System for continuously extracting lithium by using waste electrolyte

Abstract

The utility model discloses a system for continuously extracting lithium by utilizing waste electrolyte. The system comprises a control center, a continuous ball milling device, a cascade reaction kettle and a drying and packaging device, the cascade reaction kettle comprises N cascade reaction kettles and a reaction liquid overflow tank; n > = 3; n is an integer; the reaction kettles are sequentially hung on a public reaction liquid overflow tank; the plurality of reaction kettles are sequentially arranged from high to low; a stirring mechanism is arranged in the reaction kettle; the first reaction kettle is provided with a reaction liquid overflow pipeline; the rest reaction kettles are respectively provided with a reaction kettle inflow pipeline and a reaction liquid overflow pipeline; the reaction kettle inflow pipeline and the reaction liquid overflow pipeline are respectively provided with a first electric control valve; a plurality of second electric control valves are arranged on the reaction liquid overflow tank; the first electric control valve and the second electric control valve are both controlled by a field controller; the controller is in communication connection with the control center; the system disclosed by the utility model can realize continuous lithium extraction and is easy to control the whole process.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of system for continuously extracting lithium using waste electrolyte. BACKGROUND

[0002] There are three traditional methods for extracting lithium:

[0003] 1. Extracting lithium from lithium ore (lithium spodumene); the English name of lithium spodumene is: spodumene; spodumene, the composition content is: LiAl (SiO3) 2 or Li2O·Al2O3·4SiO2, the theoretical lithium content is 3.75% (lithium oxide 8.04%). As a lithium chemical raw material, it is widely used in lithium chemical industry, glass and ceramic industry, and enjoys the reputation of "industrial monosodium glutamate".

[0004] 2. Extracting lithium from salt lake

[0005] The technology of extracting lithium from salt lake has been developed since the 1970s. In the 1990s, foreign companies made a breakthrough in brine lithium extraction technology, and the production cost of lithium carbonate was much lower than that of ore extraction. Brine lithium extraction has become a major trend in future development.

[0006] The main methods of extracting lithium from salt lake include precipitation method, salt gradient solar pond method, nanofiltration and electrodialysis method, extraction method, adsorption method, one lake one method and multi-method coupling, etc. (see "discard stone into gold" - a brief description of the process of extracting lithium from salt lake, https: / / www.sohu.com / a / 484409571_121124376)

[0007] 3. Recycling and extracting lithium carbonate from lithium batteries

[0008] With the rapid development of new energy vehicles, the demand for lithium is also growing rapidly. China's dependence on foreign lithium resources has been around 70% for a long time, and it is necessary to vigorously protect self-sufficiency. How to efficiently and low-cost find suitable lithium sources is also the goal of the industry, and waste aluminum electrolyte is one of the goals. The production of electrolytic aluminum industry usually adopts cryolite-alumina fused salt electrolysis method, and the aluminum electrolyte is composed of cryolite (Na3AlF6), alumina (Al2O3) and other salt additives (such as AlF3, CaF2, MgF2, LiF), and lithium elements are embedded in the form of solid solution. However, the long-term accumulation of high-lithium salt content electrolyte system will cause low electrolytic cell temperature, poor alumina solubility, and many electrolytic cell bottom precipitates, poor stability of aluminum electrolytic cell, etc. Therefore, in order to make the electrolytic cell run normally and stably, the level and total amount of electrolyte must be controlled. The electrolytic cell usually needs to precipitate excess electrolyte to control its balance after a period of operation. The part of electrolyte precipitated is waste aluminum electrolyte. According to the "National Hazardous Waste Directory" (2021 edition), this type of waste is not a hazardous waste.

[0009] The power of new energy vehicles mainly comes from lithium ion battery packs, and therefore the recycling of waste lithium ion batteries has become the primary problem to be solved in the lithium battery industry.

[0010] The recycling steps of the waste lithium ion batteries currently are: ① preparing lithium-containing fluorine slag; ② after the lithium-containing fluorine slag is slurried with water, a leaching agent is added to dissolve lithium in the lithium-containing fluorine slag in water, filtration is performed, and a crude lithium solution is obtained; ③ an alkali reagent is used to adjust the pH value to remove impurities in the crude lithium solution, and a refined lithium solution is obtained, ④ a carbonate is added to the refined lithium solution for precipitation, and a crude lithium carbonate is obtained. The lithium carbonate is a key material for synthesizing lithium iron phosphate, and the lithium iron phosphate is mainly used in various lithium ion batteries, and therefore the recycling and synthesis of the lithium carbonate play a key role in the recycling and reuse of the lithium ion batteries. However, the current recycling method has the following disadvantages: ① poor safety in the battery disassembly process; ② easy introduction of metal impurities in the process of preparing lithium fluorine slag from disassembled batteries; ③ complex impurity removal process; and ④ high recycling cost and low recycling efficiency.

