Process and apparatus for the production of vanadium oxides

Abstract

This invention belongs to the field of vanadium oxides, specifically relating to a method and apparatus for preparing vanadium oxides. The method for preparing vanadium oxides provided by this invention includes: (a) calcining an ammonium vanadate compound under conditions where the water vapor percentage is greater than 30% to obtain +4 to +5 valence vanadium oxides; or (b) calcining an ammonium vanadate compound under conditions where the water vapor percentage is 10% to 30% to obtain +4 valence vanadium oxides; or (c) calcining an ammonium vanadate compound under conditions where the water vapor percentage is 5% to 10% to obtain +3.5 to +4 valence vanadium oxides; or (d) calcining an ammonium vanadate compound under conditions where the water vapor percentage is less than 5% to obtain +3 valence vanadium oxides; wherein the ammonium vanadate compound is ammonium metavanadate and / or ammonium polyvanadate. The preparation method of this invention can be used to precisely produce vanadium oxides of different valence states while maximizing resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of vanadium oxides, and specifically relates to a method and apparatus for preparing vanadium oxides. Background Technology

[0002] Vanadium electrolyte, as an energy storage medium, is an important component of all-vanadium redox flow battery systems. Vanadium electrolyte preparation methods include electrolysis, reduction, and chemical reduction-electrolysis of vanadium pentoxide. In addition, another method involves first preparing low-valence oxides such as vanadium dioxide and vanadium trioxide through solid-phase reduction using ammonium metavanadate / polyvanadate as raw materials, and then dissolving them to prepare the vanadium electrolyte.

[0003] When using ammonium metavanadate as a raw material for solid-phase reduction, reducing gases such as hydrogen, ammonia, and blast furnace gas need to be introduced into the rotary kiln / reduction kiln to decompose and reduce ammonium metavanadate into different low-valence oxides. However, the ammonia produced by the decomposition of ammonium metavanadate in this method will be emitted as tail gas, resulting in waste.

[0004] For example, patent application CN116995285A discloses a short-process method for preparing a +3.5 valence electrolyte. This application involves calcining ammonium metavanadate / polyvanadate in a reducing atmosphere to obtain low-valence vanadium oxide, and then dissolving the low-valence vanadium oxide to obtain a +3.5 valence vanadium oxysulfate electrolyte. This process utilizes an external reducing agent, is simple and easy to implement, and shortens the electrolyte preparation process. However, the use of an external reducing agent and the emission of ammonia gas from the decomposition of ammonium metavanadate / polyvanadate as waste gas result in resource waste.

[0005] For example, in the article "Research on Green Short-Process Preparation Technology of Low-Valence Vanadium Oxides Based on the Self-Decomposition Ammonia Reduction Effect of Ammonium Metavanadate. Central South University. 2024," the authors discussed in detail the process of preparing low-valence vanadium oxides by the decomposition of ammonium metavanadate and the influence of ammonia partial pressure on the valence state of the reduction products. They demonstrated that increasing the ammonia partial pressure can promote the forward reaction of the solid-phase reduction reaction, and that the reduction products inhibit the forward reaction. However, the preparation of V₂O₃ still requires a relatively high pressure (0.45 MPa) for the reaction.

[0006] Therefore, there is an urgent need to develop a vanadium oxide preparation process that avoids resource waste. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention proposes a method and apparatus for preparing vanadium oxides. This invention achieves the highest utilization rate of ammonia resources from the self-decomposition of ammonium vanadate compounds by controlling the water vapor generated during the calcination of these compounds.

[0008] Specifically, the present invention provides a method for preparing vanadium oxide, the method comprising: (a) Calcining ammonium vanadate compounds under conditions of greater than 30% water vapor yields +4 to +5 valence vanadium oxides; or (b) Calcining ammonium vanadate compounds under conditions of 10%-30% water vapor yields +4 valent vanadium oxides; or (c) Calcining ammonium vanadate compounds under conditions of 5%-10% water vapor yields +3.5 to +4 valent vanadium oxides; or (d) Calcining ammonium vanadate compounds under conditions where the percentage of water vapor is less than 5% yields vanadium oxides with a +3 valence. The ammonium vanadate compounds are ammonium metavanadate and / or ammonium polyvanadate; The water vapor percentage is the volume percentage of water vapor in the gas in the reaction system, and the gas in the reaction system includes one or more of ammonia, water vapor, and protective gases.

[0009] In one or more embodiments, the gas in the reaction system consists of ammonia, water vapor, and a protective gas.

[0010] In one or more embodiments, in step (a), the calcination temperature is 400-800°C.

[0011] In one or more embodiments, in step (b), the calcination temperature is 400-800°C.

[0012] In one or more embodiments, in step (c), the calcination temperature is 400-800°C.

[0013] In one or more embodiments, in step (d), the calcination temperature is 400-800°C.

[0014] In one or more embodiments, in step (a), the calcination time is 30-360 min.

[0015] In one or more embodiments, in step (b), the calcination time is 30-360 min.

