Method and device for leaching lithium from lithium-containing red mud
By preheating the red mud slurry and passing carbon dioxide gas into the lithium leach reaction at a specific temperature, the problems of many impurities and complex purification processes in the red mud leaching lithium are solved, and the purity and production efficiency of lithium products are improved.
Patent Information
- Application Number
- CN202411563136.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-02-14
AI Technical Summary
There are many types of impurities in the existing red mud leaching lithium method, and the subsequent purification process is complex and the cost is high.
By preheating the red mud slurry, then passing carbon dioxide gas at a temperature not exceeding 220°C, the lithium-enriched filtrate and deliquified red mud were obtained by solid-liquid separation. .
It reduces the impurity content of lithium products, improves the purity of lithium products, simplifies the subsequent purification process, and reduces costs.
Smart Images
Figure CN119433233A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of lithium leaching from red mud, and specifically relates to a method and device for leaching lithium from lithium-containing red mud. Background Art
[0002] The lithium content of bauxite in central my country is about 0.1%. After the lithium-containing bauxite is processed by the Bayer process, part of the lithium enters red mud and part enters alumina products. The chemical composition of red mud is determined by the ore composition and production process. It mainly contains elements such as sodium, aluminum, silicon, iron, calcium, titanium, and also contains rare metals such as gallium, scandium, vanadium, and lithium. It is a potential secondary solid resource.
[0003] Hannian Gu from the Institute of Geochemistry, Chinese Academy of Sciences, conducted experimental research on the leaching of lithium from red mud using acetic acid (Hannian Gu*, Wanyan Li, Zehai Li, Tengfei Guo, Hanjie Wen, Ning Wang. Learning behavior of lithium from bauxite residue using acetic acid. Mining, Metallurgy & Exploration, 2020, 37(2), 443-451.). This method contains many types of impurities in the leaching solution, and the subsequent purification process is complex and costly. Summary of the invention
[0004] In order to solve the current technical problem of high lithium impurities in red mud leaching, the present application provides a method and device for leaching lithium from lithium-containing red mud.
[0005] In a first aspect of the present application, a method for leaching lithium from lithium-containing red mud is provided, comprising:
[0006] preheating the red mud slurry to obtain a preheated slurry;
[0007] Carbon dioxide gas is introduced into the preheated slurry to cause carbonization and lithium leaching reaction at a temperature not exceeding 220° C. The reaction time is not less than 10 minutes, and lithium-rich filtrate and lithium-depleted red mud are obtained after solid-liquid separation.
[0008] In some embodiments, the temperature of the carbonization lithium immersion reaction is 100° C. to 220° C., and the time of the carbonization lithium immersion reaction is 10 min to 30 min.
[0009] In some embodiments, the temperature of the carbonization lithium immersion reaction is 180°C to 220°C.
[0010] In some embodiments, the pressure of the carbon dioxide gas is 1.0 MPa to 2.00 MPa.
[0011] In some embodiments, the red mud slurry is preheated to a temperature of 90°C to 110°C.
[0012] In some embodiments, the solid content of the red mud slurry is 50 g / L to 500 g / L.
[0013] In some embodiments, during the carbonization lithium leaching reaction, the red mud slurry is in a flowing state, and the flow rate of the red mud slurry is 1 to 2 m / s.
[0014] In some embodiments, the particle size of the solids in the red mud slurry is no greater than 45 μm.
[0015] In a second aspect, the present application provides a lithium-containing red mud leaching lithium device, which is used to implement the lithium-containing red mud leaching lithium method of the first aspect, and the lithium-containing red mud leaching lithium device comprises:
[0016] A solid-liquid separator, used for solid-liquid separation of the slurry after the carbonization and lithium leaching reaction;
[0017] A heating component is provided with a red mud channel and a heating channel arranged side by side, the red mud channel includes a preheating section and a reaction section arranged in sequence along the red mud flow direction, the heating channel is used to circulate a heating medium to preheat the red mud slurry flowing through the preheating section, and to heat the red mud slurry flowing through the reaction section to a temperature not exceeding 220°C; the heating component is provided with an interface connected to the red mud channel, the interface is located at the connection between the preheating section and the reaction section, so as to introduce carbon dioxide gas into the preheated slurry, and the reaction section is connected to the solid-liquid separator.
