A method of producing lithium sulfide, lithium sulfide and system

Abstract

The present application relates to a kind of preparation methods of lithium sulfide, lithium sulfide and system, the method includes the following steps: under the condition of air and moisture isolation, first raw material containing liquid lithium source and second raw material containing sulfur element are respectively passed through first spray inlet and second spray inlet located on cyclone reactor by horizontal or cyclone downward mode and sprayed into reactor to contact and react;Wherein, the liquid lithium source includes molten lithium and / or lithium-liquid ammonia solution;The second spray inlet is below the first spray inlet.The present application is by molten lithium and / or lithium-liquid ammonia solution and the material containing sulfur element are sprayed into cyclone reactor to contact and react, so that liquid lithium source and the material containing sulfur element are rapidly mixed contact, and the residence time of material in reactor can be accurately controlled, and high-purity, particle size controllable battery-grade lithium sulfide can be continuously, rapidly and large-scale produced.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a method for preparing lithium sulfide, lithium sulfide, and a system. Background Technology

[0002] Lithium sulfide (Li₂S) has a theoretical capacity far exceeding that of traditional lithium-ion battery cathode materials, making it suitable as a cathode active material for lithium-sulfur batteries and theoretically improving battery safety. Lithium sulfide can also provide an additional lithium source to compensate for irreversible lithium loss during the first cycle caused by the formation of an SEI film. Furthermore, electrolyte materials with ultra-high ionic conductivity synthesized from lithium sulfide have attracted widespread attention.

[0003] Currently, the main industrial routes for synthesizing lithium sulfide are as follows: 1) Reduction reaction at high temperature using reducing agents (such as carbon, hydrogen, etc.) with lithium compounds (such as Li₂CO₃, LiOH); 2) Direct solid-state reaction of high-purity metallic lithium with elemental sulfur under an inert atmosphere; 3) Reacting hydrogen sulfide gas into a lithium compound solution or molten salt to generate lithium sulfide; 4) Reacting lithium and sulfur under hydrothermal conditions using organic solvents or water as a medium to generate lithium sulfide. However, the reaction process for producing lithium sulfide needs to be carried out under conditions of oxygen and moisture isolation. Current methods suffer from problems such as difficulty in continuous production, numerous process steps, long reaction cycles, and difficulty in controlling impurities, leading to increased production costs. Summary of the Invention

[0004] The purpose of this invention is to improve the production efficiency of large-scale high-purity lithium sulfide and reduce the production cost of high-purity lithium sulfide.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for preparing lithium sulfide, the method comprising the following steps:

[0006] Under conditions of isolation from air and moisture, a first raw material containing liquid lithium and a second raw material containing sulfur are respectively injected into the reactor through a first inlet and a second inlet located on the cyclone reactor in a horizontal or downward swirling manner to carry out the reaction; wherein, the liquid lithium source includes molten lithium and / or lithium-liquid ammonia solution; the second inlet is located below the first inlet.

[0007] Optionally, the first inlet is connected to a first nozzle; the angle α between the first nozzle and the reactor wall section at the first inlet is 1-89 degrees; the second inlet is connected to a second nozzle; the angle α between the second nozzle and the reactor wall section at the second inlet is 1-89 degrees; the angles between the first nozzle and the second nozzle and the horizontal direction are each independently 0-10 degrees; optionally, the number of the first nozzle is 2-6; the number of the second nozzle is 2-6; preferably, the first nozzle and the second nozzle are each independently symmetrically distributed along the central axis of the cyclone reactor.

[0008] Optionally, the first raw material is molten lithium; the molten lithium is directly injected into the cyclone reactor through a nozzle or atomized by high-pressure inert gas; the flow rate of the injected molten lithium is 13.88-1388 g / min.

[0009] Optionally, the second raw material is sulfur vapor; the molar ratio of the molten lithium to the sulfur vapor injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.01; the reaction temperature is 450-800℃, and the reaction time is 1-30 min.

[0010] Optionally, the second raw material is molten sulfur; the molar ratio of molten lithium to molten sulfur injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.01; the reaction temperature is 180-400℃, and the reaction time is 1-30 min.

[0011] Optionally, the second raw material is hydrogen sulfide gas; the flow rate of the injected hydrogen sulfide gas is 34.06-3406 mL / min.

