JP6612145B2 - Method for producing lithium sulfide - Google Patents

Description

  The present invention relates to a method for producing lithium sulfide.

  As a method for producing lithium sulfide, a method for producing lithium sulfide by reacting lithium hydroxide and hydrogen sulfide is known. As a technique relating to such a method for producing lithium sulfide, for example, a technique described in Patent Document 1 (Japanese Patent Laid-Open No. 9-278423) can be cited.

  Patent Document 1 (Japanese Patent Laid-Open No. 9-278423) discloses a method for producing lithium sulfide in which lithium sulfide is synthesized by a reaction between lithium hydroxide and a gaseous sulfur source, and the particle diameter of lithium hydroxide is 0. A method for producing lithium sulfide is disclosed, wherein the powder is 1 mm to 1.5 mm in powder, and the heating temperature during the reaction is 130 ° C. or higher and 445 ° C. or lower.

JP-A-9-278423

According to the study by the present inventors, in the conventional method for producing lithium sulfide as disclosed in Patent Document 1, lithium sulfide formed on the surface of lithium hydroxide particles is partially changed to lithium polysulfide, It became clear that a phenomenon in which the progress of the reaction stagnates easily. In this case, lithium hydroxide was likely to remain in the center of the lithium sulfide particles, and the productivity was poor.
Furthermore, according to the study by the present inventors, in the conventional method for producing lithium sulfide as disclosed in Patent Document 1, particulate water is produced by water produced by the reaction between lithium hydroxide and hydrogen sulfide. It became clear that lithium oxide agglomerates, the reaction area between lithium hydroxide and hydrogen sulfide decreases, the reaction efficiency decreases, and the productivity decreases.
For the above reasons, the conventional method for producing lithium sulfide as disclosed in Patent Document 1 has poor productivity and is not suitable for industrial production.

  This invention is made | formed in view of the said situation, and provides the manufacturing method of lithium sulfide excellent in industrial production.

  The present inventors have intensively studied to achieve the above-mentioned problems. As a result, the present inventors have found that the reaction efficiency between particulate lithium hydroxide and hydrogen sulfide can be improved by bringing hydrogen sulfide into contact with particulate lithium hydroxide under reduced pressure. It came.

According to the present invention,
A method for producing lithium sulfide by synthesizing lithium sulfide by a reaction between lithium hydroxide and hydrogen sulfide,
A step (A) of disposing particulate lithium hydroxide inside a reaction vessel provided with a gas introduction pipe and a gas discharge pipe;
A reaction gas containing hydrogen sulfide is introduced into the reaction vessel from the gas introduction pipe, and the reaction gas is brought into contact with the particulate lithium hydroxide to react the particulate lithium hydroxide and the hydrogen sulfide. A step (B) for producing particulate lithium sulfide,
Including
In the step (B), a method for producing lithium sulfide in which the pressure inside the reaction vessel is less than 0.101 MPa in absolute pressure is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of lithium sulfide excellent in industrial production can be provided.

It is a schematic diagram which shows an example of the reaction container used for the manufacturing method of the lithium sulfide in this embodiment. It is a schematic diagram which shows an example of the apparatus used for the manufacturing method of the lithium sulfide in this embodiment. 2 is a diagram showing an X-ray diffraction pattern of the powder obtained in Example 1. FIG. 2 is a diagram showing an X-ray diffraction pattern of the powder obtained in Comparative Example 1. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, similar constituent elements are denoted by common reference numerals, and description thereof is omitted as appropriate. In the drawings, each component schematically shows the shape, size, and arrangement relationship to the extent that the present invention can be understood, and is different from the actual size. In addition, “to” in the numerical range represents the following from the above unless otherwise specified.