[0016] In one or more embodiments, in step (c), the calcination time is 30-360 min.

[0017] In one or more embodiments, in step (d), the calcination time is 60-360 min.

[0018] In one or more embodiments, in step (a), the calcination pressure is -0.08 to +0.02 MPa.

[0019] In one or more embodiments, in step (b), the calcination pressure is -0.08 to +0.02 MPa.

[0020] In one or more embodiments, in step (c), the calcination pressure is -0.08 to +0.02 MPa.

[0021] In one or more embodiments, in step (d), the calcination pressure is -0.08 to +0.02 MPa.

[0022] In one or more embodiments, the protective gas is ammonia and / or nitrogen.

[0023] In one or more embodiments, the method further includes venting air before the reaction.

[0024] In one or more embodiments, the method further includes controlling the water vapor percentage using condensation, liquid absorption, or solid absorption.

[0025] In one or more embodiments, the method further includes introducing a protective gas to cool down after calcination; preferably, exhaust gas treatment is performed after cooling.

[0026] In one or more embodiments, in the solid absorption method, the solid desiccant is selected from one or more of anhydrous calcium chloride, calcium oxide, quicklime, phosphorus pentoxide, silica gel, and molecular sieves.

[0027] In one or more embodiments, the protective gas is nitrogen and / or argon.

[0028] In one or more embodiments, a protective gas is introduced to cool the temperature to 25-100°C.

[0029] This invention provides an apparatus for preparing vanadium oxides, the apparatus comprising a calcining furnace, a water control system, and a gas circulation pipeline; the calcining furnace is used to calcine ammonium vanadate compounds to generate calcination gas; the calcination gas contains ammonia and water vapor; the water control system is used to control the percentage of water vapor in the apparatus; the gas circulation pipeline connects the water control system and the calcining furnace, so that the gas in the calcining furnace returns to the calcining furnace after passing through the water control system.

[0030] In one or more embodiments, the water control system includes a gas analyzer and a water removal component; the gas analyzer is used to monitor the percentage of water vapor in the device; the water removal component is used to adjust the percentage of water vapor in the device; the calcining furnace, the gas analyzer, and the water removal component are connected in sequence through a gas circulation pipeline along the direction of calcining gas flow.

[0031] In one or more embodiments, the water control system further includes a power component; the power component is used to adjust the flow direction of the calcining gas in the device.

[0032] In one or more embodiments, the water control system further includes a controller; the controller is used to control the activation and deactivation of the water removal component.

[0033] In one or more embodiments, the water removal component is selected from one or more of a condensation component, a liquid adsorption dryer, and a solid adsorption dryer.

[0034] In one or more embodiments, the apparatus further includes an air intake device for introducing a protective gas; the air intake device is connected to one end of the calcining furnace closer to the dewatering component.

[0035] In one or more embodiments, the apparatus further includes an exhaust device; the exhaust device includes an air exhaust device and a tail gas exhaust device; the exhaust device is used to exhaust air in the apparatus before the reaction and exhaust tail gas generated after the reaction; the exhaust device is connected to one end of the calcining furnace closer to the gas analyzer.

[0036] In one or more embodiments, the power component is a fan.

[0037] In one or more embodiments, the calcining furnace, the gas analyzer, the water removal component, and the power component are connected in sequence via a gas circulation pipeline along the direction of calcining gas flow.

[0038] In one or more embodiments, the controller includes a flow valve 1 and a flow valve 2; the flow valve 1 is located on a gas circulation pipeline between the power unit and the calcining furnace; the flow valve 2 is located on a gas circulation pipeline between the gas analyzer and the water removal unit.

[0039] In one or more embodiments, the condensing component is a refrigerated dryer and / or a condenser.

[0040] In one or more embodiments, the liquid adsorption dryer is an alkali absorption tower.

[0041] In one or more embodiments, the solid adsorption dryer is a drying tube, a drying tower, or an adsorption dryer.

[0042] In one or more embodiments, the solid desiccant in the solid adsorption dryer is selected from one or more of anhydrous calcium chloride, calcium oxide, quicklime, phosphorus pentoxide, silica gel, and molecular sieves.

[0043] In one or more embodiments, the flow direction of the protective gas introduced by the air intake device is the same as the flow direction of the calcining gas.

[0044] In one or more embodiments, the air or exhaust gas in the exhaust device flows in the same direction as the calcining gas.

[0045] In one or more embodiments, the air venting device is used to vent air from the device before the reaction.

[0046] In one or more embodiments, the air venting device includes a vacuum pump.

[0047] In one or more embodiments, the exhaust gas device is used to exhaust the exhaust gas generated after the reaction.

[0048] In one or more embodiments, the exhaust gas device includes an exhaust gas absorber.

[0049] This invention provides a method for preparing vanadium oxide using any of the apparatuses described herein. The method includes placing an ammonium vanadate compound in a calcining furnace to generate calcining gas. The calcining gas flows sequentially from the calcining furnace into a water control system and then back into the calcining furnace via a gas circulation pipeline. The ammonium vanadate compound is ammonium metavanadate and / or ammonium polyvanadate.