[0011] Therefore, it is necessary to design a new system for extracting lithium from waste electrolyte. Content of the utility model

[0012] The utility model solves the technical problem of providing a system for continuously extracting lithium from waste electrolyte, which adopts a cascade of reaction kettles to facilitate the implementation of a continuous lithium extraction process and facilitate control.

[0013] The technical solution of the utility model is as follows:

[0014] A system for continuously extracting lithium from waste electrolyte, comprising a control center, a continuous ball mill device, a cascade of reaction kettles, and a drying and packaging device;

[0015] The continuous ball mill device, the cascade of reaction kettles, and the drying and packaging device are all controlled by the control center.

[0016] The cascade of reaction kettles comprises N reaction kettles and a reaction liquid overflow tank; N is an integer; each reaction kettle is sequentially connected to a common reaction liquid overflow tank; and the reaction kettles are arranged from high to low.

[0017] The reaction kettles are provided with stirring mechanisms; the first reaction kettle is provided with a reaction liquid overflow pipeline; the remaining reaction kettles are each provided with a reaction kettle inflow pipeline and a reaction liquid overflow pipeline; the reaction kettle inflow pipeline and the reaction liquid overflow pipeline are each provided with a first electric control valve; the reaction liquid overflow tank is provided with a plurality of second electric control valves; the first electric control valves and the second electric control valves are each controlled by a local controller; and the controller is in communication connection with the control center.

[0018] The second electric control valves can be three-way valves.

[0019] N is 8-12. The lithium extraction process includes continuous sodium removal, continuous lithium extraction, continuous deep impurity removal, continuous lithium precipitation, etc. Each link corresponds to 1-2 reaction kettles, and at least 2 reaction kettles are reserved for standby.

[0020] It also includes a cloud server, which is in communication connection with the control center through a communication module.

[0021] The reaction kettle includes a kettle body and a stirring mechanism arranged in the kettle body.

[0022] A reaction liquid flow guide mechanism is arranged in the kettle body.

[0023] A feeding pipe is further arranged in the kettle body.

[0024] A reaction kettle inflow pipe and a reaction liquid overflow pipe of the first electric control valve are arranged on the kettle wall of the kettle body.

[0025] A heating device is arranged in the kettle body.

[0026] The first electric control valve and the heating device are controlled by the controller.

[0027] The reaction liquid flow guide mechanism is multiple; the reaction liquid flow guide mechanism is a vertical flow guide pipe, and the bottom of the flow guide pipe is in communication with the bottom of the kettle body.

[0028] The stirring mechanism has multiple layers of paddles.

[0029] A chamfer is arranged around the inner bottom surface of the reaction kettle. That is, the inner bottom of the reaction kettle is a conical bottom.

[0030] The feeding pipe is multiple, and the feeding pipe is a vertical pipe. The discharge outlets of the multiple feeding pipes are located at different depths in the kettle body. Not shown in the figure. It is convenient to add substances with different densities. The denser the substance, the deeper the feeding pipe.

[0031] Due to the height difference between different reaction kettles, if the adjacent reaction kettles are completely staggered, the slurry in the reaction kettle passes through the reaction liquid overflow pipe and the reaction liquid overflow groove to enter the next stage reaction kettle. It can also directly enter the next stage reaction kettle through the pipe with the electric control valve, and utilize the potential energy difference of the two reaction kettles and the principle of the communicating vessel to transfer the slurry.

[0032] A temperature sensor is further arranged in the reaction kettle, and the temperature sensor is connected with the controller. The control center is an industrial computer arranged in the main control room.