FIG. 1 is a schematic view showing an example of a reaction vessel 100 used in the method for producing lithium sulfide in the present embodiment.
The method for producing lithium sulfide of the present embodiment is a method for producing lithium sulfide in which lithium sulfide is synthesized by a reaction between lithium hydroxide and hydrogen sulfide. More specifically, the method for producing lithium sulfide of the present embodiment includes the following two steps.
(A) Step of disposing particulate lithium hydroxide 105 in the reaction vessel 100 provided with the gas introduction tube 101 and the gas discharge tube 103 (B) Hydrogen sulfide is introduced into the reaction vessel 100 from the gas introduction tube 101. A step of producing particulate lithium sulfide by introducing a reaction gas containing the reactant gas and bringing the reactant gas into contact with the particulate lithium hydroxide 105 to react the particulate lithium hydroxide 105 with hydrogen sulfide. In the method for producing lithium sulfide of the embodiment, in step (B), the internal pressure of the reaction vessel 100 is less than 0.101 MPa in absolute pressure, more preferably 0.100 MPa or less, still more preferably 0.8. 098 MPa or less.
When the pressure inside the reaction vessel 100 is less than or less than the above upper limit value, generation of lithium polysulfide on the surface of the lithium hydroxide particles can be suppressed, and as a result, productivity of lithium sulfide can be improved. .
Furthermore, if the pressure inside the reaction vessel 100 is less than or less than the above upper limit value, the water inside the reaction vessel 100 is likely to evaporate, and the water generated by the reaction between the lithium hydroxide 105 and hydrogen sulfide is discharged. Can promote. Thereby, it can suppress that the particulate lithium hydroxide 105 agglomerates with the water contained in the reaction gas, the reaction efficiency between the lithium hydroxide 105 and hydrogen sulfide is improved, and the productivity of lithium sulfide is improved. be able to.
In the step (B), the lower limit of the pressure inside the reaction vessel 100 is not particularly limited. For example, the absolute pressure is 0.010 MPa or more, more preferably 0.030 MPa or more, and still more preferably 0.00. It is 050 MPa or more, and particularly preferably 0.070 MPa or more. By doing so, the reaction rate between lithium hydroxide and lithium sulfide is further increased, and as a result, the productivity of lithium sulfide can be further improved.

Furthermore, according to the method for producing lithium sulfide according to the present embodiment, lithium sulfide is produced in the form of particles, and the produced lithium sulfide inherits the shape of the raw lithium hydroxide as it is and can be taken out from the reaction vessel. Further, since the obtained lithium sulfide can inherit the shape of the raw material lithium hydroxide as it is, the particle size can be increased, and therefore, oxidative decomposition of the surface due to contact with the atmosphere can be suppressed.
As mentioned above, according to the manufacturing method of lithium sulfide of this embodiment, while being excellent in productivity of lithium sulfide, it is excellent also in workability | operativity. Furthermore, lithium sulfide with high purity can be obtained. Therefore, the method for producing lithium sulfide according to this embodiment is excellent in industrial production.

  Hereinafter, each step will be described in detail.

(Process (A))
First, particulate lithium hydroxide 105 is placed inside a reaction vessel 100 including a gas introduction pipe 101 and a gas discharge pipe 103.

The reaction vessel 100 is made of a heat resistant material such as carbon, stainless steel, glass, alumina, aluminum, inconel, or hastelloy. In the obtained lithium sulfide, the reaction vessel 100 is one or two selected from stainless steel and glass from the viewpoint of reducing the amount of lithium carbonate which is an impurity, and the strength of the reaction vessel 100 and preventing the mixing of metal impurities. It is preferable to be comprised by the above, It is more preferable that it is made of glass, It is especially preferable that they are made of hard glass or quartz glass.
Further, the reaction vessel 100 may be a vessel to which a stirring function is added. Examples of the agitation function include a rotary kiln type agitation function.

The configuration in which the lithium hydroxide 105 is disposed inside the reaction vessel 100 is not particularly limited. For example, as shown in FIG. 1, the particulate hydroxide is formed on the porous sheet 111 disposed inside the reaction vessel 100. The structure which arrange | positions the lithium 105 is mentioned. Thereby, since the contact area of the reactive gas that has flowed into the lithium hydroxide 105 and the lithium hydroxide 105 can be increased, the reaction between the reactive gas and the lithium hydroxide 105 can be promoted more effectively. .
Examples of the porous sheet 111 include a metal mesh such as a stainless mesh; a punching metal such as stainless punching; an expanded metal such as stainless steel expand.

