Heating device and method for manufacturing heat-treated product

Abstract

Provided are: a heating device that is capable of reducing the use amount of introduction gas mainly required on a discharge port side by using a device, such as a rotary kiln, for heating while fluidizing a raw material; and a method for manufacturing a heat-treated object by using said heating device.　A heating device 1 according to the present disclosure continuously heats a raw material while fluidizing and conveying the raw material inside a heating cylinder 11 and comprises: a first gas introduction part 15 configured to be capable of introducing a first gas into the heating cylinder 11 from a supply port 111 side toward a discharge port 112 side of the heating cylinder 11; a second gas introduction part 16 configured to be capable of introducing a second gas into the heating cylinder 11 from the discharge port 112 side toward the supply port 111 side of the heating cylinder 11; and a pressure control part 17 configured to be capable of adjusting the pressure on the discharge port 112 side of the heating cylinder 11 to be higher than the pressure on the supply port 111 side of the heating cylinder 11.

Description

Heating device and method for producing heat-treated product

[0001] The present disclosure relates to a heating device and a method for producing a heat-treated object.

[0002] A rotary kiln is configured such that the material to be treated is supplied to a rotating cylindrical retort, and while controlling the gas atmosphere of an inert gas, air, or the like using an introduced gas, the cylindrical retort is heated from the outside to perform drying, reaction, infusibilization, firing, carbonization, coating, granulation, and the like, and if gas is generated from the material to be treated, the gas is exhausted to the outside of the cylindrical retort together with the supplied gas.

[0003] In recent years, lithium cobalt composite oxide (LiCoO) has been used as a positive electrode active material for lithium ion secondary batteries used as power sources for driving electronic devices such as AV equipment and personal computers. ２ ), lithium nickel composite oxide (LiNiO ２ ), lithium nickel cobalt manganese composite oxide (LiNi １／３ Co １／３ Mn １／３ O ２ ), lithium manganese composite oxide (LiMn ２ O ４ ) and other lithium metal composite oxides are attracting attention.

[0004] Such lithium metal composite oxides are produced by mixing a lithium source such as lithium hydroxide and various metal sources including nickel hydroxide, and firing the mixture using the rotary kiln or the like.

[0005] The formation of such lithium metal composite oxide occurs first at the raw material supply port side of the rotary kiln, where mainly hydroxide ions are released, generating water vapor. As the water vapor flows toward the raw material discharge port side, it reacts with oxygen introduced into the retort to form lithium metal composite oxide.

[0006] At this time, oxygen gas is introduced from the raw material inlet side of the rotary kiln toward the discharge outlet side, thereby promoting the reaction of forming the lithium metal composite oxide (see Patent Document 1).

[0007] JP 2019-075253 A

[0008] In the rotary kiln of Patent Document 1, oxygen gas is a substance involved in the reaction, so the oxygen concentration must be maintained at a certain level or higher. Furthermore, water vapor generated by heating the raw materials, mainly on the supply port side, may adversely affect the formation of the lithium metal composite oxide, such as by causing uneven heating. Furthermore, condensation of water vapor at the supply port and discharge port of the rotary kiln not only deteriorates the fluidity of the raw materials and the formed lithium metal composite oxide, but also leads to a deterioration in quality. For these reasons, a large amount of oxygen gas is introduced into the rotary kiln when forming the lithium metal composite oxide.

[0009] As described above, the lithium metal composite oxide production process requires the use of a large amount of expensive oxygen gas, which increases production costs. Furthermore, a large amount of oxygen must be introduced to expel water vapor, which increases the gas velocity inside the heating cylinder 11, causing the raw materials and lithium metal composite oxide to scatter, resulting in a decrease in yield. Furthermore, the ratio of the lithium source to the metal source (hydroxide, oxide, etc.) deviates from the feed ratio, which can cause a deterioration in quality.

[0010] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a heating device that can reduce the amount of introduced gas that is mainly required on the outlet side by using a device that heats raw materials while causing them to flow, such as a rotary kiln, and a method for manufacturing a heat-treated product using the same.

[0011] The present inventors conducted extensive research to solve the above-mentioned problems. As a result, they discovered that a heating device that continuously heats raw materials while causing them to flow and be transported inside a heating barrel, the heating device including a first gas inlet configured to introduce a first gas into the heating barrel from the supply port side toward the discharge port side, a second gas inlet configured to introduce a second gas into the heating barrel from the discharge port side toward the supply port side, and a pressure control unit configured to adjust the pressure on the discharge port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel, can reduce the amount of introduced gas required mainly on the discharge port side when using a device that heats raw materials while causing them to flow, such as a rotary kiln. Specifically, the present disclosure provides the following.

[0012] (1) A heating device that continuously heats raw materials while causing them to flow and be transported inside a heating barrel, comprising: a first gas inlet configured to be able to introduce a first gas into the heating barrel from the supply port side toward the discharge port side; a second gas inlet configured to be able to introduce a second gas into the heating barrel from the discharge port side toward the supply port side; and a pressure control unit configured to be able to adjust the pressure on the discharge port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

[0013] (2) The pressure control unit is provided with: a supply-side exhaust unit on the supply port side of the heating barrel, configured to be able to exhaust gas inside the heating barrel; a discharge-side exhaust unit on the discharge port side of the heating barrel, configured to be able to exhaust gas inside the heating barrel; and an exhaust control unit configured to be able to control the exhaust of the supply-side exhaust unit and / or the exhaust of the discharge-side exhaust unit, in the heating device described in (1).

