A method and device for preparing high-purity lithium sulfide based on a dynamic tubular reactor

Abstract

The application discloses a preparation method and device of high-purity lithium sulfide based on a dynamic tubular reactor and belongs to the technical field of lithium battery material preparation, and specifically comprises the following steps: in a vertical dynamic tubular reactor, a mixed slurry of solid reactants and organic solvents is introduced by using a peristaltic pump, and mixed gas is introduced; the materials are efficiently mixed and rapidly react; the reaction is continuously carried out; the reaction liquid is transported to a first evaporator to remove the organic solvents to obtain crude lithium sulfide; a mixed liquid obtained by dissolving the crude lithium sulfide with a washing agent is continuously washed in a horizontal dynamic tubular reactor to remove lithium salts or polysulfides that may be generated; then, the mixed liquid is transported to a second evaporator to remove the solvents to obtain preliminarily dried lithium sulfide; and the preliminarily dried lithium sulfide is subjected to deep drying at a high temperature with a carrier gas in a fluidized bed to obtain dried lithium sulfide. The application not only significantly reduces the process land area and the single-batch material processing capacity, effectively reduces the hydrogen sulfide leakage risk and harm, and improves the safety of the process.

Description

Technical Field

[0001] This invention relates to a method and apparatus for preparing high-purity lithium sulfide based on a dynamic tubular reactor, belonging to the field of lithium battery material preparation technology. Background Technology

[0002] With the rapid development of solid-state battery technology, sulfide solid electrolytes have become a research hotspot due to their extremely high ionic conductivity. Lithium sulfide (Li2S) is a key raw material for synthesizing sulfide electrolytes (such as LiGPS, LiSiPS, etc.), and breakthroughs in its preparation technology are crucial for promoting the commercialization of solid-state batteries.

[0003] Currently, the industrial production of lithium sulfide mainly employs high-temperature gas-solid reaction or batch reactor methods. Traditional batch reactor processes suffer from the following prominent problems: First, low gas-liquid / gas-solid contact efficiency leads to incomplete reactions and low product purity; second, while large batch throughput is possible, uneven mass and heat transfer results in poor reaction controllability; third, the use of toxic hydrogen sulfide (H2S) poses a high risk of leakage during batch reactor operation, and its inherent safety needs improvement; fourth, batch production methods are lengthy and inefficient, making it difficult to meet the demands of large-scale continuous production. Therefore, developing a safe, efficient, and continuous lithium sulfide production process is of significant practical importance. Summary of the Invention

[0004] In view of this, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method and apparatus for preparing high-purity lithium sulfide based on a dynamic tubular reactor, which features continuous process, high safety, stable product quality, and suitability for large-scale industrialization.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing high-purity lithium sulfide based on a dynamic tubular reactor includes the following steps: S1. Synthesis reaction: The lithium source and organic solvent are mixed and stirred evenly to obtain a mixed slurry. The mixed slurry is continuously fed into the reactor. At the same time, a mixture of hydrogen sulfide and carrier gas is fed into the dynamic tubular reactor to generate lithium sulfide reaction solution. S2, First Evaporation and Solvent Recovery: The lithium sulfide reaction solution is continuously fed to the evaporator to evaporate and remove the organic solvent, yielding crude lithium sulfide; S3. Washing: Crude lithium sulfide is mixed with detergent and washed continuously to obtain a washed mixture, removing the generated by-product lithium salts or polysulfides. S4. Second Evaporation and Detergent Recovery: The washed mixture is continuously fed to the evaporator to evaporate and remove the detergent, yielding preliminarily dried lithium sulfide. S5. Drying: The preliminarily dried lithium sulfide is fed into a fluidized bed dryer and dried in a mixed atmosphere of nitrogen and hydrogen sulfide to obtain dried lithium sulfide.

[0006] Preferably, the lithium source in step S1 is one of lithium oxide (Li2O), lithium hydroxide (LiOH), and lithium carbonate (Li2CO3); The organic solvent is an aprotic organic solvent; The mass ratio of lithium source to organic solvent is 1:10 to 1:50; The mixed slurry was continuously fed into the reactor at a flow rate of 30 mL / min; The carrier gas is nitrogen or argon, and the volume fraction of H2S in the mixed gas is 5%-50%. The flow rate of the mixed gas introduced into the dynamic tubular reactor is 1.5 L / min; The reaction temperature in the dynamic tubular reactor is 110°C to 200°C, and the pressure is atmospheric pressure.

