Volatile organic compound treatment system and control method therefor

Abstract

The present invention relates to an apparatus used in a heat treatment process for obtaining a purified lithium sulfide powder, and presents a method and a system for automating the lithium sulfide heat treatment process, which requires a lot of cost and time, to reduce production costs and increase the yield of products.

Description

Volatile Organic Compound Treatment System and Control Method

[0001] The present invention relates to the treatment of gases generated during the process of purifying lithium sulfide powder, which is produced by drying through a thermal reduction process, an extraction process, and a drying process, by heating the impurities contained therein. More specifically, the invention relates to a system capable of increasing gas removal efficiency by separating and capturing the gas into organic and inorganic component gases.

[0002]

[0003] As the demand for electric vehicles and large-capacity power storage devices increases, various batteries have been developed to meet this need.

[0004] Lithium-ion batteries have been widely commercialized because they have the best energy density and power output characteristics among various types of rechargeable batteries.

[0005] While lithium secondary batteries containing liquid-type electrolytes with organic solvents are mainly used, it has been pointed out that liquid-type secondary batteries cause battery expansion due to the decomposition of the liquid electrolyte by electrode reactions and pose a risk of ignition due to leakage of the liquid electrolyte.

[0006] To address the problems of these liquid-type secondary batteries, lithium secondary batteries using solid electrolytes with excellent stability have recently been attracting attention.

[0007] Solid electrolytes can be classified into oxide-based and sulfide-based types. Since sulfide-based solid electrolytes have higher lithium-ion conductivity and are stable over a wide voltage range compared to oxide-based solid electrolytes, sulfide-based solid electrolytes are primarily used for all-solid-state batteries.

[0008] However, lithium sulfide, one of the main raw materials for sulfide-based solid electrolytes, has the disadvantage of being very expensive.

[0009] The reason for this is that a process is required to increase purity by removing organic substances, such as residual ethanol and carbon molecules, as well as inorganic substances like sulfur and other impurities, that remain during the lithium sulfide manufacturing process.

[0010] Generally, a heat treatment method is used to remove the aforementioned impurities; however, gaseous impurities generated during the heat treatment process penetrate the lithium sulfide being purified, degrading its quality. Furthermore, these gaseous impurities adhere to the heat treatment equipment in the form of soot, causing malfunctions and acting as a major obstacle to improving productivity.

[0011] While existing prior art presents methods for purifying impurities contained in the lithium sulfide mentioned above, it does not introduce methods for lowering the production cost required during purification.

[0012] For example, prior art disclosed prior to the present application (Published Patent 10-2023-0054519) also introduces only a method for purifying lithium sulfide.

[0013] Therefore, it is essential to develop technology that controls gaseous impurities generated during the impurity purification process of powdered lithium sulfide to increase the speed and yield of the lithium sulfide purification process.

[0014]

[0015] The present invention provides a method to increase production volume and improve yield by automating the lithium sulfide purification process.

[0016] In addition, a method is provided to increase the purity of lithium sulfide by safely removing various impurities, such as volatile organic compounds (VOCs), generated during the lithium sulfide heat treatment process.

[0017] In addition, a method is provided to prevent damage to filters or pumps caused by various impurities, such as VOCs, generated during the lithium sulfide heat treatment process.

[0018]

[0019] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0020]

[0021] To solve the above-mentioned problem, the present invention comprises: a control unit (800) for controlling a lithium sulfide heat treatment process facility; a vertical furnace (40) that forms a sealed space composed of a side plate (419), a top plate (418), and a bottom plate (416), wherein a bottom opening (421) through which a crucible (100) loaded with lithium sulfide powder and a plate (110) supporting it enter and exit is located on one side of the bottom plate (416), a thermometer (414) and a heater (412) are located on one side of the side plate (419), and a first exhaust port (420) for sucking in gas generated during the lithium sulfide powder heat treatment is located on one side of the top plate (418); The first discharge port (420) and the first pipe (L1) are fluidly connected to the inlet of the first filter (71), and the outlet of the first filter (71) is connected to a flow control valve (74) and branched into an exhaust pipe (L21) and a second pipe (L2), respectively, and the second pipe (L2) is fluidly connected to the inlet of a plurality of chillers (721, 722), and the outlet of the plurality of chillers (721, 722) is fluidly connected to the first vacuum pump (81) through the third pipe (L3) to process the gas generated during the heat treatment, and may include a post-treatment device for processing the gas generated during the heat treatment.

[0022] In one embodiment of the present invention, a first inlet port (413) for introducing argon gas toward the crucible (100) may be installed on one side of the side plate (419).

[0023] In one embodiment of the present invention, the first input port (413) may be characterized as being a nozzle body in which the amount of input is controlled by the control unit (800).

[0024] In one embodiment of the present invention, the control unit (800) may be characterized by checking whether gas is generated during the heat treatment process using vacuum degree measurement information of the vacuum gauge (411) or mass change measurement information of the lithium sulfide powder.

[0025] In one embodiment of the present invention, the control unit (800) may be characterized by injecting argon gas into the first inlet (413) to pressurize the inside of the vertical furnace (40) when gas is generated during the heat treatment process, and discharging the argon gas and the gas generated during the heat treatment process through the first outlet (420).

[0026] In one embodiment of the present invention, the control unit (800) may be characterized by passing the argon gas discharged through the first outlet (420) and the gas generated during the heat treatment process through the first filter (71) to filter out solid impurities, and then adjusting the flow path adjustment valve (74) to supply the gas to the scrubber through the outlet (L21).

[0027] In one embodiment of the present invention, the control unit (800) may be characterized by adjusting the flow control valve (74) so ​​that if no gas is generated during the heat treatment process, the discharge port (L21) is connected to the second pipe (L2) and the remaining gas inside the vertical furnace (40) is sucked in by the first vacuum pump (81) to create a vacuum state.

