Apparatus and method for producing lithium sulfide

Abstract

This invention relates to the field of chemical equipment technology, and discloses a lithium sulfide preparation device and method, comprising: an insulated shell; a reactor rotatably disposed inside the insulated shell, with a heating chamber formed between the reactor and the insulated shell; a rotating shaft fixed to one end of the reactor, passing through one end of the insulated shell and rotatably engaging with a support assembly; a rotating assembly connected to the rotating shaft to drive its rotation; and a heat source inlet pipe fixed to one end face of the insulated shell to communicate with the interior of the heating chamber. This invention utilizes a dynamic reactor, causing the solid material to continuously tumble and shift during the reaction process, greatly increasing the contact area between the solid phase and the gaseous hydrogen sulfide, enhancing mass transfer efficiency, significantly improving product purity and reaction efficiency, shortening the production cycle, reducing equipment investment and energy consumption, and facilitating large-scale industrial production of high-purity lithium sulfide.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, specifically to an apparatus and method for preparing lithium sulfide. Background Technology

[0002] Lithium sulfide, as a key raw material for next-generation solid-state battery electrolytes, has a decisive impact on battery performance due to its purity, crystallinity, and stability. However, lithium sulfide is chemically reactive, readily reacting with water and oxygen, and its preparation process easily generates intermediate impurities such as polysulfides or lithium hydrosulfide, posing a significant challenge to the industrial production of high-purity lithium sulfide. Currently, the industry mainly employs dry ball milling, solvothermal methods, metathesis methods, and thermal reduction methods for its preparation.

[0003] Existing lithium sulfide reaction equipment is mostly static, resulting in poor contact between raw materials during the reaction. Dry ball milling is costly and can easily introduce unreacted metallic lithium or lithium polysulfide impurities. Solvent-thermal methods use flammable and explosive organic solvents, posing significant safety risks, and moisture in the system is difficult to remove. More importantly, in traditional gas-solid reaction systems, if the water vapor generated during the reaction cannot be discharged in time, it will lead to reversible reaction and promote the excessive accumulation of the intermediate product lithium hydrosulfide, making it difficult for the reaction to proceed to completion. Therefore, we propose a lithium sulfide preparation equipment and method. Summary of the Invention

[0004] The purpose of this invention is to provide a lithium sulfide preparation apparatus and method to solve the problems mentioned in the background art, which are mostly static equipment. In the traditional route for preparing lithium sulfide, the water vapor generated by the reaction is difficult to remove, leading to reversible reaction or excessive generation of intermediate product lithium hydrosulfide, making it difficult for the reaction to reach completeness and resulting in low purity.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a lithium sulfide preparation apparatus, comprising:

[0006] An insulated shell, the outer surface of which has a support assembly for support;

[0007] The reactor is rotatably disposed inside the insulation shell, and a heating chamber is formed between the reactor and the insulation shell;

[0008] A rotating shaft is fixed to one end of the reactor and rotates through one end of the insulation shell to engage with the support assembly.

[0009] A rotary assembly is connected to the shaft to drive its rotation;

[0010] A heat source inlet pipe is fixed to one end face of the insulation shell to communicate with the interior of the heating chamber, so as to adjust the reactor temperature through the heating chamber.

[0011] Preferably, the support assembly includes a base, a support, a roller, and a support block. Two supports are fixed on the base to cooperate with the two ends of the side wall of the insulation shell, respectively. The roller is disposed inside the base to provide rotational support for the other end of the reactor. The support block is fixed to one end of the upper surface of the base and has a bearing seat connected to the rotating shaft.

[0012] Preferably, the rotary assembly includes a motor and a rotary gear. The rotary gear is fixed to the outer surface of the rotating shaft, the motor is mounted on the base, and the output end of the motor is provided with a drive gear. The drive gear and the rotary gear are connected by a chain.

