Continuous leaching reaction device for lithium carbonate

Abstract

The utility model relates to a continuous leaching reaction device for lithium carbonate, which is characterized by comprising a slurry tank, a chemical cleaning and flushing water tank, a discharging tank, a discharging pipeline, a feeding pipeline, a plurality of slurry heat exchangers and a plurality of leaching reactors connected in sequence, the slurry heat exchangers are defined as a first slurry heat exchanger, a second slurry heat exchanger... an Nth slurry heat exchanger, the leaching reactors are defined as a first leaching reactor, a second leaching reactor... an Lth leaching reactor, and N and L are positive integers not smaller than 3; the pipe paths of the first slurry heat exchanger, the second slurry heat exchanger... the Nth slurry heat exchanger are sequentially connected to the feeding pipeline in series, the discharging end of the feeding pipeline is connected with the first leaching reactor, and the leaching reaction device further comprises a heating device connected with the first leaching reactor; the device solves the problem of scabbing of the heat exchange surface in the lithium-containing slurry heating process, and avoids the problem of saturated precipitation of lithium carbonate in the lithium carbonate leaching solution waste heat utilization process.

Description

Technical Field

[0001] The utility model relates to the field of metallurgy and chemical industry, in particular to a lithium carbonate continuous leaching reaction device. Background Art

[0002] In recent years, with increasing demand for lithium in industries such as lithium batteries, lubricating greases, and tire rubber, as well as expanding demand for lithium and its alloys in high-tech fields such as aerospace, aviation, and nuclear energy, the production of lithium metal has also continued to grow. Lithium carbonate, a fundamental material for the production of secondary lithium salts and lithium metal, is the most fundamental and important product in the lithium industry. Lithium carbonate is widely used in numerous fields, including electronic materials, chemistry, medicine, industrial ceramics, and metallurgy. With the rapid development of high-tech industries such as information technology, electric vehicles, and green energy, the market demand for lithium and its compounds has skyrocketed, and supply has outstripped supply, keeping prices high.

[0003] Patents CN 115124052 A, "A Method for Preparing Battery-Grade Lithium Carbonate," and CN 107500318 A, "A Method for Extracting Lithium Carbonate from Sodium Aluminate Solutions in Alumina Plants," disclose methods for extracting lithium carbonate from the alumina production process. Both utilize a process in which lithium from the alumina production process is first adsorbed onto aluminum hydroxide solids, followed by high-temperature wet leaching. Due to the early stages of industrialization of this technology, there are no reports of complete apparatuses for removing lithium carbonate from lithium-rich solids into a solution.

[0004] The spodumene soda autoclave process, a method for producing lithium carbonate from spodumene proposed in the 1960s, involves reacting β-spodumene with a sodium carbonate solution at high temperature and pressure. The lithium in the spodumene is replaced by sodium ions in the solution, precipitating as lithium carbonate. The insoluble lithium carbonate produced by the autoclave reaction is converted to lithium bicarbonate through carbonization, which is dissolved in water and separated from the reaction residue (sodalite). Finally, heating converts the lithium bicarbonate into lithium carbonate for precipitation. The soda autoclave process offers a short production process, low material throughput, high product purity, and minimal corrosion to equipment. However, to date, there have been no reports of the technology being applied industrially, nor are there established, complete processes and equipment for soda autoclave leaching of lithium carbonate.

[0005] Lithium carbonate is leached out of spodumene using soda pressure cooking method, and lithium carbonate is leached out of lithium-containing aluminum hydroxide. The main purpose of the leaching process is to leach lithium from the slurry to form a lithium-containing solution, providing the raw material basis for subsequent liquid-solid separation, impurity removal and other processes.

[0006] The traditional leaching device is mainly similar to the pipelined dissolution device in the alumina industry. The lithium-containing raw ore slurry is preheated through a multi-stage exhaust steam preheater. After being indirectly heated to the leaching temperature by steam, it enters the leaching reactor for heat preservation and leaching. After the lithium carbonate is leached, the slurry is cooled by multi-stage flash evaporation and then enters the discharge trough. The exhaust steam generated by flash evaporation is used to preheat the raw ore slurry.

