Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B17/00—Sulfur; Compounds thereof
  • C01B17/22—Alkali metal sulfides or polysulfides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
  • C01D15/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/80—Compositional purity
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the subject of the present invention is the preparation of lithium sulfide from lithium hydroxide and hydrogen sulfide by a continuous mode process using a moving bed (or circulating bed).
• lithium sulfide there are several known methods for synthesizing lithium sulfide, all of which are hampered by the extremely hydrophilic nature of this compound. Indeed, at room temperature lithium sulfide is very reactive to humidity and reacts spontaneously on contact with water to form lithium hydroxide (LiOH) by releasing hydrogen sulfide (H2S). Thus, the reaction conditions must be perfectly controlled to avoid any degradation of the lithium sulfide as it forms. Once lithium sulfide is formed, strict control of its residual water content is essential, in particular via storage in a dry and inert atmosphere.
• lithium sulfide having the highest possible degree of purity and in the form of solid particles having an average particle size of less than 1 mm. These properties lead to good stability and electrical capacity of the electrolyte.
• a known method for the synthesis of lithium sulfide consists of reacting lithium hydroxide with hydrogen sulfide, according to the following reaction:
• the starting raw material LiOH is generally in the hydrated form LiOH.HiO, and a thorough drying step is necessary before the actual sulfurization can be started.
• lithium sulfide blocks that is to say lithium sulfide particles of larger size made up of LiiS aggregates surrounding a inner core of non-sulfurized LiOH.HiO.
• the quality of the lithium sulphide obtained is greatly reduced: not only is its purity lower, but also its average particle size increases.
• the present invention aims to propose a process which makes it possible to prepare lithium sulphide on an industrial scale in continuous mode.
• the invention also aims to enable the preparation of lithium sulphide with a high degree of chemical purity, in the form of particles of small particle size.
• the Applicant has now developed an innovative process which makes it possible to produce lithium sulfide of excellent quality from lithium hydroxide and hydrogen sulfide by a process in continuous mode using a moving bed (or bed circulating) circulating in at least one reactor having a particular configuration.
• the process according to the invention is characterized in that the key step of sulfurization of lithium hydroxide is carried out in a reaction zone comprising at least one tubular reactor whose configuration is that of an ascending vibrating spiral, in which the Lithium hydroxide circulates against the current of a flow of anhydrous sulfurizing gas containing hydrogen sulfide and an inert gas.
• the subject of the present invention is a process for preparing lithium sulfide (LiiS) from lithium hydroxide (LiOH) and hydrogen sulfide (H2S), characterized in that the sulfidation of lithium hydroxide lithium is carried out in a reaction zone comprising at least one tubular moving bed reactor having the configuration of an ascending vibrating spiral, in which the lithium hydroxide circulates against the current of an anhydrous gas mixture containing hydrogen sulfide and at least one inert gas.
• the process according to the invention makes it possible to prepare lithium sulfide with high yields, and in particular with a mass yield greater than 80%.
• the lithium sulphide formed as it progresses in the reactor does not remain in contact with the water, which is eliminated with the gas flow circulating in the opposite direction.
• the process according to the invention makes it possible to obtain lithium sulfide of high purity, greater than 99.0% by mass.
• the lithium sulphide leaving the reactor only encounters the incoming flow of anhydrous sulphurizing gas based on hydrogen sulphide and inert gas, which guarantees the production of a product with a hydroxide content of Residual lithium is particularly low, less than 1% by mass.
• the reaction zone comprises at least one tubular reactor whose configuration is that of an ascending vibrating spiral.
• the LiOH particles progress upwards along a vibrating helical turn, countercurrent to the downward flow of anhydrous sulfurizing gas.
• This configuration has the additional advantage of making it possible to avoid the formation of lithium sulfide blocks in the form of LiiS aggregates surrounding an internal core of LiOH.HiO.
• the LiOH particles move in upward leaps ensured by the vibrations of the helical turn, which ensures high mixing of them within the sulfurizing gas flow and leads to better contact of the LiOH particles with the sulfurizing gas, while avoiding the formation of clusters by impact of particles on the walls of the reactor.
• this configuration also makes it possible to reduce the flow rate of sulfurizing gas and the quantity of hydrogen sulfide used, thanks to the better contact of the sulfurizing gas and the lithium hydroxide. It accelerates the sulfurization reaction of the latter and eliminates water effectively as it forms.
• FIG 1 illustrates an example of a conforming lithium sulphide production unit to the process of the invention.
• the present invention uses an anhydrous gas mixture containing hydrogen sulfide and at least one inert gas.
• the gas mixture contains hydrogen sulfide (H2S), which is the sulfurizing agent reacting with lithium hydroxide to form lithium sulfide by releasing water.
