Lithium carbonate channelization continuous leaching reaction device

Abstract

The utility model relates to a lithium carbonate channelization continuous leaching reaction device, which comprises a slurry tank, a solution tank, a discharge tank, a discharge pipeline, a first feeding pipeline, a second feeding pipeline, a plurality of slurry heat exchangers, a plurality of solution heat exchangers and a plurality of leaching reactors, the tube passes of all the slurry heat exchangers are sequentially connected to the first feeding pipeline in series, the shell passes of all the solution heat exchangers and all the slurry heat exchangers are connected to the second feeding pipeline in series in a crossed mode, the first feeding pipeline and the second feeding pipeline are connected with the first leaching reactor, and the leaching reaction device further comprises a heating device connected with the first leaching reactor. And the pipe paths of all the solution heat exchangers are sequentially connected to the discharging pipeline in series. The utility model solves the problems that in the prior art, the heat exchange surface scabs seriously in the leaching process of the lithium-containing slurry, and solid materials in the shell layer of the heat exchange pipeline are deposited and cannot be cleaned in the waste heat utilization process of the leached slurry.

Description

Technical Field

[0001] This utility model relates to the field of metallurgy and chemical engineering, and in particular to a pipeline continuous leaching reaction device for lithium carbonate. Background Technology

[0002] In recent years, with the increasing demand for lithium in industries such as lithium batteries, lubricating greases, and tire rubber, as well as the expanding demand for lithium and its alloys in high-tech fields such as aerospace, aviation, and nuclear energy, the production of metallic lithium has also been growing. In 2016, China designated lithium as one of the 24 national strategic mineral resources, which is of great strategic significance to the national economy and national defense. Since becoming the world's largest lithium producer and consumer in 2019, my country's dependence on imported lithium raw materials has reached over 70%, making the secure supply of lithium resources a "bottleneck" problem restricting the development of my country's new energy industry. Lithium carbonate is the basic material for producing secondary lithium salts and metallic lithium, and is the most basic and important product in the lithium industry. Lithium carbonate is widely used in many fields such as electronic materials, chemicals, 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 is surging, and the demand is already insufficient, resulting in persistently high prices.

[0003] my country is rich in associated lithium resources in bauxite, especially in the central region where the lithium content is high, with Li₂O exceeding 0.1%. In the Bayer process of alumina production, approximately 80% of the lithium enters the solution during leaching. Alumina is a raw material for aluminum electrolysis, and long-term use of alumina with high lithium content can severely impact the electrolysis process, leading to reduced electrolysis temperature, deterioration of furnace regularity, decreased electrolysis production stability, reduced current efficiency, and increased energy consumption. Alumina plants in central my country generally have high Li₂O content in their products. If the Li₂O content in alumina is estimated at 0.1%, and the alumina production is estimated at 12 million tons per year, then the amount of Li₂CO₃ carried away by metallurgical-grade alumina annually would reach 63,428 tons, resulting in a significant waste of resources. Therefore, the efficient recovery and utilization of lithium resources in the alumina production process not only helps improve the quality of alumina products and eliminate adverse effects on downstream aluminum electrolysis, but also opens up new avenues for the economical and efficient utilization of low-grade lithium-rich bauxite, and is of great significance to my country's strategic security of lithium resources. Patents CN 115124052 A and CN 107500318 A disclose methods for preparing battery-grade lithium carbonate and extracting lithium carbonate from sodium aluminate solution in an alumina plant, respectively. These methods involve first adsorbing lithium from the alumina production process onto solid aluminum hydroxide to form lithium-rich aluminum hydroxide, then using a high-temperature wet leaching process to extract the lithium, providing raw materials for subsequent liquid-solid separation, impurity removal, concentration, and lithium precipitation. However, as this technology is in its early stages of industrialization, mature equipment for leaching lithium from lithium-rich aluminum hydroxide is currently unavailable.