[0014] (3) The heating device according to (1) or (2), wherein the first gas and the second gas are composed of different components and / or compositions.

[0015] (4) A heating device according to (1) or (2), in which the interior of the heating cylinder is configured as a single chamber without any partitions.

[0016] (5) The heating device according to (1) or (2) for producing a ceramic material.

[0017] (6) The heating device according to (1) or (2) for producing a lithium metal composite oxide.

[0018] (7) A method for manufacturing a heat-treated product, comprising: a heating step of continuously heating raw materials for the heat-treatment product while flowing and transporting them inside a heating barrel; a first gas introduction step of introducing a first gas into the heating barrel from the supply port side toward the discharge port side; a second gas introduction step of introducing a second gas into the heating barrel from the discharge port side toward the supply port side; and a pressure control step of adjusting the pressure on the discharge port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

[0019] (8) The method for producing a heat-treated product according to (7), wherein the heat-treated product is a ceramic material.

[0020] (9) The method for producing a heat-treated product according to (7), wherein the heat-treated product is a lithium metal composite oxide.

[0021] According to the present disclosure, it is possible to provide a heating device that can reduce the amount of introduced gas that is mainly required on the outlet side by using a device that heats raw materials while causing them to flow, such as a rotary kiln, and a method for manufacturing a heat-treated product using the same.

[0022] 1 is a schematic diagram of a heating device according to a first embodiment of the present disclosure; 2 is a schematic diagram of a heating device according to a second embodiment of the present disclosure; 3 is a schematic diagram of a heating device according to a third embodiment of the present disclosure; 4 is a schematic diagram of a heating device of the prior art;

[0023] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited in any way to the description of the embodiments and can be implemented with appropriate modifications.

[0024] <Heating Device> A heating device according to an embodiment of the present disclosure is a heating device that continuously heats raw materials while causing them to flow and be transported inside a heating barrel, and includes a first gas inlet configured to be able to introduce a first gas into the interior of the heating barrel from the supply port side toward the discharge port side of the heating barrel, a second gas inlet configured to be able to introduce a second gas into the interior of the heating barrel from the discharge port side toward the supply port side of the heating barrel, and a pressure control unit configured to be able to adjust the pressure on the discharge port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

[0025] According to a heating device having such a configuration, it is possible to reduce the amount of gas introduced, which is mainly required on the discharge port side, by using a device that heats raw materials while causing them to flow, such as a rotary kiln.

[0026] [Heating Device of First Embodiment] Fig. 1 is a schematic diagram of a heating device according to a first embodiment of the present disclosure. The heating device 1 shown in Fig. 1 continuously heats raw material M while causing it to flow and be transported inside a heating cylinder 11.

[0027] The heating barrel 11 is configured as a cylindrical body with both ends open. The heating barrel 11 rotates in one direction with the central axis of the cylindrical body as the rotation axis. Raw material M is continuously supplied into the heating barrel 11 from a raw material supply unit 18, typified by a feeder, via a supply port 111, and flows toward a discharge port 112. Although not shown, the heating barrel 11 is angled with respect to the horizontal direction from the supply port 111 to the discharge port 112, and the raw material M flows in a sliding manner downward. At this time, since the heating barrel 11 is also rotating, the raw material M flows while being stirred.

[0028] A heating unit 12, such as a heater, is provided around the heating cylinder 11. In order to transfer heat from the heating unit 12 to the raw material M, the heating cylinder 11 is made of a thermally conductive material such as metal, ceramics, or a composite material of metal and ceramics (for example, a material in which ceramics is provided on the inner wall of a metal cylinder).

[0029] A front chamber 13 is provided on the supply port 111 side of the heating barrel 11, and a rear chamber 14 is provided on the discharge port 112 side, so that the heating barrel 11 forms a closed space.

[0030] The interior of the heating barrel 11, i.e., from the end of the heating barrel 11 on the supply port 111 side to the end on the discharge port 112 side, is configured as a single chamber without partitions. Here, "without partitions" means that the interior is not divided into multiple chambers by partitions. Note that even if there are gaps, the presence of partitions is considered to be partitions. It is preferable that partitions are not provided in any direction, regardless of whether there are gaps or not. In particular, it is preferable that no partitions are provided in any direction other than the longitudinal direction of the heating barrel 11 (the direction from the end of the heating barrel 11 on the supply port 111 side to the end on the discharge port 112 side). In the heating device 1 of this embodiment, it is necessary to adjust the relationship between the pressure on the discharge port 112 side of the heating barrel 11 and the pressure on the supply port 111 side. By configuring the interior of the heating barrel 11 as a single chamber without partitions, the pressure in each section can be more easily controlled.

[0031] In this closed space, a first gas introduction part 15 is provided on the supply port 111 side of the heating barrel 11. Specifically, the first gas introduction part 15 is configured to extend from the outside of the heating device 1 through the front chamber 13 to the heating barrel 11. The first gas introduction part 15 is configured to be able to introduce the first gas into the heating barrel 11 from the supply port 111 side of the heating barrel 11 toward the exhaust port 112 side.