[0018] In some embodiments, the heating assembly comprises:
[0019] An inner tube, the lumen of the inner tube constituting the red mud channel;
[0020] The outer tube has a gap outside the inner tube, and the gap between the outer tube and the inner tube
[0021] The intervals constitute the heating channel;
[0022] An air supply pipe is used to supply the carbon dioxide. The air supply pipe passes through the outer pipe and is connected with the inner pipe. The air supply pipe constitutes the interface.
[0023] According to the method for leaching lithium from lithium-containing red mud provided in the embodiment of the present application, preheating is performed first, and then carbon dioxide is passed through, and a carbonization lithium leaching reaction occurs at a temperature not exceeding 220°C. The carbon dioxide will first react with the sodium hydroxide in the red mud slurry to form sodium carbonate, and the pH value of the red mud slurry will be reduced to 5.5-6.5. Within this range, the hydrogen ions will chemically react with the lithium-containing substances in the red mud slurry to form Li +After solid-liquid separation, it enters the filtrate to form lithium leaching solution.
[0024] Since carbon dioxide is added to the red mud slurry after preheating, it can avoid the chemical reaction between carbon dioxide and aluminate in the red mud slurry at low temperature to form aluminum ions, and aluminum ions will remain in the lithium leaching solution as impurities, resulting in reduced lithium purity and affecting the quality of lithium products. Therefore, the introduction of carbon dioxide after preheating reduces the impurity content of lithium products and improves the purity of lithium products. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 A schematic structural diagram of a lithium leaching device for lithium-containing red mud in one or more embodiments of the present application is shown.
[0026] Figure 2 Shows Figure 1 Schematic diagram of the structure of the heating component.
[0027] Figure 3 A schematic diagram of the process steps of a method for leaching lithium from lithium-containing red mud is shown.
[0028] Description of reference numerals:
[0029] 100-slurrying tank, 200-first feed pump, 300-heating assembly, 310-inner tube, 311-preheating section, 312-reaction section, 313-red mud channel, 320-outer tube, 321-first pipe section, 322-second pipe section, 331-first heating section, 332-second heating section, 333-heating channel, 340-gas supply pipe, 400-retention tank, 500-cooling tank, 600-second feed pump, 700-solid-liquid separator. DETAILED DESCRIPTION
[0030] In order to make the technical personnel in the technical field to which the present application belongs to understand the present application more clearly, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0031] The first aspect of the present application provides a method for leaching lithium from lithium-containing red mud, which not only achieves lithium leaching, but also improves the purity of the lithium-rich filtrate, and has good product quality.
[0032] The method for leaching lithium from lithium-containing red mud provided in the present application comprises the following steps:
[0033] S1. preheating red mud slurry to obtain preheated slurry;
[0034] S2. Introduce carbon dioxide gas into the preheated slurry to cause carbonization and lithium leaching reaction at a temperature not exceeding 220° C. The reaction time is not less than 10 minutes, and lithium-rich filtrate and lithium-depleted red mud are obtained after solid-liquid separation.
[0035] In step S1, the red mud slurry is first preheated, which can increase the temperature of the red mud slurry and prevent carbon dioxide from chemically reacting with impurities in the red mud slurry at low temperatures, thereby improving the purity of the lithium-rich filtrate. If the red mud slurry is not preheated and carbon dioxide is directly introduced, the carbon dioxide will react with aluminate in the red mud slurry to form aluminum ions, which will enter the lithium-rich filtrate, reduce the purity of lithium, and affect the quality of the product.
[0036] In step S2, in the carbonization lithium leaching reaction, carbon dioxide will first react with sodium hydroxide in the red mud slurry, and then the lithium leaching reaction will occur, specifically:
[0037] CO2+NaOH=Na2CO3+H2O;
[0038] CO2+H2O=H2CO3;
[0039]
[0040]
[0041] LiAl2(OH)7+H + =Li + +[Al2(OH)7] - ;
[0042] The Li ions formed by the carbonization and lithium immersion reaction will enter the lithium-rich filtrate during the solid-liquid separation process, and then form lithium products through subsequent processing.