[0007] The existing problems are: lithium carbonate has low solubility, and its solubility decreases with increasing temperature. During the slurry heating and preheating process, lithium carbonate is prone to form scars on the heat exchange surface; the leachate in the leaching reactor is mostly a saturated solution of lithium carbonate. During the flash evaporation process, the concentration of the leachate will gradually increase, and lithium carbonate will precipitate due to supersaturation, causing crystallization and blockage of the flash evaporator discharge pipe, affecting the normal operation of the system. Utility Model Content

[0008] The purpose of the utility model is to provide a pipelined continuous leaching reaction device for lithium carbonate, so as to solve the problems in the prior art of severe scarring of the heat exchange surface during the leaching of lithium carbonate from lithium-containing slurry and saturated precipitation of lithium carbonate during the utilization of waste heat of the leachate.

[0009] In order to solve the above technical problems, the technical solution of a pipelined continuous leaching reaction device of lithium carbonate in the utility model is as follows:

[0010] A lithium carbonate continuous leaching reaction device, comprising a slurry tank, a chemical cleaning tank, a flushing water tank and a discharge tank, as well as a discharge pipeline and a feed pipeline. The leaching reaction device also comprises a plurality of slurry heat exchangers and a plurality of leaching reactors connected in series, wherein each slurry heat exchanger is defined as a first slurry heat exchanger, a second slurry heat exchanger, and an Nth slurry heat exchanger, and each leaching reactor is defined as a first leaching reactor, a second leaching reactor, and an Lth leaching reactor, wherein N and L are positive integers not less than 3, and the pipes of the first slurry heat exchanger, the second slurry heat exchanger, and the Nth slurry heat exchanger are connected in series in series to the feed pipeline, and the discharge end of the feed pipeline is connected to the first leaching reactor. The leaching reactor is connected, and the leaching reaction device also includes a heating device connected to the first leaching reactor, the Nth slurry heat exchanger, the N-1th slurry heat exchanger...the shell side of the first slurry heat exchanger is serially connected to the discharge pipeline, the feed end of the discharge pipeline is connected to the discharge port of the Lth leaching reactor, the discharge end of the discharge pipeline is connected to the flushing water trough and the discharge trough respectively through the discharge branch, and each discharge branch is provided with a discharge branch switch valve, the feed end of the feed pipeline is connected to the slurry trough and the flushing water trough respectively through the feed branch, and each feed branch is provided with a feed branch switch valve, and the discharge end of the feed pipeline is connected to the feed port of the first leaching reactor.

[0011] Furthermore, the leaching reaction device also includes a chemical cleaning tank, the feed end of the feed pipeline is connected to the water outlet of the chemical cleaning tank through a feed branch, and the discharge end of the discharge pipeline is connected to the water inlet of the chemical cleaning tank through a discharge branch.

[0012] Furthermore, each feed branch is provided with a delivery pump, and a high-pressure feeding pump is provided on the feed pipeline upstream of the first slurry heat exchanger.

[0013] Furthermore, the delivery pump and the high-pressure feeding pump are diaphragm pumps, plunger pumps or centrifugal pumps.

[0014] Furthermore, the heating device includes a steam buffer, which is connected to the steam inlet of each leaching reactor through steam pipes arranged in parallel.

[0015] Furthermore, each steam pipeline is serially connected with a steam regulating valve, a shut-off valve and a check valve.

[0016] Furthermore, each leaching reactor includes a reactor and a feed pipe and a discharge pipe connected to the reactor, the lower end of the feed pipe is located at the upper middle side of the reactor, and the lower end of the discharge pipe is located at the lower middle side of the reactor.

[0017] Furthermore, a pressure regulating valve is provided on the discharge pipe downstream of the first slurry heat exchanger.

[0018] Furthermore, an isolation valve is provided on the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor, and a reflux pipeline is provided between the feed pipeline connected between the tube side of the Nth slurry heat exchanger and the first leaching reactor and the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor, and a reflux pipeline valve is provided on the reflux pipeline.

[0019] Furthermore, each slurry heat exchanger adopts a multi-stage shell and tube heater connected in series.

[0020] The beneficial effects of the present invention are as follows: when in use, the slurry tank is filled with the batching slurry containing lithium ore slurry, the lithium-containing batching slurry is transported to the first leaching reactor through the feed pipeline, and the lithium carbonate solution produced by each level of leaching reactor flows back to the discharge tank through the discharge pipeline. Under the action of the heating device, the lithium carbonate solution has residual heat, and the lithium carbonate solution flows through the tube side of the Nth slurry heat exchanger, the N-1th slurry heat exchanger... the first slurry heat exchanger in sequence, so the batching slurry flowing through the shell side of the slurry heat exchanger can be heated, and the heated batching slurry flows to the The first leaching reactor increases the temperature of the lithium-containing ingredient slurry entering the leaching reactor, realizes the utilization of waste heat, and can save energy consumption in the heating process of the leaching reactor; the saturated lithium carbonate solution discharged from the Lth leaching reactor is cooled by liquid heat exchange in the shell and tube sides. During the cooling process, the solubility of the lithium carbonate solution is increased, so it is not easy to form lithium carbonate scars in the shell side. Compared with the conventional flash evaporation to recover the leaching slurry and utilize the waste heat of the flash evaporation, the concentration of the leaching slurry during the flash evaporation process can be avoided, and the supersaturated precipitation of lithium carbonate and the problem of flash condensation water carrying material can be avoided.

