Water treatment system in production of iron phosphate based on lithium battery positive electrode material

Abstract

The utility model discloses a water treatment system in production of iron phosphate based on a lithium battery anode material. The water treatment system comprises a reaction tank, a filter press, a ceramic membrane filter, a manganese sand filter, a resin tower, an ultrafiltration filter and a first RO (Reverse Osmosis) membrane filter. The water treatment system disclosed by the utility model is applied to the production process of the lithium battery positive electrode material iron phosphate, pure water and corresponding salt can be obtained without separating filtrate and raw water in the reaction tank, the treatment efficiency and controllability of a production line are improved, and meanwhile, the pure water is separated by the plate and frame filter press and then filtered by the ceramic membrane filter, so that the production efficiency is improved. The problem that the membrane filter is blocked in the subsequent process is effectively prevented, and the treatment cost and the cleaning cost of the membrane filter are reduced.

Description

Technical Field

[0001] The utility model belongs to the field of water treatment systems, and in particular relates to a water treatment system in the production of iron phosphate, a positive electrode material for lithium batteries. Background Art

[0002] During the production of iron phosphate, a positive electrode material for lithium batteries, during the operation of the water treatment process of the water treatment device, after the reaction and precipitation in the pretreatment reaction process are completed, the pretreated water generated adopts a solid-liquid separation process of filtering and removing precipitation, that is, the raw water in the pretreated water is first treated by a ceramic membrane, and the filtrate in the pretreated water is passed through a plate and frame filter press for solid-liquid separation, and filtered to form a filter cake; the concentrated liquid after ceramic membrane treatment enters the plate and frame filter press for solid-liquid separation, and is filtered to form a filter cake, and the clear water produced enters the next stage of multi-media filtration treatment, and is finally treated by an RO membrane.

[0003] However, due to the presence of certain solid particles, sediments, suspended matter, mechanical impurities, etc. in the pre-treated water, when the water becomes more abnormal or fluctuates, especially when the front-end iron phosphate production process fluctuates or is abnormal, and a large amount of sediment is generated, when it is directly filtered through the ceramic membrane, the burden on the ceramic membrane will be seriously increased, and the ceramic membrane will be blocked in a shorter period of time. The more sediment is generated, the shorter the normal water production time will be. In order to restore the water production, it is necessary to clean it. As the amount of sediment that needs to be filtered increases, the number of cleanings will become more frequent, and the cleaning time will also increase. When the ceramic membrane is cleaned, the amount of water treated in this process will decrease; at the same time, directly passing through multi-media filtration and directly entering the RO will also increase the risk of RO membrane filtration blockage, and the frequency of RO cleaning needs to be increased, which will restrict production capacity. In severe cases, there will even be a risk of suspension of production, and manpower will be increased to prepare the cleaning solution, and the amount of cleaning solution used will also need to be increased, increasing overall energy consumption.

[0004] In addition, the existing process is to treat the raw water and filtrate separately in the reaction tank in steps, which requires two production lines to control, has low controllability and a more complicated production process.

[0005] Based on this, we are now developing a new type of water treatment system for the production of iron phosphate, a positive electrode material for lithium batteries. This water treatment system can reduce the risk of membrane filter clogging and can be implemented with only one process production line, thereby improving production efficiency and reducing treatment costs. Utility Model Content

[0006] Purpose of the utility model: The technical problem to be solved by the utility model is to provide a water treatment system in the production of iron phosphate based on lithium battery positive electrode material. The water treatment system can effectively reduce the risk of membrane filter being blocked, reduce the treatment cost, and the system is more controllable.

[0007] Technical solution: The utility model is based on a water treatment system in the production of iron phosphate, a positive electrode material for lithium batteries. The water treatment system includes:

[0008] A reaction tank for subjecting the ferric phosphate mother liquor and the ferric phosphate washing water to an impurity precipitation reaction to obtain pretreated water;

[0009] A filter press is connected to the reaction tank to separate the impurities in the pre-treated water into solid and liquid to remove the impurities;

[0010] A ceramic membrane filter is connected to the filter press to filter the filtrate separated in the filter press;

[0011] The manganese sand filter and the resin tower are connected in sequence to the ceramic membrane filter to filter and remove residual calcium, iron, manganese and magnesium;

[0012] An ultrafiltration filter is connected to the resin tower to filter the filtrate obtained by filtering in the resin tower again;

[0013] The first RO membrane filter is connected to the ultrafiltration filter to obtain pure water and concentrated water.

[0014] Furthermore, the water treatment system also includes several stages of RO membrane filter 1 respectively connected to the pure water outlet of the first RO membrane filter, and several stages of RO membrane filter 2 respectively connected to the concentrated water outlet of the first RO membrane filter.

[0015] Furthermore, the water treatment system also includes an MVR evaporator connected to the concentrated water outlet of the first RO membrane filter.