[0032] For example, when a lithium metal composite oxide is produced using the heating device 1, water vapor is generated on the supply port 111 side by heating lithium hydroxide and a metal hydroxide as raw material M. In this case, it is preferable to use a decarbonated gas as the first gas, and more preferably to use a decarbonated oxidizing gas or an inert gas. By introducing the first gas from the supply port 111 side toward the exhaust port 112 side, water vapor can be caused to flow toward the exhaust port 112 side.

[0033] On the other hand, a second gas introduction part 16 is provided on the exhaust port 112 side of the heating barrel 11. Specifically, the second gas introduction part 16 is configured to extend from the outside of the heating device 1 through the rear chamber 14 to the heating barrel 11. The second gas introduction part 16 is configured to be able to introduce the second gas into the heating barrel from the exhaust port side toward the supply port side.

[0034] For example, when producing a lithium metal composite oxide using the heating device 1, the lithium source and the metal source are oxidized on the side of the outlet 112 to form a lithium metal composite oxide. The second gas may be an oxidizing gas that supplies the oxygen necessary for this reaction, such as oxygen. By introducing the second gas from the side of the outlet 112 toward the side of the supply port 111, the lithium source and the metal source can be oxidized to form a lithium metal composite oxide.

[0035] As in the example of producing a lithium metal composite oxide using the heating device 1 described above, the first gas and the second gas may be composed of the same components and compositions, or may be composed of different components and / or compositions, but are preferably composed of different components and / or compositions, which allows the first gas and the second gas to have respective functions, such as functions according to treatments required before and after the reaction.

[0036] In such a heating device 1, a pressure control unit 17 is provided to adjust the pressure on the discharge port 112 side of the heating barrel 11 to be higher than the pressure on the supply port 111 side of the heating barrel 11. The specific configuration of the pressure control unit 17 will be described later.

[0037] For example, when producing a lithium metal composite oxide using the heating device 1, by adjusting the pressure on the outlet 112 side of the heating barrel 11 to be higher than the pressure on the supply port 111 side of the heating barrel 11, water vapor generated from lithium hydroxide and metal hydroxide as raw material M will not proceed to the outlet 112 side of the heating barrel 11, but will act as a force that causes the water vapor to proceed to the supply port 111 side. This makes it possible to suppress the effect of water vapor on the lithium metal composite oxide.

[0038] In addition, in this way, the role of recovering water vapor, which in conventional methods was played by an oxidizing gas such as oxygen, which is costly, can be played by a less costly decarbonated gas (hereinafter sometimes referred to as "decarbonated gas") as the first gas, thereby making it possible to reduce the amount of oxidizing gas introduced.

[0039] The following describes a specific configuration of the pressure control unit 17. The pressure control unit 17 mainly includes a supply-side exhaust unit 171 configured to be able to exhaust gas inside the heating barrel 11 on the supply port 111 side of the heating barrel 11, a discharge-side exhaust unit 172 configured to be able to exhaust gas inside the heating barrel 11 on the discharge port 112 side of the heating barrel 11, a supply-side exhaust control unit 173 configured to be able to control the exhaust of the supply-side exhaust unit 171, and a discharge-side exhaust control unit 174 configured to be able to control the exhaust of the discharge-side exhaust unit 172.

[0040] The supply-side exhaust section 171 is mainly for exhausting the first gas remaining on the supply port 111 side of the heating barrel 11. The supply-side exhaust section 171 is configured to extend from the outside of the heating device 1 to the heating barrel 11 via the front chamber 13. The supply-side exhaust section 171 is configured to be able to exhaust the gas inside the heating barrel 11 to the supply port 111 side of the heating barrel 11. The supply-side exhaust section 171 has an opening facing from the supply port 111 side to the exhaust port 112 side of the heating barrel 11.

[0041] The supply-side exhaust unit 171 is connected to the piping 191 of the exhaust unit 19, a solid removal unit 192 such as a bag filter, piping 193, and an exhaust unit 177 such as a blower. A supply-side pressure measurement unit 175 such as a differential pressure gauge is provided inside the front chamber 13 to measure the pressure near the supply port 111. Note that some heating devices 1 do not have a front chamber 13. In this case, the pressure on the supply port 111 side of the heating barrel 11 is measured. The measurement results are sent to a supply-side exhaust control unit 173 configured to control the exhaust of the supply-side exhaust unit 171. Similarly, the supply-side exhaust control unit 173 receives the pressure of the rear chamber 14 received by the exhaust-side exhaust control unit 174 from the exhaust-side exhaust control unit 174 and calculates the relationship between the pressure on the exhaust port 112 side of the heating barrel 11 and the pressure on the supply port 111 side of the heating barrel 11.

[0042] On the other hand, the discharge-side exhaust section 172 is mainly for exhausting the second gas remaining on the discharge port 112 side of the heating barrel 11. The discharge-side exhaust section 172 is configured to extend from the outside of the heating device 1 through the rear chamber 14 to the heating barrel 11. The discharge-side exhaust section 172 is configured to be able to exhaust the gas inside the heating barrel 11 to the discharge port 112 side of the heating barrel 11. The discharge-side exhaust section 172 has an opening facing from the discharge port 112 side of the heating barrel 11 to the supply port 111 side.