[0021] Furthermore, the solution of the utility model eliminates facilities such as the slurry flash evaporator and the condensate tank, which can simplify the process and reduce investment.

[0022] Furthermore, fresh steam is introduced into the reactor for direct heating of the preheated slurry, eliminating the problem of heat exchange surface scarring and significantly extending the device's operating cycle. Because the solubility of lithium carbonate decreases with increasing temperature, conventional indirect heating methods result in high heat exchange surface temperatures, where lithium carbonate easily crystallizes and precipitates, leading to severe scarring and making it difficult to operate safely for extended periods.

[0023] Furthermore, since the solubility of lithium carbonate increases with decreasing temperature, the temperature of the lithium carbonate slurry decreases during the preheating of the raw ore slurry in the heat exchanger shell, and its solubility continues to increase. Because the heat exchange surface temperature is lower than the leaching slurry temperature, the solubility of lithium carbonate is higher near the heat exchange surface. Therefore, lithium carbonate scarring will not form on the shell heat exchange surface.

[0024] Furthermore, during the operation of the device, other scars such as aluminum hydroxide scars and calcium silicate scars may be deposited or attached in the shell. These scars are difficult to remove by mechanical cleaning or hydraulic cleaning, but these scars are easy to react with acids and alkalis. The chemical cleaning method used in the present invention can dissolve the scars, thereby achieving regeneration of the heat exchange surface.

[0025] Furthermore, the clean water in the flushing tank can flush out the material in the inner tube of the slurry heat exchanger when the device is shut down, thereby preventing material accumulation in the slurry heat exchanger.

[0026] Furthermore, the cleaning liquid in the chemical cleaning tank can chemically clean the scars of the slurry heat exchanger to achieve regeneration of the heat exchange surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0028] Figure 1 It is a structural diagram of an embodiment of the utility model;

[0029] 1. Feed pipeline; 2. Discharge pipeline; 3. High-pressure feeding pump; 4. First slurry heat exchanger; 5. Second slurry heat exchanger; 6. Nth slurry heat exchanger; 7. Pressure regulating valve; 8. Isolation valve; 9. Reflux pipeline; 10. Steam pipeline; 11. Steam buffer; 12. First leaching reactor; 13. Second leaching reactor; 14. Lth leaching reactor; 15. Feed pipe; 16. Discharge pipe; 17. Discharge branch; 18. Discharge branch switching valve; 19. Feed branch; 20. Delivery pump; 21. Feed branch switching valve; 22. Flushing water tank; 23. Discharge tank; 24. Slurry tank; 25. Chemical cleaning tank. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0031] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art in the field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0032] The embodiment of a lithium carbonate continuous leaching reaction device in the utility model is as follows Figure 1 As shown:

[0033] It includes a slurry tank 24, a chemical cleaning tank 25, a flushing tank 22 and a discharge tank 23. The flushing tank 22 is used to hold clean water, the slurry tank 24 is used to hold the ingredient slurry containing lithium ore slurry, and the chemical cleaning tank 25 is used to hold the cleaning liquid, such as liquid caustic soda, sulfuric acid, hydrochloric acid or nitric acid.

[0034] The lithium carbonate continuous leaching reaction device further includes a discharge pipeline 2 and a feed pipeline 1. The leaching reaction device also includes multiple slurry heat exchangers and multiple sequentially connected leaching reactors. The slurry heat exchangers are defined as a first slurry heat exchanger 4, a second slurry heat exchanger 5, ..., an Nth slurry heat exchanger 6, and the leaching reactors are defined as a first leaching reactor 12, a second leaching reactor 13, ..., an Lth leaching reactor 14, where N and L are positive integers not less than 3. The slurry heat exchanger is a double-tube heat exchanger having a tube side and a shell side.

[0035] The tube path of each slurry heat exchanger is composed of a single inner tube (or multiple inner tubes connected in parallel).