[0012] Optionally, the first raw material is molten lithium, which is injected into the cyclone reactor through a nozzle or by atomizing hydrogen gas; the molar ratio of the molten lithium to the hydrogen sulfide gas injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.05; the reaction temperature is 190-400℃, and the reaction time is 1-30 min.

[0013] Optionally, the first raw material is a lithium-liquid ammonia solution; the molar ratio of lithium to hydrogen sulfide gas in the lithium-liquid ammonia solution injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.1; the reaction temperature is -50~150℃, and the reaction time is 1-30 min; optionally, the flow rate of the lithium-liquid ammonia solution injected is 1.0-5.0 L / min; optionally, the lithium concentration in the lithium-liquid ammonia solution is 1.0-6.0 wt%.

[0014] A second aspect of the present invention provides a lithium sulfide, which is prepared by the preparation method described in the first aspect of the present invention; optionally, the purity of the lithium sulfide is 99.9-99.9999%; and the particle size of the lithium sulfide is 0.1-100 μm.

[0015] A third aspect of the present invention provides a system for the method of preparing lithium sulfide according to the first aspect of the present invention, the system comprising a cyclone reactor having a product outlet at the bottom and a gas outlet at the top; the cyclone reactor having a first inlet and a second inlet, wherein the second inlet is located below the first inlet;

[0016] The first inlet is connected to a first nozzle; the angle α between the first nozzle and the reactor wall section at the first inlet is 1-89 degrees.

[0017] The second inlet is connected to a second nozzle; the angle α between the second nozzle and the reactor wall section at the second inlet is 1-89 degrees;

[0018] Optionally, the number of the first nozzles is 2-6; the number of the second nozzles is 2-6;

[0019] Optionally, the system further includes a first raw material heating device and / or a second raw material heating device, wherein the first raw material heating device is connected to the cyclone reactor via a first feed pipe, and the second raw material heating device is connected to the cyclone reactor via a second feed pipe.

[0020] Through the above technical solution, the present invention allows molten lithium and / or lithium-liquid ammonia solution and sulfur-containing materials to be sprayed into a cyclone reactor for contact reaction, so that the liquid lithium source and sulfur-containing materials are rapidly mixed and fully contacted, and the residence time of the materials in the reactor can be precisely controlled, enabling continuous, rapid and large-scale production of high-purity, controllable particle size battery-grade lithium sulfide.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of a cyclone reactor in some embodiments of the present invention.

[0024] Figure 2 yes Figure 1 A cross-sectional view of one embodiment of the cyclone reactor shown.

[0025] Figure 3 yes Figure 1 A partially enlarged top view of one embodiment of the cyclone reactor shown.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100. Cyclone reactor; 101. Product outlet; 102. Gas outlet; 103. First injection inlet; 104. Second injection inlet; 105. First nozzle; 106. Second nozzle. Detailed Implementation

[0028] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0029] The "central axis" refers to the axis that passes through the center of an object and runs along its longest dimension.

[0030] A "vertical plane" is a plane drawn through an object along its longest dimension.

[0031] A first aspect of the present invention provides a method for preparing lithium sulfide, the method comprising the following steps:

[0032] Under conditions of isolation from air and moisture, a first raw material containing liquid lithium and a second raw material containing sulfur are respectively injected into the reactor through a first inlet and a second inlet located on the cyclone reactor in a horizontal or downward swirling manner to carry out the reaction; wherein, the liquid lithium source includes molten lithium and / or lithium-liquid ammonia solution; the second inlet is located below the first inlet.

[0033] This invention involves injecting molten lithium and / or a lithium-liquid ammonia solution into a cyclone reactor to allow for full contact and reaction with sulfur-containing materials. This enables rapid mixing and contact between the liquid lithium source and the sulfur-containing materials, and allows for precise control of the residence time of the materials in the reactor. This allows for the continuous, rapid, and large-scale production of high-purity, controllable-particle-size battery-grade lithium sulfide.

[0034] In some embodiments of the present invention, the first injection inlet is connected to a first nozzle; the angle α between the first nozzle and the reactor wall section at the first injection inlet can be 1-89 degrees. By using different raw material injection angles, the rotational speed of the reactants in the cyclone reactor, the residence time in the reactor, the reaction time, and the settling time of the products can be controlled, thereby optimizing the reaction process control and the physical morphology of the products, such as particle size and particle size distribution. For example, the angle α between the first nozzle and the reactor wall section at the first injection inlet can be any angle within the range of 1-89 degrees. The first raw material containing molten lithium is injected into the cyclone reactor through the first injection inlet and the first nozzle. The angle of the first nozzle relative to the cyclone reactor is appropriate, so that the first raw material entering the cyclone reactor can obtain suitable tangential velocity and axial settling velocity.

