Method for preparing catalytic rare earth oxychloride by spray pyrolysis with high recovery of hydrochloric acid

Abstract

This invention discloses a method for the efficient recovery of hydrochloric acid through spray pyrolysis to prepare rare earth chloride for catalytic oxidation. The rare earth chloride production apparatus includes a rare earth chloride feeding unit, a rare earth chloride pyrolysis furnace, a separation unit, a negative pressure forming unit, and a hydrogen chloride absorption unit. The rare earth chloride pyrolysis furnace has a feeding port and a gas-solid mixture outlet at the top, a solid product inlet at the bottom, and a solid product outlet at the bottom. The separation unit separates the gas-solid mixture to obtain a gas containing hydrogen chloride and a rare earth chloride solid product, with the solid product discharged from the solid product outlet. The negative pressure forming unit is located between the separation unit and the hydrogen chloride absorption unit. The hydrogen chloride absorption unit absorbs hydrogen chloride from the gas. Using the rare earth chloride production apparatus and method of this invention can largely avoid rare earth chloride agglomeration, improve product purity, and also recover high-concentration hydrochloric acid solutions.

Description

Technical Field

[0001] This invention relates to a method for the efficient recovery of hydrochloric acid through spray pyrolysis to prepare rare earth chlorine oxides for catalytic use, specifically to a rare earth chlorine oxide production apparatus and a method for producing rare earth chlorine oxides using the apparatus. Background Technology

[0002] Rare earth chlorides (such as lanthanum oxychloride, LaOCl) are important rare earth compounds with wide applications in catalysis. Petroleum cracking is an important refining process that breaks down heavy petroleum molecules into lighter hydrocarbons at high temperatures to obtain higher-value products. Rare earth chlorides can act as catalysts in petroleum cracking, improving reactivity, selectivity, and stability, thereby increasing the efficiency and yield of the refining process.

[0003] Currently, methods for synthesizing rare earth chlorides include chemical synthesis, solid-phase reaction, and solution precipitation. In chemical synthesis, rare earth compounds are reacted with chlorides under specific conditions to prepare rare earth chlorides. This method is simple but requires high temperatures or other special conditions to promote the reaction. In solid-phase reaction, oxygen-containing rare earth salts and sodium chloride are mixed and ground or ball-milled at room temperature, then soluble byproducts are removed by washing with water, and finally dried to obtain rare earth chlorides. In solution precipitation, a solution of rare earth element salts is mixed with a chloride solution, and rare earth chlorides are precipitated by controlling the temperature and pH value.

[0004] CN103539190B discloses a method for preparing LaOCl nanomaterials with controllable morphology. Using lanthanum chloride and ammonia as raw materials, different surfactants are added, and a hydrothermal reaction is carried out first, followed by calcination to obtain LaOCl nanoparticles with different morphologies.

[0005] CN118045637A discloses a method for preparing a LaOCl-ZnO composite catalyst, which involves calcining lanthanum chloride in air to obtain LaOCl.

[0006] CN117185337A discloses a method for preparing rare earth chloride oxides, comprising the following steps: (1) stirring a mixture of rare earth chloride, carbon-containing material, and water, and adding ammonia dropwise to the mixture to control the pH value of the mixture at 6-8, thereby obtaining a carbon-containing material loaded with rare earth chloride; wherein the carbon-containing material is selected from graphite oxide and / or graphene oxide; in the mixture, the rare earth chloride is 20-40 parts by weight, the carbon-containing material is 2-10 parts by weight, and the water is 55-100 parts by weight; (2) calcining the carbon-containing material loaded with rare earth chloride and the rare earth chloride in a weight ratio of 1:(0.6-1.5) in an oxide crucible at 300-700°C for 0.5-10 h to obtain a calcined product; (3) washing and drying the calcined product to obtain rare earth chloride oxides. The rare earth chloride oxides obtained by this preparation method are disc-shaped particles. Summary of the Invention

[0007] One object of the present invention is to provide a rare earth chloride oxide production apparatus that can be used to produce rare earth chloride oxides and can substantially avoid the agglomeration of rare earth chloride oxide products. Furthermore, it can recover high-concentration hydrochloric acid solutions. Another object of the present invention is to provide a method for producing rare earth chloride oxides using the apparatus described above. In particular, it relates to a method for the efficient recovery of hydrochloric acid through spray pyrolysis to prepare catalytic rare earth chlorination oxides. The present invention achieves the above objects using the following technical solutions.

[0008] On one hand, the present invention provides a rare earth chloride oxide production apparatus, including a rare earth chloride feeding unit, a rare earth chloride pyrolysis furnace, a separation unit, a negative pressure forming unit, and a hydrogen chloride absorption unit.

[0009] The rare earth chloride pyrolysis furnace is provided with a feed port and a gas-solid mixture discharge port at the top, a solid product inlet at the bottom, and a solid product outlet at the bottom; the rare earth chloride pyrolysis furnace is configured to thermally decompose rare earth chlorides to generate a gas-solid mixture.

[0010] The rare earth chloride feeding unit is configured to supply a rare earth chloride aqueous solution into the rare earth chloride pyrolysis furnace through the feeding port, and to spray the rare earth chloride aqueous solution.

[0011] The separation unit is connected to the gas-solid mixture outlet and the solid product inlet, respectively. The separation unit is configured to separate the gas-solid mixture from the gas-solid mixture outlet to obtain a gas containing hydrogen chloride and a rare earth chloride oxide solid product. The rare earth chloride oxide solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and is discharged from the solid product outlet.

[0012] The negative pressure forming unit is disposed between the separation unit and the hydrogen chloride absorption unit, and is used to allow the gas-solid mixture to enter the separation unit from the rare earth chloride pyrolysis furnace, and to allow the hydrogen chloride-containing gas to enter the hydrogen chloride absorption unit.

[0013] The hydrogen chloride absorption unit is configured to absorb hydrogen chloride from the gas.

[0014] According to the rare earth chloride oxide production apparatus of the present invention, preferably, the rare earth chloride feeding unit includes a storage container, an air compressor, and a spraying device; wherein, the storage container is used to contain an aqueous solution of rare earth chloride; the air compressor is configured to provide compressed air to the storage container, thereby causing the compressed air to carry the aqueous solution of rare earth chloride in the storage container into the spraying device; the spraying device is connected to the storage container, and at least a portion of the spraying device is disposed in the rare earth chloride pyrolysis furnace for spraying the aqueous solution of rare earth chloride into a spray within the rare earth chloride pyrolysis furnace.