[0007] Preferably, the aprotic organic solvent is one or both of N-methylpyrrolidone and N,N-dimethylformamide; The dynamic tubular reactor is a vertical dynamic tubular reactor.

[0008] Preferably, the organic solvent removed by evaporation in step S2 is purified in a distillation column and then recycled back to step S1 for use. The evaporator is a thin-film evaporator or a falling-film evaporator, and the temperature of the thin-film evaporator or the falling-film evaporator is 150°C to 300°C.

[0009] Preferably, in step S3, the mass ratio of crude lithium sulfide to detergent is 1:10 to 1:50; continuous washing is carried out in a horizontal dynamic tubular reactor; the detergent is anhydrous ethanol or N-methylpyrrolidone.

[0010] Preferably, the detergent removed by evaporation in step S4 is purified in a distillation column and then recycled back to step S3 for use. The evaporator is a thin-film evaporator or a falling-film evaporator, and the temperature of the thin-film evaporator or the falling-film evaporator is 150°C to 300°C.

[0011] Preferably, in step S5, the drying temperature of the fluidized bed dryer is 200°C to 600°C, the carrier gas is nitrogen or argon, and the volume fraction of hydrogen sulfide in the mixed atmosphere is 1% to 10%; the drying time is 2 hours.

[0012] Preferably, the process also includes step S6: crushing and packaging. The dried lithium sulfide is discharged from the fluidized bed outlet and enters a crusher sealed to a glove box for crushing and sieving. The particle size D50 of the product is controlled within 5-20 μm. The entire crushing and sieving process is completed in a glove box protected by high-purity nitrogen / argon gas. The final product is vacuum packaged in the glove box. The purity of the lithium sulfide product is ≥99.5%.

[0013] A device for preparing high-purity lithium sulfide based on a dynamic tubular reactor includes a first peristaltic pump, a vertical dynamic tubular reactor, a first evaporator, a second peristaltic pump, a horizontal dynamic tubular reactor, a second evaporator, a fluidized bed dryer, a pulverizer, and a glove box connected in sequence. The first evaporator is connected to a first distillation column, and the second evaporator is connected to a second distillation column.

[0014] Specifically, it includes the following units: Synthesis reaction unit: A vertical dynamic tubular reactor is adopted, which is connected to a first peristaltic pump. The first peristaltic pump is used for feeding to realize efficient mixing and continuous synthesis reaction of mixed slurry and mixed gas. First evaporator: connected to the outlet of the vertical dynamic tubular reactor, used to evaporate the lithium sulfide reaction solution to remove organic solvent and obtain crude lithium sulfide; First distillation column: connected to the steam outlet of the first evaporator, used to purify, recover and recycle the evaporated organic solvent; Continuous washing unit: A horizontal dynamic tubular reactor is adopted, the inlet of which is connected to the solid outlet of the first evaporator. It is used to receive crude lithium sulfide and mix it with washing solvent for continuous washing to remove any lithium salts or polysulfide impurities that may be generated. A second peristaltic pump is installed on the pipeline between the horizontal dynamic tubular reactor and the first evaporator. Second evaporator: connected to the outlet of the horizontal dynamic tubular reactor, used to evaporate the washed mixture to remove the detergent and obtain pre-dried lithium sulfide; Second distillation column: connected to the steam outlet of the second evaporator, used to purify, recover and recycle the evaporated detergent; Deep drying unit: A fluidized bed dryer is used and connected to the solid outlet of the second evaporator for deep drying of pre-dried lithium sulfide in a mixed atmosphere of carrier gas and hydrogen sulfide. Crushing and screening unit: includes a crusher, which is connected to the discharge port of the fluidized bed dryer, and is used to crush and screen the dried lithium sulfide to meet the particle size index; Product collection unit: includes a nitrogen / argon atmosphere glove box, and the discharge port of the crushing and screening unit is directly connected to the glove box through a flange, for filling and packaging products under conditions of water and oxygen isolation.

[0015] Preferably, the material of the part of the device that contacts the lithium sulfide material is alumina ceramic or Hastelloy C276.

[0016] As a preferred option, all connections in the system are strictly sealed throughout the entire production process to prevent air (especially water vapor and oxygen) from entering the reaction system.