[0050] In one or more embodiments, the calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, the gas analyzer, the water removal component, and the calcining furnace; preferably, the calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, the gas analyzer, the water removal component, the power component, and the calcining furnace.

[0051] In one or more embodiments, the start controller regulates the water vapor percentage through the dehydration component based on the percentage of water vapor in the gas analyzer; preferably, the start controller and the power component regulate the water vapor percentage through the dehydration component.

[0052] In one or more embodiments, the method for preparing vanadium oxide using any of the apparatuses described in this invention further includes a cooling process: after the reaction is completed, while the controller is turned off, the gas inlet device is started to introduce a protective gas for cooling; preferably, the method further includes exhaust gas treatment: after the cooling process, the exhaust gas device is started to recover the exhaust gas.

[0053] In one or more embodiments, the method for preparing vanadium oxide using any of the apparatuses described in this invention further includes an air venting process: before the reaction begins, the air venting device is activated to evacuate the air to a negative pressure; then the air venting device is closed, and the air intake device is activated to introduce a protective gas.

[0054] In one or more embodiments, the calcination temperature is 400-800°C.

[0055] In one or more embodiments, the calcination time is 30-360 min.

[0056] In one or more embodiments, the calcination pressure is -0.08 to +0.02 MPa.

[0057] In one or more embodiments, the protective gas is nitrogen and / or argon.

[0058] In one or more embodiments, a protective gas is introduced to cool the temperature to 25-100°C. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of an apparatus for preparing vanadium oxide according to some embodiments of the present invention.

[0060] Figure 2 This is a schematic diagram of a solid adsorption dryer in an apparatus for preparing vanadium oxides according to some embodiments of the present invention.

[0061] Figure 3 This is a schematic diagram of a liquid adsorption dryer in an apparatus for preparing vanadium oxides according to some embodiments of the present invention.

[0062] Figure 4 The images show the XRD patterns of product 1 obtained in Example 1, product 2 obtained in Example 2, product 3 obtained in Example 3, product 4 obtained in Example 4, and product 5 obtained in Example 5 of the present invention.

[0063] Figure 5 This is the XRD pattern of product 6 obtained in Embodiment 6 of the present invention.

[0064] Figure 6 The images are XRD patterns of product 7 obtained in Example 7 and product 8 obtained in Example 8 of the present invention.

[0065] Figure 7 The image shown is the XRD pattern of product 9 obtained in Example 9 of the present invention.

[0066] Figure 8 This is the XRD pattern of product 10 obtained in Embodiment 10 of the present invention.

[0067] Figure 9 This is the XRD pattern of product 11 obtained in Embodiment 11 of the present invention.

[0068] Figure 10 The image shown is the XRD pattern of product 12 obtained in embodiment 12 of the present invention.

[0069] Figure 11 The image shows the XRD pattern of product 13 obtained in Comparative Example 1 of this invention. Detailed Implementation

[0070] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0071] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0072] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0073] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0074] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0075] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0076] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0077] This invention provides a method for preparing vanadium oxides, the method comprising: (a) calcining ammonium vanadate compounds under conditions of a water vapor percentage greater than 30% to obtain +4 to +5 valence vanadium oxides; or (b) calcining ammonium vanadate compounds under conditions of a water vapor percentage of 10% to 30% to obtain +4 valence vanadium oxides; or (c) calcining ammonium vanadate compounds under conditions of a water vapor percentage of 5% to 10% to obtain +3.5 to +4 valence vanadium oxides; or (d) calcining ammonium vanadate compounds under conditions of a water vapor percentage less than 5% to obtain +3 valence vanadium oxides; wherein the ammonium vanadate compounds are ammonium metavanadate and / or ammonium polyvanadate; the water vapor percentage is the volume percentage of water vapor in the gas in the reaction system, and the gas in the reaction system may include one or more of ammonia, water vapor, and protective gases. This invention achieves the highest utilization rate of ammonia resources from the self-decomposition of ammonium vanadate compounds by controlling the water vapor generated during the calcination of ammonium vanadate, with mild reaction conditions, avoiding resource waste, and simultaneously enabling precise control of the valence state.

[0078] In this invention, the protective gas can be nitrogen and / or argon. In some embodiments, the gas in the reaction system can consist of ammonia, water vapor, and the protective gas.

[0079] In step (a) of this invention, the calcination temperature can be 400-800℃, for example, 400℃, 500℃, 600℃, 700℃, or 800℃. In step (a) of this invention, the calcination time can be 30-360 min, for example, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min, or 360 min. In step (a) of this invention, the calcination pressure can be -0.08 to +0.02 MPa, for example, -0.07 MPa, -0.06 MPa, -0.05 MPa, -0.04 MPa, -0.03 MPa, -0.02 MPa, -0.01 MPa, 0.00 MPa, 0.01 MPa, or 0.02 MPa.

