Roasting furnace and system for producing oxide precursors for lithium batteries, precursors for lithium battery materials, and methods and applications thereof.

Abstract

This disclosure provides a roasting furnace and a system for producing oxide precursors for lithium batteries, a precursor for lithium battery material, and a method for producing the same and its applications, relating to the technology of lithium batteries. The roasting furnace employs a spray supply method at the bottom of the furnace, where the reaction proceeds from bottom to top within the furnace, and the negative pressure at the top of the furnace is used to expel the product from the particle outlet at the top. Because the gas is expelled from the top of the furnace along with the product, this disclosure offers a longer residence time at the pyrolysis temperature compared to bottom discharge systems, which is advantageous for improving the crystallinity of the product. Furthermore, because the particles are expelled from the top of the furnace along with the gas, the particle flow is prevented from clogging the sprayer, improving the operational stability of the device. Moreover, the roasting furnace provided in this disclosure allows for adjustment of the residence time by controlling the magnitude of the negative pressure, making it easier to control the temperature in the lower zone of the roasting furnace compared to conventional supply and discharge methods, which is advantageous for precise temperature control and energy saving.

Description

[Technical Field]

[0001] Cross-reference of related applications This disclosure claims priority to the Chinese patent applications filed with the China Patent Administration on March 10, 2023, No. 2023102606119, titled "Precursor for Lithium Battery Material, Method for Manufacturing the Same and its Applications," and No. 2023102641644, titled "Roasting Furnace and System for Manufacturing Oxide Precursors for Lithium Batteries," all of which are incorporated herein by reference.

[0002] This disclosure relates to the technology of lithium batteries, and more specifically to a roasting furnace, a system for producing oxide precursors for lithium batteries, precursors for lithium battery materials, and methods for producing and applying the same. [Background technology]

[0003] Cathode materials are one of the key materials used in manufacturing lithium-ion batteries and have a broad market outlook, with the largest market size in the lithium battery field being for cathode materials. As is well known, the production of precursor materials is of paramount importance in the manufacture of cathode materials, and the main technical aspects of cathode materials are reflected in the precursor process. Therefore, the manufacturing technology for precursor materials is extremely important.

[0004] Currently, there are two main methods for synthesizing ternary precursor materials within China.

[0005] (1) Crystallized Coprecipitation Method: This method involves preparing a mixed sulfate solution of ternary metals in molar ratio, then mixing it with liquid alkali and ammonia water to produce a ternary metal hydroxide precipitate. The precipitate undergoes processes such as filtration, drying, grinding, and demagnetization to obtain the finished ternary precursor. More than 90% of companies in China use this method. Conventional coprecipitation methods have long production processes, large amounts of wastewater, high production costs, and significant environmental pressure. Statistics show that the by-products of the production process include ammonia, and the wastewater of heavy metal sodium sulfate is approximately 30 tons / ton, resulting in very high wastewater treatment costs.

[0006] (2) Spray pyrolysis method: This method involves dissolving nickel, cobalt, and manganese chloride salts as raw materials in water to prepare a mixed solution of ternary metals. The precursor solution is then atomized using a pressure / two-fluid spray device and introduced into a pyrolysis reactor, where the reaction is completed instantaneously, allowing for the production of large quantities of ternary oxide precursors in a short time. Spray pyrolysis is an eco-friendly production process for oxide precursors, being more efficient, more economical, and more environmentally friendly than the coprecipitation synthesis process. It prevents the production of sodium sulfate wastewater and ammonia-containing exhaust gas. The by-product hydrochloric acid can be used to recycle the production of chloride raw materials. Precursors produced using the spray pyrolysis process exhibit high particle size consistency, a narrow particle size distribution, and well-formed shapes, achieving atomic-level uniformity.

[0007] However, conventionally disclosed spray pyrolysis apparatuses have certain design flaws, both from a process and production standpoint. The main problem is that the sprayer is prone to clogging, leading to discontinuous and unstable reaction processes, short residence times at the pyrolysis temperature, and poor product crystallinity. Therefore, we desire to improve the structure and process of existing spray pyrolysis apparatuses to solve the problems that currently exist.

[0008] In light of this, I submit this application. [Overview of the project]

[0009] The purpose of this disclosure is to provide a roasting furnace and a system for producing oxide precursors for lithium batteries that reduce the occurrence of clogging in sprayers and increase the residence time at the pyrolysis temperature.

[0010] Another object of this disclosure is to provide a precursor for lithium battery material and a method for producing the same, which prevents clogging of sprayers or improves the crystallinity of the product by significantly increasing the residence time at the thermal decomposition temperature.

[0011] The third object of this disclosure is to provide a lithium battery cathode material, a lithium battery, and an electrical device for improving the cathode material of a lithium battery or the electrochemical performance of a lithium battery by improving the precursor.

[0012] The embodiments of this disclosure can be realized as follows.

[0013] In the first phase, the present disclosure provides a roasting furnace with a sprayer installed at the bottom for atomizing the raw material into droplets and ejecting them upward, a heating zone installed above the sprayer, and a particle outlet installed above the heating zone. The roasting furnace is further equipped with an airflow generating assembly, which generates an upward airflow within the roasting furnace, thereby providing a roasting furnace in which at least some droplets pass upward through the heating zone with the airflow and are discharged from the particle outlet.

[0014] In any embodiment, the airflow generating assembly includes a negative pressure assembly, the negative pressure assembly includes a fan.

[0015] In any embodiment, the sprayer includes at least one of an airflow sprayer, a pressure sprayer, and an ultrasonic sprayer.

[0016] In any embodiment, heating components for temperature control are installed in the heating zone, and a temperature measuring assembly is further installed in the roasting furnace.

[0017] Optionally, the heating component includes at least one of a burner, an electromagnetic heating component, and a resistance heating component.

[0018] In any embodiment, the heating component is a burner, and the burner is installed symmetrically along the furnace body cutting line.

[0019] In any embodiment, a discharge device is installed in the cavity at the bottom of the roasting furnace to discharge the accumulated material inside the furnace, an outlet is provided in the bottom wall of the roasting furnace, the outlet is connected to the inlet of a hopper, and the outlet of the hopper is connected to a discharge valve. The discharging device includes rake teeth attached to the inner wall of the roasting furnace and a motor for driving the rake teeth to rotate, and the rake teeth extend from one end to the opposite end of the roasting furnace.

[0020] In a second aspect, the present disclosure provides a system for manufacturing an oxide precursor of a lithium battery including the roasting furnace described in any of the above embodiments.

[0021] <E In any embodiment, a gas-solid separation device is connected to the particle outlet of the roasting furnace, the gas outlet of the gas-solid separation device is connected to the inlet of the dust removal device, the gas outlet of the dust removal device is connected to the gas inlet of the preliminary concentrator, the liquid inlet of the preliminary concentrator is connected to a precursor liquid storage tank for mixing precursor raw materials, and the liquid outlet of the preliminary concentrator is connected to a sprayer.

[0022] In any embodiment, the gas outlet of the preliminary concentrator is sequentially connected to a primary absorption tower and a secondary absorption tower, and the gas outlet of the primary absorption tower is connected to the secondary absorption tower. <E

[0023] In any embodiment, it further includes an exhaust fan, a horizontal droplet separator, and an alkali washing tower installed in sequence. The gas outlet of the secondary absorption tower is connected to the horizontal droplet separator through the exhaust fan, and the outlet of the horizontal droplet separator is connected to the alkali washing tower.

[0024] In a third aspect, the present disclosure performs manufacturing using the roasting furnace of any of the above embodiments, atomizes a metal salt precursor solution by a sprayer at the bottom of the roasting furnace, and after the atomized material undergoes evaporation, drying, and decomposition from bottom to top in sequence in the roasting furnace, it provides a method for manufacturing a precursor of a lithium battery material that is sent out from the furnace top with the generated oxide particles accompanied by gas.

[0025] In any embodiment, the residence time of the material in the roasting furnace is controlled by adjusting the flow rate of the air flow, optionally, the residence time of the material in the roasting furnace is 10 s to 1 min, Optionally, by installing it so that the pressure at the furnace top becomes negative pressure, upward airflow is generated in the roasting furnace by utilizing the negative pressure. Optionally, by adjusting the magnitude of the negative pressure, the magnitude of the flow velocity of the airflow in the roasting furnace is adjusted. Optionally, control is performed so that the pressure at the furnace top becomes -0.3 KPa to -0.1 KPa.