[0013] Preferably, the rotating shaft is fitted to the heat-insulating shell by a sealed bearing, and the rotating shaft has an inlet that communicates with the inside of the reactor to allow gas to enter.

[0014] Preferably, a first discharge port is provided at one end of the reactor, and a second discharge port communicating with the interior of the reactor is provided at the first discharge port. A feeding port is provided on the upper surface of one end of the reactor.

[0015] Preferably, a first sealing block is fixed to the inner wall of the other end of the heat-insulating shell, and a second sealing block corresponding to the first sealing block is fixed to the outer wall of the reactor along its circumference. The second sealing block and the side corresponding to the first sealing block are provided with air guide grooves for guiding airflow, and the cross-section of the air guide grooves is "J" shaped.

[0016] A method for preparing lithium sulfide, using the aforementioned preparation equipment, includes the following steps:

[0017] Step A: Place the lithium compound raw material in a reactor with a rotary function, heat the reactor to the reaction temperature under the protection of inert gas, then stop the inert gas supply and introduce hydrogen sulfide gas into the reactor to carry out the reaction.

[0018] Step B: During the reaction, hydrogen sulfide gas is continuously introduced and tail gas containing water vapor is simultaneously emitted. The flowing hydrogen sulfide gas is used to quickly carry away the water generated in the reaction system until the water content in the emitted tail gas is detected to be zero. Then the hydrogen sulfide gas is stopped, and a mixture containing lithium sulfide and lithium hydrosulfide is obtained.

[0019] Step C: Dry inert gas is introduced into the reactor for displacement, and under the condition of maintaining heating, the lithium hydrosulfide undergoes a high-temperature decomposition reaction until the hydrogen sulfide content in the exhaust gas is detected to be zero, thereby obtaining the lithium sulfide product.

[0020] Preferably, the lithium-containing compound raw material is one or more of lithium hydroxide, lithium oxide, or lithium carbonate.

[0021] Preferably, in step C, the temperature of the high-temperature decomposition reaction of lithium hydrosulfide is 500-550℃.

[0022] Preferably, after obtaining the lithium sulfide product in step C, the cooled lithium sulfide product is packaged into packaging containers that have undergone nitrogen purging and vacuum treatment under air-isolated and dry conditions for packaging.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention utilizes a dynamic reactor, causing the solid material to continuously tumble and shift during the reaction process. This significantly increases the contact area between the solid and gaseous hydrogen sulfide phases, enhancing mass transfer efficiency. Simultaneously, the high-speed flow of hydrogen sulfide gas rapidly carries away the water generated during the reaction, thereby inhibiting the reversible reaction between lithium sulfide and water and driving the reaction towards the formation of lithium hydrosulfide. Subsequently, within the same equipment, the temperature is increased to the decomposition range of lithium hydrosulfide, allowing it to be pyrolyzed in situ into high-purity lithium sulfide, releasing recyclable hydrogen sulfide gas. The entire process requires no material transfer, avoiding intermediate exposure and contamination. Compared with existing technologies, this invention significantly improves product purity and reaction efficiency, shortens the production cycle, and reduces equipment investment and energy consumption, providing a practical solution for the large-scale industrial production of high-purity lithium sulfide. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the mating structure of the rotating shaft and the support block of the present invention;

[0027] Figure 3 This is a schematic cross-sectional view of the thermal insulation shell of the present invention;

[0028] Figure 4 For the present invention Figure 3 A magnified structural diagram at point A;

[0029] Figure 5 This is a diagram illustrating the airflow direction effect of the present invention;

[0030] Figure 6 This is a schematic diagram of the rotating component structure of the present invention;

[0031] Figure 7 This is a schematic diagram of the device and external connections of the present invention.

