Method and device for improving centrifugal running collection of lithium battery precursor

Abstract

The application discloses a method and device for improving centrifugal run-off collection of lithium battery precursors, and belongs to the technical field of lithium batteries.The method for improving centrifugal run-off collection of lithium battery precursors comprises the following steps: washing, filtering and pressing the filtrate and filter material obtained from the centrifugal machine clear liquid; mixing the filtrate and the thickener machine clear liquid to obtain a mixed material liquid; filtering and separating the mixed material liquid to obtain a first material which is returned to the centrifugal machine for washing; returning the washed material I to the production line and mixing the material I with the lithium battery precursors obtained through normal reaction; meanwhile, the filter material is subjected to beating and iron removal to obtain a second material which is returned to the centrifugal machine for washing; and the washed material II is used as normal material on the production line for mixing.The centrifugal run-off and the thickener machine clear material are distinguished, the centrifugal run-off is all mixed and added, the thickener machine clear material is partially mixed and added, the recycling rate of the centrifugal run-off is improved, and the economic value is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery, in particular to a method and device for improving centrifugal run-off collection of lithium battery precursor. BACKGROUND

[0002] In the preparation process of lithium battery positive electrode material, the preparation process of precursor accounts for 60%, and the quality of the precursor directly affects the performance of the positive electrode material. Generally, the ternary positive electrode material is a secondary spherical particle formed by agglomeration of fine nickel-cobalt-manganese hydroxide grains and lithium hydroxide mixed and calcined. At present, the production of ternary precursor mainly adopts the coprecipitation method (continuous method and intermittent method), that is, nickel salt, cobalt salt, manganese salt or aluminum salt are mixed into a salt solution in a certain proportion, and nickel-cobalt-manganese\aluminum hydroxide precipitate is formed (reaction) in the presence of alkali and complexing agent, and then qualified products are obtained through centrifugal washing, drying, mixing, and magnetic removal.

[0003] At present, in the centrifugal process, the precursor material obtained by coprecipitation reaction is pumped into the centrifuge, and the centrifuge rotates at high speed during the feeding process to form a filter cake layer on the filter cloth. Small particles in the material penetrate the filter cake layer (i.e. centrifugal run-off) into the mother liquor tank, where they are mixed with the thickener effluent. After that, the mother liquor is treated as conventional waste water and waste material. Since the material that penetrates the filter cake layer of the centrifuge is qualified material after coprecipitation reaction, the material is simply treated as waste water and waste material, which not only wastes resources but also generates a large amount of waste. Therefore, it is urgent to reasonably recycle and utilize the centrifugal run-off.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to provide a method and device for improving centrifugal run-off collection of lithium battery precursor to overcome the defects of the prior art.

[0006] The technical problem of the present application is solved by using the following technical scheme.

[0007] The present application provides a method for improving centrifugal run-off collection of lithium battery precursor, comprising: mixing the centrifuge effluent water washing and filter pressing to obtain a filtrate, and mixing the filtrate with the thickener effluent to obtain a mixed slurry; returning the first material obtained by filtering and separating the mixed slurry to the centrifuge for washing, and returning the material I obtained by washing to the production line and mixing with the lithium battery precursor obtained by normal reaction.

[0008] The application also provides a device for improving centrifugal run-off collection of lithium battery precursor, comprising: a centrifuge, a thickener, a mother liquor tank, a precision filter, a centrifugal pump, a washing water tank, a plate-and-frame filter press, a beating-up tank, an iron remover, a waste tank, and the outlet of the centrifuge is communicated with the inlet of the washing water tank through a pipeline, the outlet of the washing water tank is communicated with the inlet of the plate-and-frame filter press through a pipeline, the filtrate outlet of the plate-and-frame filter press and the clear liquid outlet of the thickener are respectively communicated with the inlet of the mother liquor tank through a pipeline, the outlet of the mother liquor tank is communicated with the inlet of the precision filter through a pipeline, the filter material outlet of the precision filter is communicated with the inlet of the waste tank through a pipeline, and the outlet of the waste tank is communicated with the inlet of the centrifuge through a pipeline.