[0026] In any embodiment, an evaporation zone, a drying zone, and a decomposition zone are sequentially installed in the roasting furnace from bottom to top, and the temperature from the evaporation zone to the decomposition zone gradually increases. Optionally, the temperature range from the bottom to the top of the roasting furnace is 100°C to 950°C. Optionally, the temperature of the evaporation zone is 100°C to 200°C, the temperature of the drying zone is 250°C to 500°C, and the temperature of the decomposition zone is 550°C to 950°C. Optionally, the decomposition zone includes a primary thermal decomposition zone and a secondary thermal decomposition zone located above the primary thermal decomposition zone. The temperature of the primary thermal decomposition zone is 650 to 750°C, and the temperature of the secondary thermal decomposition zone is 600 to 700°C. Optionally, the tower height of the roasting furnace is 5 m to 20 m, and the inner diameter is 2 m to 6 m. Optionally, temperature control is performed using the burner as a heating component. The number of sets of burners is 3 to 5 sets, and each set of burners is symmetrically arranged along the tangent of the furnace body.

[0027] In any embodiment, the material sent out from the furnace top is subjected to gas-solid separation to obtain exhaust gas and solid products. After the exhaust gas is dust-removed by a dust removal device, it enters a preliminary concentrator, exchanges heat with a metal salt precursor solution, and after the concentrated metal salt precursor solution is filtered, it enters the bottom of the roasting furnace, is atomized by a sprayer, and then sprayed upward. Optionally, gas-solid separation is carried out using a two-stage cyclone separator. The separated solid product is dechlorinated, pulverized, and then recovered. Optionally, the temperature when the exhaust gas enters the dust removal device is 300°C to 450°C, and the temperature at the gas outlet of the preliminary concentrator is 75°C to 90°C. Optionally, before the metal salt precursor solution enters the preconcentrator, filtration and iron removal may be performed. Optionally, the sprayer is selected from either a pressure sprayer or a two-fluid nozzle, and is controlled so that the size of the atomized droplets is 100 nm to 100 μm. Optionally, the gas used in the two-fluid nozzle is selected from compressed air and nitrogen gas, the gas pressure is 0.1 MPa to 1 MPa, and the gas temperature is 75°C to 120°C.

[0028] In any embodiment, the total concentration of metal elements in the concentrated metal salt precursor solution is 200 g / L to 320 g / L, and the type of metal element in the metal salt precursor solution is one or more. Optionally, the process for producing a metal salt precursor solution may include mixing and dissolving nickel salt, cobalt salt, and manganese salt, and controlling the total concentration of nickel, cobalt, and manganese elements in the metal salt precursor solution to be between 120 g / L and 200 g / L. Optionally, each of the nickel salt, cobalt salt, and manganese salt is independently selected from perchlorates and chloride salts, The nickel salt, cobalt salt, and manganese salt are all chloride salts, by choice.

[0029] In any embodiment, the cooled exhaust gas sent from the pre-concentrator enters an absorption tower where acidic gases are absorbed, and the exhaust gas discharged from the absorption tower is alkaline-washed before being discharged. Optionally, the exhaust gas discharged from the absorption tower passes through the exhaust fan and horizontal droplet separator in sequence, then enters the alkaline scrubbing tower, where it comes into contact with the spray liquid from top to bottom in the opposite direction. The process of acidic gases being absorbed into an absorption tower may be as follows: the exhaust gas is first passed through a primary absorption tower for primary absorption; the gas discharged from the primary absorption tower enters a secondary absorption tower for secondary absorption; water is continuously supplied to the secondary absorption tower; the acidic solution obtained by secondary absorption is returned to the primary absorption tower as a spray liquid; and both primary and secondary absorption involve backflow contact between the spray liquid and filler within the tower, flowing from top to bottom. Optionally, the concentration of the regenerated acid solution after primary absorption is 170 g / L to 220 g / L, and the gas temperature at the outlet of the primary absorption column is 60°C to 70°C.

[0030] Fourth, the present disclosure provides a precursor of lithium battery material manufactured by the manufacturing method in any of the embodiments described above.

[0031] In the fifth aspect, this disclosure provides a lithium battery cathode material including a precursor of the lithium battery material in the above embodiment.

[0032] In the sixth aspect, the present disclosure provides a lithium battery including the lithium battery cathode material in the above embodiment.

[0033] In the seventh aspect, the present disclosure provides an electrical device including a lithium battery in the above embodiment.

[0034] The beneficial effects of this disclosure are as follows: By adopting a bottom-furnace spraying method for the roasting furnace, the reaction proceeds from bottom to top within the roasting furnace, and then the negative pressure at the top of the furnace is used to expel the product from the particle outlet at the top. Since the gas is expelled from the top of the furnace along with the product, this disclosure has a longer residence time at the pyrolysis temperature compared to bottom-discharge devices, which is advantageous for improving the crystallinity of the product. Furthermore, since the particles are expelled from the top of the furnace along with the gas, it is possible to prevent the particle flow from clogging the sprayer, thereby improving the stability of the device operation. In addition, the roasting furnace provided by this disclosure can further adjust the residence time by adjusting and controlling the magnitude of the negative pressure, and the temperature in the lower zone of the roasting furnace can be controlled more easily compared to conventional supply and discharge methods, which is advantageous for precise temperature control and energy saving.

[0035] To more clearly illustrate the technical concepts of the embodiments of this disclosure, the following is a brief introduction to the accompanying drawings that may be used in the embodiments. It should be understood that these accompanying drawings merely illustrate some embodiments of this disclosure and should not be considered limitations on the scope. A person skilled in the art can obtain other relevant drawings based on these accompanying drawings without any creative effort. [Brief explanation of the drawing]

[0036] [Figure 1] This is a flowchart of the oxide production equipment by the spray pyrolysis method in this disclosure. [Figure 2] This is an enlarged view of the supply system in the process of the equipment described herein. [Figure 3] This is a magnified view of the burner in the process of the equipment of this disclosure. [Figure 4] This is a diagram of a furnace bottom material sorting apparatus in the process of the equipment of this disclosure. [Figure 5] This is a flowchart of the oxide production process by spray pyrolysis as described in this disclosure. [Figure 6] This is an SEM diagram of the manufactured product of Example 1 of the present disclosure. [Figure 7] This is a PSD diagram of the manufactured product of Example 1 of the present disclosure. [Figure 8] This is an SEM diagram of the manufactured product of Example 2 of the present disclosure. [Figure 9] This is an XRD diagram of the manufactured product of Example 2 of the present disclosure. [Figure 10] This is a PSD drawing of the manufactured product of Example 2 of the present disclosure. [Figure 11] This is an SEM diagram of the manufactured product of Example 3 of the present disclosure. [Figure 12] This is an XRD diagram of the manufactured product of Example 3 of the present disclosure. [Figure 13] Figure 13 is an SEM diagram of the manufactured product of Example 4 of the present disclosure, where (a) and (b) show SEM diagrams at different magnifications. [Figure 14] Figure 14 shows an SEM diagram of the manufactured product of Example 5 of the present disclosure, where (a) and (b) show SEM diagrams at different magnifications. [Figure 15] This is an SEM diagram of the manufactured product of Example 6 of the present disclosure. [Figure 16] This is an XRD diagram of the manufactured product of Example 6 of the present disclosure. [Figure 17] This is an SEM diagram of the manufactured product of Comparative Example 1 of this disclosure. [Figure 18] This is a diagram showing the state of clogging in the sprayer of Comparative Example 1 of this disclosure. [Figure 19] Figure 19 shows an SEM diagram of the manufactured product of Comparative Example 2 of this disclosure, where (a) and (b) are SEM diagrams at different magnifications. [Figure 20] This is a diagram showing the state of sprayer clogging in Comparative Example 2 of this disclosure. [Explanation of symbols]

[0037] 1-Roasting furnace, 2-Supply system, 3-Atomizer, 31-Liquid supply pipe, 32-Carrier gas pipe, 4-Heating components, 5-Temperature measurement assembly, 6-Rake teeth, 7-Motor, 8-Hopper, 9-Discharge valve, 10-Gas-solid separator, 11-Circulation pump, 12-Debris removal device, 13-Jet mill, 14-Pre-concentrator, 15-Debris material recovery device, 16-Precursor liquid storage tank, 17-Metal liquid supply pump, 18-Primary absorption tower, 19-Secondary absorption tower, 20-Exhaust fan, 21-Horizontal droplet separator, 22-Alkali washing tower. [Modes for carrying out the invention]

[0038] To further clarify the purpose, technical proposals, and advantages of the embodiments of this disclosure, the technical proposals of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this disclosure. Needless to say, the embodiments described are some, but not all, embodiments of this disclosure. Typically, the assemblies of the embodiments of this disclosure described and shown herein in the accompanying drawings can be arranged and designed in a variety of different configurations.