[0032] In the diagram: 1. Base; 11. Feed inlet; 12. Flange pipe; 2. Support; 3. Support roller; 4. Reactor; 5. Insulated shell; 6. Support block; 63. Bearing seat; 7. Rotating shaft; 71. Motor; 72. Rotary gear; 73. Drive gear; 8. Heat source inlet pipe; 9. First outlet; 10. Feeding port; 111. First sealing block; 112. Second sealing block; 113. Air guide groove; 131. Inlet rigid pipe; 132. Connecting hose; 133. Connecting pipe; 134. Outlet hose. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] Please see Figures 1-7 The present invention provides a technical solution: a lithium sulfide preparation apparatus, comprising:

[0036] The insulation shell 5 has a support assembly on its outer surface for support;

[0037] Reactor 4 is rotatably mounted inside the insulation shell 5. A heating chamber is formed between reactor 4 and insulation shell 5. A flange tube 12 can also be provided on the lower surface of one end of reactor 4 so that a temperature sensor can be installed through the flange tube 12 to achieve more comprehensive monitoring of the temperature inside the heating chamber.

[0038] The rotating shaft 7 is fixed to one end of the reactor 4 and passes through one end of the heat-insulating shell 5 to rotate with the support assembly;

[0039] A rotary assembly is connected to the rotating shaft 7 to drive its rotation;

[0040] The heat source inlet pipe 8 is fixed to one end face of the heat insulation shell 5 to communicate with the inside of the heating chamber, so as to adjust the temperature of the reactor 4 through the heating chamber;

[0041] The heating chamber formed between the insulation shell 5 and the reactor 4 allows heat to be evenly distributed along the outer wall of the reactor 4. Multiple heat source inlet pipes 8 are provided, on which electric heaters can be installed. One end of the electric heater is inserted into the inner side of the heating chamber to electrically heat the air inside the heating chamber, thereby controlling the temperature of the reaction system. This forms the equipment basis for the gas-solid reaction to prepare high-purity lithium sulfide. When the reactor 4 moves, it is a reciprocating periodic motion, not a continuous rotation. Preferably, the reactor 4 rotates half a revolution and then returns to the initial position, and the rotation is performed periodically.

[0042] Preferably, the support assembly includes a base 1, a support 2, a roller 3, and a support block 6. The two supports 2 are fixed on the base 1 to cooperate with the two ends of the side wall of the insulation shell 5 respectively. The base 1 can be arranged at an angle so that after the raw materials react inside the reactor 4, the product obtained is discharged from the first outlet 9. The roller 3 is set inside the base 1 to provide rotational support for the other end of the reactor 4. The setting of the roller 3 enhances the stability of the reactor 4 during rotation and provides reliable support for the reciprocating rotation of the reactor 4 for a long time. The support block 6 is fixed to one end of the upper surface of the base 1, and the support block 6 has a bearing seat 63 connected to the rotating shaft 7. The bearing seat 63 can be fixed to the upper surface of the support block 6 by bolts to limit the rotating shaft 7 so that it can only rotate axially.

[0043] The rotary assembly includes a motor 71 and a rotary gear 72. The rotary gear 72 is fixed to the outer surface of the rotating shaft 7. The motor 71 is mounted on the base 1, and the output end of the motor 71 is provided with a drive gear 73. The drive gear 73 and the rotary gear 72 are connected by a chain.

[0044] Existing lithium sulfide reaction equipment is mostly a static reactor or a simple rotary kiln. In this invention, a motor 71 and a gearbox work together to drive a drive gear 73 to rotate. The rotating shaft 7 serves as the main shaft for transmitting rotary motion. The torque generated by the motor 71 is transmitted through a chain to drive the rotary gear 72 to rotate, thereby smoothly introducing it into the reactor 4 and realizing the rotary motion of the reactor 4. This ensures that the internal materials and hydrogen sulfide gas are in full contact and the reaction interface is continuously renewed. The bearing seat 63 is fixed on the support block 6, providing precise rotational constraints for the rotating shaft 7. This effectively bears the radial load and axial thrust generated by the reactor 4 after loading materials, ensuring the coaxiality and reliability of the rotary motion under high-temperature conditions. This provides a foundation for the equipment to achieve efficient material turning and enhanced reaction mass transfer.