[0043] If the temperature of the carbonization lithium leaching reaction exceeds 220°C, it will exceed the lithium leaching temperature, making it difficult for the lithium leaching reaction to occur, thereby reducing the lithium leaching rate. If the reaction time is less than 10 minutes, the reaction time is too short, which will also reduce the lithium leaching rate.
[0044] For the red mud slurry of the present application, in some embodiments, the solid content in the red mud slurry is 50g / L to 500g / L, such as 100g / L, 120g / L, 130g / L, 140g / L, 150g / L, 200g / L, 225g / L, 250g / L, 270g / L, 300g / L, 320g / L, 340g / L, 350g / L, 400g / L, 420g / L, 450g / L, 480g / L or 490g / L, etc., and the solid content in the red mud slurry is controlled so that it matches the amount of carbon dioxide introduced to improve the red mud leaching rate. In other embodiments, the solid content of the red mud slurry can also be higher than 500g / L, such as 520g / L, which can also achieve lithium leaching, but the leaching rate of the red mud will be reduced to a certain extent. In some other embodiments, the solid content of the red mud slurry may also be lower than 50 g / L, for example 40 g / L, and lithium leaching can also be achieved, but the production efficiency will be reduced to a certain extent.
[0045] In some embodiments, the particle size of the solid matter in the red mud slurry is no greater than 45 μm, that is, the particle size of the solid matter in the red mud slurry is reduced as much as possible, thereby increasing the contact area with carbon dioxide and improving the reaction efficiency.
[0046] For the preheating stage, in some embodiments, the red mud slurry is preheated to a temperature of 90°C to 110°C, such as 95°C, 98°C, 100°C, 102°C, 105°C, 106°C, 108°C or 109°C, etc. Controlling the preheating temperature of the red mud slurry can provide a more suitable reaction temperature for the subsequent carbonization lithium leaching reaction, reduce the amount of side reactions under low temperature conditions of carbon dioxide, thereby reducing the impurity content in the lithium leaching solution and improving the purity of the lithium product. In other embodiments, the preheating temperature of the red mud slurry can also exceed 110°C, such as 115°C, 120°C, etc., which can also provide a more suitable reaction temperature, but it will lead to energy waste. In some other embodiments, the preheating temperature of the red mud slurry can also be lower than 90°C, such as 85°C or 90°C, etc., which can also provide a more suitable reaction temperature for the subsequent carbonization lithium leaching reaction, but it may increase the impurities in the lithium leaching solution to a certain extent.
[0047] In some embodiments, the temperature of the carbonization lithium leaching reaction is 100°C to 220°C, such as 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or 210°C, preferably 180°C to 220°C, and controlling the temperature of the carbonization lithium leaching reaction can not only ensure the leaching of lithium, but also reduce impurities. If the temperature of the carbonization lithium leaching reaction is lower than 100°C, side reactions will increase to a certain extent, such as carbon dioxide reacting with aluminate to form aluminum ions that enter the lithium-rich filtrate, reducing the purity of the lithium product and affecting the product quality. In other embodiments, the temperature of the carbonization lithium leaching reaction can also be lower than 100°C, such as 80°C or 90°C, which can also achieve lithium leaching and recovery.
[0048] In some embodiments, the carbonization lithium leaching reaction time is 10min to 30min, for example, 12min, 15min, 16min, 17min, 18min or 19min, so that the carbon dioxide can fully react with the sodium hydroxide and LiAl2(OH)7 in the red mud to achieve lithium leaching. If the carbonization lithium leaching reaction time is too long, it will affect the production efficiency to a certain extent. In other embodiments, the carbonization lithium leaching reaction time can also be 35min, 38min, etc., which can also achieve lithium leaching.
[0049] In some embodiments, the pressure of carbon dioxide gas is 1.0MPa to 2.00MPa, such as 1.1MPa, 1.2MPa, 1.3MPa, 1.4MPa, 1.5MPa, 1.6MPa, 1.7MPa, 1.8MPa or 1.9MPa. The gas pressure of carbon dioxide is controlled to increase the flow rate of carbon dioxide so that it can quickly and evenly contact and react with red mud slurry, shorten the reaction time, and improve the reaction efficiency. In other embodiments, the pressure of carbon dioxide can also exceed 2.00MPa, and lithium leaching can also be achieved, but some waste may occur. In some other embodiments, the pressure of carbon dioxide can also be lower than 1.0MPa, and lithium leaching can also be achieved, but the reaction time will be prolonged to a certain extent.