[0004] The soda ash pressure leaching process for spodumene, proposed in the 1960s, is a method for preparing lithium carbonate from spodumene. It primarily involves reacting β-spodumene with a sodium carbonate solution at high temperature and pressure. Lithium in the spodumene is replaced by sodium ions in the solution and precipitates as lithium carbonate. Through a carbonation reaction, the sparingly soluble lithium carbonate produced in the pressure leaching reaction is converted to lithium bicarbonate, which dissolves in water and separates from the reaction residue (sofol). Finally, heating converts the lithium bicarbonate to lithium carbonate, which precipitates out. The soda ash pressure leaching process has advantages such as a short production flow, low material throughput, high product purity, and minimal corrosion to equipment. However, to date, there are no reports of this technology being applied in actual industrial production, nor are there any mature complete processes and equipment for the pressure leaching of lithium carbonate from soda ash.

[0005] The main purpose of leaching lithium carbonate using lithium-rich aluminum hydroxide and spodumene-soda ash pressure leaching is to extract lithium from the solid slurry, forming a lithium-containing solution to provide raw materials for subsequent liquid-solid separation, impurity removal, concentration, and lithium precipitation. Traditional leaching equipment is mainly similar to the pipeline leaching equipment used in the alumina industry. The lithium-containing ore slurry is preheated through a multi-stage waste steam preheater. After the steam indirectly heats the leaching temperature, it enters the leaching reactor for heat preservation leaching. The slurry after lithium carbonate leaching undergoes multi-stage flash evaporation to cool it before entering the discharge tank. The waste steam generated during flash evaporation is used to preheat the ore slurry.

[0006] The problems are as follows: Lithium carbonate has low solubility. The lithium carbonate solution is a mixture of lithium-containing ore and feed solution. The feed solution is usually water or alkaline solution. The alkaline solution can be sodium carbonate solution, and its solubility decreases with increasing temperature. During the heating and preheating of the slurry, lithium carbonate is prone to form scale on the heat exchange surface. The solution phase of the leaching slurry is 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 blockage of the flash evaporator outlet pipe and affecting the normal operation of the system. The raw ore slurry containing solids and the leaching slurry are prone to forming scale and deposits in the inner tube and shell of the shell-and-tube heat exchanger. The inner tube can be cleaned by hydraulic cleaning, but the scale and deposits formed between the shell layers are difficult to clean. Utility Model Content

[0007] The purpose of this invention is to provide a continuous pipeline leaching reaction device for lithium carbonate to solve the technical problems in the prior art, such as severe scaling on the heat exchange surface of lithium-containing slurry during the leaching of lithium carbonate, saturated precipitation of lithium carbonate during the utilization of waste heat of the leaching slurry, and accumulation of solid material in the shell of the heat exchange pipeline that cannot be cleaned.

[0008] To solve the above-mentioned technical problems, the technical solution of the lithium carbonate pipeline continuous leaching reaction device of this utility model is as follows:

[0009] A continuous pipelined leaching reactor for lithium carbonate includes a slurry tank for holding lithium-containing slurry, a solution tank for holding the loading solution, and a discharge tank. The leaching reactor also includes a discharge pipeline and a first feed pipeline and a second feed pipeline connected in parallel. The first feed pipeline is connected to the slurry tank, and the second feed pipeline is connected to the solution tank. The leaching reactor further includes multiple slurry heat exchangers, multiple solution heat exchangers, and multiple leaching reactors connected in sequence. Each slurry heat exchanger is defined as a first slurry heat exchanger, a second slurry heat exchanger, ..., the Nth slurry heat exchanger, and each solution heat exchanger is defined as a first solution heat exchanger, a second solution heat exchanger, ..., the Mth solution heat exchanger. Both the slurry heat exchangers and the solution heat exchangers are shell-and-tube type heat exchangers. The leaching reactors are designated as the first leaching reactor, the second leaching reactor, ..., the Lth leaching reactor, where N, M, and L are positive integers not less than 3. The tubes of the first slurry heat exchanger, the second slurry heat exchanger, ..., the Nth slurry heat exchanger are connected in series on the first feed pipe. The shells of each solution heat exchanger and each slurry heat exchanger are connected in series with each other on the second feed pipe. The outlet ends of the first feed pipe and the second feed pipe are connected together and then connected to the first leaching reactor. The leaching reaction device also includes a heating device connected to the first leaching reactor. The outlet pipe is connected between the Lth leaching reactor and the outlet tank. The tubes of the Mth solution heat exchanger, the M-1th solution heat exchanger, ..., the first solution heat exchanger are connected in series on the outlet pipe.