[0035] In some embodiments of the present invention, the second injection inlet is connected to a second nozzle; the angle α between the second nozzle and the reactor wall section at the second injection inlet is 1-89 degrees. For example, the angle α between the second nozzle and the reactor wall section at the second injection inlet can be any angle within the range of 1-89 degrees. The second raw material containing sulfur is injected into the cyclone reactor through the second injection inlet and the second nozzle. The angle of the second nozzle relative to the reactor is appropriate, so that the second raw material entering the cyclone reactor can obtain suitable tangential velocity and axial settling velocity.

[0036] In some embodiments of the present invention, the angle between the first nozzle and the second nozzle and the horizontal direction is independently 0-10 degrees.

[0037] In some embodiments of the present invention, when the first raw material and / or the second raw material are introduced along the inner surface of the cyclone reactor, the tangential angle α can be any angle in the range of 1-89. The nozzle used to spray and introduce the first raw material and / or the second raw material is arranged relative to the central axis of the cyclone reactor.

[0038] The inner wall of the cyclone reactor is coated with a protective coating, such as a ceramic coating or quartz glass that does not react with lithium metal, sulfur vapor, or hydrogen sulfide. The inner wall of the device used to heat the lithium metal also does not react with lithium; for example, it can be a zirconium oxide, boron nitride, or a specific type of corundum crucible, and it has undergone passivation treatment. The lithium metal is heated to a molten state under the protection of a high-purity inert gas, exhibiting good fluidity and low dynamic viscosity. The molten lithium is drawn from the heating device through a high-temperature resistant guide pipe to the nozzle or atomizing nozzle area.

[0039] In this invention, at the atomizing nozzle, a high-speed, high-pressure inert gas flow impacts and breaks down molten lithium into microdroplets. The atomizing nozzle can be selected from free-fall nozzles and / or tightly coupled nozzles, preferably tightly coupled nozzles, to produce finer, more uniform spherical droplets with lower gas consumption.

[0040] In some preferred embodiments, the first nozzle and the second nozzle are at the same angle to the reactor wall of the cyclone reactor, so that the raw materials enter the cyclone reactor at a high tangential velocity, which greatly increases the contact area of ​​the raw materials and promotes faster and more uniform reaction. The first raw material and the second raw material contact and move downward along the cyclone reactor, and the generated lithium sulfide particles are deposited at the bottom of the cyclone reactor, and the product does not need to be further separated or purified.

[0041] In some embodiments of the present invention, the number of the first nozzles can be 2-6; the number of the second nozzles can be 2-6. Specifically, a plurality of the first nozzles are symmetrically distributed along the central axis of the cyclone reactor, and a plurality of the second nozzle inlets are symmetrically distributed along the central axis of the cyclone reactor.

[0042] In some embodiments of the present invention, the first raw material can be molten lithium. Since metallic lithium has a melting point of 180.5°C, elemental sulfur has a melting point of 115.0°C and a boiling point of 444.6°C, the sulfur-containing raw material used to react with molten lithium can be molten sulfur or sulfur vapor. This avoids the grinding process required for existing solid-solid reactions, and thus avoids the purification difficulties that may result from grinding and other methods. The reaction formula for molten lithium with molten sulfur or sulfur vapor is as follows:

[0043] 2Li + S → Li₂S.

[0044] In some embodiments of the present invention, lithium metal can be heated to 190-200°C. For example, in some embodiments, lithium metal is heated to 190°C, 195°C, 200°C, or any temperature within the aforementioned range, to melt the solid lithium metal and transform it into a liquid state. Specifically, the molten lithium has a dynamic viscosity of 0.55-0.60 mPa·s, a surface tension of 398 mN / m, and a specific gravity of 0.512 g / cm³. 3The molten lithium can be directly injected into the cyclone reactor through a nozzle or atomized by a high-pressure inert gas, reacting directly with molten sulfur or sulfur vapor to generate battery-grade lithium sulfide without producing waste gas, waste liquid, or solid waste. Specifically, the molten lithium can be injected into the cyclone reactor tangentially along the reactor wall using a high-pressure nozzle, or the molten lithium can be atomized by a high-pressure inert gas and injected tangentially into the upper part of the cyclone reactor wall. Under the impact or shearing action of the high-pressure inert gas (such as helium or argon), the molten lithium forms tiny droplets, which react rapidly with the sulfur-containing compound to form small lithium sulfide particles.