[0043] The discharge-side exhaust section 172 is connected to an opening / closing section 178 such as a variable damper, and is further connected to a pipe 191 of the discharge section 19, a solid removal section 192 such as a bag filter, a pipe 193, and an exhaust section 177 such as a blower. A discharge-side pressure measurement section 176 such as a differential pressure gauge is provided inside the rear chamber 14 and measures the pressure near the discharge port 112. The measurement result is sent to a discharge-side exhaust control section 174 configured to be able to control the exhaust of the discharge-side exhaust section 112. The discharge-side exhaust control section 174 receives the pressure of the front chamber 13 received by the supply-side exhaust control section 173 from the supply-side exhaust control section 173 and calculates the relationship between the pressure on the discharge port 112 side of the heating barrel 11 and the pressure on the supply port 111 side of the heating barrel 11.

[0044] Thereafter, when the pressure on the discharge port 112 side of the heating barrel 11 is lower than or equal to the pressure on the supply port 111 side of the heating barrel 11, the opening degree of the variable damper serving as the opening / closing unit 178 is reduced while the inverter of the blower serving as the exhaust unit 177 is controlled to relatively reduce the pressure on the supply port 111 side of the heating barrel 11. Furthermore, to control the pressure on the discharge port 112 side of the heating barrel 11 and / or the pressure on the supply port 111 side of the heating barrel 11, the opening degree of the variable damper serving as the opening / closing unit 178 may be adjusted, or the blower serving as the exhaust unit 177 may be controlled with an inverter (not shown) to control its output. As a specific control method, the output of the exhaust unit 177 may be controlled by an inverter, and at the same time, the opening degree of the variable damper serving as the opening / closing unit 178 may be continuously adjusted between 0 and 100%.

[0045] In FIG. 1, the supply-side exhaust control unit 173 configured to be able to control the exhaust of the supply-side exhaust unit 171 and the exhaust-side exhaust control unit 174 configured to be able to control the exhaust of the exhaust-side exhaust unit 172 are shown as separate components, but they may be configured as separate devices as shown in FIG. 1, or they may be configured as the same device.

[0046] In addition, in FIG. 1, the supply-side exhaust section 171 has an opening facing from the supply port 111 side of the heating barrel 11 to the exhaust port 112 side, and the exhaust-side exhaust section 172 has an opening facing from the exhaust port 112 side of the heating barrel 11 to the supply port 111 side, but the orientation of the openings of the supply-side exhaust section 171 and the exhaust-side exhaust section 172 is not limited to the example in FIG. 1.

[0047] The differences between the heating device according to this embodiment and conventional heating devices will now be described in more detail with reference to the drawings. Fig. 4 is a schematic diagram of a conventional heating device. The heating device 4 shown in Fig. 4 does not have anything equivalent to the gas inlet (first gas inlet 15) on the supply port 111 side or the discharge-side exhaust part 172 that are provided in the heating device 1. Gas is supplied only through the gas inlet provided on the exhaust port 412 side, and gas is exhausted only through the supply-side exhaust part 471.

[0048] The exhaust is controlled by measuring the pressure near the exhaust port 412 using an exhaust-side pressure measuring unit 476, such as a differential pressure gauge, provided in the rear chamber 44. The result of this measurement is sent to an exhaust-side exhaust control unit 474, which is configured to be able to control the exhaust of the exhaust unit 477.

[0049] As described above, in the prior art, gas exhaust from the heating device 4 was performed only by the supply side exhaust section 471 based on the measurement results of the exhaust side pressure measurement section 476, but in the heating device 1 of this embodiment, gas exhaust from the heating device 1 is performed by both the supply side exhaust section 171 and the exhaust side exhaust section 172, and control is performed based on the measurement results from the supply side pressure measurement section 175 and the exhaust side pressure measurement section 176, respectively.

[0050] For example, when a lithium metal composite oxide is produced using the heating device 1, the supply-side exhaust section 171 mainly exhausts water vapor gas entrained in the first gas, while the discharge-side exhaust section 172 mainly exhausts oxygen. In this way, by introducing a decarbonated gas and an oxidizing gas from the supply inlet 111 side and the discharge outlet 112 side, respectively, and exhausting the gases from the respective exhaust sections (supply-side exhaust section 171, discharge-side exhaust section 172), it is not necessary to flow the oxidizing gas in one direction from the discharge outlet 112 side to the supply inlet 111 side, as in the heating device 4 shown in Fig. 4. Therefore, the heating device 1 according to this embodiment can reduce the amount of raw materials and lithium metal composite oxide that scatters compared to the heating device 4 of the conventional art, thereby improving the quality of the lithium metal composite oxide obtained and also improving productivity.

[0051] [Heating Device of Second Embodiment] In the heating device 1 shown in FIG. 1, the piping of the supply-side exhaust section 171 and the piping of the exhaust-side exhaust section 172 are both connected to the piping of the exhaust section 19 and exhausted as a single line, but they may each be provided as separate piping.

[0052] Fig. 2 is a schematic diagram of a heating device according to a second embodiment of the present disclosure. Note that in Fig. 2, reference numerals are omitted for components common to Fig. 1, and these will also be omitted in the following description. Specifically, the supply-side exhaust section, the discharge-side exhaust section, the components downstream of these in the exhaust system, and the pressure measurement sections will be described below.