[0080] In step (b) of this invention, the calcination temperature can be 400-800℃, for example, 400℃, 500℃, 600℃, 700℃, or 800℃. In this invention, at a calcination temperature of 400-800℃, controlling the water vapor percentage within the range of 10%-30% can generate +4 valent vanadium oxide. In step (b) of this invention, the calcination time can be 30-360 min, for example, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min, or 360 min. In this invention, at the same calcination temperature, the water vapor percentage and calcination time are inversely proportional; the closer the water vapor percentage is to 10%, the shorter the time required to prepare +4 valent vanadium oxide. In step (b) of this invention, the calcination pressure can be -0.08 to +0.02 MPa, for example -0.07 MPa, -0.06 MPa, -0.05 MPa, -0.04 MPa, -0.03 MPa, -0.02 MPa, -0.01 MPa, 0.00 MPa, 0.01 MPa, or 0.02 MPa.

[0081] In step (c) of this invention, the calcination temperature can be 400-800℃, for example, 400℃, 500℃, 600℃, 700℃, or 800℃. In step (c) of this invention, the calcination time can be 30-360 min, for example, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min, or 360 min. In step (c) of this invention, the calcination pressure can be -0.08 to +0.02 MPa, for example, -0.07 MPa, -0.06 MPa, -0.05 MPa, -0.04 MPa, -0.03 MPa, -0.02 MPa, -0.01 MPa, 0.00 MPa, 0.01 MPa, or 0.02 MPa.

[0082] In step (d) of this invention, the calcination temperature can be 400-800℃, for example, 400℃, 500℃, 600℃, 700℃, or 800℃. In this invention, at calcination temperatures of 400℃-800℃, the water vapor percentage is controlled to be less than 5%, resulting in the formation of +3 vanadium oxide. The calcination time is inversely proportional to the calcination temperature; the closer the calcination temperature is to 800℃, the shorter the calcination time; the lower the calcination temperature, the longer the required calcination time. In step (d) of this invention, the calcination time can be 60-360 min, for example, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min, or 360 min. In this invention, at the same calcination temperature, the water vapor percentage and calcination time are inversely proportional; the higher the calcination temperature, the shorter the time required to prepare +3 vanadium oxide. In step (d) of this invention, the calcination pressure can be -0.08 to +0.02 MPa, for example -0.07 MPa, -0.06 MPa, -0.05 MPa, -0.04 MPa, -0.03 MPa, -0.02 MPa, -0.01 MPa, 0.00 MPa, 0.01 MPa, or 0.02 MPa.

[0083] The method of this invention further includes pre-reaction air purging, specifically including evacuating to negative pressure before the reaction begins, and then introducing a protective gas to 0 MPa. In this invention, the protective gas can be nitrogen and / or argon. In this invention, the number of air purging operations can be ≥3.

[0084] In this invention, the percentage of water vapor can be controlled by condensation, liquid absorption, or solid absorption. In the solid absorption method of this invention, the solid desiccant can be one or more selected from anhydrous calcium chloride, calcium oxide, quicklime, phosphorus pentoxide, silica gel, and molecular sieves.

[0085] The method of the present invention may further include, after calcination, introducing a protective gas for cooling; preferably, exhaust gas treatment is performed after the cooling treatment. In the present invention, the protective gas can be nitrogen and / or argon. In the present invention, introducing a protective gas can cool the temperature to 25-100°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C.

[0086] This invention provides an apparatus for preparing vanadium oxides, comprising a calcining furnace, a water control system, and a gas circulation pipeline. The calcining furnace is used to calcine ammonium vanadate compounds to generate calcination gas. The calcination gas may contain ammonia and water vapor. The water control system is used to control the percentage of water vapor in the apparatus. The gas circulation pipeline connects the water control system and the calcining furnace, allowing the gas in the calcining furnace to return to the calcining furnace after passing through the water control system. This invention controls the percentage of water vapor in the system through the water control device, thereby efficiently and conveniently obtaining vanadium oxides with suitable valence states.

[0087] In the apparatus for preparing vanadium oxides according to the present invention, the calcining furnace, the water control system, and the gas circulation pipeline constitute the main components.

[0088] In this invention, the calcining furnace can be a high-temperature sintering furnace commonly used in the art, such as a tube furnace or a rotary kiln.

[0089] In this invention, the water control system may include a gas analyzer and a water removal component; the gas analyzer can be used to monitor the percentage of water vapor in the device; the water removal component can be used to adjust the percentage of water vapor in the device; the calcining furnace, gas analyzer, and water removal component can be connected sequentially along the direction of calcining gas flow via a gas circulation pipeline. By adding a water control device to the calcining furnace in this invention, water vapor in the reaction products is removed, allowing the reaction to proceed continuously in the forward direction to prepare low-valence vanadium oxide, thus achieving the highest utilization rate of ammonia resources from the self-decomposition of ammonium vanadate compounds.

[0090] In this invention, the water control system may further include a power component; the power component is used to adjust the flow direction of the calcining gas in the device. In this invention, the power component can be a fan. In this invention, the calcining furnace, gas analyzer, water removal component, and power component can be sequentially connected along the flow direction of the calcining gas via a gas circulation pipeline.