[0017] Compared with the prior art, the present invention has the following significant advantages: This invention employs a dynamic tubular reactor for lithium sulfide synthesis. Compared to traditional batch reactors, it significantly reduces the process footprint and batch material throughput. Furthermore, by enhancing mass and heat transfer and implementing continuous closed-loop operation, it effectively reduces the risk and hazard of hydrogen sulfide leakage, improving the inherent safety of the process. Simultaneously, it achieves a shift from traditional batch production to continuous synthesis, facilitating large-scale industrialization. Specifically, this is reflected in the following points: 1. High safety: The use of a dynamic tubular reactor for continuous closed operation results in a small liquid holdup in the reaction system, effectively reducing the risk and hazard of leakage of toxic hydrogen sulfide gas and significantly improving the safety of the production process.

[0018] 2. High mass and heat transfer efficiency: The enhanced mixing characteristics of the dynamic tubular reactor greatly improve the contact efficiency and heat transfer uniformity of the gas and liquid phases, making the reaction fast and controllable, and avoiding the problems of local overheating or incomplete reaction that are prone to occur in traditional batch reactors.

[0019] 3. High product purity: The innovative introduction of a continuous washing process utilizes a horizontal dynamic tubular reactor to continuously wash the crude product, effectively removing by-product lithium salts or polysulfide impurities, and obtaining high-purity lithium sulfide without additional complex purification steps.

[0020] 4. Solvent recycling, economical and environmentally friendly: By combining the evaporation unit and the distillation unit, the reaction solvent and detergent are efficiently recovered and recycled, which greatly reduces production costs and solvent emissions, and is in line with the concept of green chemical industry.

[0021] 5. High production efficiency and easy to scale up: The continuous production mode, which combines vertical and horizontal dynamic tubular reactors, significantly reduces the process footprint and realizes the transformation from intermittent production to continuous production, making it easy to achieve large-scale industrialization.

[0022] 6. Complete protection against water and oxygen: From crushing to final packaging, the entire process is completed in a nitrogen / argon atmosphere glove box, which completely solves the post-processing problem of high-activity lithium sulfide materials being easily oxidized and deteriorating by absorbing water in the air. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the device of the present invention.

[0024] In the attached diagram, 1-first peristaltic pump, 2-vertical dynamic tubular reactor, 3-first evaporator, 4-first distillation column, 5-second peristaltic pump, 6-horizontal dynamic tubular reactor, 7-second evaporator, 8-second distillation column, 9-fluidized bed dryer, 10-pulverizer, 11-glove box. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the scope of protection of this invention is not limited to the following embodiments.

[0026] Device Examples like Figure 1 As shown, an apparatus for preparing high-purity lithium sulfide based on a dynamic tubular reactor includes a first peristaltic pump 1, a vertical dynamic tubular reactor 2, a first evaporator 3, a second peristaltic pump 5, a horizontal dynamic tubular reactor 6, a second evaporator 7, a fluidized bed dryer 9, a pulverizer 10, and a glove box 11 connected in sequence. The first evaporator 3 is connected to a first distillation column 4, and the second evaporator 7 is connected to a second distillation column 8. The parts of the apparatus in contact with the lithium sulfide material are made of alumina ceramic or Hastelloy C276.

[0027] The specific connection relationships and working processes of each unit are as follows: Synthesis reaction unit: A vertical dynamic tubular reactor 2 is adopted. The vertical dynamic tubular reactor 2 and the first peristaltic pump 1 are used for feeding to realize the efficient mixing and continuous synthesis reaction of the mixed slurry and mixed gas. First evaporator 3: connected to the outlet of the vertical dynamic tubular reactor 2, used to evaporate the lithium sulfide reaction solution to remove organic solvent and obtain crude lithium sulfide; First distillation column 4: connected to the steam outlet of the first evaporator 3, used to purify, recover and recycle the evaporated organic solvent; Continuous washing unit: A horizontal dynamic tubular reactor 6 is adopted, the inlet of which is connected to the solid outlet of the first evaporator 3. It is used to receive crude lithium sulfide and mix it with washing solvent for continuous washing to remove any lithium salts or polysulfide impurities that may be generated. A second peristaltic pump 5 is installed on the pipeline between the horizontal dynamic tubular reactor 6 and the first evaporator 3. Second evaporator 7: connected to the outlet of the horizontal dynamic tubular reactor 6, used to evaporate the washed mixture to remove the detergent and obtain pre-dried lithium sulfide. Second distillation column 8: connected to the steam outlet of the second evaporator 7, used to purify, recover and recycle the evaporated detergent; Deep drying unit: A fluidized bed dryer 9 is used, which is connected to the solid outlet of the second evaporator 7, for deep drying of pre-dried lithium sulfide in a mixed atmosphere of carrier gas and hydrogen sulfide. Crushing and screening unit: including crusher 10, which is connected to the discharge port of fluidized bed dryer 9, for crushing and screening the dried lithium sulfide to meet the particle size index; Product collection unit: includes a nitrogen / argon atmosphere glove box 11, the discharge port of the crushing and screening unit is directly connected to the glove box 11 through a flange, for filling and packaging products under conditions of water and oxygen isolation.