[0050] In some embodiments, the red mud slurry is in a flowing state, such as flowing in a treatment tank while being stirred, or flowing in a pipeline, and the flow rate of the red mud slurry is 1 to 2 m / s, such as 1.2 m / s, 1.5 m / s, 1.6 m / s, 1.7 m / s, 1.8 m / s or 1.9 m / s, etc. Controlling the flow rate of the red mud slurry can improve the reaction efficiency with carbon dioxide. In other embodiments, the flow rate of the red mud slurry can also be lower than 1 m / s, such as 0.8 m / s, and the leaching of lithium in the red mud slurry can still be achieved, but the efficiency may be affected. In some other embodiments, the flow rate of the red mud slurry can also be higher than 2 m / s, such as 2.3 m / s, and the leaching of lithium in the red mud slurry can also be achieved, but the leaching rate of the red mud slurry may be reduced.
[0051] The second aspect of the present application provides a lithium leaching device for lithium-containing red mud, which is used to implement the method for leaching lithium from lithium-containing red mud in any embodiment of the first aspect.
[0052] See also Figure 1 as well as Figure 2 The device provided in the present application includes a heating component 300 and a solid-liquid separator 700.
[0053] The heating component 300 can preheat the red mud slurry and provide the temperature for the carbonization lithium leaching reaction. The heating component 300 is provided with a red mud channel 313 and a heating channel 333 arranged side by side. The red mud channel 313 includes a preheating section 311 and a reaction section 312 arranged in sequence along the red mud flow direction. The heating channel 333 is used to circulate a heating medium to heat the red mud slurry flowing through the red mud channel 313, wherein the red mud slurry flowing through the preheating section 311 is preheated, and the red mud slurry flowing through the reaction section 312 is heated to a temperature not exceeding 220°C; the heating component 300 is provided with a red mud channel 313 and a heating channel 333 arranged side by side. The interface connected to the mud channel 313 is located at the connection point between the preheating section 311 and the reaction section 312, so as to introduce carbon dioxide gas into the preheated slurry. The red mud slurry and carbon dioxide flow together in the reaction section 312. During the joint movement of the two, carbon dioxide and the red mud slurry undergo carbonization and lithium leaching reaction. The reaction section 312 is connected to the solid-liquid separator 700, so the red mud slurry after the reaction is separated into solid and liquid through the solid-liquid separator 700 to obtain lithium-rich filtrate and lithium-depleted red mud.
[0054] In some embodiments, see Figure 1 The lithium leaching device for lithium-containing red mud includes a slurrying tank 100, a first feed pump 200, a heating component 300, a retention tank 400, a cooling tank 500, a second feed pump 600 and a solid-liquid separator 700 which are sequentially arranged along the flow direction of the red mud slurry.
[0055] The slurry tank 100 is provided with an inlet, and red mud containing lithium and water can enter the slurry tank 100 through the inlet, and the water and red mud are mixed to form red mud slurry. In order to improve the mixing efficiency of water and red mud, an agitator can be provided in the slurry tank 100.
[0056] The first feed pump 200 can pump the red mud slurry in the slurrying tank 100 into the red mud channel 313 of the heating component 300 to perform preheating and carbonization lithium leaching reactions in sequence.
[0057] The heating assembly 300 includes an inner tube 310, an outer tube 320 and a gas supply pipe 340. The lumen of the inner tube 310 constitutes a red mud channel 313. The outer tube 320 is arranged outside the inner tube 310, and the interval between the outer tube 320 and the inner tube 310 constitutes a heating channel 333. The gas supply pipe 340 is used to supply carbon dioxide, and the gas supply pipe 340 passes through the outer tube 320 and communicates with the inner tube 310, and the gas supply pipe 340 constitutes the interface. The pipeline heating structure allows the red mud slurry to flow continuously in the pipeline and react with carbon dioxide to form a carbonization and lithium leaching reaction, thereby improving production efficiency.