[0010] Furthermore, the heating device includes a steam inlet pipe connected to the first leaching reactor.

[0011] Furthermore, a slurry conveying pump is installed on the first feed pipe, and a solution conveying pump is installed on the second feed pipe.

[0012] Furthermore, the inlet of the first leaching reactor is connected to a feed pipe that is connected to the first feed pipe and the second feed pipe.

[0013] The beneficial effects of this utility model are as follows: In use, the slurry tank contains the raw ore slurry composed of lithium ore and a feed solution, while the solution tank contains the feed solution without lithium ore solids. That is, the raw ore slurry containing solids is transported to the first leaching reactor via the first feed pipe, while the feed solution without solids is transported to the first leaching reactor via the second feed pipe. The leaching slurry produced by each stage of the leaching reactor flows back to the discharge tank via the discharge pipe. The lithium concentrate leaching process requires heating the lithium concentrate to promote lithium leaching. After leaching... The slurry temperature is relatively high. The leaching slurry flows sequentially through the tube side of the Mth solution heat exchanger, the N-1th solution heat exchanger, and so on, through the first solution heat exchanger. Therefore, the solid-free feed solution flowing through the shell side of the solution heat exchanger can be heated. The heated solid-free feed solution then flows through the shell side of the slurry heat exchanger, thereby heating the raw ore slurry flowing through the tube side of the slurry heat exchanger. This increases the temperature of the raw ore slurry entering the leaching reactor, enabling the recovery and utilization of waste heat from the leaching slurry and reducing the energy consumption of the heating device.

[0014] In this invention, the raw ore slurry containing solid phase and the leachate slurry containing solid phase flow within the tube side (inner tube) of the shell-and-tube heat exchanger. The resulting scale and sludge can be removed by hydraulic cleaning. The material flowing within the shell side of the shell-and-tube heat exchanger is always a second feed solution free of solids. This solution will not form scale on the heat exchange surface, nor will it accumulate, thus avoiding the technical problem of the heat exchanger shell being impossible to clean. Attached Figure Description

[0015] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of this disclosure are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding portions, wherein:

[0016] Figure 1 This is a schematic diagram of one embodiment of a continuous pipeline leaching reaction device for lithium carbonate in this utility model;

[0017] 1. Slurry tank; 2. Solution tank; 3. Discharge tank; 4. Slurry pump; 5. Solution pump; 6. First feed line; 7. Second feed line; 8. First slurry heat exchanger; 9. Second slurry heat exchanger; 10. Third slurry heat exchanger; 11. Fourth slurry heat exchanger; 12. First solution heat exchanger; 13. Second solution heat exchanger; 14. Third solution heat exchanger; 15. Fourth solution heat exchanger; 16. Fifth solution heat exchanger; 17. Discharge line; 18. First check valve; 19. Second check valve; 20. Mixer; 21. Feed line; 22. First leaching reactor; 23. Second leaching reactor; 24. Third leaching reactor; 25. Steam inlet pipe. Detailed Implementation

[0018] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings show preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0019] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0020] An example of an embodiment of the lithium carbonate pipeline continuous leaching reaction device of this utility model is shown below. Figure 1 As shown:

[0021] The system includes a slurry tank 1, a solution tank 2, and a discharge tank 3. All three tanks are equipped with stirring devices. The slurry tank holds the batching solution and lithium-containing ore slurry; that is, it contains the lithium-containing batching solution, also known as the raw ore slurry, which is the raw ore slurry containing solids. The solution tank holds the batching solution, which contains the batching solution without lithium. The discharge tank is used for the precipitation of lithium carbonate crystals. The batching solution is water or sodium carbonate alkaline solution.

[0022] The leaching reactor also includes a discharge pipe and a first feed pipe 6 and a second feed pipe 7 connected in parallel. The leaching reactor also includes multiple leaching reactors connected in sequence. In this embodiment, there are three leaching reactors, denoted as L. Along the material flow direction, the three leaching reactors are the first leaching reactor 22, the second leaching reactor 23, and the third leaching reactor 24. Each leaching reactor is equipped with a stirring device. The third leaching reactor is connected to the discharge tank 3 via the discharge pipe 17. A slurry transfer pump 4 is installed on the first feed pipe, and a solution transfer pump 5 is installed on the second feed pipe.