[0009] The application has the following beneficial effects:

[0010] The application provides a method and device for improving centrifugal run-off collection of lithium battery precursor, and the method for improving centrifugal run-off collection of lithium battery precursor comprises: mixing the filtrate obtained by washing and filter pressing the clear liquid of the centrifuge with the clear liquid of the thickener to obtain mixed material liquid; and returning the first material obtained by filtering and separating the mixed material liquid to the centrifuge for washing, and returning the material I obtained by washing to the production line and mixing with the lithium battery precursor obtained by normal reaction. Since the centrifugal run-off is normal material qualified for reaction, it can be mixed in a large amount, and the material passing through the clear liquid of the thickener is material in the reaction process, which can only be mixed in a small amount. The application distinguishes the centrifugal run-off from the clear liquid of the thickener, so that the centrifugal run-off is mixed in the whole amount and the clear liquid of the thickener is mixed in a part of the amount. The above method improves the recycling rate of the centrifugal run-off, and further improves the economic value and reduces environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0012] Figure 1 It is a centrifugal run-off collection device schematic diagram in the comparative example;

[0013] Figure 2 It is a centrifugal run-off collection device schematic diagram in the embodiment;

[0014] Drawing number: 1-centrifuge; 2-thickener; 3-mother liquor tank; 4-precision filter; 5-centrifugal pump; 6-washing water tank; 7-plate-and-frame filter press; 8-beating-up tank; 9-iron remover; 10-waste tank. DETAILED DESCRIPTION

[0015] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by manufacturers are adopted. If manufacturers of reagents or instruments are not specified, all are conventional products that can be purchased in the market.

[0016] A method and device for improving centrifugal run-off collection of lithium battery precursor are specifically described below.

[0017] In a first aspect, the embodiments of the present application provide a method for improving centrifugal run-off collection of lithium battery precursor, comprising: mixing filtrate obtained by washing and filter pressing of centrifuge outflow liquid with thickener outflow liquid to obtain mixed liquid; returning first material obtained by filtering and separating the mixed liquid to the centrifuge for washing, and returning material I obtained by washing to the production line and mixing with lithium battery precursor obtained by normal reaction.

[0018] In the preparation of lithium battery precursor by coprecipitation reaction, the lithium battery precursor that meets the reaction requirements needs to be punched into a centrifuge for centrifugal washing treatment. A large amount of centrifugal run-off will occur during the centrifugal washing process, that is, a large part of the material penetrates through the filter cloth in the centrifuge into the outflow liquid. The current treatment method is to mix the small particle material run off by centrifugal washing with the extremely small particle material outflowed by the thickener in the mother liquor tank, and intercept it through a precision filter. When the precision filter runs to a certain extent, the precision filter is back-flushed and backwashed, and the material backwashed into the waste tank is subjected to centrifugal washing treatment again in the centrifuge. However, due to the large amount of extremely small particles in the mixed material, a large amount of this part of the material cannot be timely mixed with the product.

[0019] In order to solve the above problems and improve the recycling rate of centrifuge and thickener run-off, the inventors have found through repeated practice and analysis that the material centrifugally washed is the material that meets the reaction requirements of the reaction kettle. The small particles in the material penetrate through the filter cloth into the mother liquor tank and the thickener outflow run-off mixture. This part of the material is only smaller in particle size than the normal material, and under normal circumstances, the material can be directly mixed with the product in a large amount. During the operation of the thickener, the material in the reaction kettle continuously enters the thickener, the solid particles in the material are intercepted by the filter core, and then the material is pumped into the reaction kettle for continuous circulation. The material that penetrates through the filter core enters the mother liquor tank. This part of the material is the extremely small particle material run off by the thickener through the filter core. Due to the extremely low particle size, it is extremely difficult to mix this part of the material in the actual production process.

[0020] Therefore, the inventors propose a method for improving the centrifugal running material collection of lithium battery precursors, which distinguishes the centrifugal running material from the thickener overflow material, specifically: the filter liquor obtained by water washing and filter pressing of the centrifuge overflow liquid is mixed with the thickener overflow liquid to obtain a mixed liquor, the filter liquor obtained by water washing and filter pressing of the centrifuge overflow liquid is mixed with the thickener overflow liquid, and the filter liquor has a very small particle size, which is close to the particle size of the material in the thickener overflow liquid, so the two are mixed, and then subsequent filtration and water washing treatment is performed, which can return to the production line and be used as part of the reaction precursor for mixing during the preparation of lithium battery materials.

[0021] In an optional embodiment, the filter material obtained by water washing and filter pressing of the centrifuge overflow liquid is subjected to beating and iron removal to obtain a second material, and the second material is returned to the centrifuge for washing, and the washed material II is mixed as normal material on the production line.