[0045] Preferably, the rotating shaft 7 and the insulation shell 5 are connected by a sealed bearing, which ensures smooth rotation and establishes a reliable airtight barrier at the dynamic connection between the insulation shell 5 and the rotating shaft 7, effectively preventing heat loss from the heating chamber along the shaft gap and preventing external air or impurities from entering the reaction system. Furthermore, the rotating shaft 7 and the insulation shell 5 can also be insulated and sealed with insulation cotton to reduce heat loss. The rotating shaft 7 is provided with a feed port 11 that communicates with the inside of the reactor 4 to allow gas to be introduced, so that hydrogen sulfide gas raw material can be introduced into the reactor 4 through the feed port 11.

[0046] Preferably, a first discharge port 9 is provided at one end of the reactor 4, and a second discharge port communicating with the interior of the reactor 4 is provided on the first discharge port 9. A feeding port 10 is provided on the upper surface of one end of the reactor 4.

[0047] Hydrogen sulfide gas is introduced into the reactor 4 through the feed inlet 11, and then the hydrogen sulfide tail gas is discharged through the second outlet. The first outlet 9 is the product outlet, and the raw materials for the reaction can also be fed into the reactor 4 through the first outlet 9.

[0048] like Figure 7 As shown, during use, the inlet rigid tube 131 is fixed on the rotating shaft 7 to communicate with the inside of the feed port 11, and the outer surface of the inlet rigid tube 131 along its tube direction is fixed to the inner opening of the edge of the rotary gear 72 to improve the installation stability of the inlet rigid tube 131. One end of the inlet rigid tube 131 is provided with a connecting hose 132 that connects to the external hydrogen sulfide storage tank. The connecting pipe 133 is connected to the second discharge port, and one output end of the connecting pipe 133 is connected to an outlet hose 134 that discharges the gas inside the reactor 4.

[0049] When reactor 4 stops moving, the reaction raw materials are fed into its inner side through the feed port 10, and then the feed port 10 is sealed. Motor 71 drives reactor 4 to rotate periodically through shaft 7. Hydrogen sulfide enters the inner side of reactor 4 through connecting hose 132 and inlet hard pipe 131 in sequence. The longer inlet hard pipe 131 can buffer the speed of hydrogen sulfide entering the inner side of reactor 4, so that hydrogen sulfide and other reaction raw materials can be contacted and mixed in the middle of the inner side of reactor 4, so that the materials inside reactor 4 can react fully. The gas generated in the reaction is discharged to the outside through connecting pipe 133 and outlet hose 134 until the reaction is complete and the product is obtained. Then reactor 4 stops moving. Since base 1 can be tilted, the product reacted inside reactor 4 can be discharged by opening the first discharge port 9. Alternatively, base 1 can be horizontally arranged, and a hanging ring can be set at one end of the upper surface of insulation shell 5. After the product is obtained, the lifting component cooperates with the hanging ring to tilt insulation shell 5 and reactor 4 so that the product can be poured out from the first discharge port 9.

[0050] Preferably, a first sealing block 111 is fixed to the inner wall of the other end of the heat-insulating shell 5, and a second sealing block 112 corresponding to the first sealing block 111 is fixed to the outer wall of the reactor 4 along its circumference. The second sealing block 112 and the side corresponding to the first sealing block 111 are provided with air guide grooves 113 for guiding airflow, and the cross-section of the air guide grooves 113 is "J" shaped.