Lithium hydroxide 105 is preferably preliminarily dehydrated with crystal water and dried with attached water. Thereby, since it can suppress that the lithium hydroxide 105 agglomerates or can suppress the production | generation of a hydrosulfide, reaction of a reactive gas and the lithium hydroxide 105 can be advanced more effectively.
Examples of the dehydration and drying of the lithium hydroxide 105 include a method of heating in the air, a method of heating while flowing a gas such as hydrogen gas, nitrogen gas, and argon gas, and a method of heating by reducing the pressure.

(Process (B))
Next, a reaction gas containing hydrogen sulfide is introduced into the reaction vessel 100 from the gas introduction pipe 101, and the reaction gas is brought into contact with the particulate lithium hydroxide 105 so that the particulate lithium hydroxide 105 and the hydrogen sulfide are mixed. By reacting, particulate lithium sulfide is produced.
Here, it is considered that the reaction represented by the following formula (1) occurs.
_{2LiOH + H 2 S → Li 2} S + 2H 2 O (1)
When the reaction between lithium hydroxide 105 and hydrogen sulfide progresses and the raw material lithium hydroxide 105 disappears from the reaction system, water generation due to the reaction stops. Therefore, the reaction proceeds by monitoring the amount of water generated. You can know the degree.

In the step (B), the reaction between the particulate lithium hydroxide 105 and hydrogen sulfide is performed under reduced pressure as described above.
In the step (B), it is preferable to control the pressure inside the reaction vessel 100 by adjusting the amount of reaction gas introduced into the reaction vessel 100.
Further, in the method for producing lithium sulfide according to the present embodiment, when the hydrogen sulfide is consumed, the pressure inside the reaction vessel 100 decreases, so that the pressure drop is detected by a pressure detection unit such as a pressure sensor, and the pressure is reduced. It is preferable that hydrogen sulfide corresponding to the decrease is replenished from a container storing hydrogen sulfide. These operations can be performed automatically. In this case, the amount of hydrogen sulfide used is only the amount necessary for the reaction with lithium hydroxide 105 and the amount of residence in the hydrogen sulfide circulation system, so the utilization rate of hydrogen sulfide is greatly improved and the treatment of exhaust gas is reduced. can do.

The content of hydrogen sulfide in the reaction gas is preferably 50% by volume or more, more preferably 70% by volume or more, and further preferably from the viewpoint of further increasing the reaction rate with the particulate lithium hydroxide 105. Is 90% by volume or more. The concentration of hydrogen sulfide in the reaction gas is 100% by volume or less.
Here, the content of hydrogen sulfide in the reaction gas can be controlled by adjusting the introduction amount of a dilution gas such as nitrogen gas, argon gas, or hydrogen gas introduced into the reaction vessel 100. Usually, the concentration of hydrogen sulfide contained in the exhaust gas after the end of the reaction corresponds to the concentration of hydrogen sulfide in the reaction gas.

The average particle diameter d ₅₀ in the weight-based particle size distribution of the particulate lithium hydroxide 105 by a laser diffraction / scattering particle size distribution measuring method is preferably 1.5 mm or less, more preferably 1.0 mm or less. When the average particle diameter d50 is not _more than the above upper limit value, the contact area between the lithium hydroxide 105 and the reaction gas is increased and the reaction is promoted, so that the unreacted raw material in the obtained lithium sulfide can be further reduced. it can. As a result, higher purity lithium sulfide can be obtained.
The average particle size d ₅₀ in the weight particle size distribution by a laser diffraction scattering particle size distribution measurement method of lithium hydroxide 105 is preferably 0.1mm or more, more preferably 0.2mm or more. Average the particle size d ₅₀ is not less than the above lower limit, the water generated in the reaction system can be prevented from sticking particles adhere to the lithium sulfide particles. Moreover, since it can suppress that lithium hydroxide and the obtained lithium sulfide are exhausted with a reactive gas, waste gas treatment can be made simpler. Moreover, since lithium hydroxide and the obtained lithium sulfide can be prevented from being scattered by the reaction gas, the yield of lithium sulfide can be improved.