[0036] The tube sides of the first slurry heat exchanger 4, the second slurry heat exchanger 5...the Nth slurry heat exchanger 6 are serially connected to the feed pipeline, and the shell sides of the Nth slurry heat exchanger 6, the N-1th slurry heat exchanger...the first slurry heat exchanger 4 are serially connected to the discharge pipeline 2.

[0037] The feed end of the feed pipeline is connected to the slurry tank 24, the flushing water tank 22, and the chemical cleaning tank 25 through the feed branch 19. Each feed branch is provided with a feed branch switch valve 21. The discharge end of the feed pipeline is connected to the feed port of the first leaching reactor 12. The feed end of the discharge pipeline 2 is connected to the discharge port of the Lth leaching reactor. The discharge end of the discharge pipeline is connected to the flushing water tank 22, the discharge tank 23, and the chemical cleaning tank 25 through the discharge branch 17. Each discharge branch is provided with a discharge branch switch valve 18.

[0038] Each feed branch is also provided with a delivery pump 20, and a high-pressure feeding pump 3 is provided on the feed pipeline upstream of the first slurry heat exchanger. The delivery pump and the high-pressure feeding pump are diaphragm pumps, plunger pumps or centrifugal pumps, preferably diaphragm pumps.

[0039] Each leaching reactor is a steam-heated, directly stirred reactor. The lithium carbonate continuous leaching reactor also includes a heating device connected to the first leaching reactor. The heating device includes a steam buffer 11. Hot steam first enters the steam buffer. The steam buffer is connected to the steam inlet of each leaching reactor via a parallel steam pipeline 10. Each steam pipeline is serially connected to a steam regulating valve, a shut-off valve, and a check valve. Each leaching reactor includes a reactor and a feed pipe 15 and a discharge pipe 16 connected to the reactor. The lower end of the feed pipe is located in the upper middle side of the reactor, and the lower end of the discharge pipe is located in the lower middle side of the reactor. Material enters the corresponding leaching reactor through the feed pipe and then exits the corresponding leaching reactor through the discharge pipe.

[0040] A pressure regulating valve 7 is installed on the discharge pipeline downstream of the first slurry heat exchanger. It is located between the first slurry heat exchanger 4 and the discharge trough. This valve is interlocked with the pressure of the L-stage leaching reactor to prevent vaporization of the material within the reactor due to high temperature and low pressure. The pressure regulating valve is interlocked with the L-stage leaching reactor, ensuring that the pressure in the L-stage leaching reactor is at least 0.1 MPa higher than the saturated vapor pressure of the slurry at the material's operating temperature.

[0041] An isolation valve 8 is installed on the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor. A reflux pipeline 9 is installed between the feed pipeline connecting the tube side of the Nth slurry heat exchanger and the first leaching reactor and the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor. A reflux pipeline valve is installed on reflux pipeline 9 to isolate each leaching reactor from the system during water flushing and chemical cleaning. The operating temperature of each leaching reactor is 180-260°C.

[0042] During use, the batch slurry containing lithium ore flows through the feed pipeline and passes through the tube side of the corresponding slurry heat exchanger in sequence. The lithium carbonate solution produced by the leaching reactor passes through the shell side of the corresponding slurry heat exchanger in sequence when flowing to the discharge trough through the discharge pipeline, realizing heat exchange, increasing the temperature of the slurry entering the first leaching reactor, and recovering the waste heat of the leaching slurry at the same time, which can greatly reduce the energy consumption of the system. Compared with the conventional flash evaporation to recover the waste heat of the leaching slurry, it can avoid the supersaturated precipitation of lithium carbonate and the problem of flash evaporation condensate carrying material during the flash evaporation process; the preheated slurry is directly heated by introducing new steam into the leaching reactor, and there is no problem of scarring on the heat exchange surface, which can greatly extend the operation cycle of the device. Because the solubility of lithium carbonate decreases with increasing temperature, the conventional indirect heating method will cause serious scarring of lithium carbonate on the heat exchange surface, making it difficult for the device to achieve long-term safe operation.

[0043] The clean water flushing device set up can flush out the material in the slurry heat exchanger when the device is shut down to prevent material accumulation in the heat exchanger. For example, the isolation valve and the switch valve on the feed pipe downstream of the Nth slurry heat exchanger are closed, and the clean water passes through the first slurry heat exchanger, the second slurry heat exchanger... the Nth slurry heat exchanger in sequence, and then through the return pipe, and then flows through the Nth slurry heat exchanger, the N-1th slurry heat exchanger... the shell side of the first slurry heat exchanger to achieve the cleaning of each slurry heat exchanger, and the cleaning waste liquid can flow back to the slurry tank or the discharge tank; for the same reason, the chemical cleaning tank can achieve chemical cleaning of each slurry heat exchanger. In actual use, each slurry heat exchanger can be cleaned with clean water separately, or each slurry heat exchanger can be chemically cleaned first, and then cleaned with clean water.