[0045] In some embodiments of the present invention, the flow rate of the molten lithium injection can be 13.88-1388 g / min to control the yield of lithium sulfide particles with high purity and suitable particle size. For example, the flow rate of the molten lithium injection can be 13.88 g / min, 27.76 g / min, 69.4 g / min, 138.8 g / min, 277.6 g / min, 1338 g / min, or any flow rate within the aforementioned range.

[0046] In some embodiments of the present invention, the second raw material can be sulfur vapor, and the method further includes: sublimating solid elemental sulfur to obtain sulfur vapor. Specifically, solid sulfur can be heated to 450-500°C to obtain sulfur vapor, for example, solid sulfur can be heated to 450°C to convert solid sulfur into gaseous sulfur (sulfur vapor). The sulfur vapor can be injected through a nozzle along the tangential direction of the cyclone reactor wall into the bottom of the cyclone reactor, in the same direction as the injection of molten lithium. The molar ratio of molten lithium to sulfur vapor injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.01, and particularly preferably 2.01. Specifically, the flow rate of the injected sulfur vapor can be 32.06-3206 g / min, so that the sulfur vapor reacts directly with the molten lithium to obtain battery-grade lithium sulfide. It is understood that the flow rate of the sulfur vapor injection needs to be coordinated with the flow rate of the molten lithium injection. In a preferred embodiment, the molar ratio between the molten lithium and sulfur vapor injected into the cyclone reactor per unit time is 2.01:1, so as to ensure that the raw materials are in full contact to generate lithium sulfide and reduce the generation of by-products.

[0047] In some embodiments of the present invention, the temperature at which the molten lithium reacts with the sulfur vapor can be 450-800°C, and the reaction time can be 1-30 min.

[0048] In some embodiments of the present invention, the second raw material can be molten sulfur, i.e., molten lithium is reacted with molten lithium liquid-liquid microdroplets to synthesize battery-grade lithium sulfide powder in one step. Specifically, solid sulfur can be heated to 120-150°C to obtain molten sulfur, for example, solid sulfur can be heated to 120°C, 130°C, 140°C, 150°C or any temperature within the aforementioned range to convert solid sulfur into molten sulfur. A liquid atomizer can be used to atomize the molten sulfur and molten lithium separately in an inert gas atmosphere and then spray them into a cyclone reactor. Specifically, the atomized molten sulfur can be sprayed tangentially to the wall of the cyclone reactor or downwards in a swirling motion into the bottom of the cyclone reactor, in the same direction as the molten lithium. The molar ratio of molten lithium to molten sulfur sprayed into the cyclone reactor per unit time is 2-2.15, preferably 2-2.01, and particularly preferably 2.01. Specifically, the atomized molten sulfur is injected at a flow rate of 32.06-3206 g / min so that the atomized molten sulfur reacts directly with molten lithium to obtain battery-grade lithium sulfide.

[0049] In some embodiments of the present invention, the reaction temperature of the molten lithium with the molten sulfur can be 180-400°C, and the reaction time can be 1-30 min.

[0050] In some embodiments of the present invention, the second raw material can be hydrogen sulfide gas; the hydrogen sulfide gas is injected into the cyclone reactor through a second inlet. In the present invention, the specific reaction formula for the reaction between hydrogen sulfide gas and metallic lithium is as follows:

[0051] 2Li + H2S → Li2S + H2.

[0052] In some embodiments of the present invention, the flow rate of the injected hydrogen sulfide gas can be 34.06-3406 mL / min.

[0053] In some embodiments of the present invention, the first raw material used to react with the hydrogen sulfide gas can be molten lithium, which can be injected into the cyclone reactor through a nozzle or by atomizing hydrogen gas. Specifically, the molten lithium is atomized under high-pressure hydrogen gas and injected into the cyclone reactor through a first inlet, where it undergoes gas-liquid contact with the hydrogen sulfide gas to produce battery-grade lithium sulfide in one step. The hydrogen gas generated from the reaction can be discharged from the top of the cyclone reactor and can be compressed and used as a gas for atomizing lithium metal, or the hydrogen gas can be purified and recovered.