[0091] In this invention, the water control system may further include a controller; the controller can be used to control the start and stop of the water removal component. In this invention, the controller may include a flow valve 1 and a flow valve 2; flow valve 1 may be located on the gas circulation pipeline between the water removal component and the calcining furnace; preferably, flow valve 1 may be located on the gas circulation pipeline between the power component and the calcining furnace; flow valve 2 may be located on the gas circulation pipeline between the gas analyzer and the water removal component.

[0092] In this invention, the water removal component can be one or more selected from condensation components, liquid adsorption dryers, and solid adsorption dryers. In this invention, the condensation component can be a refrigerated dryer and / or a condenser. In this invention, the liquid adsorption dryer can be an alkali absorption tower. In this invention, the solid adsorption dryer can be a drying tube, a drying tower, or an adsorption dryer. In this invention, the solid desiccant in the solid adsorption dryer can be one or more selected from anhydrous calcium chloride, calcium oxide, soda lime, phosphorus pentoxide, silica gel, and molecular sieves.

[0093] In this invention, the apparatus for preparing vanadium oxide may further include an air inlet device and an exhaust device; the air inlet device and the exhaust device may be connected to both ends of the calcining furnace respectively.

[0094] In this invention, the air inlet device can be used to introduce a protective gas. In this invention, the air inlet device is connected to the end of the calcining furnace closest to the water removal component. In this invention, the flow direction of the protective gas introduced by the air inlet device can be the same as the flow direction of the calcining gas.

[0095] In this invention, the exhaust device can be used to exhaust air from the apparatus before the reaction and to exhaust tail gas generated after the reaction. In this invention, the exhaust device can include an air exhaust device and a tail gas exhaust device. In this invention, the air exhaust device can be used to exhaust air from the apparatus before the reaction. In this invention, the air exhaust device can include a vacuum pump. In this invention, the tail gas exhaust device can be used to exhaust tail gas generated after the reaction. In this invention, the tail gas exhaust device can include a tail gas absorber, and the tail gas absorbent in the tail gas absorber can be a sulfuric acid solution. In this invention, the exhaust device is connected to the end of the calcining furnace closest to the gas analyzer. In this invention, the flow direction of the air or tail gas in the exhaust device can be the same as the flow direction of the calcining gas.

[0096] The method for preparing vanadium oxide using any of the apparatuses described in this invention includes placing an ammonium vanadate compound in a calcining furnace to generate calcining gas. The calcining gas flows sequentially from the calcining furnace into a water control system and then back into the calcining furnace through a gas circulation pipeline. The ammonium vanadate compound may be ammonium metavanadate and / or ammonium polyvanadate.

[0097] In this invention, the calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, gas analyzer, dehydration component, and calcining furnace; preferably, the calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, gas analyzer, dehydration component, power component, and calcining furnace.

[0098] In this invention, the start controller adjusts the water vapor percentage through the dehydration component based on the percentage of water vapor in the gas analyzer; preferably, the start controller and the power component adjust the water vapor percentage through the dehydration component.

[0099] The method for preparing vanadium oxide using any of the devices of the present invention further includes a cooling process: after the reaction is completed, while the controller is turned off, the gas inlet device is started to introduce a protective gas for cooling; preferably, the method further includes exhaust gas treatment: after the cooling process, the exhaust gas device is started to recover the exhaust gas.

[0100] The method for preparing vanadium oxide using any of the apparatuses of this invention further includes air purging: before the reaction begins, the air purging device is activated to evacuate to a negative pressure; then the air purging device is closed, and the air inlet device is activated to introduce a protective gas; preferably, the protective gas is introduced to 0 MPa. In this invention, when the apparatus for preparing vanadium oxide is used for the first time, the air purging operation needs to be performed with the controller open; when the apparatus for preparing vanadium oxide is used again subsequently, the air purging operation can be performed with the controller closed.

[0101] In this invention, vanadium oxides (V₂O₅, V₆O₅) 11 Vanadium oxides (V₄O₇ and V₂O₃) are the core raw materials for preparing vanadium electrolytes, and high-purity vanadium oxides are the direct vanadium source for preparing the electrolyte. The electrolyte is essentially a mixed solution of vanadium oxysulfate (VOSO₄) and vanadium sulfate, prepared by reacting vanadium oxides with sulfuric acid. In this invention, vanadium oxides are converted into active ions (V₄O₇, V₂O₃, and V₂O₃) in the electrolyte through chemical reduction, electroreduction, or chemical reduction-electroreduction. 2+ / V 3+ / VO 2+ / VO2 + This directly determines the battery's energy storage capacity and electrochemical performance.

[0102] Compared with the prior art, the present invention has the following beneficial technical effects: (1) By monitoring the percentage of water vapor in the gas inside the control device, the present invention can precisely control the valence state of vanadium oxide and obtain vanadium oxide with different valence states; (2) The process for preparing low-cost vanadium oxides, especially +3 vanadium oxides, is low-cost, mild, and simple to operate, reducing the waste of resources.