[0015] The rare earth chlorine oxide production apparatus according to the present invention is preferably:

[0016] The separation unit includes a cyclone separator; the top of the cyclone separator is connected to the gas-solid mixture outlet via a pipe for collecting the gas-solid mixture; the bottom of the cyclone separator is connected to the solid product inlet via a downward-sloping chute or pipe, the rare earth chloride solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and exits from the solid product outlet; the hydrogen chloride-containing gas enters the hydrogen chloride absorption unit via a negative pressure forming unit.

[0017] The negative pressure forming unit includes an exhaust fan; the exhaust fan is configured to form a negative pressure, so that the gas-solid mixture enters the cyclone separator from the rare earth chloride pyrolysis furnace, and the separated hydrogen chloride-containing gas enters the hydrogen chloride absorption unit.

[0018] According to the rare earth chlorine oxide production apparatus of the present invention, preferably, the hydrogen chloride absorption unit includes a condenser and a hydrogen chloride absorption device; the condenser is disposed between the negative pressure forming unit and the hydrogen chloride absorption device, and is used to condense the hydrogen chloride-containing gas into condensate gas.

[0019] According to the rare earth chlorine oxide production apparatus of the present invention, preferably, the hydrogen chloride absorption device includes an absorption device body, a gas inlet pipe and an absorption liquid spraying unit;

[0020] The absorption device body has a cavity, and a portion of the absorption liquid spraying unit extends into the cavity through the top of the absorption device body; an observation window and a liquid outlet are provided on the side wall of the absorption device body; the liquid outlet is located near the bottom of the absorption device body.

[0021] The gas inlet pipe has an inlet end and an outlet end; the inlet end is located below the outlet end; the inlet end is connected to the condenser through a pipe for receiving condensed gas; the outlet end is configured to introduce the condensed gas into the absorption device body.

[0022] The absorbent spraying unit is configured to spray absorbent into the body of the absorption device to absorb hydrogen chloride in the condensate gas.

[0023] According to the rare earth chlorine oxide production apparatus of the present invention, preferably, the gas outlet is provided in multiple ways, and the gas outlet is connected to the gas inlet provided on the side wall of the absorption device body.

[0024] According to the rare earth chlorine oxide production apparatus of the present invention, preferably, the gas-solid mixture outlet and the solid product inlet are each provided in multiple ways; the separation unit, the negative pressure forming unit and the hydrogen chloride absorption unit are each provided in multiple ways.

[0025] On the other hand, the present invention also provides a method for producing rare earth chlorine oxides using the apparatus described above, comprising the following steps:

[0026] 1) The rare earth chloride aqueous solution is added into the rare earth chloride pyrolysis furnace through the rare earth chloride feeding unit and forms a spray; wherein, the temperature inside the rare earth chloride pyrolysis furnace is 500-800℃;

[0027] 2) Rare earth chlorides decompose thermally in the presence of water and air, generating a gas-solid mixture containing rare earth chloride oxides and hydrogen chloride.

[0028] 3) A negative pressure is formed by the negative pressure forming unit, so that the gas-solid mixture enters the separation unit, and the separation unit is used to separate the rare earth chlorine oxide solid product and the gas containing hydrogen chloride.

[0029] 4) The solid products of rare earth chloride oxides enter the rare earth chloride pyrolysis furnace through the solid product inlet and are discharged from the solid product outlet.

[0030] 5) The gas containing hydrogen chloride enters the condenser and is condensed into condensate gas. The absorbent spray unit sprays absorbent liquid into the body of the absorption device, thereby absorbing the hydrogen chloride in the condensate gas to form a hydrochloric acid solution; wherein the concentration of the hydrochloric acid solution is 14.9 wt% or more.

[0031] According to the method of the present invention, preferably, the concentration of rare earth chloride in the rare earth chloride aqueous solution is 30-40 wt%.

[0032] According to the method of the present invention, preferably, the gas-solid mixture enters the separation unit at a velocity of 5 to 15 m / s.

[0033] This invention can reduce the slagging and agglomeration of rare earth chloride solid products, thereby forming powder; it also reduces the generation of byproduct hydroxyl chloride, which is beneficial to improving the purity and yield of the obtained product. According to a preferred embodiment of this invention, this invention can recover high-concentration hydrochloric acid solutions. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the rare earth chlorine oxide production apparatus of the present invention.

[0035] Figure 2 This is a schematic diagram of the structure of a hydrogen chloride absorption device according to the present invention.

[0036] Figure 3 This is a SEM image of lanthanum oxychloride obtained in Example 2.

[0037] Figure 4 This is a SEM image of lanthanum oxychloride obtained in Example 3.

[0038] Figure 5 The energy spectrum of lanthanum oxychloride obtained in Example 4 is shown.

[0039] Figure 6 This is a SEM image of lanthanum oxychloride obtained in Example 5.

[0040] Figure 7 This is a SEM image of lanthanum oxychloride obtained in Example 6.

[0041] Figure 8 This is a SEM image of lanthanum oxychloride obtained in Example 7.

[0042] Figure 9 The energy spectrum of lanthanum oxychloride obtained in Example 7 is shown.

[0043] Figure 10 This is a SEM image of lanthanum oxychloride obtained in Example 8.

[0044] Figure 11 This is a SEM image of lanthanum oxychloride obtained in Example 9.

[0045] Figure 12 This is a SEM image of lanthanum oxychloride obtained in Example 10.

[0046] Figure 13 The energy spectrum of lanthanum oxychloride obtained in Example 10 is shown.

[0047] Figure 14 This is a schematic diagram of the structure of the venturi tube used in this invention.

[0048] The annotations in the attached figures are explained as follows:

[0049] 1-Rare earth chloride feeding unit, 11-Liquid storage container, 12-Air compressor, 13-Spraying equipment; 2-Rare earth chloride pyrolysis furnace, 21-Furnace body, 22-Heating furnace chamber; 3-Separation unit; 4-Negative pressure forming unit; 5-Hydrogen chloride absorption unit, 51-Condenser, 53-Venturi tube, 531-First connecting pipe, 532-Second connecting pipe; 52-Hydrogen chloride absorption equipment, 521-Absorption equipment body, 522-Gas inlet pipe, A-Inlet end, B1-First outlet end, B2-Second outlet end, 5231-Liquid inlet pipe, 5232-Ultra-fine atomizing equipment, 524-Observation window, 525-Liquid outlet; 6-Rare earth chloride oxide collector. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0051] In this invention, rare earth chlorine oxides and rare earth chlorine oxides have the same meaning.