[0051] like Figure 4 As shown, both the first sealing block 111 and the second sealing block 112 are annular with a gap between them. This prevents wear between them when the reactor 4 rotates, reducing the frequent maintenance issues caused by conventional rubber contact seals. After sealing in this invention, the airflow inside the heating chamber is as follows... Figure 5As shown, after the temperature inside the heating chamber rises, the hot airflow from the heating chamber to the outside is obstructed by the air guide groove 113. At the same time, the obstructed part of the hot airflow is guided back to the inside of the heating chamber. The air guide groove 113 also guides the external airflow into the inside of the heating chamber. Thus, the external airflow and the returned airflow move in opposite directions with the hot airflow flowing to the outside, further obstructing the loss of hot airflow to the outside, thereby enhancing the sealing and heat preservation effect. There is a slight leakage at this point, but it will not affect the surrounding environment and the leakage amount is extremely small. Users can also arrange a hot airflow recovery component at the end of the outer surface of the insulation shell 5 for recycling. In this invention, the material of the first sealing block 111 and the second sealing block 112 is preferably insulation cotton or silica aerogel. Alternatively, it can be made directly from metal blocks to cooperate with the insulation layer inside the air guide groove 113 to achieve good heat preservation and sealing.

[0052] A method for preparing lithium sulfide, using a preparation device, includes the following steps:

[0053] Step A: Place the lithium compound raw material in a rotary reactor 4, heat the reactor 4 to the reaction temperature under inert gas protection, then stop the inert gas supply and introduce hydrogen sulfide gas into the reactor to carry out the reaction.

[0054] Step B: During the reaction, a high concentration of hydrogen sulfide gas is continuously introduced, and tail gas containing water vapor is simultaneously emitted. The high-speed flow of hydrogen sulfide gas is used to quickly carry away the water generated in the reaction system until the water content in the emitted tail gas is detected to be zero. Then the hydrogen sulfide gas is stopped, and a mixture containing lithium sulfide and lithium hydrosulfide is obtained.

[0055] Step C: Dry inert gas is introduced into reactor 4 for displacement, and under the condition of maintaining heating, lithium hydrosulfide undergoes a high-temperature decomposition reaction until the hydrogen sulfide content in the emission gas is detected to be zero, thus obtaining a high-purity lithium sulfide product.

[0056] Among the existing processing methods, dry ball milling has high raw material costs and long reaction times, and unreacted lithium metal or lithium polysulfide impurities are easily introduced during the ball milling process; solvothermal methods use flammable and explosive organic solvents, posing significant safety risks, and moisture in the system is difficult to remove; metathesis methods have lower raw material costs, but it is difficult to remove impurities such as chloride ions; thermal reduction methods have stringent requirements for equipment pressure resistance and corrosion resistance, making large-scale continuous production difficult; carbothermal reduction methods have high energy consumption, and the products are easily contaminated by carbon. More importantly, in traditional gas-solid reaction systems, if the water vapor generated by the reaction cannot be discharged in time, it will lead to reversible reaction and promote the excessive accumulation of intermediate lithium hydrosulfide, making it difficult for the reaction to proceed to completion;

[0057] In this invention, lithium-containing raw materials are placed in reactor 4 and sequentially undergo a hydrogen sulfide reaction stage and a high-temperature pyrolysis stage under inert gas protection. Steps A and B involve continuously introducing high-concentration hydrogen sulfide while simultaneously emitting water-containing tail gas. The high-speed gas flow immediately removes the water generated in the reaction from the reaction system, suppressing the reversible reaction between lithium sulfide and water from a kinetic perspective and pushing the reaction equilibrium to shift deeply towards the formation of lithium hydrosulfide. Step C involves in-situ high-temperature pyrolysis after the hydrogen sulfide supply is stopped, decomposing lithium hydrosulfide into lithium sulfide and releasing hydrogen sulfide gas, thus completing the final conversion of the target product. This method completes two key reactions in stages within the same reactor 4 without the need for intermediate material transfer, avoiding the risks of moisture absorption and oxidation during product transfer. It achieves a truly one-step high-purity lithium sulfide preparation, with comprehensive advantages of simple process, continuous operation, and high product purity.

