Graded continuous lithium extraction reaction system

Abstract

The utility model discloses a graded continuous lithium extraction reaction system which comprises a plurality of reaction kettles (1), the reaction kettles are divided into M groups, and M is greater than or equal to 4; m is an integer; the M groups of reaction kettles are arranged in a stepped manner; at least two reaction kettles are arranged in each group; each group of reaction kettles are connected through a reaction liquid overflow tank (2); each reaction kettle is provided with a reaction kettle inflow pipeline (3) and a reaction liquid overflow pipeline (4); the reaction kettle inflow pipeline and the reaction liquid overflow pipeline are respectively provided with a first electric control valve (5); a plurality of second electric control valves (6) are arranged on the reaction overflow tank; the reaction liquid overflow tanks of the adjacent groups of reaction kettles are communicated through a connecting pipeline (10) with a third electric control valve (11); and the first electric control valve, the second electric control valve and the third electric control valve are all controlled by a field controller. The graded continuous lithium extraction reaction system disclosed by the utility model can realize continuous lithium extraction, and is novel in layout and easy to control.

Description

Technical Field

[0001] This utility model relates to a staged continuous lithium extraction reaction system. Background Technology

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

[0003] 1. Lithium is extracted from lithium ore (spodumene); spodumene, also known as lithium ore, is composed of LiAl(SiO3)2 or Li2O·Al2O3·4SiO2, with a theoretical lithium content of 3.75% (8.04% lithium oxide). As a raw material for lithium chemicals, it is widely used in the lithium chemical, glass, and ceramic industries, and enjoys the reputation of being "industrial MSG".

[0004] 2. Lithium extraction from salt lakes

[0005] Lithium extraction technology from salt lakes began to be developed in the 1970s. In the 1990s, foreign companies made breakthroughs in brine lithium extraction technology. The production cost of lithium carbonate is much lower than that of lithium extraction from ore, and brine lithium extraction has become a major trend for future development.

[0006] The main methods for lithium extraction from salt lakes include precipitation, salt gradient solar pond method, nanofiltration and electrodialysis, extraction, adsorption, one method per lake, and coupling of multiple methods (see: "Turning Rocks into Gold" - A Brief Introduction to Lithium Extraction Processes from Salt Lakes, https: / / www.sohu.com / a / 484409571_121124376).

[0007] 3. Lithium carbonate extraction from lithium batteries

[0008] With the rapid development of new energy vehicles, the demand for lithium is also growing rapidly. China's dependence on imported lithium resources has long been around 70%, necessitating a strong push to ensure self-sufficiency. Finding suitable lithium sources efficiently and at low cost is a goal pursued by the industry, and waste aluminum electrolyte is one such target. Electrolytic aluminum production typically employs the cryolite-alumina molten salt electrolysis method. The aluminum electrolyte is composed of cryolite (Na3AlF6), alumina (Al2O3), and other salt additives (such as AlF3, CaF2, MgF2, and LiF), with lithium elements embedded in the electrolyte as a solid solution. However, the high lithium salt content in the electrolyte system accumulated over a long period can lead to low electrolytic cell temperature, poor alumina dissolution capacity, excessive sedimentation at the bottom of the electrolytic cell, and poor stability of the aluminum electrolytic cell. Therefore, to ensure the normal and stable operation of the electrolytic cell, the electrolyte level and total amount must be controlled. Electrolytic cells that have been operating for a period of time usually require the precipitation of excess electrolyte to maintain their balance; this precipitated electrolyte is known as waste aluminum electrolyte.

[0009] The power of new energy vehicles mainly comes from lithium-ion battery packs, so the recycling and disposal of waste lithium-ion batteries has become the primary issue that the lithium battery industry needs to address.