[0039] Therefore, the detailed descriptions of embodiments of the Disclosure provided below in the attached drawings do not limit the scope of the Disclosure that seeks to be protected, but merely illustrate selected embodiments of the Disclosure. All other embodiments obtained by a person skilled in the art based on the embodiments in the Disclosure, without paying any creative labor, are within the scope of the Disclosure.

[0040] Please note that similar symbols and letters indicate similar items in the following attached drawings; therefore, if an item is defined in one attached drawing, it does not need to be further defined or interpreted in subsequent drawings.

[0041] In the descriptions of this disclosure, if the orientation or positional relationship indicated by terms such as "up," "down," "inside," and "outside" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship of the conventional arrangement when the product of the invention is used, this is merely for the purpose of facilitating the description of this disclosure and simplifying the description, and does not indicate or suggest that the described device or component necessarily has a specific orientation, or is configured and operated in a specific orientation, and therefore should not be understood as a limitation on this disclosure.

[0042] Furthermore, when terms such as "first," "second," etc., appear, they are used solely to distinguish between descriptions and should not be understood as indicating or suggesting relative importance.

[0043] It is necessary to explain that, if not inconsistent, the features in the embodiments of this disclosure can be combined with each other.

[0044] An embodiment of the present disclosure, with reference to Figure 1, provides a system for producing an oxide precursor for a lithium battery, which includes a roasting furnace 1, employing a spray pyrolysis method to produce an oxide precursor using the roasting furnace 1, and having a product processing unit connected to the top of the roasting furnace 1 to separate and recover the acidic gas and oxide product in the product.

[0045] Referring to Figures 1 to 3, in order to achieve better temperature control, the roasting furnace 1 is equipped with multiple sets of temperature control heating components 4 and temperature measurement assemblies 5 from top to bottom, so as to heat different zones within the roasting furnace 1 and to detect the temperature.

[0046] The supply system 2 is installed above the heating component 4 located at the bottom of the roasting furnace 1, and the supply system 2 includes a sprayer 3, which atomizes the raw material into droplets that are ejected upward from the bottom of the roasting furnace 1. The sprayer 3 is connected to a liquid supply pipe 31 and a carrier gas pipe 32, a heating zone is installed above the sprayer 3, and a particle outlet is installed above the heating zone. An airflow generating assembly is further installed in the roasting furnace, and the airflow generating assembly generates an upward airflow within the roasting furnace, so that at least some of the droplets pass upward through the heating zone with the airflow and are discharged from the particle outlet.

[0047] The number of heating components 4 and temperature measurement assemblies 5 is not limited, and a standard installation can be performed based on the actual situation. In some embodiments, the height of the roasting furnace 1 is 5m to 20m, the inner diameter is 2m to 6m, the number of heating components 4 is 3 to 5, each set of heating components 4 is arranged symmetrically along the cut line of the furnace body, and the number of temperature measurement assemblies 5 may also be 3 to 5. The temperature measurement assemblies 5 may be thermocouples, but are not limited to this, and multiple sets of thermocouples (4 pairs or more) can be used to measure the temperature at different heights of the roasting furnace 1, satisfying the trend of the temperature gradually increasing from bottom to top. The heating components 4 and temperature measurement assemblies 5 can be installed in an alternating manner as shown in the figure, and the heating components 4 may be burners, but are not limited to this, and their structure and operating principle will not be excessively described. The supply system is located above the lowest burner, and the connected atomizer 3 sprays upwards, ensuring that the heat provided by the system increases gradually from bottom to top, allowing for comprehensive energy utilization and precise and flexible zone temperature control.

[0048] Specifically, the airflow generating assembly includes a negative pressure assembly, which may, but is not limited to, a fan (not shown).

[0049] Specifically, the sprayer includes at least one of an airflow sprayer, a pressure sprayer, and an ultrasonic sprayer, and may, for example, be a two-fluid sprayer. The heating component includes at least one of a burner, an electromagnetic heating component, and a resistance heating component, and any of the above commonly used heating components for a roasting furnace are within the scope of protection of the embodiments of this disclosure.

[0050] Furthermore, the product discharged from the top of the roasting furnace 1 includes an acidic gas (e.g., hydrogen chloride) and an oxide product. The gas, along with the solid material, is discharged from the top into a gas-solid separator 10 (which may be a cyclone separator). The gas outlet of the gas-solid separator 10 is connected to the inlet of a dust removal device 12. The gas outlet of the dust removal device 12 is connected to the gas inlet of a pre-concentrator 14. The liquid inlet of the pre-concentrator 14 is connected to a precursor liquid storage tank 16 for mixing the precursor raw materials. The liquid outlet of the pre-concentrator 14 is connected to a supply system 2. The pre-concentrator 14 preheats and concentrates the precursor raw materials, which then enter the roasting furnace 1 for further reaction. The pre-concentrator 14 can lower the temperature of the acidic gas, which is advantageous for the subsequent absorption step and prevents the gas temperature from being too high, which would burn and destroy the filler after the gas enters the subsequent absorption unit. Specifically, the dust removal device 12 may be a general dust remover for chemical processing equipment, but is not limited to this; any device capable of achieving a dust removal function falls within the scope of protection of the embodiments of this disclosure.

[0051] Specifically, gas-solid separation is performed by the gas-solid separation device 10, and the exhaust gas sent out from the gas-solid separation device 10 is hydrogen chloride gas mixed with a small amount of fine powder that was not thoroughly separated. This gas enters the dust removal device 12, where the fine powder is continuously collected. After high-temperature dust removal, the gas enters the pre-concentrator 14, where it undergoes contact heat exchange in the same direction as the metal salt precursor solution, mass transfer occurs, the temperature is lowered, the concentrated metal salt precursor solution is filtered, and then enters the bottom of the roasting furnace, where it is atomized by a sprayer and sprayed upwards.

[0052] In some embodiments, the gas-solid separation device 10 may employ a two-stage cyclone separator. The connection method of the equipment at the outlet of the two-stage cyclone separator may be one of the following: (1) jet mill / dust removal device / repulp tank / pressure filter / rotary kiln / mixing hopper / vibrating screen / electromagnetic iron remover and packaging machine; (2) repulp tank / pressure filter / rotary kiln / jet mill / dust removal device / mixing hopper / vibrating screen / electromagnetic iron remover and packaging machine; or (3) rotary kiln / repulp tank / pressure filter / jet mill / dust removal device / mixing hopper / vibrating screen / electromagnetic iron remover and packaging machine.

[0053] Specifically, the precursor liquid storage tank 16 is connected to the liquid inlet of the preconcentrator 14 via a metal liquid supply pump 17, and the liquid outlet of the preconcentrator 14 is connected to the supply system 2 via a circulation pump 11, which is used to return the liquid from the preconcentrator 14 to the preconcentrator 14 after it has been pumped out from the bottom.

[0054] Furthermore, the bottom outlet of the dust removal device 12 is controlled by a flap valve to connect to the jet mill 13 and the dust material recovery device 15, respectively, and the ratio of material entering the jet mill 13 and the dust material recovery device 15 can be adjusted according to demand.

[0055] Furthermore, the gas outlet of the pre-concentrator 14 is connected in order to the primary absorption tower 18, secondary absorption tower 19, exhaust fan 20, horizontal droplet separator 21, and alkaline scrubbing tower 22. The gas outlet of the primary absorption tower 18 is connected to the secondary absorption tower 19, the gas outlet of the secondary absorption tower 19 is connected to the horizontal droplet separator 21 via the exhaust fan 20, and the outlet of the horizontal droplet separator 21 is connected to the alkaline scrubbing tower 22. To ensure sufficient absorption of acidic gases, both the primary absorption tower 18 and the secondary absorption tower 19 are used to absorb acidic gases. The gas absorbed by the exhaust fan 20 is then passed through the horizontal droplet separator 21 for treatment, and after removing residual acid via the alkaline scrubbing tower 22, the gas is released.