[0058] The reaction formula of this invention is as follows:

[0059]

[0060] Preferably, the lithium-containing compound raw material is one or more of lithium hydroxide, lithium oxide, or lithium carbonate;

[0061] When lithium hydroxide or lithium oxide is selected, it can react directly with hydrogen sulfide in a medium temperature range. When lithium carbonate, which is cheaper, is selected, thermal decomposition pretreatment can be completed in the equipment to generate lithium oxide before the subsequent sulfidation reaction. All three raw materials can be converted into high-purity lithium sulfide by the method of this invention, which shows that the technical solution has good compatibility with different lithium source precursors. When the lithium compound raw material is lithium hydroxide or lithium oxide, the reaction temperature in step A is controlled at 300-550℃. When the lithium compound raw material is lithium carbonate, in step A, lithium carbonate needs to be decomposed at 750-850℃ to generate lithium oxide, and then cooled to 300-500℃ before hydrogen sulfide gas is introduced for reaction.

[0062] Preferably, in step C, the temperature of the high-temperature decomposition reaction of lithium hydrosulfide is 500-550°C;

[0063] This temperature range is an optimized range determined based on the thermal decomposition kinetics of lithium hydrosulfide: under this temperature condition, lithium hydrosulfide can complete the conversion to lithium sulfide at a suitable rate, and the released hydrogen sulfide gas can be effectively escaped and recovered by the tail gas system, promoting the decomposition reaction to be more complete. If the temperature is too low, the decomposition rate will be slow, and the residual lithium hydrosulfide will affect the purity of the product; if the temperature is too high, it may lead to excessive growth of lithium sulfide grains or sintering, affecting the activity of subsequent product processing.

[0064] Preferably, in step A, before the raw materials are fed into the reactor 4, the air inside the reactor 4 is replaced with nitrogen so that the oxygen content is detected to be zero.

[0065] To fundamentally eliminate the interference of oxygen and moisture on the reaction process, lithium sulfide and its precursors are extremely sensitive to water and oxygen in the air. Even a small amount of exposure can lead to product oxidation and deterioration, or the formation of lithium hydroxide byproducts, which seriously damages the purity of the product. By replacing the gas with nitrogen and reducing the oxygen content to zero before the reaction starts, a strictly anhydrous initial environment is created for the subsequent hydrogen sulfide reaction stage. This is a necessary prerequisite to ensure that the final product meets the high-purity battery-grade standard.

[0066] Preferably, after obtaining the high-purity lithium sulfide product in step C, the cooled high-purity lithium sulfide product is packaged into packaging containers that have been purged with nitrogen and vacuumed under air-isolated and dry conditions for packaging.

[0067] The packaging containers are pre-treated with nitrogen purging and vacuum circulation to eliminate the potential risk of product corrosion from moisture adsorbed on the inner wall of the container and residual oxygen inside; filling and sealing are completed in an air-isolated environment to ensure that the lithium sulfide product is in an inert protected state throughout the entire chain from discharge from reactor 4 to terminal storage.

[0068] Example 2

[0069] A method for preparing lithium sulfide, using the pilot-scale apparatus of the equipment described in Example 1, wherein reactor 4 in the pilot-scale apparatus is 1 meter in length, is an intermediate test conducted before formal production, mainly used to verify whether the product can be mass-produced and the stability of the process, and also includes the following methods:

[0070] Lithium sulfide is prepared by reacting lithium hydroxide with gaseous hydrogen sulfide.

[0071] Weigh 200g of lithium hydroxide and add it to reactor 4, which is equipped with a heating function. The temperature is controlled at 300-550℃. Nitrogen gas is used for purging. The oxygen content is tested and found to be zero. Hydrogen sulfide gas is then introduced. At the same time, hydrogen sulfide is discharged while ensuring the temperature is maintained. The change in the moisture content of the discharged hydrogen sulfide is detected. When the moisture content of the discharged hydrogen sulfide is zero, the hydrogen sulfide is stopped. Reactor 4 is then purged with dry nitrogen gas. Note that the temperature of reactor 4 should be controlled at 500-550℃ at this time. The hydrogen sulfide content in the gas discharged from reactor 4 is detected. When the hydrogen sulfide content in the gas discharged from reactor 4 is zero, the nitrogen purging is stopped. The temperature is then lowered to room temperature and the product is prepared for packaging.