[0028] In one embodiment of the present invention, the residual gas sucked into the second pipe (L2) may be filtered by passing through the first filter (71) and chiller (721, 722), respectively.

[0029] In one embodiment of the present invention, the plurality of chillers (721, 722) may each be characterized by having a recovery pipe (L41, L42) installed for discharging impurities.

[0030] In one embodiment of the present invention, a second filter (73) made of an activated carbon filter may be interposed between the plurality of chillers (721, 722) and the first vacuum pump (81).

[0031] In one embodiment of the present invention, the crucible (100) loaded with lithium sulfide and the plate (110) on which the crucible (100) is placed may be characterized by moving in and out of the vertical path (40) using a vertical transfer device (300) composed of a second support (310) that holds the lower end of the plate (110), a sealing plate (320) that is spaced apart from the lower end of the second support (310) and seals the opening (421) when the crucible (100) and the plate (110) enter the vertical path (40), and a second cylinder (330) that is coupled to one side of the second support (310) and the sealing plate (320) and adjusts its length using power supplied to a second driving unit (340) to move the crucible (100) and the plate (110) in and out of the vertical path (40).

[0032] In one embodiment of the present invention, the vertical path (40) and the vertical transfer device (300) are housed inside a sealed body (500), and the interior is maintained at a vacuum by a second vacuum pump installed on one side of the sealed body.

[0033] In one embodiment of the present invention, a packing (325) is located at the end of the sealing plate (320), and a coupling groove (417) for receiving the packing (325) is installed at the end of the bottom plate (416) that is coupled to the sealing plate (320).

[0034] To solve the above-mentioned problem, the present invention may include: a first step of introducing unrefined lithium sulfide into the opening (421); a second step of operating the heater (412) to heat the internal temperature of the vertical furnace (40) at a constant rate and heat-treating the unrefined lithium sulfide; a third step of determining whether gas is generated during the heat-treatment process; a fourth step of, if gas is generated during the heat-treatment process, introducing argon gas into the first outlet (413) to pressurize the inside of the vertical furnace (40) and discharging the argon gas and the gas generated during the heat-treatment process through the first outlet (420); a fifth step of filtering the argon gas discharged through the first outlet (420) and the gas generated during the heat-treatment process through a first filter (71); and a sixth step of supplying the argon gas filtered by the first filter (71) and the gas generated during the heat-treatment process to a scrubber.

[0035] In one embodiment of the present invention, if gas is not generated in the third step, the method may be characterized by performing the seventh step of closing the first discharge port (420) and the exhaust pipe (L21) fluidly connected to the scrubber; the eighth step of fluidly connecting the first pipe (L1) to the second pipe (L2); and the ninth step of sucking in the remaining gas inside the vertical path (40) with the first vacuum pump (81) to make the inside of the vertical path (40) a vacuum state.

[0036] In one embodiment of the present invention, the organic component of the residual gas sucked into the second pipe (L2) may be liquefied and filtered in the chiller (721, 722).

[0037] In one embodiment of the present invention, the residual gas that has passed through the chiller (721, 722) may be characterized by passing through the second filter (73) and filtering out inorganic components.

[0038] In one embodiment of the present invention, the organic components collected in the plurality of chillers (721, 722) may be liquefied and discharged to the outside through the recovery pipes (L41, L42).

[0039] To solve the above-mentioned problem, the present invention may include a vertical furnace (40) for heat-treating lithium sulfide; a vertical transfer device (300) for introducing lithium sulfide into and out of the vertical furnace (40); and a post-treatment device comprising a filter (71, 73) and a chiller (721, 722) for filtering impurity gas generated during the heat treatment of lithium sulfide.

[0040] In one embodiment of the present invention, the post-treatment device may be characterized by including a scrubber that dissolves and removes the impurity gas with an absorption liquid.

[0041] In one embodiment of the present invention, the impurity gas may be selectively supplied from the vertical furnace (40) to the scrubber or the filter (71, 73) and chiller (721, 722) by the control unit (800) and filtered.

[0042] In one embodiment of the present invention, the impurity gas may be supplied to the filter (71, 73) and chiller (721, 722) by the suction force of the first vacuum pump (81).

[0043] In one embodiment of the present invention, the first vacuum pump (81) may be characterized by making the vertical path (40) a vacuum.

[0044] In one embodiment of the present invention, the lithium sulfide may be introduced into and out of the lower opening (421) of the vertical furnace (40) by the vertical transfer device (300), and the impurity gas generated during heat treatment may be discharged through the first discharge port (420) at the top of the vertical furnace (40).

[0045] In one embodiment of the present invention, the post-treatment device may be characterized by being fluidly connected to the first discharge port (420).

[0046]

[0047] According to various embodiments of the present invention, the lithium sulfide powder purification process can be automated to increase productivity and ultimately lower production costs.

[0048] According to various embodiments of the present invention, the yield of the product can be increased by preventing gases containing impurities, such as VOCs generated during the lithium sulfide heat treatment process, from penetrating the lithium sulfide being heat-treated.

[0049] According to various embodiments of the present invention, maintenance costs can be minimized by preventing gases containing impurities, such as VOCs generated during the lithium sulfide heat treatment process, from damaging vacuum maintenance devices or filters.

[0050] According to various embodiments of the present invention, the operational efficiency of the heat treatment facility can be maximized by having a manager directly control the lithium sulfide powder purification process.

[0051]

[0052] FIG. 1 is a schematic diagram of the lithium sulfide powder heat treatment process system of the present invention.

[0053] FIG. 2 is an operational diagram illustrating a mechanism for introducing a crucible and a fleet loading chamber loaded with lithium sulfide powder of the present invention into a vertical furnace using a vertical transfer device when the crucible and the fleet loading chamber are moved directly downwards in a vertical furnace.