[0028] Example 1

[0029] Adopting such Figure 1 The continuous production apparatus shown is used to prepare high-purity lithium sulfide. The apparatus described in the apparatus example is employed.

[0030] (1) Synthesis reaction: Lithium hydroxide (LiOH) was used as the lithium source, and N-methylpyrrolidone (NMP) was used as the organic solvent. LiOH and NMP were mixed at a mass ratio of 1:20 and stirred until homogeneous to obtain a slurry. The slurry was continuously fed into a vertical dynamic tubular reactor at a flow rate of 30 mL / min using a peristaltic pump; simultaneously, a mixture of hydrogen sulfide and nitrogen (H2S volume fraction of 25%) was fed into the reactor at a flow rate of 1.5 L / min. The reaction temperature was controlled at 150°C and the pressure at atmospheric pressure. In the vertical dynamic tubular reactor, the gas and liquid phases were efficiently mixed and reacted rapidly to generate lithium sulfide.

[0031] (2) First evaporation and solvent recovery: The reaction solution is continuously fed to the first evaporator (thin film) at 150°C to evaporate and remove the NMP solvent, obtaining crude lithium sulfide. The evaporated NMP is purified in a distillation column and then recycled.

[0032] (3) Continuous washing: Crude lithium sulfide and anhydrous ethanol are mixed at a mass ratio of 1:20 and continuously fed into a horizontal dynamic tubular reactor for continuous washing to remove possible by-product lithium salts.

[0033] (4) Second evaporation and washing solvent recovery: The washed mixture is continuously fed to a second evaporator (membrane) at 200°C to evaporate and remove anhydrous ethanol, yielding preliminarily dried lithium sulfide. The evaporated anhydrous ethanol is purified in a second distillation column and then recycled.

[0034] (5) Drying: The preliminarily dried lithium sulfide is fed into a fluidized bed dryer and dried at 600°C for 2 hours in a mixed atmosphere of nitrogen and hydrogen sulfide (H2S volume fraction 5%) to obtain dried lithium sulfide.

[0035] (6) Crushing, sieving and packaging: The dried lithium sulfide is discharged from the fluidized bed outlet and enters the crusher sealed with the glove box for crushing and sieving, controlling the product particle size D50 within the range of 5-15μm. The entire crushing and sieving process is completed in a glove box protected by high-purity nitrogen (5N), and the final product is vacuum packaged directly in the glove box.

[0036] Testing showed that the lithium sulfide product prepared in this embodiment had a purity of ≥99.9% and extremely low impurity content, fully meeting the requirements for sulfide solid electrolyte raw materials.

[0037] Example 2

[0038] Adopting such Figure 1 The continuous production apparatus shown is used to prepare high-purity lithium sulfide. The apparatus described in the apparatus example is employed.

[0039] (1) Synthesis reaction: Lithium carbonate (Li2CO3) was used as the lithium source, and DMF was used as the organic solvent. Li2CO3 and DMF were mixed at a mass ratio of 1:10 and stirred evenly to obtain a mixed slurry. The slurry was continuously fed into a vertical dynamic tubular reactor at a flow rate of 30 mL / min using a peristaltic pump; at the same time, a mixture of hydrogen sulfide and nitrogen (H2S volume fraction of 5%) was fed into the reactor at a flow rate of 1.5 L / min. The reaction temperature was controlled at 110°C and the pressure was atmospheric pressure. In the vertical dynamic tubular reactor, the gas and liquid phases were efficiently mixed and reacted rapidly to generate lithium sulfide.