[0052] Rare Earth Chloride Oxide Production Equipment

[0053] When producing rare earth chlorides using existing production equipment, product slagging and agglomeration are prone to occur, resulting in impurities such as hydroxyl rare earth chlorides in the product. This leads to low purity of the rare earth chlorides and low recovery of hydrochloric acid solution, only around 10 wt%, which cannot be recycled in the rare earth extraction and separation production line. Therefore, this invention provides a rare earth chlorides production apparatus that can avoid agglomeration of rare earth chlorides and improve the purity of the rare earth chlorides. The obtained rare earth chlorides are very suitable as a catalyst material. In addition, the concentration of the recovered hydrochloric acid solution reaches more than 14.9 wt%. More preferably, this invention can obtain lanthanum chloride for catalytic use and can efficiently recover hydrochloric acid.

[0054] The rare earth chloride oxide production apparatus of the present invention includes a rare earth chloride feeding unit, a rare earth chloride pyrolysis furnace, a separation unit, a negative pressure forming unit, and a hydrogen chloride absorption unit. Optionally, it also includes a rare earth chloride oxide collector. A detailed description follows.

[0055] Rare earth chloride pyrolysis furnace

[0056] The rare earth chloride pyrolysis furnace of the present invention is configured to thermally decompose rare earth chlorides to generate a gas-solid mixture. The gas-solid mixture contains rare earth chloride oxide solids and hydrogen chloride gas. A feed port is provided at the top of the rare earth chloride pyrolysis furnace for adding an aqueous solution of rare earth chlorides. A gas-solid mixture discharge port is also provided at the top of the furnace for discharging the pyrolysis products (i.e., the gas-solid mixture). The feed port can be located in the middle of the top, and the gas-solid mixture discharge ports are located on either side of the feed port, their horizontal height slightly lower than the feed port. A solid product inlet is provided at the bottom of the rare earth chloride pyrolysis furnace for introducing the separated rare earth chloride oxide solid product (preferably powder) into the furnace. A solid product outlet is provided at the bottom of the furnace for discharging the rare earth chloride oxide solid product. This is advantageous for producing high-purity, high-yield micron-sized rare earth chloride oxides and for recovering hydrochloric acid solutions. The obtained rare earth chlorine oxide products mainly exhibit a hollow microbubble structure, which is more suitable for use as a catalytic material.

[0057] In some specific embodiments, the rare earth chloride pyrolysis furnace includes a furnace body and a heating furnace chamber. The furnace body has a cylindrical structure. The heating furnace chamber consists of an upper end, a middle section, and a lower end, connected sequentially. The furnace body surrounds the middle section (i.e., surrounds most of the heating furnace chamber). The upper and lower ends of the heating furnace chamber are not surrounded by the furnace body. The upper end has a frustum-shaped structure. The cross-section of the upper end is trapezoidal (the length of the upper base of the trapezoid is less than the length of the lower base). The lower end has an inverted frustum-shaped structure. The cross-section of the lower end is an inverted trapezoid (the length of the upper base of the trapezoid is greater than the length of the lower base).

[0058] The feed port is used to add an aqueous solution of rare earth chlorides into the rare earth chloride pyrolysis furnace. In some specific embodiments, the feed port is located at the middle of the top surface at the upper end.

[0059] The gas-solid mixture outlet is used to supply the gas-solid mixture obtained from the thermal decomposition reaction into the separation unit. Multiple gas-solid mixture outlets can be provided, for example, two. The gas-solid mixture outlets are evenly distributed. In some specific embodiments, two gas-solid mixture outlets are symmetrically arranged on the upper inclined surface.

[0060] The solid product inlet is used to allow the separated rare earth chloride oxide solid products to enter the rare earth chloride pyrolysis furnace. Multiple solid product inlets can be provided, for example, two. The solid product inlets are evenly distributed. In some specific embodiments, two solid product inlets are symmetrically arranged on both sides of the lower part of the rare earth chloride pyrolysis furnace. Preferably, the solid product inlets are located on the lower side wall of the middle part of the heating furnace chamber. The solid product inlets are located above the solid product outlets. According to one embodiment of the invention, the number of solid product inlets is the same as the number of gas-solid mixture outlets.

[0061] The solid product outlet is used to discharge the separated rare earth chloride oxide solid products from the rare earth chloride pyrolysis furnace. In some specific embodiments, the solid product outlet is located on the bottom surface of the lower end of the heating furnace chamber.

[0062] Rare earth chloride feeding unit, negative pressure forming unit and hydrogen chloride absorption unit

[0063] The rare earth chloride feeding unit of the present invention is configured to supply a rare earth chloride aqueous solution into the rare earth chloride pyrolysis furnace through the feeding port, and to spray the rare earth chloride aqueous solution. The resulting rare earth chloride oxide solid product is less prone to slagging and agglomeration, and the obtained product has high purity.

[0064] In some embodiments, the rare earth chloride feeding unit includes a storage container, an air compressor, and a spraying device. The storage container holds an aqueous solution of rare earth chloride. The air compressor is connected to the storage container via a pipe. The air compressor supplies compressed air to the storage container, thereby carrying the aqueous solution of rare earth chloride into the spraying device. The spraying device is connected to the storage container via a pipe, and at least a portion of the spraying device (e.g., nozzles) is positioned within the rare earth chloride pyrolysis furnace through a feed port for spraying the aqueous solution of rare earth chloride within the furnace.

[0065] According to one embodiment of the present invention, the spraying device can be a spray gun, which has a nozzle. The present invention can adjust the depth and direction of the spray gun's insertion into the rare earth chloride pyrolysis furnace so that the nozzle is located at the middle position of the top of the rare earth chloride pyrolysis furnace (i.e., the middle position of the upper end of the heating furnace). This is more conducive to preventing the agglomeration and crystallization of solid rare earth chloride oxide products. There are no particular limitations on the nozzle; preferably, the present invention can use the nozzle device disclosed in CN113198633A.

[0066] The separation unit is connected to both the gas-solid mixture outlet and the solid product inlet. The separation unit is configured to separate the gas-solid mixture exiting the outlet to obtain a gas containing hydrogen chloride and a rare earth chloride oxide solid product. The rare earth chloride oxide solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and then exits through the solid product outlet. The gas containing hydrogen chloride passes through a negative pressure forming unit and enters the hydrogen chloride absorption unit, where the hydrogen chloride is absorbed.

[0067] In some embodiments, the separation unit includes a cyclone separator. The top of the cyclone separator is connected to the outlet of the gas-solid mixture via a pipe to collect the gas-solid mixture; the bottom of the cyclone separator is connected to the solid product inlet via a downward-sloping chute or pipe to guide the rare earth chloride solid product into the rare earth chloride pyrolysis furnace, and then discharge it from the solid product outlet.