[0010] The current recycling steps for waste lithium-ion batteries are: ① preparing lithium-fluorine slag; ② mixing the lithium-fluorine slag with water to form a slurry, adding a leaching agent to dissolve the lithium in the slag in the water, filtering to obtain a crude lithium solution; ③ adjusting the pH value with an alkaline reagent to remove impurities from the crude lithium solution to obtain a refined lithium solution; ④ adding carbonate to the refined lithium solution for precipitation to obtain crude lithium carbonate. Lithium carbonate is a key material for synthesizing lithium iron phosphate, which is mainly used in various lithium-ion batteries. Therefore, recycling and synthesizing lithium carbonate plays a crucial role in the recycling and reuse of lithium-ion batteries. However, current recycling methods have the following drawbacks: ① poor safety during battery dismantling; ② the process of preparing lithium-fluorine slag from dismantling batteries easily introduces metallic impurities; ③ complex impurity removal processes; ④ high recycling costs and low recycling efficiency.

[0011] Therefore, it is necessary to design a new system for lithium extraction using waste electrolytes. Utility Model Content

[0012] The technical problem to be solved by this utility model is to provide a staged continuous lithium extraction reaction system. This staged continuous lithium extraction reaction system adopts cascaded reaction vessels, which facilitates the realization of a continuous lithium extraction process and is easy to control.

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

[0014] A staged continuous lithium extraction reaction system includes multiple reaction vessels, which are divided into M groups, where M ≥ 4; M is an integer.

[0015] The reactors in group M are arranged in a stepped manner; each group has at least 2 reactors; each group of reactors is connected by a reaction liquid overflow tank; each reactor has a reactor inlet pipe and a reaction liquid overflow pipe; both the reactor inlet pipe and the reaction liquid overflow pipe are equipped with a first electrically controlled valve.

[0016] Multiple second electrically controlled valves are installed on the reaction overflow tank;

[0017] The reaction liquid overflow tanks of adjacent reactors are connected by a connecting pipe with a third electrically controlled valve.

[0018] The first, second, and third solenoid valves are all controlled by a field controller.

[0019] M=4; the four sets of reactors are sodium removal reactor, lithium extraction reactor, impurity removal reactor and lithium precipitation reactor; the distance between adjacent sets of reactors is not less than the height of the reactor body.

[0020] The reactor includes a vessel body and a stirring mechanism installed inside the vessel body; a reaction liquid guiding mechanism is installed inside the vessel body; a feeding pipe is also installed inside the vessel body; the vessel body wall is equipped with a reactor inlet pipe and a reaction liquid overflow pipe with a first electrically controlled valve; a heating device is installed inside the vessel body.

[0021] The stirring mechanism and heating device are both controlled by a controller.

[0022] There are multiple reaction liquid guiding mechanisms; the reaction liquid guiding mechanism is a vertical guiding pipe, and the bottom of the guiding pipe is connected to the bottom of the vessel.

[0023] The stirring mechanism has multiple layers of blades; the bottom surface of the reactor is chamfered; there are multiple feed pipes, which are vertical pipes, and the outlets of the multiple feed pipes are located at different depths inside the reactor.

[0024] The reactor is also equipped with a temperature sensor, which is connected to the controller. The control center is an industrial computer located in the main control room.

[0025] Beneficial effects:

[0026] This utility model's staged continuous lithium extraction reaction system employs a stepped cascaded reactor to achieve a continuous lithium extraction process. Each process can correspond to 2-3 dedicated reactors (including one backup reactor), which improves system robustness. The backup reactor allows for on-site adjustments to the entire process should any unforeseen problem occur in any stage. Each reactor can complete all reaction stages. Even in the event of abnormal situations such as material changes, equipment failure, or human error, subsequent reactors can still complete the remaining reactions. Therefore, compared to separate, non-cascaded reactors, it offers significantly higher reliability.

[0027] Using this method, the primary reactor can also be directly removed from the entire system, effectively improving the overall system's resilience.

[0028] In addition, the reactor is equipped with multi-layered stirring blades, which is conducive to thorough mixing. Multiple flow guiding devices are installed inside the reactor to facilitate complete reaction. Multiple reactors share a single overflow tank. The flow direction of the slurry and which reactor participates in the reaction are controlled by electronically controlled valves, which facilitates continuous lithium extraction process. Attached Figure Description

[0029] Figure 1 A schematic diagram (top view) of 12 cascaded reactors;

[0030] Figure 2 Side view of the stepped arrangement of the four-stage reactor;

[0031] Figure 3 This is a schematic diagram of the reactor structure (front sectional view);

[0032] Figure 4 Top view showing the connection between the reactor and the overflow tank;

[0033] Figure 5 This is the system's electrical control block diagram.