[0040] (2) First evaporation and solvent recovery: The reaction solution is continuously fed to the first evaporator (falling film) at 200℃ to evaporate and remove the DMF solvent, obtaining crude lithium sulfide. The evaporated DMF is purified in a distillation column and then recycled.

[0041] (3) Continuous washing: Crude lithium sulfide and anhydrous ethanol are mixed at a mass ratio of 1:10 and continuously fed into a horizontal dynamic tubular reactor for continuous washing to remove possible by-product lithium salts.

[0042] (4) Second evaporation and washing solvent recovery: The washed mixture is continuously fed to a second evaporator (membrane) at 300°C to evaporate and remove anhydrous ethanol, yielding preliminarily dried lithium sulfide. The evaporated anhydrous ethanol is purified in a second distillation column and then recycled.

[0043] (5) Drying: The preliminarily dried lithium sulfide is fed into a fluidized bed dryer and dried at 400°C for 2 hours in a mixed atmosphere of nitrogen and hydrogen sulfide (H2S volume fraction 10%) to obtain dried lithium sulfide.

[0044] (6) Crushing, sieving and packaging: The dried lithium sulfide is discharged from the fluidized bed outlet and enters the crusher sealed with the glove box for crushing and sieving, controlling the product particle size D50 within the range of 5-10μm. The entire crushing and sieving process is completed in the glove box protected by high-purity nitrogen (5N), and the final product is vacuum packaged directly in the glove box.

[0045] Testing showed that the lithium sulfide product prepared in this embodiment had a purity of ≥99.9% and extremely low impurity content, fully meeting the requirements for sulfide solid electrolyte raw materials.

[0046] Example 3

[0047] Adopting such Figure 1 The continuous production apparatus shown is used to prepare high-purity lithium sulfide. The apparatus described in the apparatus example is employed.

[0048] (1) Synthesis reaction: Lithium oxide (LiO) was used as the lithium source, and N-methylpyrrolidone (NMP) was used as the organic solvent. LiO and NMP were mixed at a mass ratio of 1:50 and stirred until homogeneous to obtain a slurry. The slurry was continuously fed into a vertical dynamic tubular reactor at a flow rate of 30 mL / min using a peristaltic pump; simultaneously, a mixture of hydrogen sulfide and nitrogen (H2S volume fraction of 50%) was fed into the reactor at a flow rate of 1.5 L / min. The reaction temperature was controlled at 200°C and the pressure at atmospheric pressure. In the vertical dynamic tubular reactor, the gas and liquid phases were efficiently mixed and reacted rapidly to generate lithium sulfide.

[0049] (2) First evaporation and solvent recovery: The reaction solution is continuously fed to the first evaporator (thin film) at 300°C to evaporate and remove the NMP solvent, obtaining crude lithium sulfide. The evaporated NMP is purified in a distillation column and then recycled.

[0050] (3) Continuous washing: Crude lithium sulfide and N-methylpyrrolidone are mixed at a mass ratio of 1:50 and continuously fed into a horizontal dynamic tubular reactor for continuous washing to remove possible by-product lithium salts.

[0051] (4) Second evaporation and washing solvent recovery: The washed mixture is continuously fed to a second evaporator (falling film) at 150°C to evaporate and remove N-methylpyrrolidone, yielding preliminarily dried lithium sulfide. The evaporated N-methylpyrrolidone is then purified and recycled in a second distillation column.

[0052] (5) Drying: The preliminarily dried lithium sulfide is fed into a fluidized bed dryer and dried at 200°C for 2 hours in a mixed atmosphere of nitrogen and hydrogen sulfide (H2S volume fraction 1%) to obtain dried lithium sulfide.

[0053] (6) Crushing, sieving and packaging: The dried lithium sulfide is discharged from the fluidized bed outlet and enters the crusher sealed with the glove box for crushing and sieving, controlling the product particle size D50 within the range of 15-20μm. The entire crushing and sieving process is completed in a glove box protected by high-purity argon (5N), and the final product is vacuum packaged directly in the glove box.