[0033] Advantages:

[0034] The system for continuously extracting lithium by using waste electrolyte of the utility model adopts the cascade reaction kettle to realize the continuous lithium extraction process, so that each process can correspond to 1-2 special reaction kettles, which is beneficial to improve the robustness of the system, and a standby reaction kettle is arranged, and once unpredictable problems occur in any link, the whole process can be adjusted on site, and each reaction kettle can complete all reaction links. When abnormal conditions such as material change, equipment failure, human factors and the like occur, the subsequent reaction kettle can also complete the remaining reaction. Therefore, compared with the single reaction kettle without cascade, the system has the advantage of higher reliability.

[0035] The reaction kettle is provided with multiple layers of stirring paddles, which is beneficial to sufficient stirring, multiple flow guide devices are arranged in the kettle body, which is beneficial to sufficient reaction, multiple reaction kettles share one overflow tank, the flow direction of the slurry and which reaction kettle participates in the reaction are controlled through electric control valves, and the continuous lithium extraction process is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a cascade schematic view (front view) of 8 reaction kettles;

[0037] Figure 2 It is a reaction kettle structure schematic view (front view);

[0038] Figure 3 It is a reaction kettle and overflow tank connection view (top view);

[0039] Figure 4 It is a system block diagram.

[0040] Label explanation: 1-reaction kettle, 2-reaction liquid overflow tank, 3-reaction liquid inflow pipeline, 4-reaction liquid outflow pipeline, 5-first electric control valve, 6-second electric control valve, 7-stirring mechanism, 8-reaction liquid flow guide mechanism, 9-feeding pipe. DETAILED DESCRIPTION

[0041] The utility model will be further explained in detail in combination with the drawings and specific embodiments:

[0042] Embodiment 1: as Figures 1-4 A system for continuously extracting lithium by using waste electrolyte, comprising a control center, a continuous ball mill device, a cascade reaction kettle, a drying and packaging device;

[0043] The continuous ball mill device, the cascade reaction kettle and the drying and packaging device are controlled by the control center.

[0044] The cascade reaction kettle comprises 8 cascade reaction kettles and a reaction liquid overflow groove; each reaction kettle is sequentially connected to a common reaction liquid overflow groove; the plurality of reaction kettles are sequentially arranged from high to low; the lithium extraction process comprises the steps of continuous sodium removal, continuous lithium extraction, continuous deep impurity removal, continuous lithium precipitation, etc., each step corresponds to 2 reaction kettles, and 2 standby reaction kettles can be further arranged.

[0045] The reaction kettle is provided with a stirring mechanism; the first reaction kettle is provided with a reaction liquid overflow pipeline; the remaining reaction kettles are provided with a reaction kettle inflow pipeline and a reaction liquid overflow pipeline; the reaction kettle inflow pipeline and the reaction liquid overflow pipeline are provided with a first electric control valve; the reaction liquid overflow groove is provided with a plurality of second electric control valves; the first electric control valve and the second electric control valve are controlled by a local controller; the controller is in communication connection with a control center; the controller is a DSP or PLC processor, and is used for realizing local control of the reaction kettle.

[0046] The second electric control valve can be a three-way valve.

[0047] The control center is in communication connection with a cloud server through a communication module.

[0048] The reaction kettle comprises a kettle body and a stirring mechanism arranged in the kettle body;

[0049] The kettle body is provided with a reaction liquid flow guide mechanism;

[0050] The kettle body is further provided with a feeding pipe;

[0051] The kettle wall of the kettle body is provided with a reaction kettle inflow pipeline and a reaction liquid overflow pipeline of the first electric control valve;

[0052] The kettle body is internally provided with a heating device;

[0053] The first electric control valve and the heating device are controlled by a controller; the reaction kettle is further provided with a temperature sensor connected with the controller; the temperature sensor is used in cooperation with the heating device to ensure that the reaction temperature in the reaction kettle is constant within a preset range, and the reaction is efficiently carried out.

[0054] The reaction liquid flow guide mechanism is a plurality of vertical flow guide pipes, and the bottom of the flow guide pipe is in communication with the bottom of the kettle body. The plurality of reaction liquid flow guide mechanisms facilitate the rapid entry and exit of the reaction liquid into the reaction kettle, and are also beneficial to the full reaction.

[0055] The stirring mechanism has a plurality of layers of paddles, which facilitates more sufficient stirring.

[0056] The inside bottom of the reaction kettle is provided with a chamfered corner, i.e., the inside bottom of the reaction kettle is a conical bottom.