[0056] To better discharge the accumulated material inside the roasting furnace 1, a discharge device is installed in the cavity at the bottom of the roasting furnace 1, with a discharge port installed in the bottom wall of the roasting furnace 1, the discharge port connected to the inlet of the hopper 8, and the outlet of the hopper 8 connected to a discharge valve 9, thereby discharging the accumulated material inside the furnace. The discharge valve 9 may be a general star-shaped discharge valve.

[0057] In some embodiments, the discharge device includes a rake tooth 6 attached to the inner wall of the roasting furnace 1 and a motor 7 for driving the rake tooth 6 to rotate, and the rake tooth 6 may be a general vertical horizontal rake tooth. The rake tooth 6 extends from one end of the roasting furnace to the other opposite end to collect the accumulated material inside the furnace body, then discharges it from an outlet in the bottom wall of the roasting furnace 1, passes through a hopper 8, and then discharges the accumulated material inside the furnace during the production process via a discharge valve 9 to proceed to the next process.

[0058] To better understand the operating principles of the roasting furnace and lithium battery oxide precursor production system provided in the embodiments of this disclosure, the following manufacturing methods are also introduced.

[0059] Referring to Figures 1 and 5, this disclosure provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0060] S1, raw material formulation A solution of metal salt precursors is prepared as a raw material for spray pyrolysis, transported to the roasting furnace 1, and, if necessary, specific types of metals are added. This may be a single-element (Ni / Co / Mn) metal salt solution or a multi-element mixed salt solution prepared in a certain molar ratio. For example, it may be a nickel-cobalt-manganese precursor solution.

[0061] In some embodiments, the process for producing a metal salt precursor solution involves mixing and dissolving nickel salt, cobalt salt, and manganese salt, and controlling the concentration of the metal solution by controlling the amount of water added, so that the metal solution concentration is between 120 g / L and 200 g / L (e.g., 120 g / L, 150 g / L, 170 g / L, 200 g / L, etc.). The concentration of the metal solution refers to the total concentration of nickel, cobalt, and manganese elements, and the ratio of nickel, cobalt, and manganese is not limited. The ratio may be based on common types of nickel, cobalt, and manganese precursors. For example, the amounts of nickel salt, cobalt salt, and manganese salt used may be mixed and dissolved in a molar ratio of Ni, Co, and Mn of x:y:z, where x+y+z=1, and the molar ratio of Ni is between 33% and 95%, for example, 33%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, etc.

[0062] In some examples, the nickel salt, cobalt salt, and manganese salt are each independently selected from perchlorates and chloride salts, and may be perchlorates or chloride salts. Optionally, the nickel salt, cobalt salt, and manganese salt are all chloride salts, i.e., nickel chloride, cobalt chloride, and manganese chloride, and the process byproduct is hydrogen chloride.

[0063] In some embodiments, the compounded metal salt precursor solution is not directly introduced into the roasting furnace 1, but rather undergoes heat exchange with the high-temperature exhaust gas generated by the roasting furnace 1 in a pre-concentrator 14. The concentration of the metal salt precursor solution after concentration is 200 g / L to 320 g / L, and the concentrated metal salt precursor solution is then transported to the roasting furnace as a raw material.

[0064] Specifically, the compounded solution is stored in a precursor liquid storage tank 16, transported via a metal liquid supply pump 17 to a pre-concentrator 14, where it undergoes heat exchange with the high-temperature furnace gas emitted from the roasting furnace 1 and is then concentrated. The concentrated metal liquid, after passing through a pipe filter at a set flow rate, is sent by the supply pump to the spray bar at the bottom of the roasting furnace 1, where it is atomized into droplets by the action of a sprayer.

[0065] S2, spray pyrolysis The metal salt precursor solution is atomized by a sprayer at the bottom of the roasting furnace. The atomized material then passes sequentially through the evaporation zone, drying zone, and decomposition zone from bottom to top within the roasting furnace. The gas, along with the generated oxide particles, is then expelled from the top of the furnace. After gas-solid separation of the material expelled from the top of the furnace, exhaust gas and a solid product are obtained. Here, the temperature gradually rises from the evaporation zone to the decomposition zone within the roasting furnace, with the temperature range from 100°C to 950°C from bottom to top. This temperature range means that the temperature at the bottom of the furnace is the lowest, and may be as low as 100°C, while the temperature in the decomposition zone is the highest, and may be as high as 950°C.

[0066] In some embodiments, the sprayer is selected from either a pressure sprayer or a two-fluid nozzle, and is controlled so that the size of the atomized droplets is 100 nm to 100 μm, ensuring uniformity of the atomized droplets. Both pressure sprayers and two-fluid nozzles are suitable for existing spraying equipment, and both are suitable for the processes provided by the embodiments of this disclosure.

[0067] Furthermore, the gas used in the two-fluid nozzle is selected from either compressed air or nitrogen gas, the gas pressure is 0.1 MPa to 1 MPa, and the gas temperature is 75°C to 120°C by preheating the gas.

[0068] The embodiments of this disclosure are configured such that the pressure at the top of the furnace becomes negative, thereby utilizing the negative pressure to generate an upward airflow within the roasting furnace. By adjusting the magnitude of the negative pressure, the velocity of the airflow within the roasting furnace is adjusted, and the residence time of the material within the roasting furnace is further controlled.

[0069] In some examples, the temperature of the evaporation zone is 100°C to 200°C, the temperature of the drying zone is 250°C to 500°C, the temperature of the decomposition zone is 550°C to 950°C, the pressure at the top of the furnace is -0.3 kPa to -0.1 kPa, and the residence time of the material in the roasting furnace is 10 s to 1 min. By precisely controlling the temperature of each zone, the roasting apparatus is divided into an evaporation zone, a drying zone, and a decomposition zone, and the atomized droplets sequentially go through processes such as solvent evaporation, solute precipitation, drying, decomposition, and particle aggregation sintering, ultimately producing oxide precursors and hydrogen chloride gas. The upward flow of thermal energy from combustion not only ensures that the zone reactions of the material are carried out sufficiently, but also allows for a longer residence time at the thermal decomposition temperature, ensuring good crystallinity of the product.

[0070] In some embodiments, the decomposition zone may be divided into two stages, namely a primary pyrolysis zone and a secondary pyrolysis zone located above the primary pyrolysis zone, the temperature of the primary pyrolysis zone may be 650 to 750°C, and the temperature of the secondary pyrolysis zone may be 600 to 700°C.

[0071] Specifically, the temperature of the evaporation zone may be 100°C, 120°C, 150°C, 170°C, 200°C, etc., the temperature of the drying zone may be 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, etc., the temperature of the decomposition zone may be 550°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, etc., or any value between adjacent values, provided that the temperature field within the interval of the temperature control points at each stage is uniform. The pressure at the top of the furnace may be -0.3KPa, -0.2KPa, -0.1KPa, etc., and the residence time of the material in the roasting furnace may be 10s, 20s, 30s, 40s, 50s, 60s, etc.

[0072] Furthermore, the generated oxide particles and gas enter a subsequent gas-solid separator from the top of the furnace due to the negative pressure of the system, where they are separated to obtain exhaust gas and solid products.

[0073] S3, exhaust gas treatment The exhaust gas discharged from the gas-solid separation unit 10 (cyclone separator) is hydrogen chloride gas mixed with a small amount of fine powder that was not thoroughly separated. This gas enters the dust removal unit 12, where the fine powder is further collected by the dust removal unit. After high-temperature dust removal, the gas enters the pre-concentrator 14, where it undergoes contact heat exchange in the same direction as the metal salt precursor solution, mass transfer occurs, and the temperature is reduced. The concentrated metal salt precursor solution is then filtered and enters the bottom of the roasting furnace, where it is atomized by a sprayer and sprayed upwards. The concentration by the pre-concentrator 14 preheats the raw material, reduces the exhaust gas temperature, and prevents the gas from being too hot from burning and damaging the filler after it enters the subsequent absorption unit.