[0053] 2 , the supply-side exhaust section 271 is mainly for exhausting the first gas remaining on the supply port 211 side of the heating barrel 21. The supply-side exhaust section 271 is configured to extend from the outside of the heating device 2 through the front chamber 23 to the heating barrel 21. The supply-side exhaust section 271 is configured to be able to exhaust the gas inside the heating barrel 21 to the supply port 211 side of the heating barrel 21. The opening of this supply-side exhaust section 271 faces from the supply port 211 side to the exhaust port 212 side of the heating barrel 21.

[0054] The supply-side exhaust section 271 is connected to a solid removal section 292 typified by a bag filter, piping 293, and an exhaust section 277 typified by a blower. A supply-side pressure measurement section 275 typified by a differential pressure gauge is provided inside the front chamber 23 and measures the pressure near the supply port 211. The result of this measurement is sent to a supply-side exhaust control section 273 configured to be able to control the exhaust of the supply-side exhaust section 271. Similarly, the supply-side exhaust control section 273 receives the pressure of the rear chamber 24 received by the discharge-side exhaust control section 274 from the discharge-side exhaust control section 274, and calculates the relationship between the pressure on the discharge port 212 side of the heating barrel 21 and the pressure on the supply port 211 side of the heating barrel 21.

[0055] On the other hand, the discharge-side exhaust section 272 is mainly for exhausting the second gas remaining on the discharge port 212 side of the heating barrel 21. The discharge-side exhaust section 272 is configured to extend from the outside of the heating device 2 through the rear chamber 24 to the heating barrel 21. The discharge-side exhaust section 272 is configured to be able to exhaust the gas inside the heating barrel 21 to the discharge port 212 side of the heating barrel 21. The discharge-side exhaust section 272 has an opening facing from the discharge port 212 side of the heating barrel 21 to the supply port 211 side.

[0056] The discharge-side exhaust unit 272 is connected to a solid removal unit 294, typified by a bag filter, piping 295, and an exhaust unit 278, typified by a blower. A discharge-side pressure measurement unit 276, typified by a differential pressure gauge, is provided inside the rear chamber 24 and measures the pressure near the discharge port 212. The measurement result is sent to a discharge-side exhaust control unit 274, which is configured to be able to control the exhaust of the discharge-side exhaust unit 212. The discharge-side exhaust control unit 274 receives the pressure of the front chamber 23 received by the supply-side exhaust control unit 273 from the supply-side exhaust control unit 273, and calculates the relationship between the pressure on the discharge port 212 side of the heating barrel 21 and the pressure on the supply port 211 side of the heating barrel 21. Then, an inverter (not shown) controls the exhaust unit 277 and the blower serving as the exhaust unit 278 based on the obtained pressure relationship.

[0057] As described above, the supply-side exhaust section 271 and the exhaust-side exhaust section 272 may be controlled as independent exhaust paths. In this case, if it is desired to reduce the pressure on the supply port 211 side, the output of the inverter (not shown) of the exhaust section 277 may be controlled to increase, and if it is desired to reduce the pressure on the exhaust port 212 side, the output of the inverter of the exhaust section 278 may be controlled to increase. On the other hand, if it is desired to increase the pressure on the supply port 211 side, the output of the inverter of the exhaust section 277 may be controlled to decrease, and if it is desired to reduce the pressure on the exhaust port 212 side, the output of the inverter of the exhaust section 278 may be controlled to decrease.

[0058] In Figure 2, the supply-side exhaust control unit 273, which is configured to be able to control the exhaust of the supply-side exhaust unit 271, and the exhaust-side exhaust control unit 274, which is configured to be able to control the exhaust of the exhaust-side exhaust unit 272, are shown as separate components, but they may be configured as separate devices as shown in Figure 2, or they may be configured as the same device.

[0059] 1 and 2, the supply-side exhaust sections 171, 271 and the discharge-side exhaust sections 172, 272 are shown as L-shaped cylindrical bodies in the schematic diagrams, and these exhaust sections are fixed to the heating devices 1, 2 at the portions where they intersect with the wall surfaces of the front chambers 13, 23 and the rear chambers 14, 24. However, if the fixing strength is insufficient, for example, the pipes of these exhaust sections may be extended horizontally on the paper and fixed to the wall surfaces of the front chamber and the rear chamber.

[0060] Fig. 3 is a schematic diagram of a heating device according to a third embodiment of the present disclosure. Note that in Fig. 3, reference numerals are omitted for components common to Fig. 1, and will be omitted in the following description. Specifically, the heating device 3 shown in Fig. 3 has a discharge-side exhaust section 372 whose portion extending in the horizontal direction of the page is fixed to the wall surfaces of the front chamber 33 and the rear chamber 34.

[0061] In this case, the second gas needs to be drawn into the discharge-side exhaust section 372. For this reason, an intake port 379 is provided in a part of the pipe of the discharge-side exhaust section 372, and the second gas is drawn in from there.

[0062] The above describes an example of a manufacturing process for lithium metal composite oxide, but the heating device according to this embodiment can be used for other materials, such as various ceramic materials and various resin materials, without any particular limitations, as long as they can be heated.

[0063] Furthermore, although a rotary kiln has been described as an example above, the heating device according to this embodiment is not particularly limited in form as long as it is a heating device that continuously heats raw materials while causing them to flow and be transported inside a heating cylinder. In addition to a rotary kiln, for example, a steam tube dryer, a paddle dryer, etc. can also be used.