[0058] The setting of the retention tank 400 can, on the one hand, allow the unreacted carbon dioxide to react with the LiAl2(OH)7 in the red mud slurry to increase the leaching rate, and on the other hand, release the pressure of the gas. An agitator can be set inside the retention tank 400 to stir the red mud slurry to accelerate the reaction of the remaining material.
[0059] The cooling tank 500 can be provided to cool the red mud slurry. Air cooling can be used in specific implementation. The red mud slurry is pumped into the solid-liquid separator 700 through the second feed pump 600 to achieve solid-liquid separation.
[0060] The solid-liquid separator 700 can be a plate-and-frame filter press or a chamber filter press as a solid-liquid separation structure, and this application does not limit this.
[0061] In order to improve the heat utilization rate, in some embodiments, the heating channel 333 is divided into a first heating section 331 and a second heating section 332, the first heating section 331 corresponds to the preheating section 311, the second heating section 332 corresponds to the reaction section 312, the first heating section 331 is connected to the retention tank 400, so that the red mud slurry with a relatively high temperature in the retention tank 400 is used as a heating medium to preheat the red mud slurry from the slurry tank 100, and the second heating section 332 is used to circulate an external heating medium, such as water vapor, to heat the red mud slurry in the reaction section 312 to the carbonization and lithium leaching reaction temperature. Specifically, the red mud slurry in the first heating section 331 flows in the opposite direction to the red mud slurry in the preheating section 311, and the red mud slurry in the second heating section 332 flows in the opposite direction to the water vapor in the reaction section 312, so as to improve the heating effect.
[0062] Correspondingly, the outer pipe 320 includes a first pipe section 321 and a second pipe section 322. The gap of the first pipe section 321 is arranged outside the inner pipe 310. The gap between the first pipe section 321 and the inner pipe 310 constitutes a first heating section 331 for the red mud slurry in the retention tank 400 to flow, and the gap between the second pipe section 322 and the inner pipe 310 constitutes a second heating section 332 for water vapor to flow.
[0063] In other embodiments, the second pipe section 322 may be provided with multiple sections, for example, two second pipe sections 322 are provided, and the two second pipe sections 322 are sequentially sleeved outside the inner pipe 310 with gaps along the flow direction of the red mud slurry to achieve double heating of the red mud slurry in the reaction section 312.
[0064] In some embodiments, a mill, such as a stirred mill, a vertical mill or a ball mill, may be provided between the slurry tank 100 and the first feed pump 200 to refine the particle size of the solid matter in the red mud slurry so that the particle size is no greater than 45 μm, that is, the particle size is less than 300 mesh.
[0065] The method for leaching lithium from lithium-containing red mud provided in the present application will be further described below with reference to specific examples.
[0066] Example 1
[0067] See also Figure 3 This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0068] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.1%.
[0069] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 50 g / L.
[0070] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0071] S4, the ground lithium-containing red mud is subjected to a pipeline preheating at a flow rate of 1m / s and a two-stage high-temperature carbon dioxide carbonization lithium leaching reaction. Wherein: the first stage preheating temperature is 100°C, and the second stage high-temperature carbonization lithium leaching reaction temperature is 100°C. The high-temperature carbonization lithium leaching reaction time is 10min. The CO2 pressure of the high-temperature carbonization lithium leaching reaction is 1.0MPa.
[0072] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0073] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0074] Example 2
[0075] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0076] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.11%.
[0077] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 100 g / L.
[0078] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0079] S4, the ground lithium-containing red mud is subjected to a first-stage pipeline preheating and a second-stage high-temperature carbon dioxide carbonization lithium leaching reaction at a flow rate of 1.2 m / s. Wherein: the first-stage preheating temperature is 100° C., and the second-stage high-temperature carbonization lithium leaching reaction temperature is 120° C. The high-temperature carbonization lithium leaching reaction time is 15 min. The high-temperature carbonization lithium leaching reaction CO2 pressure is 1.2 MPa.
[0080] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0081] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0082] Example 3
[0083] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0084] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.10%.
[0085] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 200 g / L.
[0086] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0087] S4, the ground lithium-containing red mud is subjected to a first-stage pipeline preheating and a second-stage high-temperature carbon dioxide carbonization lithium leaching reaction at a flow rate of 1.8 m / s.