[0074] In some embodiments, the dust removal device 12 may be a single unit or two units may be arranged in parallel. The gas-solid separation device 10 and the dust removal device 12 can switch between materials, which can be collected individually or together, ensuring that they enter the subsequent oxide treatment device.

[0075] In some embodiments, the temperature at which the exhaust gas enters the dust removal device is 300°C to 450°C (e.g., 300°C, 350°C, 400°C, 450°C, etc.), the metal salt precursor solution can be circulated in the preconcentrator 14 by the circulation pump 11 of the preconcentrator, and the temperature of the gas outlet of the preconcentrator is set to 75°C to 90°C (e.g., 75°C, 80°C, 85°C, 90°C, etc.) to facilitate the subsequent absorption process.

[0076] In some embodiments, to prevent the introduction of impurities, the metal salt precursor solution is filtered and iron-removed before entering the preconcentrator, and the metal salt precursor solution is treated with a filter and iron remover.

[0077] Referring to Figures 1 and 5, the cooled exhaust gas sent from the pre-concentrator 14 enters the absorption tower, where acidic gases are absorbed. The exhaust gas discharged through the absorption tower is then alkaline-washed before being released into the atmosphere. The absorption tower effectively absorbs acidic gases from the exhaust gas, and as a byproduct, the residual acidic gases are reabsorbed by alkaline washing, after which the exhaust gas meets emission standards.

[0078] In some embodiments, the process of acidic gas being absorbed into an absorption tower involves first passing the exhaust gas through a primary absorption tower 18 for primary absorption, then sending the gas from the primary absorption tower into a secondary absorption tower 19 for secondary absorption, and continuously replenishing the secondary absorption tower 19 with water to return the acidic solution obtained by secondary absorption back into the primary absorption tower to form a spray solution. This two-stage absorption allows for sufficient absorption of acidic gas in the exhaust gas and improves the utilization rate of the raw materials. By controlling the absorption time, the concentration of the regenerated acid solution after primary absorption is set to 170 g / L to 220 g / L (e.g., 170 g / L, 180 g / L, 190 g / L, 200 g / L, 210 g / L, 220 g / L, etc.), and the gas temperature at the outlet of the primary absorption tower is set to 60°C to 70°C (e.g., 60°C, 65°C, 70°C, etc.).

[0079] Specifically, the cooled gas enters the primary absorption tower 18, where it comes into contact with the spray liquid and filler in opposite directions from top to bottom, absorbing hydrogen chloride gas and forming regenerated acid. Any gas that is not completely absorbed enters the secondary absorption tower 19 and is absorbed again. The low-concentration acid solution after secondary absorption returns to the primary absorption tower 18 as the spray liquid for primary absorption, increasing the concentration of the regenerated acid. Once the acid solution reaches the required level, it is discharged from the system and enters the approved acid tank. During the operation, the same amount of deionized water is continuously replenished in the secondary absorption tower 19.

[0080] In some embodiments, in order to reabsorb residual acidic gas, the exhaust gas discharged through the absorption tower passes sequentially through an exhaust fan 20 and a horizontal droplet separator 21 before entering an alkaline scrubbing tower 22, where it comes into contact with the top-to-bottom spray liquid in the opposite direction. The gas discharged from the exhaust fan 20 contains a small amount of moisture, which is separated into gas and liquid by the horizontal droplet separator 21 to remove the moisture.

[0081] The overall exhaust gas treatment process is as follows: The exhaust gas discharged from the outlet of the gas-solid separation unit 10 passes through the dust removal unit 12 and then enters the pre-concentrator 14. The solid discharge port at the bottom of the dust removal unit 12 is controlled by a flap valve and connected to the jet mill 13 and the high-temperature dust removal material recovery unit 15, respectively. The pre-concentrator 14 is connected to the precursor liquid storage tank 16 via a pipe. The precursor solution is transported to the pre-concentrator 14 by the metal liquid supply pump 17. The gas outlet of the pre-concentrator 14 is sequentially connected to the primary absorption tower 18, secondary absorption tower 19, exhaust fan 20, horizontal droplet separator 21, and alkaline washing tower 22. The entire manufacturing process may be controlled by a DCS control system.

[0082] S4, Post-processing of the product The solid product separated from the gas-solid separation device 10 is dechlorinated, crushed, and recovered in powder form. As shown in Figure 5, this solid product may be further subjected to steps such as washing, drying, mixing, sieving, and iron removal, after which the final precursor product is obtained and packaged. Washing removes impurities remaining on the oxide surface, and after steps such as drying and sieving, a product with a particle size that meets the requirements is obtained.

[0083] It should be explained that the grinding method is not limited, and processing may be carried out using the jet mill method 13 shown in Figure 1.

[0084] It is necessary to explain that the embodiments of this disclosure do not specifically limit the structure of the oxide treatment unit, and any oxide treatment system disclosed in the prior art or an oxide treatment apparatus not disclosed in the new art can be used in the embodiments of this disclosure.

[0085] Examples The embodiments of this disclosure further provide a precursor of a lithium battery material produced by the above-described manufacturing method, which has sufficient reaction and relatively good crystallinity, and can be used to further produce lithium battery cathode material and lithium battery, which is advantageous for improving the electrochemical performance of the material.

[0086] The features and performance of this disclosure will be described in more detail below in conjunction with examples.

[0087] It is necessary to explain that the parameters of the roasting furnace used in the following embodiment are as follows: the height of the roasting furnace is 10m, the inner diameter is 4m, there are 4 sets of burners, there are 4 pairs of thermocouples for temperature measurement in the temperature zone, and there is 1 outlet at the top of the furnace.

[0088] Example 1 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0089] (1) Preparation of metal salt precursor solution NiCl2·6H2O and C with a constant mass in molar ratio Ni:Co:Mn = 0.5:0.2:0.3 O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 130 g / L.

[0090] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -150 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, the temperature values ​​are set, and the fuel gas amount is adjusted by automatic control to control the zone temperatures. The temperature of the evaporation zone is set to 130°C, the temperature of the drying zone to 300°C, the temperature of the primary pyrolysis zone to 720°C, and the temperature of the secondary pyrolysis zone to 660°C.

[0091] Deionized water is injected into the pyrolysis apparatus using a two-fluid nozzle. After the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 50 seconds for the material in the roasting furnace and a droplet size of 25 μm for atomized liquid.

[0092] (3) Utilization of exhaust heat The material sent from the top of the furnace is separated into gas and solid by a cyclone separator to obtain exhaust gas and solid products. The exhaust gas is then dust-removed by a dust collector and enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 220 g / L. After the concentration is filtered, the metal salt precursor solution enters the bottom of the roasting furnace, is atomized by a sprayer, and then sprayed upwards.

[0093] (4) Material processing The solid product passes through a cyclone separator and into a jet mill. The crushed material is then washed in a repulp tank, and after passing through equipment such as rotary kiln drying, mixing, sieving, and iron removal, it is collected at the packaging stage. A sample of the roasted ternary oxide is taken and designated as Sample 1.

[0094] (5) Acid recovery The cooled exhaust gas sent from the pre-concentrator enters the absorption tower where the acidic gas is absorbed. The exhaust gas first passes through the primary absorption tower for primary absorption, and the gas sent from the primary absorption tower enters the secondary absorption tower for secondary absorption. Water is continuously supplied to the secondary absorption tower, and the acidic solution obtained from secondary absorption is returned to the primary absorption tower as a spray liquid. In both primary and secondary absorption, the spray liquid comes into contact with the filler in a reverse flow from top to bottom within the tower. The exhaust gas discharged from the absorption tower passes through the exhaust fan and horizontal droplet separator in sequence before entering the alkaline scrubbing tower, where it comes into contact with the spray liquid in the opposite direction from top to bottom. The exhaust gas discharged from the absorption tower is then discharged after being alkaline-washed.

[0095] Test Analysis: The sprayer was observed for any clogging issues, and the collected samples were used for SEM and PSD testing. The results for the ternary 523 oxide particles obtained are shown in Figures 6 and 7.

[0096] The results analysis showed that the sprayer did not experience clogging. As can be seen from the SEM image, the primary particle size of the product manufactured using the two-fluid sprayer was relatively small and irregular. As can be seen from the PSD image, the particle size distribution of the manufactured oxide was wide, had a large span, and exhibited relatively poor consistency.