[0016] Furthermore, the water treatment system also includes an MVR evaporator connected to the concentrated water outlet of the second RO membrane filter.

[0017] Furthermore, the water treatment system also includes a circulation tank located between the filter press and the ceramic membrane filter.

[0018] Furthermore, the concentrated water obtained in the ultrafiltration filter of the water system is circulated to the circulation tank for re-filtration.

[0019] Furthermore, the concentrated water obtained in the ceramic membrane filter of the water system is returned to the filter press and the circulation tank respectively.

[0020] Furthermore, the reaction tank, filter press, ceramic membrane filter, manganese sand filter, resin tower, ultrafiltration filter and first RO membrane filter of the water system are all connected through connecting pipes, and each connecting pipe is provided with a feed pump.

[0021] Furthermore, the RO membrane filter 1 and the first RO membrane filter, the several levels of RO membrane filters 1, and the RO membrane filter 2 and the first RO membrane filter of the water system are connected through connecting pipes, and a feed pump is provided on the connecting pipes.

[0022] Beneficial effect: Compared with the prior art, the advantages of the utility model are as follows: the water treatment system is applied to the production process of iron phosphate, a positive electrode material for lithium batteries. There is no need to separate and treat the filtrate and raw water in the reaction tank. Pure water and corresponding salt can be obtained by directly treating the pretreated water, thereby improving the processing efficiency and controllability of the production line. At the same time, the water is first separated by a plate and frame filter press and then filtered by a ceramic membrane filter, which effectively prevents the problem of membrane filter being blocked in subsequent processes and reduces the processing cost and the cleaning cost of the membrane filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a water treatment system according to Example 1 of the utility model. DETAILED DESCRIPTION

[0024] The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] It should be noted that the system components used in the water treatment system of the utility model are all well-known system components in the art, and no relevant structural improvements have been made thereto. The filter press used in the utility model is a plate-frame filter press.

[0026] Example 1

[0027] The water treatment system of the embodiment 1 comprises a reaction tank 1 for first performing impurity precipitation reaction filtration on the iron phosphate mother liquor and the iron phosphate washing water, and the reaction tank obtains pretreated water; a plate-frame filter press 2 connected to the pretreated water outlet of the reaction tank 1 through a connecting pipe, and the plate-frame filter press 2 performs solid-liquid separation on the large particle impurities in the pretreated water to obtain a filtrate; a circulation tank 9 connected to the filtrate outlet of the plate-frame filter press 2 through a connecting pipe, and a ceramic membrane filter 3 connected to the liquid outlet of the circulation tank 9 through a connecting pipe, so as to separate the solid and liquid impurities obtained in the plate-frame filter press 2. The filtrate is filtered to obtain a clear liquid and a concentrated liquid, wherein the concentrated liquid can be circulated to the plate-frame filter press 2 or the circulation tank 9 through a connecting pipe for solid-liquid separation or filtration again; the manganese sand filter 4 is connected to the clear liquid outlet of the ceramic membrane filter 3 through a connecting pipe, and the manganese sand filter 4 is a multi-media filter filled with medium manganese sand; the liquid outlet of the manganese sand filter 4 is connected to the liquid inlet of the resin tower 5 through a connecting pipe, and the residual calcium, iron, manganese, and magnesium in the clear liquid are filtered and removed through the manganese sand filter 4 and the resin tower 5 to soften. The liquid outlet of the resin tower 5 is connected to the ultrafiltration filter 6 through a connecting pipe to finely filter the clear liquid obtained in the resin tower 5. The clear liquid obtained in the ultrafiltration filter 6 enters the first RO membrane filter 7 to finally obtain pure water and concentrated liquid, and the concentrated liquid is evaporated and crystallized by the MVP evaporator 8 connected to the concentrated liquid outlet of the first RO membrane filter 7 to obtain the corresponding ammonium salt. Similarly, the MVP evaporator 8 is connected to the concentrated liquid outlet of the first RO membrane filter 7 through a connecting pipe. Figure 1 shown.

[0028] That is, the water treatment system of the embodiment 1 is to first subject the mixed raw water of the iron phosphate mother liquor and the iron phosphate washing water in the reaction tank 1 to an impurity precipitation reaction, and then the obtained pre-treated water is subjected to solid-liquid separation by the plate-frame filter press 2, and the obtained filtrate is filtered into the ceramic membrane filter 3 through the circulation tank 9 to obtain a clear liquid, and the clear liquid is then filtered through the manganese sand filter 4 and the resin tower 5 to remove metals to obtain a clear liquid, and the clear liquid is filtered through the ultrafiltration filter 6 and the first RO membrane filter 7 in turn to finally obtain pure water and a concentrated solution, and the concentrated solution is evaporated and crystallized to obtain the corresponding salt. That is, when the water treatment system is used for the early stage of treatment, it is not necessary to purify the pre-treated water composed of the raw water and the filtrate step by step to obtain pure water and the corresponding salt, and the pre-treated water is directly purified and then the pure water and the corresponding salt are obtained in steps, thereby improving the water treatment effect and the controllability of the operation.