[0088] Among them: the first stage preheating temperature is 100°C, the second stage high temperature carbonization lithium immersion reaction temperature is 130°C, the high temperature carbonization lithium immersion reaction time is 10min, and the high temperature carbonization lithium immersion reaction CO2 pressure is 1.3MPa.
[0089] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0090] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0091] Example 4
[0092] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0093] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.12%.
[0094] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 300 g / L.
[0095] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0096] S4, the ground lithium-containing red mud is subjected to a first-stage pipeline preheating and a second-stage high-temperature carbon dioxide carbonization lithium leaching reaction at a flow rate of 1.5 m / s.
[0097] Among them: the first stage preheating temperature is 100°C, the second stage high temperature carbonization lithium immersion reaction temperature is 140°C, the high temperature carbonization lithium immersion reaction time is 20min, and the high temperature carbonization lithium immersion reaction CO2 pressure is 1.4MPa.
[0098] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0099] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0100] Example 5
[0101] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0102] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.10%.
[0103] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 400 g / L.
[0104] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0105] S4, the ground lithium-containing red mud is subjected to a first-stage pipeline preheating and a second-stage high-temperature carbon dioxide carbonization lithium leaching reaction at a flow rate of 1.6 m / s.
[0106] Among them: the first stage preheating temperature is 105℃, the second stage high temperature carbonization lithium immersion reaction temperature is 150℃, the high temperature carbonization lithium immersion reaction time is 20min, and the high temperature carbonization lithium immersion reaction CO2 pressure is 1.05MPa.
[0107] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0108] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0109] Example 6
[0110] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0111] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.12%.
[0112] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 500 g / L.
[0113] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0114] S4, the ground lithium-containing red mud is subjected to a pipeline preheating at a flow rate of 1.8 m / s and a two-stage high-temperature carbon dioxide carbonization lithium leaching reaction. Wherein: the first stage preheating temperature is 96°C, and the second stage high-temperature carbonization lithium leaching reaction temperature is 200°C. The high-temperature carbonization lithium leaching reaction time is 30 minutes. The CO2 pressure of the high-temperature carbonization lithium leaching reaction is 2.0 MPa.
[0115] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0116] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0117] Example 7
[0118] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0119] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.1%.
[0120] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 250 g / L.
[0121] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0122] S4, the ground lithium-containing red mud is subjected to a pipeline preheating at a flow rate of 1.9 m / s and a two-stage high-temperature carbon dioxide carbonization lithium leaching reaction. Wherein: the preheating temperature of the first stage is 98°C, and the temperature of the second stage high-temperature carbonization lithium leaching reaction is 180°C. The high-temperature carbonization lithium leaching reaction time is 15 minutes. The CO2 pressure of the high-temperature carbonization lithium leaching reaction is 1.5 MPa.
[0123] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0124] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0125] Example 8
[0126] This embodiment provides a method for extracting lithium from lithium-containing red mud, comprising the following steps:
[0127] S1. Obtain lithium-containing red mud, wherein the lithium content in the red mud is 0.11%.
[0128] S2. Mixing lithium-containing red mud with water to prepare red mud slurry with a solid content of 200 g / L.
[0129] S3, grinding the red mud slurry to a particle size less than 300 mesh.
[0130] S4, the ground lithium-containing red mud is subjected to a pipeline preheating at a flow rate of 3.0 m / s and a two-stage high-temperature carbon dioxide carbonization lithium leaching reaction. Wherein: the first stage preheating temperature is 103°C, and the second stage high-temperature carbonization lithium leaching reaction temperature is 200°C. The high-temperature carbonization lithium leaching reaction time is 15 minutes. The CO2 pressure of the high-temperature carbonization lithium leaching reaction is 1.5 MPa.
[0131] S5. The high-temperature leaching slurry and the red mud slurry undergo countercurrent heat exchange and then enter the cooling tank.
[0132] S6. After cooling, use a plate and frame filter press to separate the solid and liquid to obtain lithium-rich filtrate and lithium-depleted red mud.