[0022] The embodiment of the present application provides a method for improving the centrifugal running material collection of lithium battery precursors, which is obtained by beating and iron removal of the filter material obtained by water washing and filter pressing of the centrifuge overflow liquid to obtain a second material, and then returning the second material to the centrifuge for washing, and mixing the washed material II as normal material on the production line. Since the filter material obtained by water washing and filter pressing of the centrifuge has large particles, and is a qualified reaction material, it can be fully recycled after water washing. As can be seen from the above, the method provided by the embodiment of the present application, by water washing and filter pressing of the centrifuge running material to obtain filter liquor and filter material, then treating the filter liquor and the filter material respectively, mixing the filter liquor with the thickener overflow liquid for recycling, and separately treating the filter material for recycling, basically realizes the full recycling of the centrifuge running material and the thickener running material, which not only reduces the amount of waste generated, but also has very high economic value.

[0023] In an optional embodiment, the material I obtained by washing in the centrifuge is returned to the production line for mixing, and the material II is mixed as normal material on the production line.

[0024] In an optional embodiment, the centrifuge overflow liquid is washed in a water washing tank, then pumped into a plate and frame filter press by a centrifugal pump and filtered in the plate and frame filter press to obtain filter liquor, and then the filter liquor discharged from the plate and frame filter press is mixed with the thickener overflow liquid to obtain a mixed liquor.

[0025] In an optional embodiment, the mixed liquor in the mother liquor tank is pumped into a precision filter by a centrifugal pump, and the first material and the first filter liquor are separated by filtration in the precision filter, and then the first material is input into a waste tank for storage, and then pumped into a centrifuge for washing, and the washed material I is returned to the production line for mixing, and the first filter liquor is sent to a public auxiliary workshop for treatment.

[0026] In an optional embodiment, the filter material obtained by washing the centrifuge clear liquid, filter pressing is beaten in a beating tank to obtain pulp, and then the pulp is input into an iron remover to remove iron to obtain a second material.

[0027] In an optional embodiment, the pulp in the beating tank is pumped into the iron remover by a centrifugal pump, the pulp circulates between the iron remover and the beating tank until the second material qualified for magnetic foreign matter is obtained, and then the second material is returned to the centrifuge for washing, and the material II obtained by washing is mixed as normal material on the production line.

[0028] In a second aspect, the embodiments of the present application also provide a device for improving centrifugal material collection of lithium battery precursor, comprising: a centrifuge; a thickener; a mother liquor tank; a precision filter; a centrifugal pump; a washing tank; a plate and frame filter press; a beating tank; an iron remover; a waste tank, and the outlet of the centrifuge is communicated with the inlet of the washing tank through a pipeline, the outlet of the washing tank is communicated with the inlet of the plate and frame filter press through a pipeline, the filtrate outlet of the plate and frame filter press and the outlet of the thickener are respectively communicated with the inlet of the mother liquor tank through a pipeline, the outlet of the mother liquor tank is communicated with the inlet of the precision filter through a pipeline, the filter material outlet of the precision filter is communicated with the inlet of the waste tank through a pipeline, and the outlet of the waste tank is communicated with the inlet of the centrifuge through a pipeline.

[0029] In an optional embodiment, the filter material outlet of the plate and frame filter press is communicated with the inlet of the beating tank through a pipeline, the outlet of the beating tank is communicated with the inlet of the iron remover through a pipeline, and the outlet of the iron remover is respectively communicated with the inlet of the beating tank and the inlet of the centrifuge through a pipeline.

[0030] In an optional embodiment, a centrifugal pump is arranged on the pipeline between the washing tank and the plate and frame filter press, a centrifugal pump is arranged on the pipeline between the beating tank and the iron remover, a centrifugal pump is arranged on the pipeline between the mother liquor tank and the precision filter, and a centrifugal pump is arranged on the pipeline between the waste tank and the centrifuge.

[0031] The features and performances of the present application are further described in detail below in combination with embodiments.

[0032] Comparative example

[0033] A device for collecting centrifugal material of lithium battery precursor, referring to Figure 1 , comprising: a centrifuge 1; a thickener 2; a mother liquor tank 3; a precision filter 4; a centrifugal pump 5; a waste tank 10, and the clear liquid outlet of the centrifuge 1 and the clear liquid outlet of the thickener 2 are respectively communicated with the inlet of the mother liquor tank 3 through a pipeline, the outlet of the mother liquor tank 3 is communicated with the inlet of the precision filter 4 through a centrifugal pump, the filter material outlet of the precision filter 4 is communicated with the inlet of the waste tank 10 through a pipeline, and the outlet of the waste tank 10 is communicated with the inlet of the centrifuge 1 through a centrifugal pump.