In the step (B), for example, the reaction gas and the lithium hydroxide 105 are reacted by heating while bringing the reaction gas and the lithium hydroxide 105 into contact with each other. Thereby, lithium sulfide can be produced.
The temperature for heating the reaction gas and the lithium hydroxide 105 is preferably 445 ° C. or less, and more preferably 420 ° C. or less. When the heating temperature is equal to or lower than the above upper limit value, the lithium hydroxide 105 can be prevented from melting, so that fusion between lithium hydroxides and the formation of a lump can be suppressed. Thereby, reaction of reaction gas and lithium hydroxide 105 can be advanced more effectively.
Moreover, as temperature which heats reaction gas and the lithium hydroxide 105, 130 degreeC or more is preferable and 200 degreeC or more is more preferable. When the heating temperature is equal to or higher than the lower limit, the reaction rate between the reaction gas and lithium hydroxide 105 can be further improved.

  The heating apparatus for heating the lithium hydroxide 105 is not particularly limited. For example, a heating unit that can heat the inside of the reaction vessel 100 and an output of the heating unit are adjusted to maintain the inside of the reaction vessel 100 at a constant temperature. It is composed of a temperature controller that can. The heating means is not particularly limited, and any known heating means such as a heating wire or lamp heating can be used, and any heating means can be used as long as the inside of the reaction vessel 100 can be heated.

  In the step (B), the flow rate of the reaction gas introduced into the reaction vessel 100 is increased, and the particulate lithium hydroxide 105 is suspended and suspended in the reaction gas. You may make it react with hydrogen sulfide. That is, the reaction between the particulate lithium hydroxide 105 and hydrogen sulfide may be performed in a fluidized bed. By doing so, the reaction efficiency between the reaction gas and the lithium hydroxide 105 can be further increased.

Further, the method for producing lithium sulfide according to the present embodiment may further include a step (C) of discharging a reaction gas containing unreacted hydrogen sulfide from the gas discharge pipe 103 to the outside of the reaction vessel 100.
The unreacted reaction gas and the exhaust gas containing water generated by the reaction of the reaction gas and the lithium hydroxide 105 are discharged from the gas discharge pipe 103 to the outside of the reaction vessel 100, for example.

  In the step (B), the reaction gas discharged to the outside of the reaction vessel 100 is reintroduced into the reaction vessel 100 from the gas introduction pipe 101, and the reaction is introduced again with the unreacted particulate lithium hydroxide 105. It is preferable to further include a step (D) of generating particulate lithium sulfide by reacting with a gas. Thereby, the utilization factor of hydrogen sulfide can be significantly improved and the treatment of exhaust gas can be reduced.

  Here, it is preferable to provide a water recovery unit for capturing water generated when lithium sulfide is generated outside the reaction vessel 100. When the reaction between the reaction gas and the lithium hydroxide 105 is completed, water generated when lithium sulfide is generated does not condense to the water recovery unit. Therefore, the amount of exhaust gas can be minimized by performing the above step (B) until water generated when lithium sulfide is generated does not condense in the water recovery unit.

  In the step (D), moisture contained in the reaction gas discharged to the outside of the reaction vessel 100 is removed, and then the reaction gas from which the moisture has been removed is reintroduced into the reaction vessel 100 from the gas introduction pipe 101. It is preferable to do. Thereby, it can suppress that the particulate lithium hydroxide 105 agglomerates with the water contained in the reaction gas, the reaction efficiency between the lithium hydroxide 105 and hydrogen sulfide is further improved, and the productivity is further improved. Can do.

In the step (D), for example, moisture contained in the reaction gas discharged to the outside of the reaction vessel 100 using a dehydrating agent can be removed. More specifically, by passing the reaction gas discharged to the outside of the reaction vessel 100 through a column filled with a dehydrating agent, moisture is adsorbed on the dehydrating agent, and moisture contained in the reaction gas is removed. be able to.
The dehydrating agent is not particularly limited as long as it adsorbs moisture and does not adsorb hydrogen sulfide, and examples thereof include activated carbon, zeolite, activated alumina, silica gel, calcium chloride, and niline pentoxide. Among these, zeolite is preferable from the viewpoint that only moisture can be adsorbed more effectively without adsorbing hydrogen sulfide.

  Through the above steps, lithium sulfide can be obtained.