[0133] Table 2
[0134] The method for leaching lithium from lithium-containing red mud provided in the present application uses carbon dioxide instead of acetic acid as a raw material for adjusting the pH of red mud slurry, and controls the reaction temperature to provide an acidic environment for Li precipitation, thereby achieving lithium leaching. At the same time, the red mud slurry is preheated before adding carbon dioxide, which reduces side reactions, makes the impurity elements such as aluminum and iron in the red mud slurry insoluble, improves the purity of the lithium-rich filtrate, and can reduce the subsequent complex melt purification process. And the process is simple, the selectivity is good, the lithium leaching rate is high, the cost is low, and it is convenient for the preparation and application of high-quality lithium carbonate. The method for leaching lithium from lithium-containing red mud provided in the present application has a lithium leaching rate of 95.0% to 99.0%, a high leaching rate, an aluminum impurity content of 12 to 26 ppm, a silicon impurity content of 50 to 68 ppm, and a low impurity content.
[0135] The lithium-containing red mud leaching device provided in the present application uses the red mud channel as a reaction structure, and cooperates with the method of leaching lithium from carbon dioxide to achieve continuous red mud slurry lithium leaching production with high production efficiency. The red mud slurry after the reaction is used as a heating medium to achieve the recovery and utilization of heat energy and improve the utilization rate of heat energy.
[0136] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0137] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0138] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0139] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0140] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A method for leaching lithium from lithium-containing red mud, characterized in that: include: preheating the red mud slurry to obtain a preheated slurry; Carbon dioxide gas is introduced into the preheated slurry to cause carbonization and lithium leaching reaction at a temperature not exceeding 220° C. The reaction time is not less than 10 minutes, and lithium-rich filtrate and lithium-depleted red mud are obtained after solid-liquid separation.
2. The method for leaching lithium from lithium-containing red mud according to claim 1, characterized in that: The temperature of the carbonization lithium immersion reaction is 100° C. to 220° C., and the time of the carbonization lithium immersion reaction is 10 min to 30 min.
3. The method for leaching lithium from lithium-containing red mud according to claim 2, characterized in that: The temperature of the carbonization lithium immersion reaction is 180°C to 220°C.
4. The method for leaching lithium from lithium-containing red mud according to claim 2, characterized in that: The pressure of the carbon dioxide gas is 1.0 MPa to 2.00 MPa.
5. The method for leaching lithium from lithium-containing red mud according to any one of claims 1 to 4, characterized in that: The red mud slurry is preheated to a temperature of 90°C to 110°C.
6. The method for leaching lithium from lithium-containing red mud according to any one of claims 1 to 4, characterized in that: The solid content of the red mud slurry is 50 g / L to 500 g / L.
7. The method for leaching lithium from lithium-containing red mud according to any one of claims 1 to 4, characterized in that: During the carbonization and lithium leaching reaction, the red mud slurry is in a flowing state, and the flow rate of the red mud slurry is 1 to 2 m / s.
8. The method for leaching lithium from lithium-containing red mud according to any one of claims 1 to 4, characterized in that: The particle size of the solid matter in the red mud slurry is no greater than 45 μm.
9. A lithium leaching device for lithium from lithium-containing red mud, used for implementing the method for leaching lithium from lithium-containing red mud according to any one of claims 1 to 8, characterized in that: The lithium-containing red mud leaching lithium device comprises: A solid-liquid separator, used for solid-liquid separation of the slurry after the carbonization and lithium leaching reaction; A heating component is provided with a red mud channel and a heating channel arranged side by side, the red mud channel includes a preheating section and a reaction section arranged in sequence along the red mud flow direction, the heating channel is used to circulate a heating medium to preheat the red mud slurry flowing through the preheating section, and to heat the red mud slurry flowing through the reaction section to a temperature not exceeding 220°C; the heating component is provided with an interface connected to the red mud channel, the interface is located at the connection between the preheating section and the reaction section, so as to introduce carbon dioxide gas into the preheated slurry, and the reaction section is connected to the solid-liquid separator.
10. The lithium leaching device for lithium-containing red mud according to claim 9, characterized in that: The heating assembly comprises: An inner tube, the lumen of the inner tube constituting the red mud channel; An outer tube, the gap being arranged outside the inner tube, and the interval between the outer tube and the inner tube forming the heating channel; An air supply pipe is used to supply the carbon dioxide. The air supply pipe passes through the outer pipe and is connected with the inner pipe. The air supply pipe constitutes the interface.