[0034] Labeling explanations: 1-Reaction vessel, 2-Reaction liquid overflow tank, 3-Reaction liquid inflow pipe, 4-Reaction liquid outflow pipe, 5-First solenoid valve, 6-Second solenoid valve, 7-Stirring mechanism, 8-Reaction liquid guiding mechanism, 9-Feeding pipe, 10-Connecting pipe, 11-Third solenoid valve. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0036] Example 1: As Figure 1-5 A staged continuous lithium extraction reaction system, characterized in that it includes 12 reaction vessels 1, which are divided into 4 groups;

[0037] The four sets of reactors are arranged in a stepped manner; each set consists of three reactors (including one spare reactor); each set of reactors is connected by a reaction liquid overflow tank 2; each reactor has a reactor inlet pipe 3 and a reaction liquid overflow pipe 4; both the reactor inlet pipe and the reaction liquid overflow pipe are equipped with a first electrically controlled valve 5;

[0038] Multiple second electrically controlled valves 6 are installed on the reaction overflow tank;

[0039] The reaction liquid overflow tanks of adjacent reactors are connected by a connecting pipe 10 with a third electrically controlled valve 11.

[0040] The first, second, and third solenoid valves are all controlled by a field controller.

[0041] The four sets of reactors are sodium removal reactor, lithium extraction reactor, impurity removal reactor, and lithium precipitation reactor; the distance between adjacent sets of reactors is not less than the height of the reactor body.

[0042] The processes corresponding to the sodium removal reactor, lithium extraction reactor, impurity removal reactor, and lithium precipitation reactor are as follows:

[0043] Step 1: Sodium Removal Step; Add bottom water to the sodium removal reactor, transfer the ball-milled slurry (slurry after ball milling raw material waste aluminum electrolyte) into the sodium removal reactor and start stirring; heat the slurry in the sodium removal reactor to 25-100℃; then add lime milk and stir, so that the lime milk reacts with the slurry, and a precipitate is obtained after the reaction; Step 2: Continuous Lithium Extraction Step; In the continuous lithium extraction reactor, prepare insoluble solids and water at a mass ratio of 1:0.5-10, start stirring, and add sulfuric acid; convert aluminum sulfate into insoluble aluminum hydroxide and calcium sulfate precipitates; Step 3: Impurity Removal Step; Step 4: Lithium Precipitation Step; Add the impurity-removed lithium sulfate solution and soda ash solution to the continuous lithium precipitation reactor, heat to carry out the lithium precipitation reaction, so that lithium carbonate precipitates;

[0044] After solid-liquid separation, lithium carbonate and lithium precipitation mother liquor were obtained.

[0045] The reactor includes a vessel body and a stirring mechanism 7 installed inside the vessel body; a reaction liquid guiding mechanism 8 is provided inside the vessel body; a feeding pipe 9 is also provided inside the vessel body; a reactor inflow pipe 3 with a first electrically controlled valve 5 and a reaction liquid overflow pipe 4 are provided on the vessel wall of the vessel body; a heating device is provided inside the vessel body.

[0046] The stirring mechanism and heating device are both controlled by a controller.

[0047] The reaction liquid guiding mechanism consists of multiple vertical guide pipes, the bottom of which is connected to the bottom of the reactor body. The stirring mechanism has multiple layers of blades; the bottom surface of the reactor body is chamfered; there are multiple feed pipes, which are vertical, and the outlets of the multiple feed pipes are located at different depths inside the reactor body.

[0048] The controller is a DSP or PLC processor used to achieve on-site control of the reactor.

[0049] The second electrically controlled valve can be a three-way valve.

[0050] It also includes communication with cloud servers, and the cloud servers and control center communicate with each other via a communication module.

[0051] The reactor is also equipped with a temperature sensor, which is connected to the controller. The temperature sensor works in conjunction with the heating device to ensure that the reaction temperature inside the reactor remains constant within a preset range, guaranteeing efficient reaction.