• H2S hydrogen sulfide
• the hydrogen sulfide content of the gas mixture is advantageously in the range going from 30 to 90% by volume, preferably from 40 to 80%, more preferably from 50 to 70%, and better still from 55 to 65% by volume. , relative to the total volume of said mixture.
• the gas mixture also comprises at least one inert gas, that is to say a non-reactive gas. Inert gases are well known to those skilled in the art.
• a particularity of the process of the invention is that the conversion of lithium hydroxide into lithium sulphide is carried out in a tubular reactor at the inlet of which the lithium hydroxide particles are introduced and are circulated towards the outlet. .
• HAS Conversely, the sulfurizing gas is introduced at the outlet of the reactor and circulates towards the entrance thereof.
• the gas flow consists of sulfur gas, that is to say the anhydrous gas mixture containing hydrogen sulfide and at least one inert gas. As it progresses downward in the reactor, the gas flow becomes depleted of hydrogen sulphide and enriched in water vapor.
• said anhydrous gas mixture is introduced into the reaction zone at at least two points therein: at the exit from the reaction zone and at at least one point located between the exit and the entrance to the zone reaction.
• said anhydrous gas mixture is introduced at the outlet of the reaction zone and at at least two different successive points positioned between the outlet and the inlet of the reaction zone.
• the pressure inside the reactor(s) is maintained at a value less than 3 bars (3.10 5 Pa), preferably less than 2 bars (2.10 5 Pa), and more preferably still less than 1.3 bars (1, 3. 10 5 Pa).
• a particular reactor used in the invention consists of a vibrating spiral of substantially tubular shape winding helically around a vertical axis, and having at least two pitches.
• the cross section of the spiral is preferably circular and in this case, the spiral is a tube.
• the tube has a diameter between 100 and 300 mm. It typically has a developed length of up to 400 m.
• the tube is hollow, that is to say it does not include elements in its interior part.
• the total height of the spiral can range from 5 to 40 m, preferably 10 to 20 m.
• the reactor has a number of turns preferably ranging from 15 to 60, more preferably from 25 to 40.
• the number of turns is such that it allows a particle circulation speed which can range from 50 to 6,000 kg/h, preferably from 50 to 500 kg/h, and an hourly space speed of gas (or "Gas”).
• Hourly Space Velocity typically from 50 to 1500 h 1 , preferably from 50 to 500 h 1 .
• the solid particles typically occupy 5 to 80% of the volume of the turns, preferably 10 to 50%.
• Said vibrating spiral is advantageously made of a metallic material.
• it is made of a metal tube made of a metal alloy, more preferably steel.
• a central barrel makes it possible to stiffen and support the helix formed by the spiral.
• the spiral can be electrically isolated from the central barrel by the fixing system.
• a transformer supplies the vibrating spiral in at least one step (that is to say at least one turn) with low voltage current, less than 50V, which allows direct heating by the Joule effect. the metallic mass of the tube at the required temperature in the reactor.
• one or more steps are heated by the Joule effect to a temperature of 150 to 450°C, particularly in the lower part of the reactor, in the entry zone of the LiOH particles.
• the Joule effect has the direct consequence of generating heat in the mass of the turn. It makes it possible to obtain greater flexibility for controlling the temperature at the heart of the turn compared to indirect heating, for example by means of a heat transfer fluid.
• the vibrations of the reactor in the form of a spiral can be produced by at least one system placed at any suitable level, for example at the base or at the top of the barrel or even positioned around the spiral.
• suitable vibration systems we can cite the following systems: unbalance motors, electromagnetic vibrators (excited by a variable cycle, with creation of pulses) and unbalance excitations.
• the vibrations are produced by a table serving as a support for the central barrel and actuated by two unbalance motors.
• the reaction zone may consist of one or more moving bed reactors.
• the reaction zone contains at least two moving bed reactors.
• the reaction zone can thus consist of several moving bed reactors, which can be arranged in series and/or in parallel.
• Said moving bed reactors can be of identical configurations (in particular when they are arranged in parallel) or different.
• the lithium sulfide is recovered in the form of small solid particles such as for example beads, particles of more or less cylindrical shape or of irregular shape.
• the number-average size of the lithium sulfide particles is preferably less than or equal to 4 mm, and more preferably less than or equal to 1 mm.
• the average size designates here the average value in number of the diameter of the particles by assimilating them to spheres, and is defined by the median diameter d50, measured by laser diffraction particle size analysis for example by means of a known device such as a laser diffraction particle size analyzer (Laser Diffraction Particle Size Analyzer), which makes it possible to determine the size distribution of a population of particles.
• Laser Diffraction Particle Size Analyzer Laser Diffraction Particle Size Analyzer
• the average size is equal to the average diameter.