[0054] Testing showed that the lithium sulfide product prepared in this embodiment had a purity of ≥99.9% and extremely low impurity content, fully meeting the requirements for sulfide solid electrolyte raw materials.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing high-purity lithium sulfide based on a dynamic tubular reactor, characterized in that, Includes the following steps: S1. Synthesis reaction: The lithium source and organic solvent are mixed and stirred evenly to obtain a mixed slurry. The mixed slurry is continuously fed into the reactor. At the same time, a mixture of hydrogen sulfide and carrier gas is fed into the dynamic tubular reactor to generate lithium sulfide reaction solution. S2, First Evaporation and Solvent Recovery: The lithium sulfide reaction solution is continuously fed to the evaporator to evaporate and remove the organic solvent, yielding crude lithium sulfide; S3. Washing: Crude lithium sulfide is mixed with detergent and washed continuously to obtain a washed mixture, removing the generated by-product lithium salts or polysulfides. S4. Second Evaporation and Detergent Recovery: The washed mixture is continuously fed to the evaporator to evaporate and remove the detergent, yielding preliminarily dried lithium sulfide. S5. Drying: The preliminarily dried lithium sulfide is fed into a fluidized bed dryer and dried in a mixed atmosphere of carrier gas and hydrogen sulfide to obtain dried lithium sulfide.

2. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 1, characterized in that, The lithium source mentioned in step S1 is one of lithium oxide (Li2O), lithium hydroxide (LiOH), and lithium carbonate (Li2CO3); The organic solvent is an aprotic organic solvent; The mass ratio of lithium source to organic solvent is 1:10 to 1:50; The mixed slurry was continuously fed into the reactor at a flow rate of 30 mL / min; The carrier gas is nitrogen or argon, and the volume fraction of H2S in the mixed gas is 5%-50%. The flow rate of the mixed gas introduced into the dynamic tubular reactor is 1.5 L / min; The reaction temperature in the dynamic tubular reactor is 110°C to 200°C, and the pressure is atmospheric pressure.

3. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 2, characterized in that, The aprotic organic solvent is one or both of N-methylpyrrolidone and N,N-dimethylformamide; The dynamic tubular reactor is a vertical dynamic tubular reactor.

4. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 2, characterized in that, The organic solvent removed by evaporation in step S2 is purified in a distillation column and then recycled back to step S1 for use. The evaporator is a thin-film evaporator or a falling-film evaporator, and the temperature of the thin-film evaporator or the falling-film evaporator is 150°C to 300°C.

5. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 1, characterized in that, In step S3, the crude lithium sulfide and detergent are added at a mass ratio of 1:10 to 1:50; continuous washing is carried out in a horizontal dynamic tubular reactor; the detergent is anhydrous ethanol or N-methylpyrrolidone.

6. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 1, characterized in that, The detergent removed by evaporation in step S4 is purified in a distillation column and then recycled back to step S3 for use. The evaporator is a thin-film evaporator or a falling-film evaporator, and the temperature of the thin-film evaporator or the falling-film evaporator is 150°C to 300°C.

7. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 1, characterized in that, In step S5, the fluidized bed dryer operates at a drying temperature of 200°C to 600°C, the carrier gas is nitrogen or argon, and the volume fraction of hydrogen sulfide in the mixed atmosphere is 1% to 10%; the drying time is 2 hours.

8. The method for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 1, characterized in that, It also includes step S6, crushing and packaging: the dried lithium sulfide is discharged from the fluidized bed outlet and enters a crusher sealed to the glove box for crushing and sieving, controlling the product particle size D50 within 5-20μm. The entire crushing and sieving process is completed in a glove box protected by high-purity nitrogen / argon gas, and the final product is vacuum packaged in the glove box; the purity of the lithium sulfide product is ≥99.5%.

9. The apparatus for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to any one of claims 1-8, characterized in that, The system includes a first peristaltic pump (1), a vertical dynamic tubular reactor (2), a first evaporator (3), a second peristaltic pump (5), a horizontal dynamic tubular reactor (6), a second evaporator (7), a fluidized bed dryer (9), a pulverizer (10), and a glove box (11) connected in sequence. The first evaporator (3) is connected to the first distillation column (4), and the second evaporator (7) is connected to the second distillation column (8).

10. The apparatus for preparing high-purity lithium sulfide based on a dynamic tubular reactor according to claim 9, characterized in that, The material of the part of the device that comes into contact with lithium sulfide material is alumina ceramic or Hastelloy C276.

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