Next, an example of a method for producing lithium sulfide in the present embodiment will be described more specifically. FIG. 2 is a schematic diagram showing an example of an apparatus 500 used in the method for producing lithium sulfide in the present embodiment.
An apparatus 500 used in the method for producing lithium sulfide in the present embodiment includes, for example, a hydrogen sulfide circulation system 200 and a hydrogen sulfide introduction system 300.
In the apparatus 500, the pressure in the hydrogen sulfide circulation system 200 is measured by the pressure sensor 119, the reaction gas is introduced into the hydrogen sulfide circulation system 200 from the hydrogen sulfide introduction system 300, and the pressure in the hydrogen sulfide circulation system 200 is kept constant. It can be adjusted within the range.

First, the hydrogen sulfide circulation system 200 will be described.
The end point of the reaction between lithium hydroxide 105 and hydrogen sulfide can be confirmed by measuring the dew point using a dew point meter 113, for example.
Here, if all of the water generated during the reaction between lithium hydroxide 105 and hydrogen sulfide is caused to flow to the dew point meter 113, the inside of the piping may dew and an accurate dew point may not be measured. Therefore, for example, it is preferable that most of the water is condensed in the cooling unit 109 and stored in the water recovery unit 107.
The dew point may be measured at all times, but when a certain amount of reaction proceeds, for example, when the amount of water stored in the water recovery unit 107 does not increase, a reaction gas is flowed into the dew point meter 113 to measure the dew point and the reaction is completed. It is preferable to check.
The dew point meter 113 may be of any model as long as it can measure the dew point even when it touches hydrogen sulfide. For example, a lithium chloride dew point meter or the like can be used.

As the cooling unit 109, for example, a container to which a cooling jacket is attached can be used. In order to advance the condensation efficiently, it is preferable that the contact area with the reaction gas is large, so a column or the like provided with a cooling serpentine tube is suitable. For example, cooling water of 5 ° C. to 30 ° C. can flow through the cooling unit 109.
The water recovery unit 107 is, for example, a container that stores water condensed by the cooling unit 109. Since hydrogen sulfide is circulated, a container having a water discharge valve with excellent airtightness is suitable.

Since lithium sulfide is decomposed by contact with water, the reaction gas that has passed through the water recovery unit 107 is preferably dehydrated using a dehydrating agent.
The dehydrating unit 110 is, for example, a column filled with a dehydrating agent. It is preferable to provide two or more dehydration units 110. In this way, when one of the dehydrating units 110 is saturated, it is possible to switch to the other dehydrating unit 110 and perform the regeneration process of one of the dehydrating units 110 during that time.

The pump 115 is, for example, a diaphragm pump, and is a pump for circulating the reaction gas in the hydrogen sulfide circulation system 200. Any pump that does not lose its function even when it comes into contact with hydrogen sulfide may be used. For example, a diaphragm pump is preferable because the reaction gas does not contact the metal part of the pump.
The flow meter 117 only needs to be able to control the flow rate of the reaction gas that communicates with the reaction vessel 100. For example, a material having corrosion resistance that does not lose its function even when it is in contact with hydrogen sulfide is preferable.
The flow rate of the reaction gas is not particularly limited, but when the flow rate is large, the lithium hydroxide 105 becomes a fluidized bed and the synthesis is completed in a short time. When the flow rate is small, the lithium hydroxide 105 becomes a fixed bed and the synthesis time becomes long, but the contamination of the circulation system and the reduction of the recovery yield due to the scattering of the lithium hydroxide 105 are suppressed.

Next, the hydrogen sulfide introduction system 300 will be described.
The hydrogen sulfide container 127 is a container filled with hydrogen sulfide. For example, a cylinder filled with liquefied hydrogen sulfide can be used. A hydrogen sulfide production facility for producing hydrogen sulfide from sulfur and hydrogen via a catalyst may be connected. In this case, the hydrogen sulfide production facility is provided with a container that can temporarily store liquefied hydrogen sulfide, such as a buffer tank, so that hydrogen sulfide can be supplied from the buffer tank, thereby enabling stable replenishment.
Since hydrogen sulfide is a corrosive gas, it is preferable to use the air operated valves 131 and 133 so that the coil portion does not come into contact with the gas.
The gas container 129 is used, for example, to replace the gas in the piping of the hydrogen sulfide circulation system 200 with a gas other than hydrogen sulfide. In FIG. 2, it is used instead of air for driving the air operated valves 131 and 133. The air operated valves 131 and 133 may be driven by compressed air. Examples of the gas filled in the gas container 129 include argon gas, nitrogen gas, and hydrogen gas.