[0068] A negative pressure forming unit is located between the separation unit and the hydrogen chloride absorption unit to create a negative pressure, thereby allowing the gas-solid mixture to enter the separation unit from the rare earth chloride pyrolysis furnace.

[0069] In some specific implementations, the negative pressure forming unit includes an exhaust fan; the exhaust fan is used to create negative pressure, thereby allowing the gas-solid mixture to enter the cyclone separator from the rare earth chloride pyrolysis furnace.

[0070] The hydrogen chloride absorption unit is configured to absorb hydrogen chloride in the gas.

[0071] In some embodiments, the hydrogen chloride absorption unit includes a condenser and a hydrogen chloride absorption device; the condenser is positioned between the negative pressure forming unit and the hydrogen chloride absorption device to condense the hydrogen chloride-containing gas into a condensate. This facilitates better recovery of hydrogen chloride from the gas and reduces water consumption (water is used as the absorbent). The structure of the condenser is not particularly limited and commonly used types can be used. In some preferred embodiments, the hydrogen chloride absorption unit includes a condenser, a Venturi tube, and a hydrogen chloride absorption device. The Venturi tube is positioned between the condenser and the hydrogen chloride absorption device, and is close to the hydrogen chloride absorption device. The Venturi tube includes a constriction section, a throat, and a diffuser section connected in sequence. The fluid flows from the constriction section to the diffuser section. Due to its unique structural design, the Venturi tube guides the fluid to accelerate as it flows through the constriction section, resulting in a pressure reduction and the formation of a negative pressure environment. This structure enhances the concentration of waste acid liquid, effectively increasing the waste acid concentration and creating more favorable conditions for subsequent waste acid recovery and reuse, thus improving waste acid treatment efficiency.

[0072] The venturi tube is connected to a pressure indicator via a first connecting pipe and a second connecting pipe.

[0073] In some embodiments, the hydrogen chloride absorption device includes an absorption device body, a gas inlet pipe, and an absorbent spraying unit; preferably, it also includes an exhaust pipe.

[0074] The absorption device body has a cavity, which can be formed by a series of interconnected small cylindrical structures, a frustum-shaped structure, and a large cylindrical structure (with a bottom surface). The large cylindrical structure is the main body, and its diameter is larger than that of the small cylindrical structures. A portion of the absorbent spray unit extends into the cavity through the top of the absorption device body. In some specific embodiments, a portion of the absorbent spray unit extends into the interior of the frustum-shaped structure through the top surface of the small cylindrical structures. The absorbent spray unit is configured to spray absorbent into the absorption device body, thereby absorbing hydrogen chloride in the condensed gas.

[0075] The absorbent spray unit includes a connected inlet pipe and an ultrafine atomizing device. The ultrafine atomizing device sprays the absorbent into the absorbent body in the form of an ultrafine spray, facilitating the absorption of hydrogen chloride from the gas. The ultrafine atomizing device can be conventional equipment in the art. The gas inlet pipe has an inlet end and an outlet end. There can be one or more inlet ends; there can be multiple outlet ends. The inlet end is located below the outlet end. In some embodiments, the inlet end is connected to a condenser via a pipe for receiving condensed gas. In other embodiments, the inlet end is connected in sequence to a venturi tube and a condenser via a pipe for receiving condensed gas. The outlet end is used to introduce the condensed gas into the absorbent body. In some specific embodiments, the outlet end is connected to a gas inlet provided on the side wall of the absorbent body.

[0076] The absorption device features a large cylindrical structure with observation windows, a liquid outlet, and a gas inlet on its side wall. Multiple observation windows are provided, such as two or more, preferably three or more. All observation windows are located on the side wall of the large cylindrical structure. One observation window is located near the gas outlet and is used to observe the spray absorption process. Another observation window is located near the liquid outlet and is used to observe the liquid level near the outlet. Through these observation windows, operators can monitor the operating status of the hydrogen chloride absorption device in real time, promptly identify and address any potential problems, thereby ensuring smooth system operation and successful collection of hydrochloric acid solution. This design not only improves the system's operability but also enhances the safety and controllability of the entire process, while guaranteeing the hydrochloric acid solution collection rate. The liquid outlet is used to discharge the formed hydrochloric acid solution. The liquid outlet is located near the bottom of the absorption device. The liquid outlet can be located near the gas inlet end of the gas inlet pipe. The gas inlet is connected to the gas outlet end.

[0077] Hydrogen chloride in the condensate is absorbed by the absorbent to form hydrochloric acid solution and exhaust gas. The exhaust pipe is connected to the exhaust gas outlet of the absorption unit. In some specific embodiments, the exhaust gas outlet is located at the top of a small cylindrical structure. The resulting exhaust gas is discharged outside the absorption unit through the exhaust pipe.

[0078] In this invention, multiple separation units, negative pressure forming units, and hydrogen chloride absorption units are configured. The number of separation units, negative pressure forming units, and hydrogen chloride absorption units is the same as the number of outlets for the gas-solid mixture.

[0079] Rare earth chloride oxide collector

[0080] A rare earth chlorine oxide collector is used to collect rare earth chlorine oxide solid products discharged from a solid product outlet. The collector has a containment space into which the solid product outlet can extend. The shape of the collector is not particularly limited; for example, it can be a container with an opening at the top.

[0081] <Methods for producing rare earth chlorine oxides>

[0082] In this invention, the rare earth element in the rare earth chloride oxide can be selected from at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. Preferably, the rare earth element in the rare earth chloride oxide is selected from at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, and terbium. More preferably, the rare earth chloride oxide is lanthanum chloride oxide.

[0083] This invention also provides a method for producing rare earth chlorine oxides using the rare earth chlorine oxide production apparatus described above, comprising the following steps: 1) a feeding step; 2) a thermal decomposition step; 3) a separation step; 4) a collection step; and 5) a gas absorption step. Steps 4) and 5) are not sequential and can be performed simultaneously. Optionally, a batching step is also included. A detailed description follows.

[0084] Ingredient preparation steps

[0085] Rare earth chlorides are dissolved in water to obtain an aqueous solution of rare earth chlorides. In some embodiments, rare earth chlorides are dispersed in water, stirred, and ultrasonically dispersed to obtain an aqueous solution of rare earth chlorides. The concentration of the aqueous solution of rare earth chlorides can be 30-40 wt%, preferably 32-40 wt%, and more preferably 34-37 wt%. In some specific embodiments, lanthanum chloride is dispersed in water, stirred, and ultrasonically dispersed to obtain an aqueous solution of lanthanum chloride. The concentration of the aqueous solution of lanthanum chloride can be 30-40 wt%, preferably 32-40 wt%, and more preferably 34-37 wt%.