[0054] FIG. 3 is a conceptual diagram illustrating another embodiment of the vertical furnace of the present invention.

[0055] FIG. 4 is a measurement diagram illustrating the components of volatile organic compounds generated as the internal temperature of the vertical furnace of the present invention increases.

[0056] FIG. 5 is a measurement diagram illustrating the phenomenon in which the mass of lithium sulfide powder decreases with increasing internal temperature of the vertical furnace of the present invention.

[0057] FIG. 6 is a schematic diagram of the post-processing device of the present invention.

[0058] FIG. 7 is a flowchart illustrating an embodiment of a control method for a volatile organic compound treatment system of the present invention.

[0059]

[0060] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0061] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0062] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0063] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0064] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0065] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0066] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0067]

[0068] Hereinafter, a lithium sulfide vacuum heat treatment apparatus according to various embodiments will be described with reference to the attached drawings.

[0069]

[0070] [Basic Configuration]

[0071] High-purity lithium sulfide powder can be produced through a thermal reduction process, an extraction process, a drying process, and a heat treatment process.

[0072] Among the above processes, the heat treatment process described in the present invention is pointed out as the biggest cause of the increase in the unit price of lithium sulfide because it requires a lot of time and cost to remove impurities.

[0073] FIG. 1 schematically illustrates the configuration of a lithium sulfide vacuum heat treatment system proposed in the present invention to solve these problems.

[0074] The lithium sulfide vacuum heat treatment device presented in the present invention can have the operation and function of all components controlled by a control unit (800).

[0075] The above control unit (800) can report the control results to the lithium sulfide vacuum heat treatment device manager in real time or by creating a database of control and measurement result information.

[0076] The device configuration used in the heat treatment process can be broadly divided into a dryer (10), a first glove box (21), a loading chamber (30), a first transfer path (91), a vertical path (40), a second glove box (22), and an impurity post-treatment device.

[0077] The above vertical path (40) is a collective name for the aforementioned plurality of vertical paths (41, 42, 43, 44).

[0078] The above loading chamber (30), first transfer path (91), and vertical path (40) can be installed inside a sealed body (500) and configured to be isolated from external air or moisture.

[0079] The interior of the above-mentioned seal (500) can always maintain a vacuum level above a certain level through a plurality of vacuum pumps.

[0080] The above dryer (10) is a device used at the end of the aforementioned drying process and performs the role of finally producing lithium sulfide containing impurities.

[0081] The above impurities occur because the previous process involves preparing a mixture by mixing a sulfide-based solid electrolyte raw material containing carbon-containing lithium sulfide in an ethanol solvent.

[0082] In addition, other causes of impurities may arise because various elements, such as phosphorus (P) or chlorine (Cl), are used as raw materials for sulfide-based solid electrolytes.

[0083] Lithium sulfide produces hydrogen sulfide, which is harmful to the human body, when it reacts with oxygen or moisture. Furthermore, since it is an impurity itself, it must never be exposed to outside air or moisture.

[0084] Generally, for lithium sulfide powder to be commercialized, the oxygen content must be managed to be 0.4% or less.

[0085] Accordingly, the lithium sulfide produced in the dryer (10) is transferred into the interior through the inlet (25) of the first glove box (21), and then argon gas can be injected through the second outlet (24) installed on one side of the first glove box (21) to prevent the lithium sulfide from reacting with oxygen.

[0086] Inside the first glove box (21), the unrefined lithium sulfide can be divided and loaded into a crucible (100) and then placed on a plate (110) with markings on the side.

[0087] To facilitate movement within the first glove box (21), the crucible (100) and plate (110) can be placed back on the support (120).

[0088] The crucible (100) and plate (110) placed on the support (120) can first be moved to the loading chamber (30) for the heat treatment process.

[0089] The loading chamber (30) above serves as a transition section to create a complete vacuum state before heat-treating the unrefined lithium sulfide.

[0090] First, when the crucible (100) and plate (110) placed on the support (120) arrive at the entrance of the loading chamber (30), the first sealing window (31) that seals between the first glove box (21) and the loading chamber (30) can be opened.

[0091] When the first sealing window (31) is opened, argon and air inside the first glove box (21) penetrate into the loading chamber (30).

[0092] A second transfer path (92) composed of a plurality of rollers (90) is installed at the bottom of the first glove box (21), and a mover (200) may be installed at the bottom of the second transfer path.

[0093] When the first sealed window (31) is opened, the mover (200) can protrude above the second transfer path (92) to move the crucible (100) and plate (110) loaded with the unrefined lithium sulfide into the loading chamber (30).

[0094] The mover (200) may be composed of a first support (210) that holds the lower end of the plate (110), and a first cylinder (220) which has one side connected to the first support (210) and the other side connected to a first driving unit (230), and which moves the plate (110) from the first glove box (21) to the loading chamber (30) by adjusting its length using the power transmitted by the first driving unit (230).

[0095] When the crucible (100) and plate (110) are introduced into the loading chamber (30), the first sealing window (31) is driven to isolate them from the first glove box (21), and then the discharge device (33) is driven to discharge the internal air and argon gas to the outside, thereby creating a vacuum inside.

[0096] In addition, the above mover (200) can be hidden again in the lower part of the second transfer path (92).

[0097] The interior of the loading chamber (30) is at most 10 by the discharge device (33). -4 The vacuum state is maintained up to torr, and the vacuum level can be measured through a barometer (34) installed on one side of the loading chamber (30) and then transmitted to the control unit (800).

[0098] When the vacuum level inside the loading chamber (30) is sufficient, the control unit (800) can open the second sealing window (32) that seals between the first glove box (21) and the first transfer path (91), and then drive the roller (90) of the second transfer path (92) to move the crucible (100) and plate (110) loaded with the unrefined lithium sulfide to the first transfer path (91).