[0072] The lithium sulfide product obtained was verified using the above equipment and methods, and its weight was 143g.

[0073] Example 3

[0074] A method for preparing lithium sulfide, using the pilot-scale apparatus of the equipment described in Example 1, wherein reactor 4 in the pilot-scale apparatus is 1 meter in length, is an intermediate test conducted before formal production, mainly used to verify whether the product can be mass-produced and the stability of the process, and also includes the following methods:

[0075] Lithium sulfide is prepared by reacting lithium oxide with gaseous hydrogen sulfide.

[0076] Weigh 200g of lithium oxide and add it to reactor 4, which is equipped with a heating function. The temperature is controlled at 300-550℃. Nitrogen gas is used for purging. The oxygen content is checked and found to be zero. Hydrogen sulfide gas is then introduced. At the same time, hydrogen sulfide is discharged while ensuring the temperature is maintained. The change in the moisture content of the discharged hydrogen sulfide is monitored. When the moisture content of the discharged hydrogen sulfide is zero, the hydrogen sulfide is stopped. Reactor 4 is then purged with dry nitrogen gas. Note that the temperature of reactor 4 should be controlled at 500-550℃ at this time. The hydrogen sulfide content in the gas discharged from reactor 4 is monitored. When the hydrogen sulfide content in the gas discharged from reactor 4 is zero, the nitrogen purging is stopped. The temperature is then lowered to room temperature and the product is ready for packaging.

[0077] The lithium sulfide product obtained was verified using the above equipment and methods, and its weight was 216g.

[0078] Example 4

[0079] A method for preparing lithium sulfide, using the pilot-scale apparatus of the equipment described in Example 1, wherein reactor 4 in the pilot-scale apparatus is 1 meter in length, is an intermediate test conducted before formal production, mainly used to verify whether the product can be mass-produced and the stability of the process, and also includes the following methods:

[0080] Lithium sulfide is prepared by reacting lithium carbonate with gaseous hydrogen sulfide.

[0081] Weigh 200g of lithium carbonate and add it to reactor 4, which is equipped with a heating function. The temperature is controlled at 750-850℃. Nitrogen gas is used for purging. The oxygen content is tested and found to be zero. After maintaining the temperature for 4 hours, the temperature is lowered to 300-500℃. Hydrogen sulfide gas is introduced. At the same time, hydrogen sulfide is discharged while ensuring the temperature is maintained. The change in the moisture content of the discharged hydrogen sulfide is detected. When the moisture content of the discharged hydrogen sulfide is zero, the hydrogen sulfide is stopped. Reactor 4 is then purged with dry nitrogen gas. Note that the temperature of reactor 4 should be controlled at 500-550℃ at this time. The hydrogen sulfide content in the gas discharged from reactor 4 is detected. When the hydrogen sulfide content in the gas discharged from reactor 4 is zero, the nitrogen purging is stopped. The temperature is then lowered to room temperature and the product is ready for packaging.

[0082] The lithium sulfide product obtained through the above equipment and methods weighed 91g.

[0083] That is, through the above embodiments two to four, it can be verified that the yield of this equipment and method is about 70%, the process is stable, and it can be used for large-scale production.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for preparing lithium sulfide, characterized in that, include: The thermal insulation shell (5) has a support assembly on its outer surface; The reactor (4) is rotatably disposed inside the heat-insulating shell (5), and a heating chamber is formed between the reactor (4) and the heat-insulating shell (5); The rotating shaft (7) is fixed to one end of the reactor (4) and rotates through one end of the heat-insulating shell (5) to engage with the support assembly. A rotary assembly is connected to the rotating shaft (7) to drive its rotation; The heat source inlet pipe (8) is fixed to one end face of the heat insulation shell (5) to communicate with the inside of the heating chamber, so as to adjust the temperature of the reactor (4) through the heating chamber.