[0086] Adding steps

[0087] A rare earth chloride solution is added to the rare earth chloride pyrolysis furnace via a rare earth chloride feeding unit, forming a spray. Specifically, an aqueous rare earth chloride solution is added to a storage container for later use. Once the rare earth chloride pyrolysis furnace reaches 500–800°C, an air compressor is activated. Compressed air is used as a carrier to carry the aqueous rare earth chloride solution from the storage container through a pipeline into the spraying device. The spraying device then sprays the aqueous rare earth chloride solution into the heating chamber of the rare earth chloride pyrolysis furnace in the form of an ultrafine spray. This invention reveals that the preparation of rare earth chlorides from a single aqueous rare earth chloride solution is prone to slagging. However, by employing the rare earth chloride production apparatus of this invention, the distribution and orientation of gas and particles can be controlled, effectively avoiding particle agglomeration and slagging, and reducing impurities such as hydroxyl rare earth chlorides in the product. Therefore, the rare earth chlorides of this invention are highly suitable as a catalyst material.

[0088] In this invention, the rare earth chloride pyrolysis furnace is heated to 500–800°C, for example, to 550°C, 600°C, 650°C, 700°C, 750°C, or 800°C. This temperature is the temperature during the thermal decomposition reaction of rare earth chlorides.

[0089] Thermal decomposition steps

[0090] Rare earth chlorides undergo thermal decomposition in a rare earth chloride pyrolysis furnace, generating a gas-solid mixture containing rare earth chloride oxides and hydrogen chloride. Specifically, the rare earth chlorides are thermally decomposed in the presence of water vapor and air in the rare earth chloride pyrolysis furnace, generating a gas-solid mixture containing rare earth chloride oxides and hydrogen chloride. Furthermore, the gas-solid mixture may also contain air.

[0091] In some specific implementations, lanthanum chloride is thermally decomposed in a rare earth chloride pyrolysis furnace in the presence of steam and air to generate a gas-solid mixture containing lanthanum oxychloride and hydrogen chloride.

[0092] Separation steps

[0093] In this invention, a negative pressure is formed in the system by a negative pressure forming unit, so that the gas-solid mixture enters the separation unit, thereby using the separation unit to separate rare earth chlorine oxide solid products and hydrogen chloride-containing gas.

[0094] In some specific implementations, a negative pressure is created within the rare earth chlorine oxide production unit by drawing air from the exhaust fan of the negative pressure forming unit. This causes the gas-solid mixture, carried by hot air, to enter the separation unit at a velocity of 5–15 m / s for gas-solid separation. Specifically, this separation can be performed using a cyclone separator to obtain solid rare earth chlorine oxide products and a gas containing hydrogen chloride. Preferably, the gas-solid mixture enters the separation unit at a velocity of 8–12 m / s. More preferably, the gas-solid mixture enters the separation unit at a velocity of 10–11 m / s.

[0095] Solid product collection and hydrogen chloride absorption steps

[0096] In this invention, the separated rare earth chloride oxide solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and is then discharged from the solid product outlet.

[0097] The separated hydrogen chloride-containing gas enters the hydrogen chloride absorption unit through a negative pressure forming unit, forming a hydrochloric acid solution. In the hydrogen chloride absorption unit, hydrogen chloride is absorbed by an aqueous solution (pure water or dilute hydrochloric acid solution) to form a hydrochloric acid solution. The concentration of the hydrochloric acid solution is 14.9 wt% or more, preferably 15.5 wt% or more, and more preferably 19.5 wt% or more. The concentration of the hydrochloric acid solution can be 40 wt% or less, preferably 38 wt% or less, and more preferably 37 wt% or less.

[0098] In some embodiments, the hydrogen chloride absorption unit may include a condenser and a hydrogen chloride absorption device. The separated hydrogen chloride-containing gas is rapidly condensed in the condenser to form condensate gas, which then enters the hydrogen chloride absorption device. The process of absorbing hydrogen chloride-containing gas using the hydrogen chloride absorption device is as follows: The condensed hydrogen chloride-containing gas (i.e., condensate gas) first enters the gas inlet pipe through the inlet end and is then transported to the absorption device body through the outlet end. Simultaneously, an aqueous solution (pure water or dilute hydrochloric acid solution) is introduced into the absorption device body through an absorbent spray unit, and an ultra-fine atomizer is used to evenly distribute the aqueous solution within the absorption device body. This not only increases the effective contact area between water and hydrogen chloride molecules but also reduces the amount of water used for spraying, efficiently capturing hydrogen chloride molecules. During contact with water, the hydrogen chloride molecules are converted into hydrochloric acid solution. Subsequently, the formed hydrochloric acid solution flows out from the outlet under gravity and is then collected. The collected hydrochloric acid solution has a concentration of 14.9 wt% to 40 wt% and is safely stored to meet different industrial needs.

[0099] In some preferred embodiments, the hydrogen chloride absorption unit further includes a Venturi tube. The separated hydrogen chloride-containing gas is rapidly condensed in a condenser to form condensate gas, which then enters the hydrogen chloride absorption equipment through the Venturi tube. This enhances the concentration of waste acid liquid, effectively increases the concentration of waste acid, and creates more favorable conditions for subsequent waste acid recovery and reuse, thereby improving waste acid treatment efficiency.

[0100] The testing method of this invention is described below:

[0101] SEM analysis: Analysis was performed using a JEOL-JSM-6510 tungsten filament scanning electron microscope manufactured by Nippon Electronics.

[0102] Energy dispersive spectroscopy analysis: The analysis was performed using an EDAX 20 energy dispersive spectrometer.

[0103] The contents of lanthanum, oxygen and chloride ions were all determined using an EDAX 20 energy dispersive spectrometer.

[0104] Unless otherwise stated, all hydrochloric acid concentrations in this invention are mass percentages, in wt%.

[0105] Example 1

[0106] Figure 1 This is a schematic diagram of a rare earth chlorine oxide production device according to the present invention. Figure 2 This is a schematic diagram of the hydrogen chloride absorption device of the present invention.

[0107] like Figure 1 As shown, the rare earth chloride oxide production apparatus of this embodiment includes a rare earth chloride feeding unit 1, a rare earth chloride pyrolysis furnace 2, a separation unit 3, a negative pressure forming unit 4, a hydrogen chloride absorption unit 5, and a rare earth chloride oxide collector 6.