[0099] As described above, the first transfer path (91) is normally at a maximum of 10 -4 Since a vacuum state of about torr is maintained, even if the second sealing window (32) is opened, no change in the vacuum level may occur.

[0100] The first conveyor (91) above is also composed of a plurality of rollers (90) and can convey the crucible (100) and plate (110) loaded with the unrefined lithium sulfide in one direction.

[0101] A plurality of vertical furnaces (40) may be arranged on the side of the first transfer path (91) to heat-treat unpurified active lithium powder and remove internal impurities (ethanol, carbon, sulfur, etc.).

[0102] The reason the above vertical furnace (40) is installed in multiple numbers may be that the time spent heat-treating in the vertical furnace (40) is longer than the number of crucibles (100) and plates (110) loaded with unrefined lithium sulfide supplied from the first glove box (21).

[0103] Accordingly, the number of vertical furnaces (40) can be modified or changed according to the number of crucibles (100) and plates (110) loaded with unrefined lithium sulfide supplied from the first glove box (21).

[0104] A plurality of position sensors (410) may be arranged on one side of the vertical path (40) or the first transfer path (91).

[0105] A pattern (111) or identification symbol, etc., may be placed on one side of the plate (110) supporting the crucible (100).

[0106] The position sensor (410) can identify the pattern (111) or identification symbol of the plate (110), detect a change in position, and transmit measurement information to the control unit (800).

[0107] As illustrated in FIG. 2, the vertical furnace (40) is formed as a sealed space consisting of a side plate (419), a top plate (418), and a bottom plate (416). On one side of the bottom plate (416), a bottom opening (421) is located for vertical entry and exit of a crucible (100) loaded with lithium sulfide powder and a plate (110) supporting it. On one side of the side plate (419), a heater (412) for heat treatment of lithium sulfide powder is located, and on one side of the top plate (418), a first discharge port (420) for sucking in volatile organic compounds (VOCs, CO2, CO) and inorganic substances (H2S, COS, SO2), etc., generated during heat treatment of lithium sulfide powder may be located.

[0108] The heater (412) can raise the temperature inside the vertical furnace (40) to 1,000°C to heat-treat the lithium sulfide powder, thereby gasifying and removing impurities contained in the lithium sulfide powder.

[0109] The first discharge port (420) is fluidly connected to the inlet of the first filter (71) through the first pipe (L1), the outlet of the first filter (71) is fluidly connected to the inlet of a plurality of chillers (721, 722) through the second pipe (L2), and the outlet of the plurality of chillers (721, 722) can be fluidly connected to the first vacuum pump (81) through the third pipe (L3).

[0110] The configuration following the first discharge port (420) described above will be explained in detail later.

[0111] A first inlet (413) through which argon gas is discharged may be disposed on one side of the bottom plate (416) or side plate (419).

[0112] The first inlet (413) above may be composed of a nozzle body capable of controlling the direction or intensity of the argon gas discharge.

[0113] The above argon gas can prevent impurities from being gasified during the heat treatment of the lithium sulfide powder and penetrating back into the lithium sulfide powder or adhering in the form of soot inside the vertical furnace (40), and can also perform the role of guiding the gas generated during the heat treatment process to be discharged through the first outlet (420) without interference.

[0114] Additionally, the process manager or the control unit (800) can check the amount and condition of the gas generated during the heat treatment process through the vacuum gauge (411) or thermometer (414) installed inside the vertical furnace (40) and adjust the amount of argon gas discharged from the first inlet (413).

[0115] Since the gas generated during the above heat treatment is not always generated in a constant form, the process manager or the control unit (800) can adjust the nozzle body to change the position of the argon gas in the direction in which the gas is generated.

[0116] Additionally, a vertical transfer device (300) may be arranged at the lower end of the opening (421), comprising a second support (310) that holds the lower end of a plate (110) on which a crucible (100) loaded with lithium sulfide is placed, a sealing plate (320) that is spaced apart from the lower end of the second support (310) and seals the opening (421) when the crucible (100) and the plate (110) enter the vertical path (40), and a second cylinder (330) that is coupled to one side of the second support (310) and the sealing plate (320) and adjusts its length using power supplied to a second drive unit (340) to move the crucible (100) and the plate (110) in and out through the opening (421).

[0117] That is, the vertical transfer device (300) performs the function of transferring the crucible (100) loaded with unrefined lithium sulfide powder and the plate (110) supporting it to the area directly below the opening (421) by vertically raising and lowering it so that heat treatment is performed within the vertical furnace (40), and also discharges the refined lithium sulfide after heat treatment is completed.

[0118] The sealing plate (320) may have a packing (325) installed at its end so that impurity gas generated during heat treatment does not leak out through the opening (421) through complete contact with the bottom plate (416).

[0119] The above packing (325) can fill the uneven bonding surface between the sealing plate (320) and the bottom plate (416) end with internal elasticity.

[0120] Additionally, a coupling groove (417) for accommodating the packing (325) may be installed at the end of the bottom plate (416).

[0121] Ultimately, the crucible (100) and plate (110) can be fixed at a position higher than the bottom plate (416) within the vertical furnace (40) by the distance between the second support (310) and the sealing plate (320).

[0122] This is to ensure that the unrefined lithium sulfide inside the crucible (100) receives heat energy transferred from the heater (412).

[0123] A plurality of movers (200) may be arranged at the bottom of the first transfer path facing the front of each vertical path (40), comprising a first support (210) that holds the bottom of the plate (110), and a first cylinder (220) which has one side connected to the first support (210) and the other side connected to the first drive unit (230), and which adjusts the length using power transmitted by the first drive unit (230) to move the plate (110) on which a crucible (100) loaded with lithium sulfide that has not undergone a heat treatment process in the vertical path (40) is placed from the first transfer path (91) to the lower end of the opening (421), or move the plate (110) on which a crucible (100) loaded with lithium sulfide powder that has undergone heat treatment in the vertical path (40) is placed from the lower end of the opening (421) to the first transfer path (91).

