve is provided on the dense phase liquid outlet pipe.

7. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 6, characterized in that: It also includes an air blowing and cleaning pump, which is connected to the water outlet pipe of the repulp return water pump through an air inlet pipe, and is used to blow and clean the first micro-ultrafilter and the second micro-ultrafilter.

8. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 7, characterized in that: A reslurry suction pump and a belt filter are also provided between the reslurry intermediate tank and the storage tank. The reslurry suction pump is used to pump out the reslurry in the reslurry intermediate tank and pump it to the belt filter for filtration. The belt filter is used to dehydrate the reslurry.

9. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 8, characterized in that: A storage tank water inlet pipe is connected between the belt filter and the storage tank, and the repulp return water formed by dehydrating the repulp liquid by the belt filter is transported into the storage tank through the storage tank water inlet pipe for storage.

10. The micro-ultrafiltration system for reducing the conductivity of repulp return water according to claim 9, characterized in that: The belt filter also includes a storage area, where the solidified material formed by dehydration of the belt filter is transported to the storage area for storage.

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