• part of the flow of particles leaving the reaction zone is recycled in said zone, either at its entrance or at an intermediate point therein. Recycling at an intermediate point is particularly facilitated when the reaction zone comprises several reactors in series, the recycled particles being introduced for example between two successive individual reactors.
• the lithium hydroxide introduced at the entrance to the reaction zone is in the form of small solid particles such as, for example, beads, particles of more or less cylindrical shape or of irregular shape.
• the number-average size of the lithium hydroxide particles is preferably in the range from 10 pm to 4 mm.
• the average size designates here the average value in number of the diameter of the particles by assimilating them to spheres, and is defined by the median diameter d50, measured by laser diffraction particle size analysis for example by means of a known device such as A laser diffraction particle size analyzer (Laser Diffraction Particle Size Analyzer), which makes it possible to determine the size distribution of a population of particles.
• a laser diffraction particle size analyzer Laser Diffraction Particle Size Analyzer
• the average size is equal to the average diameter.
• the lithium hydroxide prior to its introduction into the reaction zone, undergoes a drying step.
• This step is typically carried out in a drying zone and aims to produce lithium hydroxide in anhydrous form according to the following process:
• the drying step is preferably carried out by subjecting the lithium hydroxide to heat treatment at a temperature in the range from 150 to 350°C, preferably from 175 to 250°C, and by circulating at least an inert gas in the drying zone so as to eliminate water.
• the inert gas(es) may in particular be chosen from nitrogen (N 2 ) and noble gases such as argon, helium, krypton, neon and xenon, and mixtures thereof.
• the inert gas(es) are chosen from argon, nitrogen and mixtures thereof, and more preferably the inert gas is nitrogen.
• the pressure inside the drying zone is advantageously maintained at a value less than 3.10 5 Pa (3 bars), preferably less than 2.10 5 Pa (2 bars) and better still less than or equal to 1.3. 10 5 Pa (1.3 bars).
• the drying step is preferably carried out in continuous mode, and more preferably in a drying zone comprising one or more moving bed reactors in which the lithium hydroxide particles circulate.
• the flow of inert gas can then circulate, in the drying zone, in co-current or counter-current to the flow of lithium hydroxide particles.
• the inert gas flow circulates in the co-current drying zone of the lithium hydroxide particle flow
• At least one moving bed reactor of the drying zone is a tubular reactor in the form of an ascending vibrating spiral.
• the particles progress upwards along a spiral, in which they are gradually converted to anhydrous LiOH with removal of water.
• Tubular reactors in the form of a vibrating spiral have been described above.
• the flow of inert gas preferably circulates upwards in said vibrating spiral (that is to say co-current with the flow of solid particles).
• a circulation of the inert gas flow downwards in the vibrating spiral i.e. countercurrent to the flow of solid particles can also be implemented.
• At least one moving bed reactor of the drying zone is a horizontal tubular reactor comprising a thermal screw, that is to say an endless screw, or Archimedes screw, in which the particles are conveyed and dried in a continuous flow, with removal of water.
• a thermal screw that is to say an endless screw, or Archimedes screw
• the LiOH.HiO particles progress along the blades of a screw, in which they are gradually converted into anhydrous LiOH with the elimination of water.
• the thermal screw can be heated electrically or by a heat transfer fluid and the heat exchange can occur through the trough, the central core or the turns.
• the inert gas flow can be injected co- or counter-current to the flow of solid particles, preferably co-current.
• pre-sulfurization of the lithium hydroxide is also carried out during the drying step as described above.
• pre-sulfurization we mean a partial sulfurization of the hydroxide of lithium, such that the anhydrous lithium hydroxide at the end of the drying step contains from 5 to 40% by mass of lithium sulfide Li 2 S.
• This gas mixture is anhydrous, that is to say its water content is less than or equal to 1% by volume.
• the hydrogen sulfide content of the gas mixture used for pre-sulfurization is more preferably in the range going from 10 to 15% by volume, relative to the total volume of said mixture.
• the inert gas(es) are chosen from those described above for the drying step, including nitrogen (N 2 ), noble gases and their mixtures.
• the inert gas(es) are chosen from argon, nitrogen and mixtures thereof, and more preferably the inert gas is nitrogen.
• the inert gas(es) present in the gas mixture used for the pre-sulfurization of lithium hydroxide is(are) that(those) used for drying.
• pre-sulfurization can be carried out by adding hydrogen sulfide, or a mixture comprising hydrogen sulfide, inert gas and optionally hydrogen, directly to the gas flow circulating in the drying zone. as described below.
• the gas mixture used for pre-sulfurization also comprises hydrogen (H 2 ).
• the hydrogen content of the gas mixture is advantageously in the range going from 1 to 10% by volume, preferably from 2 to 5% by volume, relative to the total volume of said mixture.
• said gas mixture used for the pre-sulphurization of lithium hydroxide consists entirely or partly of the gas mixture recovered at the outlet of the reaction zone, previously dried to eliminate the water.