[0064] <Method for manufacturing a heat-treated product> A method for manufacturing a heat-treated product according to an embodiment of the present disclosure includes a heating step of continuously heating the raw materials of the heat-treated product while flowing and transporting them inside a heating barrel, a first gas introduction step of introducing a first gas into the interior of the heating barrel from the supply port side toward the discharge port side of the heating barrel, a second gas introduction step of introducing a second gas into the interior of the heating barrel from the discharge port side toward the supply port side of the heating barrel, and a pressure control step of adjusting the pressure on the discharge port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

[0065] The method for producing a heat-treated product according to this embodiment can be carried out using, for example, the heating device according to the embodiment of the present disclosure described above.

[0066] [Heating Step] The heating step is a step of continuously heating the raw material of the heat treatment object while causing it to flow and be transported inside a heating cylinder. In one embodiment, the heating step is achieved by a heating unit 12 such as a heater.

[0067] [First Gas Introduction Step] The first gas introduction step is a step of introducing a first gas into the heating barrel from the supply port side toward the discharge port side. In one embodiment, the first gas introduction step is achieved by the first gas introduction unit 15. In this case, the specific introduction method in the first gas introduction step is similar to the operation of the first gas introduction unit 15, and therefore a detailed description thereof will be omitted here.

[0068] The first gas introduction step is preferably carried out simultaneously with heating of the raw material of the heat treatment product in the heating step.

[0069] [Second Gas Introduction Step] The second gas introduction step is a step of introducing a second gas into the heating barrel from the outlet side toward the supply side. In one embodiment, the second gas introduction step is achieved by the second gas introduction unit 16. In this case, the specific introduction method in the second gas introduction step is the same as the operation of the second gas introduction unit 16, and therefore a detailed description thereof will be omitted here.

[0070] The second gas introduction step is preferably carried out simultaneously with heating of the raw material of the heat treatment product in the heating step.

[0071] In one embodiment, the heat-treated product may be a ceramic material, or may be a lithium metal composite oxide.

[0072] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0073] Example 1 (Operation of Calcination Apparatus and Preparation of Calcined Product) A metal composite hydroxide was prepared as a precursor of a lithium metal composite oxide having Ni, Co, and Al in a ratio of Ni:Co:Al = 90:5:5. This metal composite hydroxide and lithium hydroxide hydrate were weighed out so that the total amount of Li, Ni, Co, and Al and the molar ratio Li / (Ni + Co + Al) were 1.025, and then charged into a mixer and precision mixed to prepare a raw material mixture.

[0074] The raw material mixture was then charged from the mixture storage tank into a rotary kiln having the configuration shown in Fig. 1 and subjected to firing. Specifically, firing was performed using a rotary kiln having a retort diameter of 700 mm and six scraping blades installed circumferentially at an angle of 30° on the surface of the furnace core tube, with the retort rotation speed set to 0.9 rpm, the filling rate set to 20%, and the maximum surface temperature of the furnace core tube set to 640°C, while the raw material mixture was stirred and continuously flowed while being scraped up for 13 hours so that the maximum temperature of the raw material mixture reached approximately 600°C.

[0075] During the firing, decarbonated air (carbon concentration: 10 ppm or less) at 200°C was introduced from the first gas inlet 15 at a flow rate of 60 m ３ Meanwhile, oxygen gas (oxygen concentration: 99.7 vol%) at 300°C was injected from the second gas inlet 16 at a rate of 50 m ３ The pressure control unit 17 controlled the differential pressure set value at the supply side pressure measuring unit 175 to −0.20 kPa and the differential pressure set value at the supply side pressure measuring unit 176 to −0.10 kPa.

[0076] (Results) An oxygen concentration measuring device was installed at a location outside the rotary kiln between the supply-side exhaust section 171 and the pipe 191, and the oxygen concentration in the exhaust gas (concentration not including water vapor) was measured to be 28.1%. Meanwhile, an oxygen concentration measuring device was also installed at a location outside the rotary kiln between the discharge-side exhaust section 172 and the opening / closing section 178, and the oxygen concentration in the exhaust gas (concentration not including water vapor) was measured to be 93.5%.

[0077] In addition, a water vapor amount measuring device was installed near each oxygen concentration measuring device, and the amount of water vapor in the exhaust gas discharged from the supply side exhaust section 171 and the amount of water vapor in the exhaust gas discharged from the discharge side exhaust section 172 were measured, and the ratio was approximately 8:2.

[0078] The mass of the scattered powder collected by the bag filter serving as the solid removal section 192 was also measured. Specifically, after the rotary kiln serving as the firing apparatus 1 was continuously operated for one hour, the mass of the scattered powder relative to the total mass of the raw materials (metal composite hydroxide and lithium hydroxide hydrate) (mass of scattered powder / total mass of raw materials) was measured and found to be 4.5 mass%.

[0079] The fired product discharged from the outlet 112 was sampled every hour for a total of 5 hours, and titration analysis was performed using the Warder method described below. The residual Li content was found to be 1.02% by mass. (Measurement of Residual Li Content) The residual Li content was measured and calculated using the Warder method in neutralization titration. Specifically, 20 g of the sample particle powder was added to 100 ml of water, stirred for 20 minutes at room temperature, and the solids were filtered off and removed. The resulting supernatant was titrated with 0.2 N hydrochloric acid to determine the residual Li content. On a pH curve plotting the titration volume (ml) on the horizontal axis and the pH of the supernatant on the vertical axis, the two points with the greatest slope were designated the first and second titration points, in descending order of the titration volume. The values ​​were calculated using a formula based on the titration volumes at these points.