The pressure sensor 119 measures the pressure in the hydrogen sulfide circulation system 200. As the pressure sensor 119, for example, a sensor with a stainless steel casing that does not corrode with hydrogen sulfide can be used.
The indicator 125 is a control device that receives the signal from the pressure sensor 119 and drives the electromagnetic valves 121 and 123 connected to the hydrogen sulfide container 127 and the gas container 129. Although relay control may be used, when the control is performed by the PLC, the control can be performed by linking a plurality of data such as temperature and dew point.
The air operated valves 131 and 133 are valves that control replenishment and stoppage of the gas by driving the solenoid valves 121 and 123 that have received a signal from the display unit 125.
The pump 135 is used to discharge the gas inside the hydrogen sulfide circulation system 200 to the outside. By using the pump 135, the gas staying in the hydrogen sulfide circulation system 200 can be forcibly discharged when the internal pressure of the hydrogen sulfide circulation system 200 increases due to some abnormality or before or after the start of synthesis.

The lithium sulfide obtained by the production method of the present embodiment can be suitably used as, for example, an intermediate material for a positive electrode active material, a negative electrode active material, a solid electrolyte material, and a chemical for a lithium ion battery. Since the lithium sulfide obtained by the production method of the present embodiment has a high purity, it is particularly used as a raw material for battery materials such as a positive electrode active material, a negative electrode active material, and a solid electrolyte material for lithium ion batteries that require particularly high purity. It can be used suitably.
In addition, since lithium sulfide obtained by the production method of the present embodiment has high purity, it is obtained when used as a raw material for battery materials such as a positive electrode active material, a negative electrode active material, and a solid electrolyte material for a lithium ion battery. The lithium ion conductivity of the obtained battery material is particularly excellent.

  As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and various structures other than the above are also employable.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

Example 1
The reaction vessel 100 shown in FIG. 1 and the apparatus shown in FIG. 2 were used. As the reaction vessel 100, a quartz vertical vessel was used. A column filled with zeolite was used for the dehydration unit 110.
First, particulate lithium hydroxide 105 (average particle diameter d ₅₀ : 0.7 mm, 6.6 mol) was placed on the porous sheet 111.
Next, a reaction gas containing 99% pure hydrogen sulfide (manufactured by Sumitomo Seika Co., Ltd.) was introduced into the reaction vessel 100 from the gas introduction pipe 101 installed at the lower part of the reaction vessel 100 at a flow rate of 10 L / min. Here, 100 volume% hydrogen sulfide gas was used as the reaction gas. The heating temperature of the particulate lithium hydroxide 105 is 300 ° C. The pressure in the hydrogen sulfide circulation system 200 was controlled in the range of 0.081 MPa or more and 0.096 MPa or less (0.8 to 0.95 atm) in absolute pressure.
Here, the average particle size d ₅₀ of lithium hydroxide, a laser diffraction scattering particle size distribution analyzer (manufactured by Malvern Instruments Ltd., Mastersizer 3000) was used for the measurement.