[0034] The method for collecting the centrifuge running material by using the above device is as follows:

[0035] The small particle material in the material in the centrifuge 1 penetrates the filter cake layer into the mother liquor tank 3, and is mixed together with the clear liquid from the thickener 2 in the mother liquor tank 3, and is intercepted by the precision filter 4 through the centrifugal pump 5, the clear liquid is sent to the auxiliary workshop, the intercepted material is adsorbed on the filter core, when the pressure difference of the precision filter 4 becomes small, the precision filter 4 is backwashed and forward washed by compressed air and pure water, the swept material enters the waste tank 10, and the material is normally washed out by the centrifuge 1 for blending.

[0036] Embodiment

[0037] A device for improving the centrifuge running material collection of lithium battery precursors, referring to Figure 2 , comprising: a centrifuge 1; a thickener 2; a mother liquor tank 3; a precision filter 4; a centrifugal pump 5; a washing tank 6; a plate and frame filter press 7; a beating tank 8; an iron remover 9; a waste tank 10, and the outlet of the centrifuge 1 is communicated with the inlet of the washing tank 6 through a pipeline, the outlet pipeline of the washing tank 6 is communicated with the inlet of the plate and frame filter press 7 through a centrifugal pump, the filter material outlet of the plate and frame filter press 7 is communicated with the inlet of the beating tank 8, the outlet of the beating tank 8 is communicated with the inlet of the iron remover 9 through a centrifugal pump, and the outlet of the iron remover 9 is respectively communicated with the inlet of the beating tank 8 and the inlet of the centrifuge 1 through a pipeline. The filtrate outlet of the plate and frame filter press 7 and the clear liquid outlet of the thickener 2 are respectively communicated with the inlet of the mother liquor tank 3 through a pipeline, the outlet of the mother liquor tank 3 is communicated with the inlet of the precision filter 4 through a centrifugal pump, the filter material outlet of the precision filter 4 is communicated with the inlet of the waste tank 10 through a pipeline, and the outlet of the waste tank 10 is communicated with the inlet of the centrifuge 1 through a centrifugal pump.

[0038] The method for collecting the centrifuge running material by using the above device is as follows:

[0039] The small particle material in the material in the centrifuge 1 penetrates the filter cake layer into the washing tank 6, the liquid in the washing tank 6 is pumped into the plate and frame filter press 7 through the centrifugal pump 5, the clear liquid from the plate and frame filter press 7 flows to the mother liquor tank 3, and is mixed together with the clear liquid from the thickener 2 in the mother liquor tank 3, and is intercepted by the precision filter 4 through the centrifugal pump 5, the clear liquid is sent to the auxiliary workshop, the intercepted material is adsorbed on the filter core, when the pressure difference of the precision filter 4 becomes small, the precision filter 4 is backwashed and forward washed by compressed air and pure water, the swept material enters the waste tank 10, and the material is normally washed out by the centrifuge 1 for blending. The material in the plate and frame filter press 7 is unloaded into the beating tank 8, the material in the beating tank 8 is circulated into the iron remover 9 through the centrifugal pump 5 to reduce the magnetic foreign matter, when the magnetic foreign matter is qualified, it is put into the centrifuge 1 through the centrifugal pump 5, and the material is normally washed out by the centrifuge 1 for blending.

[0040] Experimental results

[0041] Before the modification (such as the method in the comparative example), to produce a 4um particle size product:

[0042] 1. The centrifuge run-off filter amount is about 8%, such as producing 100 tons of product, 8 tons of centrifugal run-off filter material will be produced.

[0043] 2. The thickener clear run material during the reaction process is about 0.5%, such as producing 100 tons of product, about 500 kilograms of fine powder material with very small particle size will be produced.

[0044] 3. Producing 100 tons of product, a total of 8500 kilograms of mixed fine powder unqualified material is produced, mixed at a ratio of about 15:1, 100 tons of product can be mixed with 6700 kilograms of unqualified material, and finally about 1800 kilograms of material cannot be processed.

[0045] After the modification (such as the method in the embodiment), to produce a 4um particle size product:

[0046] 1. The centrifuge run-off filter amount is about 8%, such as producing 100 tons of product, 8 tons of centrifugal run-off filter material will be produced. Since the centrifuge clear liquid and the thickener clear liquid are processed differently, the filter material and the filtrate obtained by centrifugal processing can all be mixed, that is, 8 tons of centrifugal run-off filter material can be directly dried together with qualified products.