[0103] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art, unless otherwise stated. The raw material compounds in the embodiments are all commercially available.

[0104] In this invention, the percentage of water vapor refers to the percentage (volume percentage) of water vapor in the total gas content of the reaction system. In the embodiments and comparative examples of this invention, all gases in the reaction system include ammonia, nitrogen and water vapor.

[0105] Equipment Example 1

[0106] This example equipment is an apparatus for preparing vanadium oxide, which includes a calcining furnace, a water control system, a gas circulation pipeline, an air inlet device, and an exhaust device. The calcining furnace is used to calcine ammonium vanadate compounds to generate calcination gases; the calcining furnace is a tubular furnace. The gas circulation pipeline connects the water control system and the calcining furnace, allowing the gas in the calcining furnace to return to the calcining furnace after passing through the water control system; The water control system is used to control the percentage of water vapor in the device; the water control system includes a gas analyzer, a water removal component, a power component, and a controller; the gas analyzer is used to monitor the percentage of water vapor in the device; the water removal component is used to adjust the percentage of water vapor in the device; the water removal component includes a solid adsorption dryer; the solid adsorption dryer is filled with calcium oxide; the power component is used to adjust the flow direction of the calcining gas in the device, and the power component is a fan; the controller is used to control the start and stop of the water removal component, and the controller includes flow valve 1 and flow valve 2; the calcining furnace, gas analyzer, water removal component, and power component are connected in sequence along the flow direction of the calcining gas through a gas circulation pipeline; flow valve 1 is located on the gas circulation pipeline between the power component and the calcining furnace; flow valve 2 is located on the gas circulation pipeline between the gas analyzer and the water removal component; The air inlet device is used to introduce protective gas; the air inlet device is connected to the end of the calcining furnace closest to the water removal component. In this invention, the flow direction of the protective gas introduced by the air inlet device is the same as the flow direction of the calcining gas.

[0107] The exhaust device can be used to exhaust air from the apparatus before the reaction and exhaust tail gas generated after the reaction; the exhaust device includes an air exhaust device and a tail gas exhaust device; the air exhaust device is used to exhaust air from the apparatus before the reaction; the air exhaust device includes a vacuum pump; the tail gas exhaust device is used to exhaust tail gas generated after the reaction; the tail gas exhaust device may include a tail gas absorber, in which the tail gas absorbent is a sulfuric acid solution; in this invention, the exhaust device is connected to the end of the calcining furnace closest to the gas analyzer; the flow direction of the air or tail gas in the exhaust device is the same as the flow direction of the calcining gas.

[0108] Example 1

[0109] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 40 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 1. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 1 was performed, and the results are as follows. Figure 4 As shown, product 1 is VO2.

[0110] Example 2

[0111] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 60 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 2. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 2 was performed, and the results are as follows: Figure 4 As shown, product 2 consists of VO2 and V4O7.

[0112] Example 3

[0113] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 150 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen and cool to 90℃, yielding product 3. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 3 was performed, and the results are as follows: Figure 4 As shown, product 3 consists of VO2 and V4O7.

[0114] Example 4

[0115] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 240 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen and cool to 90℃, yielding product 4. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 4 was performed, and the results are as follows: Figure 4 As shown, product 4 consists of VO2 and V4O7.

[0116] Example 5

[0117] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 300 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen and cool to 90℃, yielding product 5. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis was performed on product 5, and the results are as follows. Figure 4 As shown, product 5 is V4O7.

[0118] Example 6

[0119] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 50g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 600℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 28% and the pressure to 0.02MPa via the dehydration unit. After calcination for 60 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 6. The exhaust system was activated, and the tail gas was absorbed using a 25wt% sulfuric acid solution in the tail gas absorber. XRD analysis was performed on product 6, and the results are as follows. Figure 5 As shown, product 6 is VO2.

[0120] Example 7

[0121] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 450℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 8% and the pressure to 0.02MPa via the dehydration unit. After calcination for 300 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen and cool to 90℃, yielding product 7. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis was performed on product 7, and the results are as follows. Figure 6 As shown, product 7 is V6O 11 .

[0122] Example 8

[0123] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 450℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 13% and the pressure to 0.02MPa via the dehydration unit. After calcination for 300 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 8. The exhaust system was activated, and the tail gas was absorbed using a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis was performed on product 8, and the results are as follows. Figure 6 As shown, product 8 is VO2.

[0124] Example 9

[0125] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the inlet system was activated to introduce protective gas to 0MPa). Then, the inlet and exhaust systems were closed, and the temperature was raised to 500℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 3% and the pressure to 0.02MPa via the dehydration unit. After calcination for 360 minutes, flow valves 1 and 2 were closed, and the inlet system was activated to introduce nitrogen and cool to 90℃, yielding product 9. The exhaust system was activated, and the tail gas was absorbed using a 10wt% sulfuric acid solution in the tail gas absorber. XRD analysis was performed on product 9, and the results are as follows. Figure 7 As shown, product 9 is V2O3.