[0080] [Example 2] The same raw material mixture as in Example 1 was charged from the mixture storage tank into a rotary kiln having the configuration shown in Figure 2 and fired. The internal configuration of the rotary kiln, the retort rotation speed, the filling rate, the maximum surface temperature of the furnace core tube, the maximum temperature of the raw material mixture, and the operating time were also the same as in Example 1.

[0081] (Operation of the baking device and adjustment of baked product) During baking, 60 m of decarbonated air (carbon concentration: 10 ppm or less) at 200°C was introduced from the first gas inlet 25. ３ Meanwhile, oxygen gas (oxygen concentration: 99.7 vol%) at 300°C was injected from the second gas inlet 26 at a rate of 50 m ３ The pressure control unit 27 controlled the differential pressure set value at the supply side pressure measuring unit 275 to −0.30 kPa and the differential pressure set value at the discharge side pressure measuring unit 276 to −0.10 kPa.

[0082] (Results) An oxygen concentration measuring device was installed at a location outside the rotary kiln between the supply-side exhaust section 271 and the pipe 291, and the oxygen concentration in the exhaust gas (concentration not including water vapor) was measured to be 26.5%. On the other hand, an oxygen concentration measuring device was installed at a location outside the rotary kiln between the discharge-side exhaust section 272 and the opening / closing section 294, and the oxygen concentration in the exhaust gas (not including water vapor) was measured to be 94.1%.

[0083] In addition, a water vapor amount measuring device was installed near each oxygen concentration measuring device, and the amount of water vapor in the exhaust gas discharged from the supply side exhaust section 271 and the amount of water vapor in the exhaust gas discharged from the discharge side exhaust section 272 were measured, and the ratio was found to be approximately 9:1.

[0084] The mass of the scattered powder collected by the bag filters serving as solid removal units 292 and 294 (the total amount of scattered powder collected by each of solid removal units 292 and 294) was also measured. Specifically, after the rotary kiln serving as firing apparatus 2 was continuously operated for one hour, the mass of scattered powder relative to the total mass of the raw materials (metal composite hydroxide and lithium hydroxide hydrate) (mass of scattered powder / total mass of raw materials) was measured and found to be 3.7% by mass.

[0085] The fired product discharged from the outlet 212 was sampled every hour for a total of 5 hours, and titration analysis was carried out by the Warder method described above. As a result, the amount of residual Li was found to be 1.01% by mass.

[0086] Comparative Example 1 (Operation of the Firing Apparatus and Preparation of the Firing Product) The same raw material mixture as in Example 1 was charged from the mixture storage tank into a rotary kiln having the configuration shown in Figure 4, and firing was carried out. The internal configuration of the rotary kiln, the retort rotation speed, the filling rate, the maximum surface temperature of the furnace core tube, the maximum temperature of the raw material mixture, and the operating time were also the same as in Example 1.

[0087] During firing, 135 m of oxygen gas (oxygen concentration: 99.5 vol%) at 300°C was introduced from the gas inlet 46. ３ The differential pressure set value in the supply side pressure measuring unit 474 was set to −0.15 kPa and controlled by the pressure control unit 47.

[0088] (Results) An oxygen concentration measuring device was installed at a location outside the rotary kiln between the supply side exhaust port 471 and the pipe 491, and the oxygen concentration in the exhaust gas (concentration excluding water vapor) was measured and found to be 92.5%.

[0089] The mass of the scattered powder collected by the bag filter serving as the solid removal section 492 was also measured. Specifically, after the rotary kiln serving as the calcination device 4 was continuously operated for one hour, the mass of the scattered powder relative to the total mass of the raw materials (metal composite hydroxide and lithium hydroxide hydrate) (mass of scattered powder / total mass of raw materials) was measured and found to be 12.4 mass%.

[0090] The fired product discharged from the outlet 412 was sampled every hour for a total of five hours, and titration analysis was carried out by the Warder method described above. As a result, the amount of remaining Li was found to be 1.02 mass %.

[0091] When a raw material mixture is heat-treated using a conventional calcination apparatus 4 as shown in Fig. 4, it is necessary to supply a large amount of oxygen from the gas inlet 46 in order to discharge water vapor. This increases the gas flow rate inside the heating cylinder, which in turn causes a large amount of scattered powder to be discharged, resulting in composition deviation and a decrease in production volume.

[0092] [Comparative Example 2] (Operation of the calcination apparatus and adjustment of the calcined product) The raw material mixture was calcined in a rotary kiln in the same manner as in Example 1, except that the differential pressure setting value in the supply side pressure measurement unit 175 was set to -0.10 kPa and the differential pressure setting value in the discharge side pressure measurement unit 176 was set to -0.20 kPa, and a calcined product was obtained.

[0093] (Results) An oxygen concentration measuring device was installed at a location outside the rotary kiln between the supply-side exhaust section 171 and the pipe 191, and the oxygen concentration in the exhaust gas (concentration not including water vapor) was measured to be 20.9%. Meanwhile, an oxygen concentration measuring device was also installed at a location outside the rotary kiln between the discharge-side exhaust section 172 and the opening / closing section 178, and the oxygen concentration in the exhaust gas (concentration not including water vapor) was measured to be 63.2%.