More specifically, it is as follows. After the valves V1, V3, V6 and V7 were closed and the valves V2, V4 and V5 were opened, the reaction gas circulation was started. After raising the temperature of the reaction vessel 100 to 300 ° C., no increase in the amount of water stored in the water recovery unit 107 was observed in 2 hours. Three hours after starting the gas circulation, the valve V2 was closed, the valve V1 was opened, and the dew point was measured with a dew point meter 113 (lithium chloride dew point meter). Synthesis time 3 hours).
When the reaction vessel 100 becomes 40 ° C. or lower, the pump 115 (diaphragm pump) of the hydrogen sulfide circulation system 200 is stopped, the valve V6 is opened, and the gas remaining in the hydrogen sulfide circulation system 200 is removed by the pump 135 of the hydrogen sulfide introduction system 300. Discharged. After discharging the staying gas, the valve V6 was closed, the valve V7 was opened, and the argon gas was introduced from the gas container 129 into the hydrogen sulfide circulation system 200 until reaching the normal pressure, and then stopped. Thereafter, the powder was recovered from the reaction vessel 100.
About the obtained powder, the X-ray-diffraction pattern was measured with the X-ray-diffraction apparatus (XRD). The X-ray diffraction pattern of the obtained powder is shown in FIG.
The powder obtained from this X-ray diffraction pattern was found to be lithium sulfide. Moreover, the peak of lithium hydroxide as a raw material was not recognized, and it was found that the purity of the obtained lithium sulfide was high.
The yield was 99.9%. The amount of staying gas in the hydrogen sulfide circulation system 200 substantially corresponds to the amount of gas discharged by the pump 135 of the hydrogen sulfide introduction system 300, and its value was 12L. Therefore, the hydrogen sulfide used for the reaction was about (3.3 mol × 22.4 L) +12 L = 85.9 L.

(Comparative Example 1)
A reaction vessel 100 shown in FIG. 1 was used. As the reaction vessel 100, a quartz vertical vessel was used. Particulate lithium hydroxide 105 (average particle diameter d ₅₀ : 0.7 mm, 6.6 mol) was placed on the porous sheet 111. A cooling unit 109, a water recovery unit 107, a dehydration unit 110 (a column filled with zeolite), a valve V1, a valve V2, and a dew point meter 113 shown in FIG. 2 are connected to the gas discharge pipe 103 of the reaction vessel 100. External release. Here, the external release is a state in which the reaction gas discharged from the gas discharge pipe 103 is discharged outside without being circulated through the reaction vessel 100 by closing V5 and opening V6 in FIG.
Next, a reaction gas containing 99% pure hydrogen sulfide (manufactured by Sumitomo Seika Co., Ltd.) was introduced into the reaction vessel 100 from the gas introduction pipe 101 installed at the lower part of the reaction vessel 100 at a flow rate of 10 L / min. Here, 100 volume% hydrogen sulfide gas was used as the reaction gas. The heating temperature of the particulate lithium hydroxide 105 is 300 ° C. The pressure indicated by the pressure sensor connected after the dew point meter 113 was 0.106 MP (1.05 atm) in absolute pressure.

More specifically, it is as follows. After replacing the inside of the reaction vessel 100 with argon gas, the reaction vessel 100 was heated to 300 ° C. while introducing hydrogen sulfide. After the temperature was raised to 300 ° C., no increase in the amount of water stored in the water recovery unit 107 was observed in 2.5 hours. After 4 hours, the valve V2 was closed, the valve V1 was opened, and the dew point was measured with a dew point meter 113 (lithium chloride dew point meter). As a result, it was 0 ° C., so the heating of the reaction vessel 100 was stopped (synthesis time 4 hours). Next, the hydrogen sulfide gas was switched to argon gas, and when the reaction vessel 100 became 40 ° C. or lower, the powder was recovered from the reaction vessel 100.
About the obtained powder, the X-ray-diffraction pattern was measured with the X-ray-diffraction apparatus (XRD). The X-ray diffraction pattern of the obtained powder is shown in FIG.
The powder obtained from this X-ray diffraction pattern was found to be lithium sulfide. Moreover, the peak of lithium hydroxide which is a raw material was not recognized, and it was found that the purity of the obtained lithium sulfide was high.
The yield was 99.9%. The hydrogen sulfide used in the reaction was about (10 L / min × 60 minutes × 4 hours) = 2400 L.

From the above, it was found that the lithium sulfide synthesis time can be shortened according to the lithium sulfide production method of the present embodiment. Furthermore, according to the manufacturing method of lithium sulfide of this embodiment, it turned out that the usage-amount of hydrogen sulfide can also be reduced.
That is, it can be understood that the method for producing lithium sulfide of the present embodiment is excellent in industrial production.