[0124] The control unit (800) can operate the mover (200) by capturing the moment when the crucible (100) loaded with unrefined lithium sulfide and the plate (110) supporting it, which are moving along the first transport path (91), reach the front of the vertical path (40), or conversely, when the crucible (100) loaded with lithium sulfide and the plate (110) supporting it, which has finished heat treatment in the vertical path (40), are placed directly below the opening (421).

[0125] In addition, the mover (200) is protruded above the first transfer path (91) to perform the function described above when in operation, but in other states, it is hidden below the first transfer path (91) so as not to interfere with the movement of other crucibles (100) and plates (110).

[0126] A crucible (100) loaded with refined lithium sulfide that has been heat-treated through the vertical furnace (40) and a plate (110) supporting it can be transferred to an unloading chamber (50) along the first transfer path (91).

[0127] The above unloading chamber (50) can serve as a transition device to prevent external air or moisture from entering the seal (500) and lowering the internal vacuum level during the process in which the heat-treated refined lithium sulfide is transferred to the second glove box (22) and discharged to the outside.

[0128] When the crucible (100) loaded with the refined lithium sulfide and the plate (110) supporting it arrive at the entrance of the unloading chamber (50), the third sealing window (51) that was sealing the passage with the first transfer path (91) can be opened to bring the crucible (100) and the plate (110) into the unloading chamber (50).

[0129] A third transfer path (93) composed of a plurality of rollers (90) is installed at the bottom of the above unloading chamber (50), and a mover (200) may be installed at the bottom of the above third transfer path.

[0130] Additionally, on one side of the unloading chamber (50), an exhaust device (53) for maintaining the internal vacuum level and a barometer (54) for checking the appropriateness of the vacuum level may be installed.

[0131] Even in the step where the crucible (100) loaded with the refined lithium sulfide and the plate (110) supporting it are introduced into the unloading chamber (50), the fourth sealing window (52) that seals the passage between the unloading chamber (50) and the second glove box (22) is closed, so the interior can be maintained in a vacuum state.

[0132] When the crucible (100) loaded with the refined lithium sulfide and the plate (110) supporting it are fully inserted into the unloading chamber (50), the third sealing window (51) can be closed, and after a certain period of time, the fourth sealing window (52) can be opened.

[0133] This is because if the opening times of the third sealing window (51) and the fourth sealing window (52) overlap, the vacuum level inside the sealing body (500) may be damaged.

[0134] When the fourth sealed window (52) is opened, the mover (200) can protrude above the third transfer path (93) to move the crucible (100) and plate (110) loaded with the refined lithium sulfide into the second glove box (22).

[0135] At this time, the crucible (100) and plate (110) loaded with the refined lithium sulfide can be placed on the support (120) for ease of movement.

[0136] When the crucible (100) and plate (110) are moved to the second glove box (22), the fourth sealing window (52) is closed again, and the air and argon gas, etc. delivered from the second glove box (22) are removed through the discharge device (53) to maintain a vacuum level equivalent to that of the sealing body (500).

[0137] The interior of the second glove box (22) may perform a process of vacuum packaging the purified lithium sulfide powder from which impurities have been removed, or measuring the concentration of impurities in the lithium sulfide powder that has undergone heat treatment through XRD analysis, and transmitting the result to the control unit (800).

[0138] In addition, argon gas can be discharged through the second outlet (24) to minimize exposure to external air and moisture during the above processing.

[0139] The above XRD analysis can measure the concentration of lithium hydroxide generated when the lithium sulfide powder reacts with oxygen during the heat treatment process, and can serve as a reference for determining whether there is leakage inside the seal (500).

[0140] The above XRD analysis results can be transmitted to the process manager or the control unit (800) and provided as information for changing process operations or performing maintenance.

[0141] FIG. 3 illustrates a modified example of the above vertical path (40).

[0142] In the above modified example, the first inlet (413) and the first outlet (420) are installed at the same height so that argon gas flows to the top of the crucible (100), thus having the advantage that there is no need to configure the first inlet (413) as a nozzle body as described above.

[0143] Figure 4 illustrates that the composition of the impurity gas generated as the internal temperature of the vertical furnace (40) increases gradually changes through TG-MS results.

[0144] In particular, when the above lithium sulfide is heated to about 200°C, it can be confirmed that the ethanol component gas that lowers the purity of lithium sulfide and the gas component Diethyl Sulfide that corrodes heat treatment equipment increases rapidly.

[0145] FIG. 5 illustrates the process of mass reduction as unrefined lithium sulfide powder is heat-treated inside the vertical furnace (40), and it can be seen that the mass of lithium sulfide begins to decrease at about 200°C and no further mass change occurs at about 500°C.

[0146] This means that, as already explained in the result of Figure 4 above, the various organic or inorganic components contained in the unrefined lithium sulfide powder are gasified and discharged until the temperature inside the vertical furnace (40) reaches about 500°C, thereby reducing the mass.

[0147] In the present invention, the post-treatment device can be controlled using the aforementioned lithium sulfide heat treatment characteristics to remove impurity gases generated during the lithium sulfide heat treatment process.

[0148] This will be explained in detail later through drawings and flowcharts.

[0149]

[0150] [Post-processing device]

[0151] FIG. 6 illustrates a conceptual diagram of the configuration arrangement of a post-treatment device fluidly connected to the first discharge port (420).

[0152] As described above, the impurity gas generated while heat-treating lithium sulfide powder in the vertical furnace (40) can be divided into organic components and inorganic components.