[0047] 2. The thickener clear run material during the reaction process is about 0.5%, such as producing 100 tons of product, about 500 kilograms of fine powder material with very small particle size will be produced. Under the premise of ensuring product quality, the material is difficult to mix, about 100:0.3, that is, 100 tons of product can be mixed with 300 kilograms, and the remaining 200 kilograms is used as an intermediate product. As can be seen, the scheme provided by the embodiment can greatly improve the recycling rate of run-off material, especially the centrifuge run-off material.

[0048] In summary, the embodiment of the present application provides a method and device for improving the centrifugal run-off collection of lithium battery precursors. Since the centrifugal run-off is a normal material that has passed the reaction, it can be mixed in large quantities, and the normal material on the production line can be mixed normally. The material discharged by the thickener is only a small amount of material during the reaction process, which can only be mixed in a small amount. The purpose of the present application is to add a device to distinguish between centrifugal run-off and thickener clear material, so that centrifugal run-off is fully mixed, and thickener clear material is partially mixed. Thus, the centrifugal run-off material and the normal centrifugal washing material can be mixed in large quantities, and a small part of the thickener clear run material is used, thereby reducing the amount of intermediate product.

[0049] The above merely describes the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for improving the collection of centrifugal materials that have been lost in lithium battery precursors, characterized in that, include: The filtrate obtained by washing and pressing the centrifuge effluent with water and then filtering it is mixed with the thickener effluent to obtain a mixed liquid. The first material obtained by filtering and separating the mixed liquid is returned to the centrifuge for washing. The washed material I is returned to the production line and mixed with the lithium battery precursor obtained by normal reaction for use. The filter material obtained by washing and pressing the effluent from the centrifuge is then pulped and iron removed to obtain a second material. The second material is then returned to the centrifuge for washing, and the washed material II is mixed as a normal material on the production line. Material I obtained from washing in the centrifuge is returned to the production line for blending, while material II is blended as normal material on the production line. After the centrifuge effluent is washed in a washing tank, it is pumped into a plate and frame filter press by a centrifugal pump and filtered in the plate and frame filter press to obtain filtrate. Then, the filtrate filtered by the plate and frame filter press and the thickener effluent are discharged into a mother liquor tank to obtain a mixed liquid. The mixed liquid in the mother liquor tank is pumped into a precision filter by a centrifugal pump. The first material and the first filtrate are obtained by filtering and separating in the precision filter. The first material is then sent into a waste tank for storage, and then sent into the centrifuge for washing. The washed material I is returned to the production line and mixed with the lithium battery precursor obtained by normal reaction. The first filtrate is sent to the auxiliary workshop for processing. The filter media obtained by washing and pressing the centrifuge effluent is pulped in a pulping tank to obtain slurry. The slurry is then fed into an iron remover to remove iron and obtain the second material. The slurry in the pulping tank is pumped into the iron separator by a centrifugal pump. The slurry circulates between the iron separator and the pulping tank until a second material with qualified magnetic foreign matter is obtained. The second material is then returned to the centrifuge for washing. The washed material II is then mixed as a normal material on the production line.

2. A device for improving the collection of centrifugal materials that have been lost in the process of lithium battery precursors, characterized in that, include: Centrifuge; Thickener; Mother liquor tank; Precision filters; Centrifugal pump; Washing sink; Plate and frame filter press; Pulping tank; Iron separator; The centrifuge outlet is connected to the inlet of the washing tank via a pipeline, the washing tank outlet is connected to the inlet of the plate and frame filter press via a pipeline, the filtrate outlet of the plate and frame filter press and the clear liquid outlet of the thickener are respectively connected to the inlet of the mother liquor tank via pipelines, the mother liquor tank outlet is connected to the inlet of the precision filter via a pipeline, the precision filter media outlet is connected to the inlet of the waste tank via a pipeline, and the waste tank outlet is connected to the inlet of the centrifuge via a pipeline.

3. The apparatus according to claim 2, characterized in that, Also includes: The filter media outlet of the plate and frame filter press is connected to the inlet of the pulping tank via a pipeline, the outlet of the pulping tank is connected to the inlet of the iron remover via a pipeline, and the outlet of the iron remover is connected to the inlet of the pulping tank and the inlet of the centrifuge via pipelines.

4. The apparatus according to claim 2, characterized in that, A centrifugal pump is installed on the pipeline between the washing tank and the plate and frame filter press; a centrifugal pump is installed on the pipeline between the pulping tank and the iron remover; a centrifugal pump is installed on the pipeline between the mother liquor tank and the precision filter; and a centrifugal pump is installed on the pipeline between the waste tank and the centrifuge.

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