[0054] In some embodiments of the present invention, the molar ratio of molten lithium to hydrogen sulfide gas injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.05, and particularly preferably 2.05. Specifically, the flow rate of the molten lithium or molten lithium atomized with hydrogen is 13.88-1388 g / min to obtain lithium sulfide with a suitable particle size.

[0055] In some embodiments of the present invention, the temperature at which the molten lithium reacts with hydrogen sulfide gas is 190-400°C and the reaction time is 1-30 min.

[0056] In some embodiments of the present invention, the first raw material can be a lithium-liquid ammonia solution. A lithium-liquid ammonia solution is obtained by mixing metallic lithium with liquid ammonia. This solution is injected into a cyclone reactor through a first inlet. The liquid ammonia rapidly vaporizes, causing the dissolved metallic lithium to precipitate as nanoscale particles in a manner similar to "flash evaporation." Simultaneously, it rapidly reacts with hydrogen sulfide to generate lithium sulfide powder. The resulting lithium sulfide powder is rotary deposited at the bottom of the reactor. The generated hydrogen and vaporized ammonia are discharged from the top of the cyclone reactor and can be recovered separately after separation and purification.

[0057] In some embodiments, the molar ratio of lithium to hydrogen sulfide gas in the lithium-liquid ammonia solution injected into the cyclone reactor per unit time is 2-2.15, preferably 2-2.01, and particularly preferably 2.01.

[0058] In some embodiments of the present invention, the flow rate of the lithium-liquid ammonia solution injected is 1.0-5.0 L / min.

[0059] In some embodiments of the present invention, the lithium concentration in the lithium-liquid ammonia solution is 1.0-6.0 wt%.

[0060] In some embodiments of the present invention, the reaction temperature is -50 to 150°C, and the reaction time is 1-30 min. By injecting a lithium-liquid ammonia solution into a cyclone reactor to react with hydrogen sulfide gas, the temperature during the reaction process can be significantly reduced. This reduces costs and avoids the side reaction of lithium polysulfide formation that may occur during high-temperature reactions. The reaction between lithium-liquid ammonia solution and hydrogen sulfide is exothermic, but the vaporization of liquid ammonia is endothermic. Therefore, the reaction temperature can be controlled by adjusting the concentration of the lithium-liquid ammonia solution and / or the amount of hydrogen sulfide injected.

[0061] It is understood that the above reactions are all carried out under conditions of oxygen and moisture isolation. The inert gas produced during the reaction is discharged from the top of the cyclone reactor and can be recovered and reused. The cyclone reactor in this invention can be equipped with heating or cooling pipes inside the reactor, or a heating or cooling jacket can be installed on the outside of the reactor wall to facilitate temperature control inside the reactor.

[0062] A second aspect of the present invention provides a lithium sulfide, which is prepared by the preparation method described in the first aspect of the present invention.

[0063] In the aforementioned method for preparing lithium sulfide, the first raw material containing liquid lithium source is injected into the reactor from the top and reacts with the second raw material containing sulfur element injected from the bottom to generate micron-sized and / or nano-sized lithium sulfide powder. The lithium sulfide powder rotates and sinks within the cyclone reactor and deposits at the bottom of the reactor, enabling continuous and large-scale production of high-purity battery-grade lithium sulfide powder with particle sizes in the nano and micron ranges. This fully meets the process requirements for subsequent preparation of sulfur-based solid electrolytes or sulfur-based solid lithium batteries.

[0064] The lithium sulfide prepared by the above method has a purity of 99.9-99.9999% and a particle size of 0.1-100 μm.

[0065] A third aspect of the present invention provides a system for the method of preparing lithium sulfide according to the first aspect of the present invention, the system comprising a cyclone reactor, such as... Figure 1 As shown, the cyclone reactor 100 has a product outlet 101 at the bottom and a gas outlet 102 at the top. The cyclone reactor 100 is provided with a first injection inlet 103 and a second injection inlet 104, and the second injection inlet 104 is located below the first injection inlet 103.

[0066] The first injection inlet 103 is connected to a first nozzle 105; the angle α between the first nozzle 105 and the reactor wall section at the first injection inlet 103 can be 1-89 degrees.

[0067] The second injection inlet 104 is connected to a second nozzle 106; the included angle α between the reactor wall cross-section at the second nozzle 106 and the second injection inlet 104 can be 1-89 degrees. Specifically, the first raw material containing molten lithium and the second raw material containing sulfur are injected in the same direction, so that the first raw material and the second raw material can quickly contact and react.