[0097] Example 2 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0098] (1) Preparation of metal salt precursor solution NiCl2·6H2O with a constant mass and molar ratio Ni:CO:Mn = 0.5:0.2:0.3, C O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 150 g / L.

[0099] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -200 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 150°C, the temperature of the drying zone to 350°C, the temperature of the primary pyrolysis zone to 700°C, and the temperature of the secondary pyrolysis zone to 650°C.

[0100] Deionized water is injected into the pyrolysis apparatus using a pressure nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 45 s for the material in the roasting furnace and a droplet size of 40 μm for atomized liquid.

[0101] (3) Exhaust heat utilization The material discharged from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is dust-removed by a dust collector and then enters a pre-concentrator, where it undergoes heat exchange with the metal salt precursor solution to concentrate it to a concentration of 255 g / L. The concentrated metal salt precursor solution is then filtered and enters the bottom of the roasting furnace, where it is atomized by a sprayer and then sprayed upwards.

[0102] (4) Material processing The solid product passes through a cyclone separator and into a jet mill. After pulverization, the material enters a repulp tank for washing, then undergoes rotary kiln drying, mixing, sieving, and iron removal. It is then collected at the packaging stage, and a sample of the roasted ternary oxide is taken and designated as Sample 2.

[0103] (5) Acid recovery The specific steps are the same as in Example 1.

[0104] Test Analysis: The sprayer was observed for any clogging issues, and the collected particles were subjected to SEM, XRD, and PSD testing. The results for the ternary 523 oxide particles are shown in Figures 8 to 10.

[0105] Results analysis showed that the sprayer did not clog. As can be seen from the SEM image, the oxide particles obtained by the pressure sprayer had relatively good crystallinity and a single-crystal octahedral structure, but the particle surface was uneven. This is presumed to be because the gas generated during the reaction process could not escape rapidly due to the relatively low spray pyrolysis temperature. As can be seen from the XRD image, the main components of the particles were NiO, Ni6MnO8, and MnC. O2 It is O4, has a large peak intensity, and is explained as having produced a ternary oxide precursor by thermal decomposition reaction. As can be seen from the PSD figure, the dispersion of the manufactured oxide particles is uniform, and the consistency is relatively good.

[0106] Example 3 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0107] (1) Preparation of metal salt precursor solution NiCl2·6H2O with a constant mass and molar ratio Ni:CO:Mn = 0.5:0.2:0.3, C O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 180 g / L.

[0108] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -250 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 180°C, the temperature of the drying zone to 400°C, the temperature of the primary pyrolysis zone to 750°C, and the temperature of the secondary pyrolysis zone to 700°C.

[0109] Deionized water is injected into the pyrolysis apparatus using a pressure nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 40 s for the material in the roasting furnace and a droplet size of 50 μm for atomized liquid.

[0110] (3) Exhaust heat utilization The material discharged from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is dust-removed by a dust collector and then enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 280 g / L. The concentrated metal salt precursor solution is filtered and then enters the bottom of the roasting furnace, where it is atomized by a sprayer and then sprayed upwards.

[0111] (4) Material processing The solid product passes through a cyclone separator and into a jet mill. After pulverization, the material enters a repulp tank for washing, and then undergoes processes such as rotary kiln drying, mixing, sieving, and iron removal. It is then collected at the packaging stage, and a sample of the roasted ternary oxide is taken and designated as Sample 3.

[0112] (5) Acid recovery The specific steps are the same as in Example 1.

[0113] Test Analysis: The sprayer was observed for any clogging issues, and the collected particles were used for SEM, XRD, and testing. The results for the ternary 523 oxide particles are shown in Figures 11 and 12.

[0114] Results analysis showed that the sprayer did not experience clogging. As can be seen from the SEM image, the obtained oxide particles had good crystallinity, a single-crystal octahedral structure, and a smooth particle surface. As can be seen from the XRD image, the main components of the particles were NiO, Ni6MnO8, and MnC. O2 The presence of O4 and its high peak intensity suggest that a ternary oxide precursor was produced by a thermal decomposition reaction.

[0115] Example 4 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0116] (1) Preparation of metal salt precursor solution NiCl2·6H2O with a constant mass and molar ratio Ni:CO:Mn = 0.5:0.2:0.3, C O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 120 g / L.

[0117] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -100 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The evaporation zone temperature is set to 100°C, the drying zone temperature to 250°C, the primary pyrolysis zone temperature to 650°C, and the secondary pyrolysis zone temperature to 550°C.

[0118] Deionized water is injected into the pyrolysis apparatus using a two-fluid nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 55 s for the material in the roasting furnace and a droplet size of 25 μm for atomized liquid.

[0119] (3) Exhaust heat utilization The material sent from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is then dust-removed by a dust collector and entered a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 200 g / L. After the concentrated metal salt precursor solution is filtered, it enters the bottom of the roasting furnace, is atomized by a sprayer, and then sprayed upwards.

[0120] (4) Material processing The solid product passes through a cyclone separator and into a jet mill. The crushed material is then washed in a repulp tank, and after passing through equipment such as rotary kiln drying, mixing, sieving, and iron removal, it is collected at the packaging stage. A sample of the roasted ternary oxide is taken and designated as Sample 4.

[0121] (5) Acid recovery The specific steps are the same as in Example 1.

[0122] Test Analysis: The sprayer was observed for any clogging issues, and the collected particles were subjected to SEM testing. The results for the ternary 523 oxide particles are shown in Figure 13.

[0123] Results Analysis: No clogging occurred in the sprayer. As can be seen from the SEM image, when the temperatures in the primary and secondary pyrolysis zones were relatively low, the atomized particles became hollow spheres with relatively good sphericity, but the primary particles were small and did not grow.

[0124] Example 5 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0125] (1) Preparation of metal salt precursor solution NiCl2·6H2O with a constant mass and molar ratio Ni:CO:Mn = 0.5:0.2:0.3, C O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 200 g / L.

[0126] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -300 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 200°C, the temperature of the drying zone to 500°C, the temperature of the primary pyrolysis zone to 950°C, and the temperature of the secondary pyrolysis zone to 800°C.

[0127] Deionized water is injected into the pyrolysis apparatus using a two-fluid nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 15 seconds for the material in the roasting furnace and a droplet size of 100 μm for atomized liquid.

[0128] (3) Exhaust heat utilization The material discharged from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is then dust-removed by a dust collector and then enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 320 g / L. After the concentrated metal salt precursor solution is filtered, it enters the bottom of the roasting furnace, is atomized by a sprayer, and then sprayed upwards.

[0129] (4) Material processing The solid product passes through a cyclone separator and enters a jet mill. The crushed material is then washed in a repulp tank, and after passing through equipment such as rotary kiln drying, mixing, sieving, and iron removal, it is collected at the packaging stage. A sample of the roasted ternary oxide is taken and designated as Sample 5.

[0130] (5) Acid recovery The specific steps are the same as in Example 1.

[0131] Test Analysis: The sprayer was observed for any clogging issues, and the collected particles were used for SEM testing. The results for the ternary 523 oxide particles are shown in Figure 14.

[0132] Analysis of results: No clogging occurred in the sprayer. As can be seen from the SEM image, when the temperature of the reaction zone 1 / zone 2 was relatively high, the atomized particles exploded at high temperatures and had relatively poor sphericity, but when the residence time was relatively short, the primary particles grew.

[0133] Example 6 This embodiment provides a method for producing a precursor of a lithium battery material, comprising the following steps.

[0134] (1) Preparation of metal salt precursor solution NiCl2·6H2O was weighed, hot pure water was added, and the mixture was stirred to prepare a nickel chloride solution with a concentration of 150 g / L.

[0135] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -200 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 130°C, the temperature of the drying zone to 350°C, the temperature of the primary pyrolysis zone to 670°C, and the temperature of the secondary pyrolysis zone to 630°C.

[0136] Deionized water is injected into the pyrolysis apparatus using a pressure nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a ternary metal solution. The control parameters during the process are a residence time of 40 s for the material in the roasting furnace and a droplet size of 50 μm for atomized liquid.