[0126] Example 10

[0127] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 800℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 3% and the pressure to 0.02MPa via the dehydration unit. After calcination for 60 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 10. The exhaust system was activated, and the tail gas was absorbed using a 10wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 10 was performed, and the results are as follows: Figure 8 As shown, product 10 is V2O3.

[0128] Example 11

[0129] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 400℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2, along with the power unit, were activated to adjust the water vapor percentage to 3% and the pressure to 0.02MPa via the dehydration unit. After calcination for 300 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen and cool to 90℃, yielding product 11. The exhaust system was activated, and the tail gas was absorbed using a 10wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 11 was performed, and the results are as follows. Figure 9 As shown, product 11 is V2O3.

[0130] Example 12

[0131] This embodiment uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 50g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were activated, and the air purging process was repeated three times (the vacuum pump in the exhaust system was activated, evacuating to a pressure of -0.08MPa, then the vacuum pump was closed, and the intake system was activated to introduce protective gas to 0MPa). Then, the intake and exhaust systems were closed, and the temperature was raised to 400℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was monitored using a gas analyzer. Based on the water vapor percentage in the gas analyzer, flow valves 1 and 2 were activated, and the power unit was activated to adjust the water vapor percentage to 28% and the pressure to 0.02MPa via the dehydration unit. After calcination for 30 minutes, flow valves 1 and 2 were closed, and the intake system was activated to introduce nitrogen gas to cool the temperature to 90℃, yielding product 12. The exhaust system was activated, and the tail gas was absorbed using a 25wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 12 was performed, and the results are as follows. Figure 10 As shown, product 12 is VO2.

[0132] Comparative Example 1

[0133] This comparative example uses the apparatus of Example 1 to produce vanadium oxide. The specific steps are as follows: 100g of ammonium metavanadate was placed in a tube furnace. Flow valves 1 and 2 were started, and the air purging process was repeated three times (the vacuum pump in the exhaust system was started, evacuated to a pressure of -0.08MPa, then the vacuum pump was turned off, and the inlet device was started to introduce protective gas to 0MPa). Then, the inlet and exhaust devices were closed, and the temperature was raised to 650℃ for calcination. Calcination produced calcination gases, including ammonia and water vapor. The water vapor percentage was not controlled. After calcination for 300min at a pressure of 0.02MPa, flow valves 1 and 2 were closed, and the inlet device was started to introduce nitrogen to cool the temperature to 90℃, yielding product 13. The exhaust device was started, and the tail gas was absorbed by a 15wt% sulfuric acid solution in the tail gas absorber. XRD analysis of product 13 was performed, and the results are as follows. Figure 11 As shown, product 13 is V6O 13 .

[0134] Test case

[0135] Test the ratio of vanadium oxides with different valence states: Weigh 5g of the products obtained in Examples 1-12 and Comparative Example 1, and dissolve them in 20wt% sulfuric acid solution to prepare vanadium solution. The specific test method is carried out in accordance with GB / T 37204-2018 "Electrolytes for Vanadium Redox Flow Batteries". Measure the valence state of vanadium in the vanadium solution. Based on the valence state of vanadium, calculate the molar ratio of vanadium oxides with different valence states in the products obtained in Examples 1-12 and Comparative Example 1.

[0136] Table 1: Reaction conditions and products of Examples 1-12 and Comparative Example 1 .

Claims

1. A method for preparing vanadium oxide, characterized in that, The method includes: (a) Calcining ammonium vanadate compounds under conditions of greater than 30% water vapor yields +4 to +5 valence vanadium oxides; or (b) Calcining ammonium vanadate compounds under conditions of 10%-30% water vapor yields +4 valent vanadium oxides; or (c) Calcining ammonium vanadate compounds under conditions of 5%-10% water vapor yields +3.5 to +4 valent vanadium oxides; or (d) Calcining ammonium vanadate compounds under conditions where the percentage of water vapor is less than 5% yields vanadium oxides with a +3 valence. The ammonium vanadate compounds are ammonium metavanadate and / or ammonium polyvanadate; The water vapor percentage is the volume percentage of water vapor in the gas in the reaction system, and the gas in the reaction system includes one or more of ammonia, water vapor, and protective gases.

2. The method as described in claim 1, characterized in that, The method has one or more of the following characteristics; In step (a), the calcination temperature is 400-800℃; In step (b), the calcination temperature is 400-800℃; In step (c), the calcination temperature is 400-800℃; In step (d), the calcination temperature is 400-800℃; In step (a), the calcination time is 30-360 min; In step (b), the calcination time is 30-360 min; In step (c), the calcination time is 30-360 min; In step (d), the calcination time is 60-360 min; In step (a), the calcination pressure is -0.08 to +0.02 MPa; In step (b), the calcination pressure is -0.08 to +0.02 MPa; In step (c), the calcination pressure is -0.08 to +0.02 MPa; In step (d), the calcination pressure is -0.08 to +0.02 MPa; The protective gas is nitrogen and / or argon; The method also includes air removal treatment before the reaction; The method also includes controlling the water vapor percentage using condensation, liquid absorption, or solid absorption methods. The method further includes introducing a protective gas for cooling after calcination; preferably, exhaust gas treatment is performed after cooling.