[0108] The rare earth chloride pyrolysis furnace 2 has a feed port and a gas-solid mixture discharge port at the top, a solid product inlet at the bottom, and a solid product outlet at the bottom. Specifically, the rare earth chloride pyrolysis furnace 2 includes a furnace body 21 and a heating furnace chamber 22. The furnace body 21 has a cylindrical structure. The heating furnace chamber 22 consists of an upper end, a middle part, and a lower end connected sequentially from top to bottom. The furnace body 21 surrounds the middle part. The upper and lower ends of the heating furnace chamber 22 are not surrounded by the furnace body 21. The upper end has a frustum-shaped structure. The cross-section of the upper end is trapezoidal (the length of the upper base of the trapezoid is less than the length of the lower base). The lower end has an inverted frustum-shaped structure. The cross-section of the lower end is an inverted trapezoid (the length of the upper base of the trapezoid is greater than the length of the lower base). The middle part has a cylindrical structure. The feed port is located in the middle of the top surface of the upper end. There are multiple gas-solid mixture discharge ports (for example, two), symmetrically arranged on the inclined surface of the upper end. There are multiple solid product inlets (e.g., two), symmetrically arranged on both sides of the lower part of the middle section. The solid product outlet is located on the bottom surface of the lower end of the heating furnace 22.

[0109] Rare earth chlorides are thermally decomposed in rare earth chloride pyrolysis furnace 2 in the presence of water and air to generate a gas-solid mixture containing rare earth chloride oxides and hydrogen chloride.

[0110] The rare earth chloride feeding unit 1 supplies a rare earth chloride aqueous solution to the rare earth chloride pyrolysis furnace 2 through a feeding port, and sprays the rare earth chloride aqueous solution. Specifically, the rare earth chloride feeding unit 1 includes a storage container 11, an air compressor 12, and a spraying device 13. The storage container 11 is used to contain the rare earth chloride aqueous solution. The air compressor 12 and the storage container 11 are connected by a pipeline. The air compressor 12 supplies compressed air to the storage container 11, thereby causing the compressed air to carry the rare earth chloride aqueous solution into the spraying device 13. The spraying device 13 is connected to the storage container 11 by a pipeline. At least a portion of the spraying device 13 (e.g., a nozzle) extends into the interior of the rare earth chloride pyrolysis furnace 2, thereby forming a spray of the rare earth chloride aqueous solution within the rare earth chloride pyrolysis furnace 2, and dispersing it uniformly.

[0111] Separation unit 3 is connected to both the gas-solid mixture outlet and the solid product inlet. Separation unit 3 separates the gas-solid mixture exiting the gas-solid mixture outlet to obtain a gas containing hydrogen chloride and a solid product containing lanthanum oxychloride. The lanthanum oxychloride solid product enters the solid product inlet through a pipeline and then exits through the solid product outlet. The lanthanum oxychloride solid product is collected uniformly by the rare earth chlorine oxide collector 6. In this embodiment, the number of separation units 3 can be the same as the number of gas-solid mixture outlets.

[0112] Specifically, separation unit 3 includes a cyclone separator. The top of the cyclone separator is connected to the outlet of the gas-solid mixture via a pipe, thereby collecting the gas-solid mixture; the bottom of the cyclone separator is connected to the solid product inlet via a downward-sloping chute, thereby guiding the lanthanum oxychloride solid product into the rare earth chloride pyrolysis furnace 2 through the solid product inlet, and then discharging it from the solid product outlet. The hydrogen chloride-containing gas enters the hydrogen chloride absorption unit 5 via the negative pressure forming unit 4.

[0113] A negative pressure forming unit 4 is disposed between the separation unit 3 and the hydrogen chloride absorption unit 5 to create a negative pressure in the system, thereby allowing the gas-solid mixture to enter the separation unit 3 from the rare earth chloride pyrolysis furnace 2, and allowing the hydrogen chloride-containing gas to enter the hydrogen chloride absorption unit 5. The negative pressure forming unit 4 includes an exhaust fan. Specifically, the exhaust fan is connected via pipes to both the cyclone separator and the condenser 51 of the hydrogen chloride absorption unit 5. Under the action of the exhaust fan, the gas-solid mixture enters the cyclone separator from the rare earth chloride pyrolysis furnace 2, and the hydrogen chloride-containing gas enters the hydrogen chloride absorption unit 5. In this embodiment, the number of negative pressure forming units 4 is the same as the number of separation units 3.

[0114] In the hydrogen chloride absorption unit 5, hydrogen chloride in the gas is absorbed. The hydrogen chloride absorption unit 5 includes a condenser 51 and a hydrogen chloride absorption device 52, and also includes a venturi tube 53. The venturi tube 53 is disposed between the condenser 51 and the hydrogen chloride absorption device 52, and is close to the hydrogen chloride absorption device 52. The condenser 51 is disposed between the negative pressure forming unit 4 and the venturi tube 53. Specifically, the condenser 51 is disposed between the exhaust fan and the venturi tube 53, and the condenser 51 condenses the hydrogen chloride-containing gas into condensate. In this embodiment, the number of hydrogen chloride absorption units 5 is the same as the number of negative pressure forming units 4.

[0115] like Figure 14 As shown, the Venturi tube 53 includes a constriction section, a throat section, and a diffusion section connected in sequence. Figure 14 In the diagram, the arrows indicate the direction of fluid flow. The fluid flows from the contraction section to the diffusion section. The venturi tube 53 is connected to a pressure indicator via a first connecting pipe 531 and a second connecting pipe 532. The first connecting pipe 531 is located on the contraction section and near the inlet of the venturi tube 53, while the second connecting pipe 532 is connected to the throat of the venturi tube 53.

[0116] like Figure 2As shown, the hydrogen chloride absorption device 52 includes an absorption device body 521, a gas inlet pipe 522, an absorbent spray unit, and an exhaust pipe (not shown). The absorption device body 521 has a cavity, which can be formed by a small cylindrical structure, a frustum-shaped structure, and a large cylindrical structure (with a bottom surface) connected sequentially from top to bottom. A portion of the absorbent spray unit extends into the interior of the frustum-shaped structure through the top surface of the small cylindrical structure. An observation window 524 and a liquid outlet 525 are provided on the side wall of the large cylindrical structure of the absorption device body 521. There can be multiple observation windows 524. The liquid outlet 525 is located near the bottom of the large cylindrical structure of the absorption device body 521. The gas inlet pipe 522 has an inlet end A and at least one outlet end. The inlet end A is connected sequentially to a venturi tube 53 and a condenser 51 through a pipe for receiving condensed gas. The outlet is connected to a gas inlet (not shown) on the side wall of the large cylindrical structure of the absorption device body 521, thereby allowing condensed gas to enter the absorption device body 521. There can be multiple outlets, for example, two: a first outlet B1 and a second outlet B2. The inlet A is located below the outlet. The liquid outlet 525 can be located near the inlet A.