[0137] (3) Exhaust heat utilization The material discharged from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is then dust-removed by a dust collector and then enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 220 g / L. After the concentrated metal salt precursor solution is filtered, it enters the bottom of the roasting furnace, is atomized by a sprayer, and then sprayed upwards.

[0138] (4) Material processing The solid product passes through a cyclone separator and enters a jet mill. The crushed material is then washed in a repulp tank, and after passing through equipment such as rotary kiln drying, mixing, sieving, and iron removal, it is collected at the packaging stage. A sample of the roasted ternary oxide is taken and designated as Sample 6.

[0139] (5) Acid recovery The specific steps are the same as in Example 1.

[0140] Test analysis: The sprayer was observed for any clogging issues, and the collected particles were subjected to SEM and XRD testing. The results for the nickel oxide particles are shown in Figures 15 and 16.

[0141] Analysis of results: No clogging occurred in the sprayer. As can be seen from the XRD analysis results, the crystallinity was relatively good, the phase of the sample was relatively pure, and both the main peak and the second intensity peak were NiO phase. In relation to the detection results, the main content in the sample was 77.05%, which is in close agreement with the theoretical value of nickel.

[0142] Overall, the crystallinity of Examples 2-3 and 6 was relatively good. Examples 1-5 all applied to the nickel-cobalt-manganese 523 system. Example 1 used a two-fluid supply, resulting in a worse effect than Examples 2-3. Examples 4-5 controlled parameters such as temperature, resulting in a worse crystallinity effect than Examples 2-3.

[0143] Comparative Example 1 This comparative example employs a furnace top-feed system in which evaporation zones, drying zones, primary pyrolysis zones, and secondary pyrolysis zones are arranged sequentially from top to bottom, and provides a method for producing a precursor of lithium battery material, which includes the following steps.

[0144] (1) Preparation of metal salt precursor solution NiCl2·6H2O with a constant mass and molar ratio Ni:CO:Mn = 0.5:0.2:0.3, C O Cl2·6H2O and MnCl2·4H2O were accurately weighed, and hot pure water was added and stirred to prepare a solution with a metal (nickel cobalt manganese) concentration of 180 g / L.

[0145] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -200 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 180°C, the temperature of the drying zone to 400°C, the temperature of the primary pyrolysis zone to 750°C, and the temperature of the secondary pyrolysis zone to 700°C.

[0146] Deionized water is injected into the pyrolysis apparatus from the top of the furnace (with the nozzle facing downwards) using a pressure nozzle. After the temperature in each temperature zone within the furnace stabilizes, the process switches to a ternary metal solution. The control parameters during the process are a residence time of 20 seconds for the material in the roasting furnace and a droplet size of 50 μm for atomized liquid.

[0147] (3) Exhaust heat utilization The fine powder material sent from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid product are obtained. The exhaust gas is then dust-removed by a dust remover and enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 280 g / L. After the concentrated metal salt precursor solution is filtered, it enters the top of the roasting furnace, is atomized by a sprayer, and then sprayed downwards.

[0148] (4) Material treatment The solid product enters the jet mill through a cyclone separator. After the crushed material enters the repulper tank and is washed, it passes through equipment such as rotary kiln drying, mixing, screening, and iron removal, and is then collected at the packaging stage. The ternary oxide produced by roasting is sampled and described as Sample 7.

[0149] (5) Acid recovery The specific steps are the same as those in Example 1.

[0150] Test analysis: Observe whether there is a problem of clogging in the sprayer. Use the collected particles for SEM testing. The results of the obtained ternary 523 oxide particles are shown in Figure 17.

[0151] Result analysis: As shown in Figure 18, a clogging phenomenon occurred. As can be seen from the SEM diagram after crushing, in the case of the top-furnace feeding method, the residence time of the atomized particles in the furnace is short, so an octahedral structure has not been formed, the crystallization is relatively insufficient, and there is a partial over-sintering phenomenon.

[0152] Comparative Example 2 This comparative example adopts the top-furnace feeding method, and an evaporation zone, a drying zone, a primary pyrolysis zone, and a secondary pyrolysis zone are installed in sequence from top to bottom, and provides a method for manufacturing a precursor of a lithium battery material including the following steps.

[0153] (1) Preparation of metal salt precursor solution Weigh accurately a certain mass of NiCl2·6H2O, C O Cl2·6H2O and MnCl2·4H2O in a molar ratio of Ni:Co:Mn = 0.5:0.2:0.3, add hot pure water, stir, and prepare a solution with a metal (nickel cobalt manganese) concentration of 130 g / L.

[0154] (2) Spray pyrolysis reaction The exhaust fan is activated, and the PLC automatic control adjusts the negative pressure at the top of the furnace to -150 Pa. The burners in the evaporation zone, drying zone, and decomposition zone are activated sequentially, and the zone temperatures are controlled by setting temperature values ​​and automatically adjusting the amount of fuel gas. The temperature of the evaporation zone is set to 130°C, the temperature of the drying zone to 300°C, the temperature of the primary pyrolysis zone to 720°C, and the temperature of the secondary pyrolysis zone to 660°C.

[0155] Deionized water is injected into the pyrolysis apparatus using a two-fluid nozzle, and after the temperature in each temperature zone of the furnace stabilizes, it is switched to a metal solution. The control parameters during the process are a residence time of 25 seconds for the material in the roasting furnace and a droplet size of 25 μm for atomized liquid.

[0156] (3) Exhaust heat utilization The material discharged from the top of the furnace is separated into gas and solid by a cyclone separator, after which exhaust gas and solid products are obtained. The exhaust gas is then dust-removed by a dust collector and then enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The resulting concentrated metal salt precursor solution has a concentration of 220 g / L. After the concentrated metal salt precursor solution is filtered, it enters the top of the roasting furnace, is atomized by a sprayer, and then sprayed downwards.

[0157] (4) Material processing The solid product passes through a cyclone separator and into a jet mill. The crushed material is then washed in a repulp tank, and after passing through equipment such as rotary kiln drying, mixing, sieving, and iron removal, it is collected at the packaging stage. A sample of the roasted ternary oxide is taken and designated as Sample 8.

[0158] (5) Acid recovery The specific steps are the same as in Example 1.

[0159] Test Analysis: The sprayer was observed for any clogging issues, and the collected particles were subjected to SEM testing. The results for the ternary 523 oxide particles are shown in Figure 19.

[0160] Analysis of results: As shown in Figure 20, a clogging phenomenon occurred. As can be seen from the SEM image, the top two-fluid feed resulted in a short material residence time, insufficient reaction, escape of fine particles, incomplete growth, and smaller primary particles produced compared to the bottom feed.

[0161] In summary, the embodiments of this disclosure provide a roasting furnace and a system for producing oxide precursors for lithium batteries, employing a spray supply method at the bottom of the roasting furnace, in which the product reacts from bottom to top within the roasting furnace, and then uses the negative pressure at the top of the furnace to expel the product from the particle outlet at the top. Compared to conventional bottom discharge devices, it has the following advantages.

[0162] (1) Since the gas is discharged from the top of the furnace along with the product, compared to a bottom discharge system, this disclosure has a longer residence time at the pyrolysis temperature, which is advantageous for improving the crystallinity of the product. (2) Since the particles are sent out from the top of the furnace along with the gas, the flow of particles can be prevented from blocking the sprayer, and the stability of the device operation can be improved. (3) The residence time can be adjusted by adjusting the magnitude of the negative pressure. (4) Conventional supply and discharge methods increase the amount of heat, making it difficult to control the temperature in the lower zone of the roasting furnace. The apparatus provided in the embodiment of this disclosure is advantageous for precise temperature control and energy saving.

[0163] The above are merely specific embodiments of the present disclosure; however, the scope of protection of the present disclosure is not limited thereto, and any modifications or substitutions that a person skilled in the art can easily conceive within the scope of the art disclosed by the present invention fall within the scope of protection of the present disclosure. Accordingly, the scope of protection of the present disclosure should be the same as the scope of protection of the claims. [Industrial applicability]

[0164] This disclosure describes a method in which a spray is supplied at the bottom of a roasting furnace, causing the product to react from bottom to top within the furnace, and then the negative pressure at the top of the furnace is used to expel the product from the particle outlet at the top. Since the gas is expelled from the top of the furnace along with the product, this invention has a longer residence time at the pyrolysis temperature compared to bottom discharge devices, which is advantageous for improving the crystallinity of the product. The invention is easy to implement and has very good industrial applicability.