[0029] Example 2

[0030] In order to further improve the cleanliness of pure water, this embodiment 2 is respectively provided with several stages of RO membrane filter 1 and several RO membrane filter 2 on the basis of embodiment 1. Specifically, the RO membrane filter 1 can be provided with two stages, namely, the primary RO membrane filter 2 and the secondary RO membrane filter 2, the liquid inlet of the primary RO membrane filter 1 is connected with the pure water inlet of the first RO membrane filter, the clear liquid outlet of the primary RO membrane filter 1 is connected with the liquid inlet of the secondary RO membrane filter 1, and the concentrated liquid of the secondary RO membrane filter 1 is circulated to the liquid inlet of the primary RO membrane filter 1 through the connecting pipe.

[0031] Several RO membrane filters 2 may include medium-pressure RO membrane filters 2 and high-pressure RO membrane filters 2. The medium-pressure RO membrane filter 2 is connected to the concentrated water outlet of the first RO membrane filter, the concentrated liquid outlet of the medium-pressure RO membrane filter 2 is connected to the liquid inlet of the high-pressure RO membrane filter 2, the clear liquid outlet of the medium-pressure RO membrane filter 2 is connected to the liquid inlet of the first-stage RO membrane filter 1, and the concentrated liquid outlet of the first-stage RO membrane filter 1 is connected to the liquid inlet of the medium-pressure RO membrane filter 2. The concentrated liquid outlet of the high-pressure RO membrane filter 2 is connected to the MVR evaporator to evaporate and crystallize the final concentrated liquid to obtain the corresponding salt. The clear liquid outlet of the high-pressure RO membrane filter 2 is transported to the first-stage RO membrane filter 1 through the medium-pressure RO membrane filter 2 for pure water extraction.

[0032] In addition to the above embodiments, it should be noted that, in order to make the entire water treatment system operate efficiently, feed pumps are provided on the connecting pipes of the system components of the utility model, and the operation of the entire system is completed under the conditions of these feed pumps.

Claims

1. A water treatment system in the production of iron phosphate as a positive electrode material for lithium batteries, characterized in that: The water treatment system includes: A reaction tank (1) is used to perform an impurity precipitation reaction on the ferric phosphate mother liquor and the ferric phosphate washing water to obtain pretreated water; A filter press (2) is connected to the reaction tank (1) to perform solid-liquid separation on the pretreated water to remove impurities; A ceramic membrane filter (3) is connected to the filter press (2) to filter the filtrate separated in the filter press (2); The manganese sand filter (4) and the resin tower (5) are sequentially connected to the ceramic membrane filter (3) to filter and remove residual calcium, iron, manganese and magnesium; An ultrafiltration filter (6) is connected to the resin tower (5) to filter the filtrate obtained by filtering in the resin tower (5) again; The first RO membrane filter (7) is connected to the ultrafiltration filter (6) to obtain pure water and concentrated water.

2. The water treatment system in the production of iron phosphate based on lithium battery positive electrode material according to claim 1 is characterized in that: The water treatment system further comprises a plurality of stages of RO membrane filters 1 respectively connected to the pure water outlet of the first RO membrane filter (7), and a plurality of stages of RO membrane filters 2 respectively connected to the concentrated water outlet of the first RO membrane filter (7).

3. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 1, characterized in that: The water treatment system also includes an MVR evaporator (8) connected to the concentrated water outlet of the first RO membrane filter (7).

4. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 2, characterized in that: The water treatment system also includes an MVR evaporator connected to the concentrated water outlet of the second RO membrane filter.

5. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to any one of claims 1 to 4, characterized in that: The water treatment system also includes a circulation tank (9) located between the filter press (2) and the ceramic membrane filter (3).

6. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 5, characterized in that: The concentrated water obtained in the ultrafiltration filter (6) is circulated to the circulation tank (9) for further filtration.

7. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 5, characterized in that: The concentrated water obtained in the ceramic membrane filter (3) flows back to the filter press (2) and the circulation tank (9) respectively.

8. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 1, characterized in that: The reaction tank (1), the filter press (2), the ceramic membrane filter (3), the manganese sand filter (4), the resin tower (5), the ultrafiltration filter (6) and the first RO membrane filter (7) are all connected via connecting pipes, and each connecting pipe is provided with a feed pump.

9. The water treatment system in the production of lithium battery positive electrode material iron phosphate according to claim 2, characterized in that: The RO membrane filter 1 and the first RO membrane filter (7), the several stages of RO membrane filters 1, and the RO membrane filter 2 and the first RO membrane filter (7) are all connected via connecting pipes, and a feed pump is provided on the connecting pipes.

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