DESCRIPTION OF SYMBOLS 100 Reaction container 101 Gas introduction pipe 103 Gas discharge pipe 105 Lithium hydroxide 107 Water recovery part 109 Cooling part 110 Dehydration part 111 Porous sheet 113 Dew point meter 115 Pump 117 Flow meter 119 Pressure sensor 121 Electromagnetic valve 123 Electromagnetic valve 125 Display 127 Hydrogen sulfide container 129 Gas container 131 Air operated valve 133 Air operated valve 135 Pump 200 Hydrogen sulfide circulation system 300 Hydrogen sulfide introduction system 500 Device V1 Valve V2 Valve V3 Valve V4 Valve V5 Valve V6 Valve V7 Valve

Claims (12)

A method for producing lithium sulfide by synthesizing lithium sulfide by a reaction between lithium hydroxide and hydrogen sulfide,
A step (A) of disposing particulate lithium hydroxide inside a reaction vessel provided with a gas introduction pipe and a gas discharge pipe;
A reaction gas containing hydrogen sulfide is introduced into the reaction vessel from the gas introduction pipe, and the reaction gas is brought into contact with the particulate lithium hydroxide to react the particulate lithium hydroxide with the hydrogen sulfide. A step (B) for producing particulate lithium sulfide,
Including
The method for producing lithium sulfide, wherein in the step (B), the pressure inside the reaction vessel is less than 0.101 MPa in absolute pressure. The method for producing lithium sulfide according to claim 1,
In the step (B), a method for producing lithium sulfide in which the pressure inside the reaction vessel is controlled by adjusting the amount of the reaction gas introduced into the reaction vessel. The method for producing lithium sulfide according to claim 1 or 2,
The step (B) is a method for producing lithium sulfide, further comprising a step (C) of discharging a reaction gas containing unreacted hydrogen sulfide from the gas discharge pipe to the outside of the reaction vessel. The method for producing lithium sulfide according to claim 3,
In the step (B), the reaction gas discharged to the outside of the reaction vessel is reintroduced into the reaction vessel through the gas introduction pipe, and the reaction gas is reintroduced with unreacted particulate lithium hydroxide. A process for producing lithium sulfide, further comprising a step (D) of producing particulate lithium sulfide by reacting with. The method for producing lithium sulfide according to claim 4,
In the step (D), after removing moisture contained in the reaction gas discharged to the outside of the reaction vessel, the reaction gas from which the moisture has been removed is reintroduced into the reaction vessel through the gas introduction pipe. A method for producing lithium sulfide. The method for producing lithium sulfide according to claim 5,
In the step (D), a method for producing lithium sulfide in which moisture contained in the reaction gas discharged to the outside of the reaction vessel using a dehydrating agent is removed. The method for producing lithium sulfide according to any one of claims 1 to 6,
In the step (B), the flow rate of the reaction gas introduced into the reaction vessel is increased, and the particulate lithium hydroxide is suspended and suspended in the reaction gas. A method for producing lithium sulfide, comprising reacting lithium oxide with the hydrogen sulfide. The method for producing lithium sulfide according to any one of claims 1 to 7,
A method for producing lithium sulfide, wherein the content of the hydrogen sulfide in the reaction gas is 50% by volume or more and 100% by volume or less. The method for producing lithium sulfide according to any one of claims 1 to 8,
The average particle size d ₅₀ is the manufacturing method of the lithium sulfide is 0.1mm or more 1.5mm or less in weight particle size distribution by a laser diffraction scattering particle size distribution measuring method of the particulate lithium hydroxide. The method for producing lithium sulfide according to any one of claims 1 to 9,
A water recovery unit for capturing water generated when the lithium sulfide is generated outside the reaction vessel;
A method for producing lithium sulfide, wherein the step (B) is performed until the water is not condensed to the water recovery unit. In the manufacturing method of lithium sulfide according to any one of claims 1 to 10,
A porous sheet is disposed inside the reaction vessel,
A method for producing lithium sulfide, wherein the particulate lithium hydroxide is disposed on the porous sheet. The method for producing lithium sulfide according to any one of claims 1 to 11,
In the step (B), a method for producing lithium sulfide, wherein the reaction gas and the lithium hydroxide are brought into contact at 130 ° C. or higher and 445 ° C. or lower.

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