[0094] In addition, a water vapor amount measuring device was installed near each oxygen concentration measuring device, and the amount of water vapor in the exhaust gas discharged from the supply side exhaust section 171 and the amount of water vapor in the exhaust gas discharged from the discharge side exhaust section 172 were measured, and the ratio was found to be approximately 1:1.

[0095] The mass of the scattered powder collected by the bag filter serving as the solid removal section 192 was also measured. Specifically, after the rotary kiln serving as the firing apparatus 1 was continuously operated for one hour, the mass of the scattered powder relative to the total mass of the raw materials (metal composite hydroxide and lithium hydroxide hydrate) (mass of scattered powder / total mass of raw materials) was measured and found to be 6.2 mass%.

[0096] The fired product discharged from the outlet 112 was sampled every hour for a total of 5 hours, and titration analysis was carried out by the Warder method described below. The residual Li content was found to be 1.11 mass %.

[0097] When the pressure on the discharge port 112 side becomes lower than the pressure on the supply port 111 side, water vapor generated by the lithiation reaction of the metal composite hydroxide and decarbonated air injected from the first gas inlet 25 flow toward the discharge port 112 side, and a large amount of gas is sucked into the discharge-side exhaust section 172. As a result, an air current is generated, causing a large amount of powder to fly from the raw material mixture, causing a compositional deviation of the fired product from the raw material mixture (the Li in the fired product increases compared to the raw material mixture), resulting in a decrease in quality and an increase in scattered powder.

[0098] Table 1 shows the injection speed (air volume) of the first gas inlet, the injection speed (air volume) of the second gas inlet, the differential pressure at the supply-side pressure measuring section, the differential pressure at the discharge-side pressure measuring section, and the O2 content of the gas exhausted from the supply-side exhaust section for Examples 1 and 2 and Comparative Examples 1 and 2. ２ concentration, detected value of water vapor amount in the exhaust gas on the supply side / theoretical value of water vapor amount, O ２ The figures show the concentration, the detected value of the water vapor amount in the exhaust gas on the discharge side / theoretical value of the water vapor amount, the scattering rate of the scattered powder, and the amount of remaining lithium.

[0099]

[0100] 1, 2, 3 Heating device 11, 21, 31, 41 Heating barrel 111, 211, 311, 411 Supply port 112, 212, 312, 412 Discharge port 12, 22, 32, 42 Heating section 13, 23, 33, 43 Front chamber 14, 24, 34, 44 Rear chamber 15, 25, 35 First gas introduction section 16, 26, 36 Second gas introduction section 17, 27, 37, 47 Pressure control section 171, 271, 371, 471 Supply side exhaust section 172, 272, 372 Discharge side exhaust section 173, 273, 373 Supply side exhaust control section 174, 274, 374, 474 Discharge side exhaust control section 175, 275, 375 Supply side pressure measurement section 176, 276, 376, 476 Discharge side pressure measurement section 177, 277, 377, 477 Exhaust section 178, 278, 378 Opening and closing section 18, 28, 38, 48 Raw material supply section 19, 29, 39, 49 Discharge section 191, 291, 391, 491 Pipe 192, 292, 392, 492 Solid removal section 193, 293, 294, 393, 493 Pipe 295 Pipe 379 Inlet 46 Gas introduction section

Claims

1. A heating device that continuously heats raw materials while flowing and transporting them inside a heating barrel, comprising: a first gas inlet configured to be able to introduce a first gas into the interior of the heating barrel from the supply port side toward the exhaust port side of the heating barrel; a second gas inlet configured to be able to introduce a second gas into the interior of the heating barrel from the exhaust port side toward the supply port side of the heating barrel; and a pressure control unit configured to be able to adjust the pressure on the exhaust port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

2. The heating device described in claim 1, wherein the pressure control unit comprises: a supply side exhaust unit configured to be capable of exhausting gas inside the heating barrel on the supply inlet side of the heating barrel; an exhaust side exhaust unit configured to be capable of exhausting gas inside the heating barrel on the exhaust outlet side of the heating barrel; and an exhaust control unit configured to be capable of controlling the exhaust of the supply side exhaust unit and / or the exhaust of the exhaust side exhaust unit.

3. The heating device according to claim 1 or 2, wherein the first gas and the second gas are composed of different components and / or compositions.

4. A heating device as claimed in claim 1 or 2, wherein the inside of the heating barrel is configured as a single chamber without any partitions.

5. The heating device according to claim 1 or 2 for producing ceramic materials.

6. The heating device according to claim 1 or 2 for producing lithium metal composite oxide.

7. A method for manufacturing a heat-treated product, comprising: a heating step of continuously heating the raw material of the heat-treated product while flowing and transporting it inside a heating barrel; a first gas introduction step of introducing a first gas into the interior of the heating barrel from the supply port side toward the exhaust port side of the heating barrel; a second gas introduction step of introducing a second gas into the interior of the heating barrel from the exhaust port side toward the supply port side of the heating barrel; and a pressure control step of adjusting the pressure on the exhaust port side of the heating barrel to be higher than the pressure on the supply port side of the heating barrel.

8. The method for producing a heat-treated object according to claim 7, wherein the heat-treated object is a ceramic material.

9. The method for producing a heat-treated product according to claim 7, wherein the heat-treated product is a lithium metal composite oxide.

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