[0057] The feed pipe is multiple, the feed pipe is a vertical pipe, and the discharge outlets of the multiple feed pipes are located at different depths in the kettle body; not shown in the figure. It is convenient to add substances with different densities, and the substances with greater density are added from the feed pipe with greater depth.

[0058] The reaction kettle has the following characteristics:

[0059] 1. The reaction kettle is arranged in 8 or more rows (including 8), and when applied to continuous reaction, any 3 or more of the reaction kettles can complete the reaction, and the reaction kettles can be switched at any time. The controller can switch which reaction kettle is put into use through the first electric control valve and the second control valve, and can also control whether the reaction liquid passes through or bypasses a certain reaction kettle through the second valve.

[0060] 2. The reaction kettles are arranged from high to low to save energy consumption.

[0061] 3. The reaction kettle inlets are arranged at upper, middle and lower positions of the kettle body. The heavy material inlet is arranged at the upper position, and the light material is fed from the lower position, which is beneficial to the uniformity of the material reaction.

[0062] 4. A plurality of flow guide devices are arranged inside the reaction kettle, which is beneficial to the full reaction.

[0063] 5. The reaction liquid overflow outlet is generally arranged at the upper middle part of the kettle body, and the qualified liquid specific gravity of the solid-liquid phase reaction is generally smaller than that of the solid phase.

[0064] 6. The inlet and outlet of each reaction kettle are arranged with an automatic controllable baffle for controlling the flow and opening and closing.

[0065] 7. The peripheral bottom surface of the reaction kettle is provided with a chamfer to prevent material deposition.

[0066] 8. The reaction kettle is provided with a heating device.

[0067] 9. The reaction kettle is provided with stirring, which is generally provided with multiple layers of paddles to facilitate the full mixing reaction of materials with different specific gravities.

[0068] Any modification, equivalent replacement and improvement within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims

1. A system for continuous lithium extraction using a waste electrolyte, characterized by, The control center, the continuous ball mill device, the cascade reaction kettle, the drying and packaging device are all controlled by the control center. The continuous ball mill device, the cascade reaction kettle, the drying and packaging device are all controlled by the control center. The cascade reaction kettle comprises N cascade reaction kettles and a reaction liquid overflow groove; N≥3; N is an integer. The reaction kettles are sequentially connected to the common reaction liquid overflow groove; the reaction kettles are arranged from high to low. The reaction kettle is provided with a stirring mechanism; the first reaction kettle is provided with a reaction liquid overflow pipeline; the remaining reaction kettles are provided with a reaction kettle inflow pipeline and a reaction liquid overflow pipeline; the reaction kettle inflow pipeline and the reaction liquid overflow pipeline are provided with first electric control valves; the reaction liquid overflow groove is provided with a plurality of second electric control valves; the first electric control valves and the second electric control valves are controlled by the on-site controller; the controller is in communication connection with the control center.

2. The system for continuous lithium extraction using waste electrolyte according to claim 1, characterized in that, N is 8-12.

3. The system for continuous lithium extraction using waste electrolyte according to claim 1, characterized in that, The cloud server is further provided; the cloud server is in communication connection with the control center through the communication module.

4. The system for continuous lithium extraction using waste electrolyte according to claim 1, wherein, The reaction kettle comprises a kettle body and a stirring mechanism (7) arranged in the kettle body; The kettle body is provided with a reaction liquid flow guide mechanism (8); The kettle body is further provided with a feeding pipe (9); The kettle wall of the kettle body is provided with a reaction kettle inflow pipeline (3) and a reaction liquid overflow pipeline (4) of the first electric control valve (5); The kettle body is provided with a heating device; The first electric control valve and the heating device are controlled by the controller.

5. The system for continuous lithium extraction using a waste electrolyte according to claim 1, wherein, The reaction liquid flow guide mechanism is a plurality of vertical flow guide pipes, and the bottom of the flow guide pipe is in communication with the bottom of the kettle body.

6. The system for continuous lithium extraction using a waste electrolyte according to claim 1, wherein, The stirring mechanism has a plurality of layers of paddles.

7. The system for continuous lithium extraction using a waste electrolyte according to claim 1, wherein, The internal bottom surface of the reaction kettle is provided with a chamfered corner.

8. The system for continuous lithium extraction using waste electrolyte according to any one of claims 1-7, characterized in that, The feeding pipe is a plurality of vertical pipes, and the discharge ports of the plurality of feeding pipes are located at different depths in the kettle body.

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