Claims

1. A sprayer is installed at the bottom of the roasting furnace to atomize the raw material into droplets and spray them upward, a heating zone is installed above the sprayer, and a particle outlet is installed above the heating zone. The roasting furnace is characterized in that an airflow generating assembly is further installed in the roasting furnace, and the airflow generating assembly generates an upward airflow within the roasting furnace, so that at least some of the droplets pass upward through the heating zone with the airflow and are discharged from the particle outlet.

2. The roasting furnace according to claim 1, characterized in that the airflow generating assembly includes a negative pressure assembly, and the negative pressure assembly includes a fan.

3. The roasting furnace according to claim 1 or 2, characterized in that the sprayer includes at least one of an airflow sprayer, a pressure sprayer, and an ultrasonic sprayer.

4. A heating component for temperature control is installed in the heating zone, and a temperature measurement assembly is installed in the roasting furnace. The roasting furnace according to any one of claims 1 to 3, wherein the heating component optionally includes at least one of a burner, an electromagnetic heating component, and a resistance heating component.

5. The roasting furnace according to claim 4, characterized in that the heating component is a burner, and the burners are arranged symmetrically along the cutting lines of the furnace body.

6. A discharge device is installed in the cavity at the bottom of the roasting furnace to discharge the accumulated material inside the furnace, a discharge port is installed in the bottom wall of the roasting furnace, the discharge port is connected to the inlet of the hopper, and the outlet of the hopper is connected to a discharge valve. The roasting furnace according to any one of claims 1 to 5, wherein the discharge device includes a rake tooth attached to the inner wall of the roasting furnace and a motor that drives the rake tooth to rotate, and the rake tooth extends from one end of the roasting furnace to the other end.

7. A system for producing an oxide precursor for a lithium battery, characterized by including a roasting furnace according to any one of claims 1 to 6.

8. A gas-solid separator is connected to the particle outlet of the roasting furnace, the gas outlet of the gas-solid separator is connected to the inlet of a dust removal device, and the gas outlet of the dust removal device is connected to the gas inlet of a pre-concentrator. The system for producing an oxide precursor for a lithium battery according to claim 7, characterized in that the liquid inlet of the preconcentrator is connected to a precursor liquid storage tank for mixing precursor raw materials, and the liquid outlet of the preconcentrator is connected to the sprayer.

9. The system for producing an oxide precursor for a lithium battery according to claim 8, characterized in that a primary absorption tower and a secondary absorption tower are connected in order to the gas outlet of the pre-concentrator, and the gas outlet of the primary absorption tower is connected to the secondary absorption tower.

10. The system for producing an oxide precursor for a lithium battery according to claim 9, further comprising an exhaust fan, a horizontal droplet separator, and an alkaline scrubbing tower installed in sequence, wherein the gas outlet of the secondary absorption tower is connected to the horizontal droplet separator via the exhaust fan, and the outlet of the horizontal droplet separator is connected to the alkaline scrubbing tower.

11. A method for producing a precursor for lithium battery material, characterized by atomizing a metal salt precursor solution with a sprayer at the bottom of a roasting furnace, and after the atomized material undergoes sequential evaporation, drying, and decomposition from bottom to top within the roasting furnace, the gas is discharged from the top of the furnace along with the generated oxide particles.

12. By adjusting the airflow rate, the residence time of the material in the roasting furnace is controlled. The residence time of the material in the roasting furnace is optionally 10 s to 1 min. By arbitrarily setting the furnace to create negative pressure at the top, an upward airflow can be generated within the roasting furnace using this negative pressure. The magnitude of the negative pressure can be arbitrarily adjusted to control the airflow velocity inside the roasting furnace. The manufacturing method according to claim 11, characterized in that the pressure at the top of the furnace is optionally controlled to be between -0.3 kPa and -0.1 kPa.

13. An evaporation zone, a drying zone, and a decomposition zone are arranged sequentially from bottom to top inside the roasting furnace, and the temperature gradually rises from the evaporation zone to the decomposition zone. Optionally, the temperature range from bottom to top of the roasting furnace is 100°C to 950°C. Optionally, the temperature of the evaporation zone is 100°C to 200°C, the temperature of the drying zone is 250°C to 500°C, and the temperature of the decomposition zone is 550°C to 950°C. Optionally, the decomposition zone includes a primary pyrolysis zone and a secondary pyrolysis zone located above the primary pyrolysis zone, wherein the temperature of the primary pyrolysis zone is 650 to 750°C and the temperature of the secondary pyrolysis zone is 600 to 700°C. The roasting furnace may optionally have a tower height of 5m to 20m and an inner diameter of 2m to 6m. The manufacturing method according to claim 11 or 12, characterized in that a burner is optionally used to control the temperature of a heating component, the number of burner sets is 3 to 5, and the burners in each set are arranged symmetrically along the cutting lines of the furnace body.

14. The material sent from the top of the furnace is separated into gas and solid, after which exhaust gas and solid products are obtained. The exhaust gas is then dust-removed by a dust removal device and enters a pre-concentrator where it undergoes heat exchange with the metal salt precursor solution. The concentrated metal salt precursor solution is then filtered and enters the bottom of the roasting furnace, where it is atomized by the sprayer and then sprayed upwards. Optionally, gas-solid separation is performed using a two-stage cyclone separator, the separated solid product is dechlorinated, crushed, and then recovered. Optionally, the temperature of the exhaust gas when it enters the dust removal device is 300°C to 450°C, and the temperature of the gas outlet of the pre-concentrator is 75°C to 90°C. Optionally, before the metal salt precursor solution enters the preconcentrator, filtration and iron removal may be performed. Optionally, the sprayer is selected from either a pressure sprayer or a two-fluid nozzle, and the size of the atomized droplets is controlled to be between 100 nm and 100 μm. The manufacturing method according to any one of claims 11 to 13, wherein the gas used in the two-fluid nozzle is optionally selected from compressed air and nitrogen gas, the gas pressure is 0.1 MPa to 1 MPa, and the gas temperature is 75°C to 120°C.

15. The total concentration of metal elements in the concentrated metal salt precursor solution is 200 g / L to 320 g / L, and the type of metal element in the metal salt precursor solution is one or more types. Optionally, the process for producing the metal salt precursor solution includes mixing and dissolving nickel salt, cobalt salt, and manganese salt to control the total concentration of nickel, cobalt, and manganese elements in the metal salt precursor solution to be between 120 g / L and 200 g / L. Optionally, each of the nickel salt, cobalt salt, and manganese salt is independently selected from perchlorates and chloride salts, The manufacturing method according to claim 14, characterized in that, optionally, all of the nickel salt, cobalt salt, and manganese salt are chloride salts.

16. The cooled exhaust gas sent from the aforementioned pre-concentrator enters the absorption tower where acidic gases are absorbed, and the exhaust gas discharged through the absorption tower is alkaline-washed before being discharged. Optionally, the exhaust gas discharged through the absorption tower passes through the exhaust fan and horizontal droplet separator in sequence before entering the alkaline scrubbing tower, where it comes into contact with the spray liquid from top to bottom in the opposite direction. Optionally, the process by which acidic gas is absorbed into an absorption tower involves first passing the exhaust gas through a primary absorption tower for primary absorption, then sending the gas from the primary absorption tower into a secondary absorption tower for secondary absorption, continuously replenishing the secondary absorption tower with water, and returning the acidic solution obtained by the secondary absorption to the primary absorption tower as a spray liquid. Hereinafter, both the primary and secondary absorption processes involve reverse flow contact between the spray liquid and filler within the tower, moving from top to bottom. The manufacturing method according to claim 14 or 15, wherein the concentration of the regenerated acid solution after primary absorption is optionally 170 g / L to 220 g / L, and the gas temperature at the outlet of the primary absorption tower is 60°C to 70°C.

17. A precursor for a lithium battery material, characterized by being obtained by the manufacturing method described in any one of claims 11 to 16.

18. A lithium battery cathode material characterized by containing a precursor of the lithium battery material described in claim 17.

19. A lithium battery characterized by comprising the lithium battery cathode material described in claim 18.

20. An electrical device characterized by including the lithium battery described in claim 19.

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