[0153] The above organic component gas, namely volatile organic compound VOC (CO2, CO, C2H6O) and inorganic gas (H2S, C, COS, SO2), can be delivered to the first filter (71) along the first pipe (L1) connected to the first outlet (420).

[0154] All of the above gases are generated during the lithium sulfide purification process; if not promptly discharged and treated, they may re-react with lithium sulfide to reduce purity or adhere to heat treatment equipment in the form of soot, potentially causing malfunctions.

[0155] In particular, since volatile organic compounds (VOCs) can have adverse effects on human health if exposed directly, they must all be captured and treated to prevent leakage.

[0156] The first pipe (L1) that is fluidly connected to the first outlet (420) of the vertical path (40) can be combined with the flow control valve (74).

[0157] The above Euro control valve (74) can be branched into an exhaust pipe (L21) and a second pipe (L2), respectively.

[0158] The exhaust pipe (L21) can deliver the supplied gas to the scrubber.

[0159] The scrubber above can remove VOCs, impurities, etc. contained in the gas by spraying an absorbent liquid into the gas and dissolving them in the absorbent liquid.

[0160] The first pipe (L1) may be equipped with a first filter (71) capable of filtering solid impurities.

[0161] In the case of impurities in the form of solid matter rather than gas, if they are delivered to the scrubber or the first vacuum pump (81), they can reduce filtration performance and, in particular, cause failure of the first vacuum pump (81), so they must be removed in advance.

[0162] The control unit (800) can adjust the Euro control valve (74) to selectively supply the gas generated during the process of heat-treating the unrefined lithium sulfide powder in the vertical furnace (40) to the scrubber or the second pipe (L2).

[0163] The second pipe (L2) is fluidly connected to the inlet of a plurality of chillers (721, 722), and the outlet of the plurality of chillers (721, 722) can be fluidly connected to the first vacuum pump (81) through the third pipe (L3).

[0164] The first vacuum pump (81) sucks in residual gas generated during the heat treatment process inside the vertical furnace (40) and 10 -4 It can be maintained at a vacuum state greater than torr.

[0165] The above chiller (721, 722) can be maintained at approximately minus 30°C.

[0166] In addition, the chillers (721, 722) can be installed in series or parallel with the second pipe (L2) to remove VOC components contained in the impurity gas.

[0167] In this embodiment, the chillers (721, 722) are arranged in series, but it is evident that the number and arrangement method of the chillers (721, 722) may be changed depending on the scale and speed of the lithium sulfide heat treatment.

[0168] When the above chillers (721, 722) are arranged in series, VOC components can be processed more effectively, but the processing speed is slow, so it may not be suitable if a large amount of impurity gas is generated.

[0169] When the above chillers (721, 722) are connected in parallel, they can process VOC components quickly, unlike when connected in series, but the impurity recovery rate may be lower than that of the series arrangement.

[0170] The gas supplied to the above chiller (721, 722) can be filtered by liquefying organic components including VOCs, etc.

[0171] The above-mentioned liquefied organic components can be discharged to the outside through the recovery pipes (L41, L42) installed in the chiller (721, 722).

[0172] The remaining inorganic impurities from which the above VOC impurities have been removed can be supplied to and removed by a second filter (73) having an activated carbon filter structure installed between the plurality of chillers (721, 722) and the first vacuum pump (81).

[0173] As described above, the second filter (73) can capture inorganic impurities such as sulfur, phosphorus, carbon, and chlorine contained in the unrefined lithium sulfide.

[0174] The second filter (73) can also be maintained at approximately minus 30°C, just like the chiller (721, 722).

[0175] Maintaining the second filter (73) and chiller (721, 722) at a low temperature in this way may be intended to more easily capture impurities by cooling the impurity gas supplied from the vertical furnace (40) to the post-treatment device, as the impurity gas is in a high temperature state of at least 400°C or higher, thereby lowering the activity of the impurity gas.

[0176] Organic and inorganic impurity gases generated during the heat treatment process, which are removed by the above-mentioned post-treatment device, can affect the purity of the lithium sulfide powder. Furthermore, as mentioned above, they can adhere to the heat treatment device (especially the vacuum pump) in the form of soot and cause malfunctions; therefore, complete removal of these impurities is of the utmost importance.

[0177]

[0178] [Impurity Gas Treatment System Control]

[0179] FIG. 7 illustrates a method for controlling the process of treating impurity gases generated during the aforementioned lithium sulfide heat treatment process.

[0180] First, the control unit (800) can feed the crucible (100) loaded with the unrefined lithium sulfide and the plate (110) on which the crucible (100) is placed into the lower opening (421) of the vertical furnace (40) using the vertical transfer device (300).

[0181] As described above, the opening (421) of the vertical furnace (40) can be sealed with a sealing plate (330) at the same time as the crucible (100) is introduced.

[0182] As a result, the gas generated during the process of heat-treating the lithium sulfide in the vertical furnace (40) can be discharged only through the first outlet (420).

[0183] At this time, the vertical path (40) may be in an atmospheric pressure state similar to the outside.

[0184] When the control unit (800) confirms that the crucible (100) is located in the center of the vertical furnace (40), it can operate the heater (412) to raise the internal temperature of the vertical furnace (40) at a constant rate.

[0185] At this time, the above unrefined lithium sulfide is positioned at the center of the vertical furnace (40), so that it can receive heat energy delivered by the heater (412) from all directions and be heat-treated evenly.

[0186] The control unit (800) can check the point at which gas is generated during the heat treatment process based on the mass change measurement information according to the internal temperature of the vertical furnace (40) or the temperature of the lithium sulfide powder measured by the thermometer (414) during the heat treatment process.

[0187] As mentioned above, the gas generated during the heat treatment process tends to be concentrated at about 500°C.