[0023] A first check valve 18 is installed at the end of the first feed pipe 6, and a second check valve 19 is installed at the end of the second feed pipe 7. The inlet of the first leaching reactor is connected to a feed pipe 21 that is connected to the first and second feed pipes via a mixer 20. The leaching reaction apparatus also includes a heating device connected to the first leaching reactor. In this embodiment, the heating device includes a steam inlet pipe 25 connected to the first leaching reactor. In use, high-temperature, high-pressure steam is introduced into the first leaching reactor through the steam inlet pipe to directly heat the material in the first leaching reactor. In other embodiments of this utility model, the heating device can also be a heat exchanger that uses heat transfer oil, molten salt, or hot steam for indirect heating.

[0024] The leaching reaction apparatus also includes N slurry heat exchangers and M solution heat exchangers, where N and M are both positive integers not less than 3. In this embodiment, N is four and M is five. The slurry heat exchangers are defined as the first slurry heat exchanger 8, the second slurry heat exchanger 9, the third slurry heat exchanger 10, and the fourth slurry heat exchanger 11, and the solution heat exchangers are defined as the first solution heat exchanger 12, the second solution heat exchanger 13, the third solution heat exchanger 14, the fourth solution heat exchanger 15, and the fifth solution heat exchanger 16. All slurry heat exchangers and all solution heat exchangers are tubular heat exchangers. Tubular heat exchangers are existing technology, and their specific structure will not be described in detail here. A tubular heat exchanger includes a tube side and a shell side disposed around the tube side. During use, the two fluids to be exchanged flow through the tube side and the shell side, respectively.

[0025] In this embodiment, the tube sides of the first, second, third, and fourth slurry heat exchangers are sequentially connected in series on the first feed pipeline. The shell sides of each solution heat exchanger and each slurry heat exchanger are cross-connected in series on the second feed pipeline. That is, the feed solution in the solution tank flows sequentially through the shell sides of the first solution heat exchanger, the first slurry heat exchanger, the second solution heat exchanger, the second slurry heat exchanger, the third solution heat exchanger, the third slurry heat exchanger, the fourth solution heat exchanger, the fourth slurry heat exchanger, and the fifth solution heat exchanger before flowing through the second check valve to the feed pipeline.

[0026] The tubes of the fifth solution heat exchanger, the fourth solution heat exchanger, the third solution heat exchanger, the second solution heat exchanger, and the first solution heat exchanger are connected in series along the direction of the material in the discharge pipeline.

[0027] The discharge flow rate of the first feed pipe is 1 to 5 times that of the second feed pipe; the flow velocity of the first feed pipe is 0.5 to 3 m / s; and the temperature inside the leaching reactor is 150 to 300℃.

[0028] In other embodiments of this utility model, the number of solution heat exchangers can be selected as needed, such as three, four or other numbers; the number of slurry heat exchangers can be selected as needed, such as three, five or other numbers; the number of leaching reactors can be selected as needed, such as four, five or other numbers.

[0029] The process of using this utility model is as follows: the lithium-containing feed solution flows through the first feed pipe, sequentially through the tube side of the first slurry heat exchanger, the second slurry heat exchanger, the third slurry heat exchanger, and the fourth slurry heat exchanger, and then flows to the first leaching reactor through the feed pipe; the feed solution without lithium ore solid phase flows through the second feed pipe, sequentially through the shell side of the first solution heat exchanger, the shell side of the first slurry heat exchanger, the shell side of the second solution heat exchanger, the shell side of the second slurry heat exchanger, the shell side of the third solution heat exchanger, the shell side of the third slurry heat exchanger, the shell side of the fourth solution heat exchanger, the shell side of the fourth slurry heat exchanger, and the shell side of the fifth solution heat exchanger, and then flows to the first leaching reactor through the feed pipe. Steam heats the material in the first leaching reactor, and the material reacts in the first, second and third leaching reactors to generate a leaching slurry composed of lithium-containing solution and solid leaching residue. The slurry then flows sequentially through the tubes of the fifth, fourth, third, second and first solution heat exchangers via the discharge pipeline, and finally flows back to the discharge tank.