3. The method as described in claim 2, characterized in that, In the solid absorption method, the solid desiccant is selected from one or more of anhydrous calcium chloride, calcium oxide, quicklime, phosphorus pentoxide, silica gel, and molecular sieves; and / or Introduce protective gas to cool down to 25-100℃.

4. An apparatus for preparing vanadium oxide, characterized in that, The device includes a calcining furnace, a water control system, and a gas circulation pipeline; the calcining furnace is used to calcine ammonium vanadate compounds to generate calcining gas; the calcining gas contains ammonia and water vapor; the water control system is used to control the percentage of water vapor in the device; the gas circulation pipeline connects the water control system and the calcining furnace, so that the gas in the calcining furnace returns to the calcining furnace after passing through the water control system.

5. The apparatus as described in claim 4, characterized in that, The water control system includes a gas analyzer and a water removal component; the gas analyzer is used to monitor the percentage of water vapor in the device; the water removal component is used to adjust the percentage of water vapor in the device; the calcining furnace, the gas analyzer, and the water removal component are connected in sequence through a gas circulation pipeline along the direction of calcining gas flow.

6. The apparatus as claimed in claim 5, characterized in that, The device has one or more of the following features: The water control system also includes a power component; the power component is used to adjust the flow direction of the calcining gas in the device; The water control system also includes a controller; the controller is used to control the start and stop of the water removal component; The water removal component is selected from one or more of the following: condensation component, liquid adsorption dryer, and solid adsorption dryer; The device further includes an air intake device; the air intake device is used to introduce protective gas; the air intake device is connected to one end of the calcining furnace closer to the water removal component. The device also includes an exhaust device; the exhaust device includes an air exhaust device and a tail gas exhaust device; the exhaust device is used to exhaust the air in the device before the reaction and to exhaust the tail gas generated after the reaction; the exhaust device is connected to the end of the calcining furnace closest to the gas analyzer.

7. The apparatus as claimed in claim 6, characterized in that, The device has one or more of the following features: The power component is a fan; The calcining furnace, the gas analyzer, the water removal component, and the power component are connected in sequence through a gas circulation pipeline along the direction of calcining gas flow; The controller includes a flow valve 1 and a flow valve 2; the flow valve 1 is located on the gas circulation pipeline between the power unit and the calcining furnace; the flow valve 2 is located on the gas circulation pipeline between the gas analyzer and the water removal unit. The condensing component is a refrigerated dryer and / or a condenser; The liquid adsorption dryer is an alkali absorption tower; The solid adsorption dryer is a drying tube, a drying tower, or an adsorption dryer. The solid desiccant in the solid adsorption dryer is selected from one or more of anhydrous calcium chloride, calcium oxide, quicklime, phosphorus pentoxide, silica gel, and molecular sieves. The flow direction of the protective gas introduced by the air intake device is the same as the flow direction of the calcining gas. The air or exhaust gas in the exhaust device flows in the same direction as the calcining gas. The air venting device is used to vent the air inside the device before the reaction; The air venting device includes a vacuum pump; The exhaust gas device is used to exhaust the exhaust gas generated after the reaction. The exhaust gas device includes an exhaust gas absorber.

8. A method for preparing vanadium oxide using the apparatus according to any one of claims 4-7, characterized in that, The method includes placing an ammonium vanadate compound in a calcining furnace to generate calcining gas, the calcining gas flowing sequentially from the calcining furnace into a water control system and then back into the calcining furnace through a gas circulation pipeline; the ammonium vanadate compound is ammonium metavanadate and / or ammonium polyvanadate.

9. The method as described in claim 8, characterized in that, The method has one or more of the following characteristics: The calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, gas analyzer, water removal component, and calcining furnace; preferably, the calcining gas flows sequentially through a gas circulation pipe along the calcining furnace, gas analyzer, water removal component, power component, and calcining furnace. Based on the percentage of water vapor in the gas analyzer, the start controller regulates the water vapor percentage through the dehydration component; preferably, the start controller and the power component regulate the water vapor percentage through the dehydration component. The method further includes a cooling process: after the reaction is completed, while the controller is turned off, the air intake device is started to introduce protective gas for cooling; preferably, the method further includes exhaust gas treatment: after the cooling process, the exhaust gas treatment device is started to recover the exhaust gas. The method also includes air venting: before the reaction begins, the air venting device is activated to evacuate the air to a negative pressure; then the air venting device is turned off and the air intake device is activated to introduce protective gas. The calcination temperature is 400-800℃; The calcination time is 30-360 minutes; The calcination pressure is -0.08 to +0.02 MPa.

10. The method as described in claim 9, characterized in that, The protective gas is nitrogen and / or argon; and / or Introduce protective gas to cool down to 25-100℃.

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