[0052] The reactor has multiple reaction liquid guiding mechanisms; each mechanism is a vertical guiding pipe, with its bottom connected to the bottom of the reactor body. The multiple mechanisms facilitate the rapid entry and exit of the reaction liquid from the reactor, and also promote the complete progress of the reaction.

[0053] The bottom surface of the reactor interior is chamfered, meaning the bottom of the reactor interior is conical.

[0054] There are multiple vertical feed pipes, and the outlets of these feed pipes are located at different depths within the reactor vessel; these are not shown in the diagram. This allows for the addition of substances of different densities, with denser substances being added from the deeper feed pipes.

[0055] Features of the reaction vessel of this utility model:

[0056] 1. The reactors are grouped and arranged in stages, allowing for easy switching when used in continuous reactions. The controller can switch which reactor is in use via a first electrically controlled valve and a second control valve. It can also control whether the reaction liquid passes through or bypasses a particular reactor by controlling the second valve.

[0057] 2. The multi-stage reactors are arranged from high to low to save energy.

[0058] 3. The reactor inlets are located at the top, middle, and bottom of the reactor body. This arrangement, with the heavy materials entering from the top and the light materials from the bottom, promotes uniformity in the material reaction.

[0059] 4. Multiple flow guiding devices are arranged inside the reactor to facilitate a complete reaction.

[0060] 5. The overflow port of the reaction liquid is generally located in the upper middle part of the vessel. Generally, the specific gravity of the qualified liquid in the solid-liquid phase reaction is smaller than that of the solid phase.

[0061] 6. Each reactor inlet and outlet is equipped with an automatically controllable baffle to control flow rate and opening / closing.

[0062] 7. The bottom surface of the reactor is chamfered to prevent material from settling.

[0063] 8. A heating device is installed inside the reactor.

[0064] 9. The reactor is equipped with a stirrer, usually with multiple layers of paddles, to ensure that materials of different specific gravities are fully mixed and reacted.

[0065] Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model shall be included within the protection scope of this utility model.

Claims

1. A staged continuous lithium extraction reaction system, characterized in that, It includes multiple reaction vessels (1), the reaction vessels are divided into M groups, M≥4; M is an integer; The M group of reactors is arranged in a stepped manner; each group has at least 2 reactors; each group of reactors is connected by a reaction liquid overflow tank (2); each reactor has a reactor inlet pipe (3) and a reaction liquid overflow pipe (4); both the reactor inlet pipe and the reaction liquid overflow pipe are equipped with a first electrically controlled valve (5); Multiple second electrically controlled valves (6) are installed on the reaction overflow tank; The reaction liquid overflow tanks of adjacent reactors are connected by a connecting pipe (10) with a third electrically controlled valve (11); The first, second, and third solenoid valves are all controlled by a field controller.

2. The staged continuous lithium extraction reaction system according to claim 1, characterized in that, M=4; the four sets of reactors are sodium removal reactor, lithium extraction reactor, impurity removal reactor and lithium precipitation reactor; the distance between adjacent sets of reactors is not less than the height of the reactor body.

3. The staged continuous lithium extraction reaction system according to claim 1, characterized in that, The reactor includes a vessel body and a stirring mechanism (7) installed inside the vessel body; a reaction liquid guiding mechanism (8) is provided inside the vessel body; a feeding pipe (9) is also provided inside the vessel body; a reactor inflow pipe (3) with a first electrically controlled valve (5) and a reaction liquid overflow pipe (4) are provided on the vessel wall of the vessel body; a heating device is provided inside the vessel body; The stirring mechanism and heating device are both controlled by a controller.

4. The staged continuous lithium extraction reaction system according to claim 1, characterized in that, There are multiple reaction liquid guiding mechanisms; the reaction liquid guiding mechanism is a vertical guiding pipe, and the bottom of the guiding pipe is connected to the bottom of the vessel.

5. The staged continuous lithium extraction reaction system according to any one of claims 1-4, characterized in that, The stirring mechanism has multiple layers of blades; the bottom surface of the reactor is chamfered; there are multiple feed pipes, which are vertical pipes, and the outlets of the multiple feed pipes are located at different depths inside the reactor.

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