[0068] Specifically, the number of the first nozzle 105 can be 2-6; the number of the second nozzle 106 can be 2-6.

[0069] Figure 2for Figure 1 A cross-sectional view of one embodiment of the cyclone reactor is shown. (Refer to...) Figure 2 A first nozzle 105 connected to the first injection inlet 103 is installed on the cyclone reactor, and a second nozzle 106 connected to the second injection inlet is installed on the reactor.

[0070] The angles between the first nozzle and the second nozzle and the horizontal direction are each independently 0-10 degrees.

[0071] Figure 3 yes Figure 1 The diagram shows a partial enlarged top view of one embodiment of the cyclone reactor. The first nozzle 105 is used as an example to illustrate the possible installation configurations of the first nozzle and / or the second nozzle within the reactor. See also... Figure 3 The angle α between the first nozzle 105 and the reactor wall section at the first inlet is 1-89 degrees.

[0072] The first raw material is introduced into the first inlet in the form of a continuous fluid and injected into the cyclone reactor through the first nozzle. In some preferred embodiments, the second raw material is injected into the cyclone reactor through the second inlet and the second nozzle, and has the same rotation direction as the first material, and the angle α between the second nozzle and the reactor wall section at the second inlet is also 1-89 degrees.

[0073] In some embodiments of the system of the present invention, the system may further include a first raw material heating device and a second raw material heating device, wherein the first raw material heating device is connected to the cyclone reactor through a first feeding pipe, and the second raw material heating device is connected to the cyclone reactor through a second feeding pipe.

[0074] The present invention will be further described in detail below through embodiments, but the invention is not limited thereto. All raw materials used in the embodiments are commercially available.

[0075] In the following embodiments, the angle between the first nozzle and the second nozzle and the horizontal direction is 0 degrees, and the angle α between each nozzle and the reactor wall section at the nozzle inlet is 10 degrees (facing the same direction). The cyclone reactor contains four first nozzles and four second nozzles.

[0076] Example 1

[0077] This embodiment illustrates the preparation method of lithium sulfide according to the present invention, including the following steps:

[0078] (1) Heat lithium metal to 200°C to make it molten; and heat solid sulfur to 450°C to make it turn into sulfur vapor;

[0079] (2) Under conditions of oxygen and moisture isolation, molten lithium is atomized using high-pressure inert gas (argon). The atomized molten lithium is injected into the upper part of the cyclone reactor through the first nozzle of the first injection inlet, and sulfur vapor is injected into the bottom of the cyclone reactor through the second nozzle of the second injection inlet, so that the atomized molten lithium comes into contact with the sulfur vapor to react. The reaction temperature is 480℃; the distance between the first and second injection inlets is 15 cm; the flow rate of the atomized molten lithium is 138.8 g / min, and the flow rate of the sulfur vapor is 320.6 g / min. The reaction time between the atomized molten lithium and the sulfur vapor is 5 min.

[0080] The lithium sulfide product obtained in this embodiment has a particle size D50 of 10 μm and a particle size distribution span of 1.25.

[0081] Example 2

[0082] The method for preparing lithium sulfide in this embodiment is basically the same as that in Example 1, except that in step (2), the molten lithium is not atomized by high-pressure inert gas, but is directly injected into the cyclone reaction through the first nozzle of the first injection inlet. The particle size D50 of lithium sulfide is 50 μm and the particle size distribution span is 1.25.

[0083] Example 3

[0084] The method for preparing lithium sulfide in this embodiment includes the following steps:

[0085] (1) Heat lithium metal to 190°C to make it liquid; and heat solid sulfur to 120°C to make it molten.

[0086] (2) Under conditions of oxygen and moisture isolation, molten lithium is atomized using high-pressure inert gas (argon). The atomized molten lithium is injected into the upper part of the cyclone reactor through the first nozzle of the first inlet. Molten sulfur is atomized using high-pressure inert gas and injected into the bottom of the cyclone reactor through the second nozzle of the second inlet, so that the atomized molten lithium and atomized molten sulfur can come into contact and react. The reaction temperature is 195℃; the distance between the first and second inlets is 15 cm; the injection velocity of the atomized molten lithium is 138.8 g / min, and the injection velocity of the atomized molten sulfur is 320.6 g / min. The reaction time between the atomized molten lithium and atomized molten sulfur is 10 min. The particle size of the lithium sulfide product is 10 μm.