2. The lithium sulfide preparation apparatus according to claim 1, characterized in that: The support assembly includes a base (1), a support (2), a roller (3) and a support block (6). The two supports (2) are fixed on the base (1) to cooperate with the two ends of the side wall of the heat insulation shell (5) respectively. The roller (3) is set inside the base (1) to support the other end of the reactor (4) for rotation. The support block (6) is fixed on one end of the upper surface of the base (1) and has a bearing seat (63) connected to the rotating shaft (7).

3. The lithium sulfide preparation apparatus according to claim 2, characterized in that: The rotary assembly includes a motor (71) and a rotary gear (72). The rotary gear (72) is fixed on the outer surface of the rotating shaft (7). The motor (71) is mounted on the base (1), and the output end of the motor (71) is provided with a drive gear (73). The drive gear (73) and the rotary gear (72) are connected by a chain.

4. The lithium sulfide preparation apparatus according to claim 1, characterized in that: The rotating shaft (7) is connected to the heat-insulating shell (5) by a sealed bearing, and the rotating shaft (7) is provided with an inlet (11) that communicates with the inside of the reactor (4) to allow gas to enter.

5. The lithium sulfide preparation apparatus according to claim 1, characterized in that: The reactor (4) is provided with a first discharge port (9) at one end, and the first discharge port (9) has a second discharge port that communicates with the inside of the reactor (4). The upper surface of one end of the reactor (4) is provided with a feeding port (10).

6. The lithium sulfide preparation apparatus according to claim 1, characterized in that: The inner wall of the other end of the heat-insulating shell (5) is fixed with a first sealing block (111), and the outer wall of the reactor (4) is fixed with a second sealing block (112) corresponding to the first sealing block (111) along its circumference. The second sealing block (112) and the side corresponding to the first sealing block (111) are both provided with air guide grooves (113) for guiding airflow, and the cross-section of the air guide groove (113) is "J" shaped.

7. A method for preparing lithium sulfide, using the preparation equipment described in any one of claims 1-6, characterized in that, Includes the following steps: Step A: Place the lithium compound raw material in a reactor (4) with a rotary function, heat the reactor (4) to the reaction temperature under the protection of inert gas, then stop the inert gas supply and introduce hydrogen sulfide gas into the inside of the reactor to carry out the reaction. Step B: During the reaction, hydrogen sulfide gas is continuously introduced and tail gas containing water vapor is simultaneously emitted. The flowing hydrogen sulfide gas is used to quickly carry away the water generated in the reaction system until the water content in the emitted tail gas is detected to be zero. Then the hydrogen sulfide gas is stopped, and a mixture containing lithium sulfide and lithium hydrosulfide is obtained. Step C: Dry inert gas is introduced into the reactor (4) for replacement, and under the condition of maintaining heating, the lithium hydrosulfide undergoes a high-temperature decomposition reaction until the hydrogen sulfide content in the emission gas is detected to be zero, and lithium sulfide product is obtained.

8. The method for preparing lithium sulfide according to claim 7, characterized in that: The lithium-containing compound raw material is one or more of lithium hydroxide, lithium oxide, or lithium carbonate.

9. The method for preparing lithium sulfide according to claim 7, characterized in that: In step C, the temperature of the high-temperature decomposition reaction of lithium hydrosulfide is 500-550℃.

10. A method for preparing lithium sulfide according to claim 7, characterized in that: After obtaining the lithium sulfide product in step C, the cooled lithium sulfide product is packaged into packaging containers that have undergone nitrogen purging and vacuum treatment under air-isolated and dry conditions.

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