[0030] The solid-free feed solution in the second feed line exchanges heat with the leaching slurry in the tube side of each solution heat exchanger. After the lithium-free feed solution is heated, it flows through the shell side of the slurry heat exchanger and exchanges heat with the lithium-containing raw ore slurry in the tube side of the slurry heat exchanger. The lithium-containing raw ore slurry in the first feed line is heated. Finally, the solutions in the first feed line and the second feed line are combined and flow to the first leaching reactor. This achieves the recovery and utilization of waste heat from the leaching reactor, while also heating the reaction solution.

[0031] This utility model also has the following technical effects:

[0032] 1. The lithium carbonate slurry flows through the tube side (i.e., the inner tube) of the tubular heat exchanger, and its scale is easy to clean mechanically. The shell side of the tubular heat exchanger does not contain lithium solution, so there is no problem of solid particles accumulating and being difficult to clean.

[0033] 2. The leaching slurry is heated directly by steam, without a heat exchange surface, thus eliminating the problem of scaling on the heat exchange surface.

[0034] 3. The leaching unit does not contain a slurry flash evaporation system, thus avoiding the scaling problem in the flash evaporator and flash evaporator discharge pipe caused by the precipitation of lithium carbonate crystals due to the increase in lithium carbonate concentration during the flash evaporation process.

[0035] 4. It can achieve continuous leaching of lithium carbonate, and the waste heat of the leaching slurry is recovered and utilized relatively fully.

[0036] In the foregoing description of this specification, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "joined" should be interpreted broadly. For example, the term "joined" can refer to 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; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this specification, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] Based on the above description in this specification, those skilled in the art will also understand that terms used, such as "upper," "lower," "front," "rear," "left," "right," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "center," "longitudinal," "transverse," "clockwise," or "counterclockwise," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not imply that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0038] Furthermore, the terms "first" or "second," etc., used in this specification to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as indicating, explicitly or implicitly, relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this specification, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A continuous pipeline leaching reactor for lithium carbonate, characterized in that: The leaching reactor includes a slurry tank for holding the raw ore slurry containing lithium ore, a solution tank for holding the loading solution, and a discharge tank. The reactor also includes a discharge pipeline and a first feed pipeline and a second feed pipeline connected in parallel. The first feed pipeline is connected to the slurry tank, and the second feed pipeline is connected to the solution tank. The reactor further includes multiple slurry heat exchangers, multiple solution heat exchangers, and multiple leaching reactors connected in sequence. Each slurry heat exchanger is defined as the first slurry heat exchanger, the second slurry heat exchanger, ..., the Nth slurry heat exchanger, and each solution heat exchanger is defined as the first solution heat exchanger, the second solution heat exchanger, ..., the Mth solution heat exchanger. Both the slurry heat exchangers and the solution heat exchangers are shell-and-tube type heat exchangers. Each leaching reactor is... The leaching reactor is designated as the first leaching reactor, the second leaching reactor, ..., the Lth leaching reactor, where N, M, and L are positive integers not less than 3. The tubes of the first slurry heat exchanger, the second slurry heat exchanger, ..., the Nth slurry heat exchanger are connected in series on the first feed pipe. The shells of each solution heat exchanger and each slurry heat exchanger are connected in series on the second feed pipe. The outlet ends of the first feed pipe and the second feed pipe are connected and then connected to the first leaching reactor. The leaching reaction device also includes a heating device connected to the first leaching reactor. The outlet pipe is connected between the Lth leaching reactor and the outlet tank. The tubes of the Mth solution heat exchanger, the M-1th solution heat exchanger, ..., the first solution heat exchanger are connected in series on the outlet pipe.

2. The continuous leaching reactor for lithium carbonate via pipeline according to claim 1, characterized in that: The heating device includes a steam inlet pipe connected to the first leaching reactor.

3. The continuous leaching reactor for lithium carbonate pipeline according to claim 1 or 2, characterized in that: The inlet of the first leaching reactor is connected to a feed pipe that is connected to the first feed pipe and the second feed pipe.

Images