[0087] Example 4

[0088] The method for preparing lithium sulfide in this embodiment is basically similar to that in Example 3, except that in step (2), the molten lithium is not atomized by high-pressure inert gas, but is directly injected into the cyclone reaction through the first nozzle of the first injection inlet.

[0089] Example 5

[0090] This embodiment illustrates the preparation method of lithium sulfide according to the present invention, including the following steps:

[0091] (1) Heat lithium metal to 200°C to make it liquid;

[0092] (2) Under conditions of oxygen and moisture isolation, molten lithium is atomized using high-pressure hydrogen. The atomized molten lithium is injected tangentially into the upper part of the cyclone reactor through the first nozzle of the first inlet along the first direction of the reactor wall, while hydrogen sulfide gas is injected into the bottom of the cyclone reactor through the second nozzle of the second inlet, so that the atomized molten lithium comes into contact with the hydrogen sulfide to react. The reaction temperature is 200℃; the distance between the first and second inlets is 15cm; the flow rate of the atomized molten lithium is 138.8 g / min, and the flow rate of the hydrogen sulfide is 340.6 g / min. The reaction time between the atomized molten lithium and hydrogen sulfide is 5 min. The lithium sulfide product obtained in this embodiment has a particle size D50 of 10 μm and a particle size distribution span of 1.15.

[0093] Example 6

[0094] The method for preparing lithium sulfide in this embodiment is basically similar to that in Example 3, except that in step (2), the molten lithium is not atomized by high-pressure hydrogen, but is directly injected into the cyclone reaction through the first nozzle of the first injection inlet.

[0095] Example 7

[0096] This embodiment illustrates the preparation method of lithium sulfide according to the present invention, including the following steps:

[0097] (1) Dissolve metallic lithium in liquid ammonia to obtain a lithium-liquid ammonia solution; wherein the concentration of metallic lithium in the lithium-liquid ammonia solution is 4.0 wt%;

[0098] (2) Under conditions of oxygen and moisture isolation, a lithium-liquid ammonia solution is injected into the upper part of the cyclone reactor through the first nozzle of the first inlet, and hydrogen sulfide is injected into the bottom of the cyclone reactor through the second nozzle of the second inlet, so that lithium and hydrogen sulfide come into contact and react; wherein, the reaction temperature is 30°C; the distance between the first and second inlets is 15 cm; the injection flow rate of the lithium-liquid ammonia solution is 5.0 L / min, and the injection flow rate of hydrogen sulfide is 170.30 g / min. The reaction time of lithium and hydrogen sulfide is 5 min. The lithium sulfide product obtained in this embodiment has a smaller particle size, with a particle size D50 of 0.1 μm.

[0099] Comparative Example 1

[0100] The conventional method for preparing lithium sulfide in this comparative example includes the following steps:

[0101] Elemental sulfur and metallic lithium were weighed into a ball mill at a molar ratio of 1:2 and ground in an argon atmosphere. The reaction temperature during the grinding process was 180℃, the ball mill speed was 400 rpm, and the time was 15 h.

[0102] Comparative Example 2

[0103] The method for preparing lithium sulfide in this comparative example is basically similar to that in Example 2, except that: the lithium liquid is atomized, and the atomized droplets fall naturally from the top of the reactor. At the same time, sulfur vapor is introduced into the reaction chamber of the reactor through a pipe, and the lithium droplets rotate and fall and react with the sulfur vapor.

[0104] The lithium sulfide particles prepared in Examples 1-7 and Comparative Examples 1-2 were analyzed, and their properties are shown in Table 1.

[0105] Table 1

[0106]

[0107] As can be seen from the data of the embodiments and comparative examples 1-2 in the table above, the method of the present invention can produce high-purity lithium sulfide in one continuous and large-scale process, and the particle size of the obtained lithium sulfide is controllable, thereby reducing production costs.