[0188] Accordingly, the control unit (800) can inject argon gas into the vertical furnace (40) through the first inlet (413) at the time when it is confirmed that gas is being generated or when it is predicted that gas is being generated.

[0189] The above argon gas serves to prevent the gas generated during the heat treatment process from adhering to the heat treatment device, etc., or from re-penetrating into the lithium sulfide powder.

[0190] When the above argon gas is introduced, the inside of the vertical furnace (40), which was in a normal atmospheric pressure state, can be pressurized to a higher pressure than the outside.

[0191] The control unit (800) can adjust the Euro control valve (74) to supply the argon gas and gas generated during the heat treatment process, which are directed to the first outlet (420) due to the pressure difference, to the scrubber after passing through the first filter (71) to filter out impurities.

[0192] At this time, the gas generated during the heat treatment is not filtered by the chiller (721, 722) and the second filter (73) installed in the second pipe (L2) because the gas is generated in large quantities while being heated from room temperature to about 500°C, and there is a problem that maintenance costs such as filter replacement are excessively incurred if these gases are treated only by the chiller (721, 722) and the second filter (73). Moreover, if the gas that is not treated by the chiller (721, 722) and the second filter (73) is sucked into the first vacuum pump (81), the organic components of the gas may adhere inside the first vacuum pump (81) in the form of soot and cause a malfunction.

[0193] Unlike filters, which are relatively easy to maintain, vacuum pumps are expensive precision machines that require a long time to repair when they break down, and since the entire lithium sulfide refining process must be stopped during the repair period, it may be a major reason to minimize factors that cause failure.

[0194] Accordingly, the present invention proposes a method to improve the maintainability of heat treatment equipment and simultaneously increase the yield of produced lithium sulfide by treating gases generated in large quantities up to a certain temperature using a scrubber with high filtration capacity and removing residual gases using the filtering configurations described above.

[0195] When the control unit (800) determines that no more gas is being generated during the heat treatment process, it can close the first inlet (413) to cut off the supply of argon gas.

[0196] Additionally, the above Euro control valve (74) can be adjusted to close the exhaust pipe (L21) that is fluidly connected to the scrubber, and the first pipe (L1) can be fluidly connected to the second pipe (L2).

[0197] Since the first vacuum pump (81) is installed at one end of the second pipe (L2), the control unit (800) can operate the first vacuum pump (81) to suck up residual gas remaining inside the vertical pipe (40).

[0198] Due to the above suction, the vertical furnace (40) is maintained in a vacuum state so that impurities such as remaining residual gas or floating matter penetrate into the lithium sulfide being heat-treated, thereby preventing the purification level of the lithium sulfide from decreasing.

[0199] If the above residual gas remains inside the vertical furnace (40), the organic component can be carbonized by the heater (412) and changed into carbon, and since the carbon component can penetrate back into the lithium sulfide powder being purified, maintaining a vacuum inside the vertical furnace (40) during the remaining heat treatment process is a very important process.

[0200] The lithium sulfide purified through the heat treatment process in the vertical furnace (40) can be discharged to the outside by the vertical transfer device (300) in the reverse order of being introduced into the vertical furnace (40).

[0201] The quality of the above-mentioned purified lithium sulfide, after heat treatment is complete, can be verified through XRD analysis.

[0202] The control unit (800) can determine that a problem has occurred in some processes during the heat treatment process, such as the heating speed of the heater (412) of the vertical furnace (40), the output of the first vacuum pump (81), the discharge amount and discharge location of the argon gas, when the concentration of lithium hydroxide inside the lithium sulfide powder obtained through the XRD analysis is higher than the reference value (about 0.4%), and can use it as an indicator to re-examine the entire heat treatment system, such as the system vacuum level, argon gas operation, and sensor accuracy.

[0203]

[0204] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. A control unit (800) that controls the lithium sulfide heat treatment process equipment; A vertical furnace (40) forming a sealed space composed of a side plate (419), a top plate (418), and a bottom plate (416), wherein a bottom opening (421) through which a crucible (100) loaded with lithium sulfide powder and a plate (110) supporting it enter and exit is located on one side of the bottom plate (416), a thermometer (414), a vacuum gauge (411), and a heater (412) are located on one side of the side plate (419), and a first exhaust port (420) for sucking in gas generated during the heat treatment of lithium sulfide powder is located on one side of the top plate (418); and A volatile organic compound treatment system comprising a post-treatment device for treating gas generated during heat treatment, wherein the first discharge port (420) and the first pipe (L1) are fluidly connected to the inlet of the first filter (71), the outlet of the first filter (71) is connected to a flow path control valve (74) and branches into an exhaust pipe (L21) and a second pipe (L2), respectively, the second pipe (L2) is fluidly connected to the inlets of a plurality of chillers (721, 722), and the outlets of the plurality of chillers (721, 722) are fluidly connected to the first vacuum pump (81) via the third pipe (L3).

2. In Claim 1, A volatile organic compound treatment system characterized by having a first inlet (413) installed on one side of the above-mentioned side plate (419) for introducing argon gas toward the above-mentioned crucible (100).

3. In Claim 2, A volatile organic compound treatment system characterized in that the first input port (413) is a nozzle body whose input amount is controlled by the control unit (800).

4. In Claim 3, A volatile organic compound treatment system characterized in that the above control unit (800) checks whether gas is generated during the heat treatment process using vacuum level measurement information of the vacuum gauge (411) or mass change measurement information according to temperature of the lithium sulfide powder.

5. In Claim 4, A volatile organic compound treatment system characterized in that, when gas is generated during the heat treatment process, the control unit (800) injects argon gas through the first inlet (413) to pressurize the inside of the vertical furnace (40) and discharges the argon gas and the gas generated during the heat treatment process through the first outlet (420).