[0044] In the above description of this specification, unless otherwise expressly specified or limited, terms such as "fixed," "mounted," "connected," or "connected" should be understood broadly. For example, the term "connected" can refer to a fixed connection, a removable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal connection between two components or the interaction between two components. Therefore, unless otherwise expressly defined in this specification, those skilled in the art can understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0045] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "center", "longitudinal", "lateral", "clockwise" or "counterclockwise", etc., which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the utility model and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the utility model.

[0046] In addition, the terms "first" or "second" used in this specification to refer to numbers or ordinal numbers are used for descriptive purposes only and should not be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this specification, "plurality" means at least two, such as two, three or more, etc., unless otherwise clearly specified.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A lithium carbonate continuous leaching reaction device, characterized in that: The leaching reaction device includes a slurry tank, a chemical cleaning tank, a flushing water tank and a discharge tank, as well as a discharge pipeline and a feed pipeline. The leaching reaction device also includes multiple slurry heat exchangers and multiple leaching reactors connected in sequence. The slurry heat exchangers are defined as the first slurry heat exchanger, the second slurry heat exchanger... the Nth slurry heat exchanger, and the leaching reactors are defined as the first leaching reactor, the second leaching reactor... the Lth leaching reactor. N and L are positive integers not less than 3. The pipes of the first slurry heat exchanger, the second slurry heat exchanger... the Nth slurry heat exchanger are connected in series on the feed pipeline, and the discharge end of the feed pipeline is connected to the first leaching reactor. The leaching reaction device also includes a heating device connected to the first leaching reactor, the Nth slurry heat exchanger, the N-1th slurry heat exchanger...the shell side of the first slurry heat exchanger is serially connected to the discharge pipeline, the feed end of the discharge pipeline is connected to the discharge port of the Lth leaching reactor, the discharge end of the discharge pipeline is connected to the flushing water trough and the discharge trough respectively through the discharge branch, each discharge branch is provided with a discharge branch switch valve, the feed end of the feed pipeline is connected to the slurry trough and the flushing water trough respectively through the feed branch, each feed branch is provided with a feed branch switch valve, and the discharge end of the feed pipeline is connected to the feed port of the first leaching reactor.

2. The lithium carbonate continuous leaching reaction device according to claim 1, characterized in that: The leaching reaction device also includes a chemical cleaning tank, the feed end of the feed pipeline is connected to the water outlet of the chemical cleaning tank through a feed branch, and the discharge end of the discharge pipeline is connected to the water inlet of the chemical cleaning tank through a discharge branch.

3. The lithium carbonate continuous leaching reaction device according to claim 1, characterized in that: Each feed branch is also provided with a delivery pump, and a high-pressure feeding pump is provided on the feed pipeline upstream of the first slurry heat exchanger.

4. The lithium carbonate continuous leaching reaction device according to claim 3, characterized in that: The delivery pump and high-pressure feeding pump are diaphragm pumps, plunger pumps or centrifugal pumps.

5. The lithium carbonate continuous leaching reaction device according to claim 1, characterized in that: The heating device comprises a steam buffer, which is connected to the steam inlet of each leaching reactor through steam pipes arranged in parallel.

6. The lithium carbonate continuous leaching reaction device according to claim 5, characterized in that: Each steam pipeline is serially connected with a steam regulating valve, a shut-off valve and a check valve.

7. The lithium carbonate continuous leaching reaction device according to claim 1, characterized in that: Each leaching reactor includes a reactor and a feed pipe and a discharge pipe connected to the reactor. The lower end of the feed pipe is located at the upper middle side of the reactor, and the lower end of the discharge pipe is located at the lower middle side of the reactor.

8. The lithium carbonate continuous leaching reaction device according to claim 1, characterized in that: A pressure regulating valve is provided on the discharge pipe downstream of the first slurry heat exchanger.

9. The lithium carbonate continuous leaching reaction device according to any one of claims 1 to 8, characterized in that: An isolation valve is provided on the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor, a reflux pipeline is provided between the feed pipeline connecting the tube side of the Nth slurry heat exchanger and the first leaching reactor and the discharge pipeline between the shell side of the Nth slurry heat exchanger and the Lth leaching reactor, and a reflux pipeline valve is provided on the reflux pipeline.

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