[0117] The absorbent spray unit includes a connected inlet pipe 5231 and an ultrafine atomizing device 5232. In this embodiment, a portion of the inlet pipe 5231 extends through the top surface of a small cylindrical structure into the interior of a frustum-shaped structure, that is, it is inserted into the absorbent device body 521 from the top end. The ultrafine atomizing device 5232 is located inside the frustum-shaped structure of the absorbent device body 521. The ultrafine atomizing device 5232 forms an ultrafine spray of absorbent liquid, uniformly distributing the absorbent liquid within the absorbent device body 521, thereby absorbing hydrogen chloride in the condensed gas. The unabsorbed gas becomes the exhaust gas.

[0118] Taking an aqueous solution as the absorbent as an example, spraying not only increases the effective contact area between the aqueous solution and the gas, but also utilizes the absorption properties of the aqueous solution to reduce the amount of water used in spraying, efficiently capturing hydrogen chloride molecules in the gas. The hydrogen chloride molecules in the gas contact with the aqueous solution and are converted into hydrochloric acid solution. The generated hydrochloric acid solution flows downwards to the outlet 525 under gravity, exiting from the hydrogen chloride absorption device 52 and then being collected. The collected hydrochloric acid solution has a concentration of 14.9%–40% and is safely stored to meet different industrial needs. To ensure stable and efficient operation of the equipment, the entire hydrogen chloride absorption device 52 can be observed through multiple observation windows 524. Through the observation windows 524, operators can monitor the operating status of the equipment in real time, promptly identify and address any potential problems, thereby ensuring smooth system operation and successful collection of hydrochloric acid solution. This design not only improves the operability of the system but also enhances the safety and controllability of the entire process, while guaranteeing the collection rate of hydrochloric acid solution.

[0119] The top of the small cylindrical structure of the absorption device body 521 is also provided with an exhaust gas outlet. An exhaust pipe (not shown) is connected to the exhaust gas outlet for discharging exhaust gas.

[0120] Example 2

[0121] The production of lanthanum oxychloride using the rare earth chlorine oxide production apparatus of Example 1 includes the following steps:

[0122] Prepare a 35 wt% lanthanum chloride aqueous solution. Add the prepared lanthanum chloride aqueous solution to the storage container 11.

[0123] Once the rare earth chloride pyrolysis furnace 2 is heated to 650°C, the air compressor 12 is turned on. Using compressed air as a carrier, the lanthanum chloride aqueous solution is transported from the storage container 11 through a pipeline to the spray device 13. The spray device 13 sprays the solution into the heating furnace chamber 22 of the rare earth chloride pyrolysis furnace 2, forming a spray. Lanthanum chloride undergoes a thermal decomposition reaction to generate a gas-solid mixture containing lanthanum oxychloride and hydrogen chloride.

[0124] By drawing air out of the exhaust fan, a negative pressure is created in the rare earth chlorine oxide production device, causing the gas-solid mixture, carried by hot air, to enter the separation unit 3 at a speed of 10 m / s for gas-solid separation, resulting in lanthanum chloride solid product and gas containing hydrogen chloride.

[0125] Lanthanum oxychloride solid product (powder) enters the lower part of rare earth chloride pyrolysis furnace 2 through the solid product inlet via an inclined chute, and then exits from the solid product outlet, where it is collected by rare earth chloride oxide collector 6. The SEM image of the obtained lanthanum oxychloride is shown below. Figure 3 .

[0126] The hydrogen chloride-containing gas is condensed in condenser 51 and then enters the hydrogen chloride absorption device 52 through venturi tube 53. Specifically, the condensed hydrogen chloride-containing gas (i.e., condensate) enters the gas inlet pipe 522 through inlet A after passing through venturi tube 53, and then enters the absorption device body 521 through outlet. The absorbent spray unit supplies an aqueous solution (pure water or dilute hydrochloric acid solution) through inlet pipe 5231, and uses an ultrafine atomizer 5232 to evenly distribute the aqueous solution within the absorption device body 521, thereby absorbing the hydrogen chloride in the condensate to form a hydrochloric acid solution. The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0127] Example 3

[0128] Except for the following differences, all other conditions are the same as in Example 2:

[0129] The concentration of the lanthanum chloride aqueous solution is 30 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 850℃.

[0130] SEM images of the obtained lanthanum oxychloride are shown below. Figure 4 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0131] Example 4

[0132] Except for the following differences, all other conditions are the same as in Example 2:

[0133] The concentration of the lanthanum chloride aqueous solution is 40 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 850℃.

[0134] The energy spectrum of the obtained lanthanum oxychloride is shown in the figure. Figure 5 Energy dispersive spectroscopy (EDS) analysis showed that the product mainly consisted of La, Cl, and O elements, consistent with the elemental composition of lanthanum oxychloride. The purity and yield of the obtained lanthanum oxychloride, and the concentration of the hydrochloric acid solution, are shown in Table 1.

[0135] Example 5

[0136] Except for the following differences, all other conditions are the same as in Example 2:

[0137] The concentration of the lanthanum chloride aqueous solution is 32 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 750℃.

[0138] SEM images of the obtained lanthanum oxychloride are shown below. Figure 6 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0139] Example 6

[0140] Except for the following differences, all other conditions are the same as in Example 2:

[0141] The concentration of the lanthanum chloride aqueous solution is 36 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 750℃.

[0142] SEM images of the obtained lanthanum oxychloride are shown below. Figure 7 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0143] Example 7

[0144] Except for the following differences, all other conditions are the same as in Example 2:

[0145] The concentration of the lanthanum chloride aqueous solution is 40 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 750℃.

[0146] SEM images of the obtained lanthanum oxychloride are shown below. Figure 8 See the energy spectrum. Figure 9 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0147] Example 8

[0148] Except for the following differences, all other conditions are the same as in Example 2:

[0149] The concentration of the lanthanum chloride aqueous solution is 33 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 650℃.

[0150] SEM images of the obtained lanthanum oxychloride are shown below. Figure 10 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0151] Example 9

[0152] Except for the following differences, all other conditions are the same as in Example 2:

[0153] The concentration of the lanthanum chloride aqueous solution is 34 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 650℃.

[0154] SEM images of the obtained lanthanum oxychloride are shown below. Figure 11 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0155] Example 10

[0156] Except for the following differences, all other conditions are the same as in Example 2:

[0157] The concentration of the lanthanum chloride aqueous solution is 40 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 650℃.