• This mixture gas can be diluted with inert gas if necessary to adjust the hydrogen sulfide content to the concentration required for presulfurization.
• the gas mixture used for pre-sulfurization can be introduced at one or more points in the drying zone, preferably located downstream of the entry zone of the lithium hydroxide particles. Indeed, the pre-sulfurization step is advantageously initiated at a point in the drying zone where the water content of the lithium hydroxide is sufficiently low.
• the gas mixture used for pre-sulfurization is preferentially brought into contact with the lithium hydroxide circulating in the drying zone at one or more injection points located in the downstream part thereof, i.e. that is to say in its second half, relative to the point of injection of the solid.
• the gas mixture used for pre-sulfurization circulates in the drying zone in co-current with the flow of lithium hydroxide particles.
• the gas mixture used for pre-sulfurization is introduced at one, two or three points, preferably located in the upper half of the spiral.
• the lithium hydroxide pre-sulfurization step is advantageously carried out at a temperature in the range from 150 to 350°C, preferably from 175 to 250°C.
• This pre-sulfurization step makes it possible to improve the drying rate of the lithium hydroxide and to increase the rate of sulfurization in the reaction zone located downstream.
• FIG. 1 in the appendix illustrates a non-limiting example of a lithium sulphide production unit.
• lithium hydroxide LiOH
• LiiS lithium sulfide
• a reaction zone 9 which comprises a tubular moving bed reactor consisting of an ascending vibrating spiral 9a.
• the lithium hydroxide particles are introduced into the lower part of the reaction zone 9 via line 4. The particles progress upwards in the spiral 9a, this progression being caused by the vibrations of the spiral.
• An anhydrous gas mixture containing hydrogen sulphide in stoichiometric excess and nitrogen is introduced into the upper part of the reaction zone 9.
• This mixture is conveyed via line 10 and introduced into the spiral reactor 9a at two injection points successive 10a and 10b located in the upper part of said reactor. It circulates downward in the spiral reactor 9a, countercurrent to the upward flow of particles.
• a gas mixture containing nitrogen, water and a residue of hydrogen sulphide is evacuated at two successive points 12a and 12b and conveyed via line 12 to a unit of treatment 13.
• the mixture from line 12 is treated in order to eliminate the water which is separated by line 14. It is also possible to carry out dust removal (not shown) of the gas mixture, in order to ' eliminate any dust particles possibly entrained.
• the mixture of nitrogen and residual hydrogen sulphide is then evacuated via line 15.
• the lithium hydroxide Prior to its introduction into the reaction zone, the lithium hydroxide undergoes a drying step carried out in the drying zone 2 which comprises a tubular reactor with a moving bed which in this example consists of an ascending vibrating spiral 2a.
• the particles of hydrated lithium hydroxide (LiOH.HiO) are introduced into the lower part of the drying zone 2 via line 1.
• the particles progress upwards in the spiral 2a, this progression being caused by the vibrations of the spiral.
• An inert gas consisting of nitrogen conveyed via line 3 is also introduced into the lower part of drying zone 2, and injected into spiral 2a at injection points 3a and 3b. Nitrogen progresses ascending manner in the spiral reactor 2a, co-current with the particle flow.
• the dried lithium hydroxide particles are evacuated via line 4 and transferred to the reaction zone 9. Also in the upper part of the drying zone 2, a mixture of water and The nitrogen is evacuated at successive points 5a and 5b, and transported via line 5 to a treatment unit 6.
• the mixture from line 5 is treated in order to eliminate the water which is separated by line 7. It is also possible to carry out dust removal (not shown) of the gas mixture, in order to ' eliminate any dust particles possibly entrained.
• the nitrogen is then evacuated via line 8. According to an advantageous embodiment not shown, the nitrogen thus recovered at the exit of the drying zone is recycled towards the unit, either at the drying zone 2 or at the level of reaction zone 9.
• the gaseous mixture of nitrogen and residual hydrogen sulphide from reaction zone 9 and dried, recovered by line 15, is recycled via line 16 to drying zone 2 where it is introduced into the second upper half of the spiral reactor 2a.
• This recycled gas mixture contains a hydrogen sulfide content lower than that of the gas mixture introduced into the reaction zone 9. This recycling makes it possible to carry out in the second upper half of the drying zone 2 a presulfurization of the hydroxide particles of lithium, upstream of reaction zone 9.

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• Chemical & Material Sciences (AREA)
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• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
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• 2022
  • 2022-12-20 FR FR2213974A patent/FR3143861B1/fr active Active
• 2023
  • 2023-12-05 CN CN202380086680.0A patent/CN120344487A/zh active Pending
  • 2023-12-05 EP EP23834271.1A patent/EP4638355A1/de active Pending
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