6. In Claim 5, A volatile organic compound treatment system characterized in that the control unit (800) passes the argon gas discharged through the first outlet (420) and the gas generated during the heat treatment process through the first filter (71) to filter out solid impurities, and then adjusts the flow path adjustment valve (74) to supply the gas to the scrubber through the outlet (L21).

7. In Claim 4, A volatile organic compound treatment system characterized by the above control unit (800) adjusting the flow control valve (74) to connect the discharge port (L21) with the second pipe (L2) when no gas is generated during the heat treatment process, and sucking in the residual gas inside the vertical furnace (40) with the first vacuum pump (81) to create a vacuum state.

8. In Claim 7, A volatile organic compound treatment system characterized in that the residual gas sucked into the second pipe (L2) is filtered by passing through the first filter (71) and chillers (721, 722), respectively.

9. In Claim 8, A volatile organic compound treatment system characterized in that each of the plurality of chillers (721, 722) is equipped with a recovery pipe (L41, L42) for discharging impurities.

10. In Claim 9, A volatile organic compound treatment system characterized by having a second filter (73) made of an activated carbon filter interposed between the plurality of chillers (721, 722) and the first vacuum pump (81).

11. In Claim 1, A volatile organic compound treatment system characterized by moving the crucible (100) loaded with lithium sulfide and the plate (110) on which the crucible (100) is seated into and out of the vertical path (40) using a vertical transfer device (300) comprising: a second support (310) that grips the lower end of the plate (110); a sealing plate (320) that is spaced apart by a predetermined distance from the lower end of the second support (310) and seals the opening (421) when the crucible (100) and the plate (110) enter the vertical path (40); and a second cylinder (330) that is coupled to one side of the second support (310) and the sealing plate (320) and adjusts its length using power supplied to a second drive unit (340) to move the crucible (100) and the plate (110) in and out of the vertical path (40).

12. In Claim 11, A volatile organic compound treatment system characterized in that the above-mentioned vertical path (40) and vertical transfer device (300) are housed inside a sealed body (500), and the interior is maintained at a vacuum by a second vacuum pump installed on one side of the sealed body.

13. In Claim 12, A volatile organic compound treatment system characterized in that a packing (325) is located at the end of the sealing plate (320), and a coupling groove (417) for receiving the packing (325) is installed at the end of the bottom plate (416) that is coupled to the sealing plate (320).

14. A method for controlling a volatile organic compound treatment system according to Claim 1, A first step in which unrefined lithium sulfide enters through the opening (421); A second step of operating the heater (412) to heat the internal temperature of the vertical furnace (40) at a constant rate and heat-treating the unrefined lithium sulfide; A third step of determining whether gas is generated during the above heat treatment process; A fourth step in which, if gas is generated during the heat treatment process, argon gas is introduced through the first inlet (413) to pressurize the inside of the vertical furnace (40), and the argon gas and the gas generated during the heat treatment process are discharged through the first outlet (420); A fifth step of filtering the argon gas discharged through the first discharge port (420) and the gas generated during the heat treatment process through the first filter (71); and A volatile organic compound treatment method comprising: a sixth step of supplying the argon gas filtered by the first filter (71) and the gas generated during the heat treatment process to a scrubber.

15. In Claim 14, If gas is not generated during the heat treatment process in the third step above Step 7, closing the first inlet (413) and the exhaust pipe (L21) that is fluidly connected to the scrubber; Step 8, fluidly connecting the first pipe (L1) with the second pipe (L2); A method for treating volatile organic compounds characterized by performing a 9th step of sucking in residual gas inside the vertical furnace (40) with the first vacuum pump (81) to make the inside of the vertical furnace (40) a vacuum state.

16. In Claim 15, A method for treating volatile organic compounds characterized in that organic components among the residual gas sucked into the second pipe (L2) are liquefied and filtered in the chillers (721, 722).

17. In Claim 16, A method for treating volatile organic compounds characterized in that the residual gas passing through the chillers (721, 722) passes through a second filter (73) and inorganic components are filtered.

18. In Claim 16, A method for treating volatile organic compounds characterized in that organic components collected in the plurality of chillers (721, 722) are liquefied and discharged to the outside through the recovery pipes (L41, L42).

19. A vertical furnace (40) for heat-treating lithium sulfide; A vertical transfer device (300) for moving lithium sulfide into and out of the vertical path (40); A lithium sulfide manufacturing apparatus comprising a post-treatment device consisting of a filter (71, 73) and a chiller (721, 722) for filtering impurity gases generated during lithium sulfide heat treatment.

20. In Claim 19, A lithium sulfide manufacturing apparatus characterized by the above-mentioned post-treatment device including a scrubber that dissolves and removes the impurity gas with an absorption liquid.

21. In claim 20, A lithium sulfide manufacturing apparatus characterized in that the above impurity gas is selectively supplied from the vertical furnace (40) to the scrubber or the filter (71, 73) and chiller (721, 722) by the control unit (800) and filtered.

22. In Claim 21, A lithium sulfide manufacturing apparatus characterized in that the above impurity gas is supplied to the filter (71, 73) and chiller (721, 722) by the suction force of the first vacuum pump (81).

23. In Claim 22, A lithium sulfide manufacturing apparatus characterized by the first vacuum pump (81) making the vertical furnace (40) a vacuum.

24. In Claim 19, A lithium sulfide manufacturing apparatus characterized in that the lithium sulfide is introduced into and out of the lower opening (421) of the vertical furnace (40) by the vertical transfer device (300), and the impurity gas generated during heat treatment is discharged through the first discharge port (420) at the top of the vertical furnace (40).

25. In Claim 24, A lithium sulfide manufacturing device characterized in that the above post-treatment device is fluidly connected to the first discharge port (420).

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