[0108] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0109] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0110] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for producing lithium sulfide, characterized by, The method includes the following steps: Under conditions of isolation from air and moisture, a first raw material containing liquid lithium and a second raw material containing sulfur are respectively injected into the reactor through a first inlet and a second inlet located on the cyclone reactor in a horizontal or downward swirling manner to carry out the reaction; the reaction time is 1-30 min. Wherein, the liquid lithium source is molten lithium and / or lithium-liquid ammonia solution; the second raw material is selected from sulfur vapor, molten sulfur, and hydrogen sulfide gas; when the second raw material is sulfur vapor or molten sulfur, the molten lithium is directly injected into the cyclone reactor through a nozzle or atomized by high-pressure inert gas; when the second raw material is hydrogen sulfide gas, the molten lithium is injected into the cyclone reactor through a nozzle or atomized by hydrogen gas. The second injection inlet is located below the first injection inlet; The first spray inlet is connected to a first nozzle; the angle α between the first nozzle and the reactor wall section at the first spray inlet is 1-89 degrees; the second spray inlet is connected to a second nozzle; the angle α between the second nozzle and the reactor wall section at the second spray inlet is 1-89 degrees; and the angles between the first nozzle and the second nozzle and the horizontal direction are each independently 0-10 degrees.

2. The production method according to claim 1, characterized by, The number of the first nozzle is 2-6; the number of the second nozzle is 2-6.

3. The preparation method according to claim 2, characterized in that, The first nozzle and the second nozzle are each independently and symmetrically distributed along the central axis of the cyclone reactor.

4. The preparation method according to claim 1, characterized in that, The flow rate of the molten lithium injected is 13.88-1388 g / min.

5. The preparation method according to claim 4, characterized in that, The molar ratio of molten lithium to sulfur vapor injected into the cyclone reactor per unit time is 2-2.15; The reaction temperature is 450-800℃, and the reaction time is 1-30 min.

6. The preparation method according to claim 5, characterized in that, The molar ratio of molten lithium to sulfur vapor injected into the cyclone reactor per unit time is 2-2.

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7. The preparation method according to claim 4, characterized in that, The molar ratio of molten lithium to molten sulfur injected into the cyclone reactor per unit time is 2-2.15; The reaction temperature is 180-400℃, and the reaction time is 1-30 min.

8. The preparation method according to claim 7, characterized in that, The molar ratio of molten lithium to molten sulfur injected into the cyclone reactor per unit time is 2-2.

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9. The preparation method according to claim 1, characterized in that, The hydrogen sulfide gas was injected at a flow rate of 34.06-3406 g / min.

10. The preparation method according to claim 9, characterized in that, The molar ratio of molten lithium to hydrogen sulfide gas injected into the cyclone reactor per unit time is 2-2.15; the reaction temperature is 190-400℃, and the reaction time is 1-30 min.

11. The preparation method according to claim 10, characterized in that, The molar ratio of the molten lithium to the hydrogen sulfide gas injected into the cyclone reactor per unit time is 2-2.

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12. The preparation method according to claim 9, characterized in that, The first raw material is a lithium-liquid ammonia solution; the molar ratio of lithium to hydrogen sulfide gas in the lithium-liquid ammonia solution injected into the cyclone reactor per unit time is 2-2.15; the reaction temperature is -50~150℃, and the reaction time is 1-30 min.

13. The preparation method according to claim 12, characterized in that, The molar ratio of lithium to hydrogen sulfide gas in the lithium-liquid ammonia solution injected into the cyclone reactor per unit time is 2-2.

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14. The preparation method according to claim 12, characterized in that, The flow rate of the lithium-liquid ammonia solution injected is 1.0-5.0 L / min; The lithium concentration in the lithium-liquid ammonia solution is 1.0-6.0 wt%.

15. A lithium sulfide, characterized in that, The lithium sulfide is prepared by the preparation method according to any one of claims 1-14; The lithium sulfide has a purity of 99.9-99.9999% and a particle size of 0.1-100 μm.

16. A system for the preparation method of lithium sulfide according to any one of claims 1-14, characterized in that, The system includes a cyclone reactor, which has a product outlet at the bottom and a gas outlet at the top; the cyclone reactor is provided with a first injection inlet and a second injection inlet, and the second injection inlet is located below the first injection inlet; The first inlet is connected to a first nozzle; the angle α between the first nozzle and the reactor wall section at the first inlet is 1-89 degrees. The second inlet is connected to a second nozzle; the angle α between the second nozzle and the reactor wall section at the second inlet is 1-89 degrees; The system further includes a first raw material heating device and / or a second raw material heating device, wherein the first raw material heating device is connected to the cyclone reactor via a first feed pipe, and the second raw material heating device is connected to the cyclone reactor via a second feed pipe.

17. The system according to claim 16, wherein, The number of the first nozzle is 2-6; the number of the second nozzle is 2-6.

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