[0158] SEM images of the obtained lanthanum oxychloride are shown below. Figure 12 See the energy spectrum. Figure 13 The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0159] Example 11

[0160] Except for the following differences, all other conditions are the same as in Example 2:

[0161] The concentration of the lanthanum chloride aqueous solution is 30 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 500℃.

[0162] The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0163] Example 12

[0164] Except for the following differences, all other conditions are the same as in Example 2:

[0165] The concentration of the lanthanum chloride aqueous solution is 35 wt%. The rare earth chloride pyrolysis furnace 2 is heated to 550℃.

[0166] The purity and yield of the obtained lanthanum oxychloride and the concentration of the hydrochloric acid solution are shown in Table 1.

[0167] Table 1

[0168]

[0169] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A rare earth chlorine oxide production apparatus, characterized in that, It includes a rare earth chloride feeding unit, a rare earth chloride pyrolysis furnace, a separation unit, a negative pressure forming unit, and a hydrogen chloride absorption unit. The rare earth chloride pyrolysis furnace is provided with a feed port and a gas-solid mixture discharge port at the top, a solid product inlet at the bottom, and a solid product outlet at the bottom; the rare earth chloride pyrolysis furnace is configured to thermally decompose rare earth chlorides to generate a gas-solid mixture. The rare earth chloride feeding unit is configured to supply a rare earth chloride aqueous solution into the rare earth chloride pyrolysis furnace through the feeding port, and to spray the rare earth chloride aqueous solution. The separation unit is connected to the gas-solid mixture outlet and the solid product inlet, respectively. The separation unit is configured to separate the gas-solid mixture from the gas-solid mixture outlet to obtain a gas containing hydrogen chloride and a rare earth chloride oxide solid product. The rare earth chloride oxide solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and is discharged from the solid product outlet. The negative pressure forming unit is disposed between the separation unit and the hydrogen chloride absorption unit, and is used to allow the gas-solid mixture to enter the separation unit from the rare earth chloride pyrolysis furnace, and to allow the hydrogen chloride-containing gas to enter the hydrogen chloride absorption unit. The hydrogen chloride absorption unit is configured to absorb hydrogen chloride from the gas.

2. The rare earth chlorine oxide production apparatus according to claim 1, characterized in that, The rare earth chloride feeding unit includes a storage container, an air compressor, and a spraying device; wherein, the storage container is used to contain a rare earth chloride aqueous solution; the air compressor is configured to supply compressed air to the storage container, thereby allowing the compressed air to carry the rare earth chloride aqueous solution in the storage container into the spraying device; the spraying device is connected to the storage container, and at least a portion of the spraying device is disposed within the rare earth chloride pyrolysis furnace, for forming a spray of the rare earth chloride aqueous solution within the rare earth chloride pyrolysis furnace.

3. The rare earth chlorine oxide production apparatus according to claim 2, characterized in that: The separation unit includes a cyclone separator; the top of the cyclone separator is connected to the gas-solid mixture outlet via a pipe for collecting the gas-solid mixture; the bottom of the cyclone separator is connected to the solid product inlet via a downward-sloping chute or pipe, the rare earth chloride solid product enters the rare earth chloride pyrolysis furnace through the solid product inlet and exits from the solid product outlet; the hydrogen chloride-containing gas enters the hydrogen chloride absorption unit via a negative pressure forming unit. The negative pressure forming unit includes an exhaust fan; the exhaust fan is configured to form a negative pressure, so that the gas-solid mixture enters the cyclone separator from the rare earth chloride pyrolysis furnace, and so that the hydrogen chloride-containing gas enters the hydrogen chloride absorption unit.

4. The rare earth chlorine oxide production apparatus according to claim 3, characterized in that, The hydrogen chloride absorption unit includes a condenser and a hydrogen chloride absorption device; the condenser is disposed between the negative pressure forming unit and the hydrogen chloride absorption device, and is used to condense the hydrogen chloride-containing gas into condensate.

5. The rare earth chlorine oxide production apparatus according to claim 4, characterized in that, The hydrogen chloride absorption device includes an absorption device body, a gas inlet pipe, and an absorption liquid spraying unit; The absorption device body has a cavity, and a portion of the absorption liquid spraying unit extends into the cavity through the top of the absorption device body; an observation window and a liquid outlet are provided on the side wall of the absorption device body; the liquid outlet is located near the bottom of the absorption device body. The gas inlet pipe has an inlet end and an outlet end; the inlet end is located below the outlet end; the inlet end is connected to the condenser through a pipe for receiving condensed gas; the outlet end is configured to introduce condensed gas into the body of the absorption device. The absorbent spraying unit is configured to spray absorbent into the body of the absorption device to absorb hydrogen chloride in the condensate gas.

6. The rare earth chlorine oxide production apparatus according to claim 5, characterized in that, The gas outlet is configured with multiple outlets, and each outlet is connected to a gas inlet located on the side wall of the absorption device body.

7. The rare earth chlorine oxide production apparatus according to any one of claims 1 to 6, characterized in that, The gas-solid mixture outlet and solid product inlet are each configured to be multiple; the separation unit, negative pressure forming unit and hydrogen chloride absorption unit are each configured to be multiple.

8. A method for producing rare earth chlorine oxides using the rare earth chlorine oxide production apparatus of claim 6, characterized in that, Includes the following steps: 1) The rare earth chloride aqueous solution is added into the rare earth chloride pyrolysis furnace through the rare earth chloride feeding unit and forms a spray; wherein, the temperature inside the rare earth chloride pyrolysis furnace is 500-800℃; 2) Rare earth chlorides decompose thermally in the presence of water and air, generating a gas-solid mixture containing rare earth chloride oxides and hydrogen chloride. 3) A negative pressure is formed by the negative pressure forming unit, so that the gas-solid mixture enters the separation unit, and the separation unit is used to separate the rare earth chlorine oxide solid product and the gas containing hydrogen chloride. 4) The solid products of rare earth chloride oxides enter the rare earth chloride pyrolysis furnace through the solid product inlet and are discharged from the solid product outlet. 5) The gas containing hydrogen chloride enters the condenser and is condensed into condensate gas. The absorbent spray unit sprays absorbent liquid into the body of the absorption device, thereby absorbing the hydrogen chloride in the condensate gas to form a hydrochloric acid solution; wherein the concentration of the hydrochloric acid solution is 14.9 wt% or more.

9. The method according to claim 8, characterized in that, The concentration of rare earth chlorides in the aqueous solution of rare earth chlorides is 30–40 wt%.

10. The method according to claim 8, characterized in that, The gas-solid mixture enters the separation unit at a velocity of 5–15 m / s.

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