Method and device for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination method

Abstract

The invention belongs to the technical field of preparation of anhydrous aluminum trichloride, and particularly relates to a method and device for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, and the method comprises the following steps: introducing chlorine gas into a molten medium material Me at 185-650 DEG C, so that the molten medium material Me and chlorine gas are subjected to chlorination reaction to generate chloride, then, AlCl3 is generated through a replacement reaction between the solid Al and chloride, aluminum chloride generated through the reaction is sublimated and enters a trap, and an anhydrous aluminum trichloride finished product is obtained after trapping; wherein the melting point of the medium material Me is 185-650 DEG C, the medium material Me can react with chlorine to generate chloride, and the chloride of the medium material Me can be subjected to replacement reaction with aluminum to generate metal or alloy of AlCl3; according to the method and the device for preparing the anhydrous aluminum trichloride based on the low-temperature indirect chlorination process, the aim of preparing the high-purity anhydrous aluminum trichloride with low cost, low energy consumption, low investment and high yield can be achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of anhydrous aluminum chloride, and particularly relates to a method and device for preparing anhydrous aluminum chloride based on a low-temperature indirect chlorination method. BACKGROUND

[0002] Anhydrous aluminum chloride is an important inorganic chemical product. The pure product is a colorless, odorless, transparent hexagonal plate-shaped crystalline solid. The industrial product is usually light yellow, yellow or light gray due to the presence of impurities such as iron, free chlorine and free aluminum, and has a strong hydrochloric acid odor, and is easily soluble in water, alcohol, chloroform, carbon tetrachloride and other solvents. Anhydrous aluminum chloride is widely used in the industrial field, covering medicine, pesticide, dye, perfume, metallurgy, plastic, lubricating oil and other industries, and is mainly used as an organic synthesis catalyst, detergent, dehydrating agent, nucleating agent and the like. It is particularly widely used and mature as a catalyst in the Friedel-Crafts reaction.

[0003] At present, the mainstream methods for preparing anhydrous aluminum chloride in the industry mainly include aluminum ingot method and aluminum oxide method. The aluminum ingot method is the most widely used process at home and abroad, and almost all domestic anhydrous aluminum chloride production adopts this process route. The process principle of the aluminum ingot method is as follows: chlorine gas is directly introduced into molten metal aluminum, and a chlorination reaction occurs to generate anhydrous aluminum chloride. The reaction temperature is generally controlled at about 800°C. The gaseous anhydrous aluminum chloride generated by the reaction is introduced into a trap after sublimation, and is treated by capture and condensation to obtain anhydrous aluminum chloride product. The chemical equation of the chlorination reaction is as follows: 2Al (liquid) + 3Cl2 (gas) = 2AlCl3 (gas) gas-solid reaction Although the aluminum ingot method is widely used in industrial production and the process is relatively mature, the method has many inherent defects that are difficult to overcome. These defects seriously affect product quality, production efficiency and production operating environment, and are specifically described as follows: (1) High raw material costs and poor economic benefits: The core reaction of the aluminum ingot method is the chlorination reaction between metallic aluminum and chlorine in the gas-molten phase contact state. This reaction can only proceed smoothly under high temperature conditions above 800℃. In this high temperature environment, the iron, silicon, magnesium, calcium and other metal impurities commonly contained in industrial low-purity aluminum materials, such as aluminum chips, aluminum slag, and waste aluminum materials, have high reactivity with chlorine and will undergo chlorination reaction with aluminum to generate chloride impurities such as FeCl3, SiCl4, and MgCl2. Among them, FeCl3 is a yellow-brown solid that easily undergoes co-sublimation with AlCl3, directly causing product coloring, and cannot be effectively separated by simple collection processes; SiCl4 is a volatile liquid that will mix into the anhydrous aluminum trichloride product, significantly aggravating the product's moisture absorption performance; various metal chloride impurities will also greatly reduce the activity of anhydrous aluminum trichloride as a catalyst, causing it to lose its industrial application value. Therefore, the aluminum ingot method has rigid requirements on the purity of aluminum raw materials and cannot be adapted to low-purity aluminum materials. It must use A00 pure aluminum ingots with an aluminum content of ≥99.7% as raw materials, which directly leads to a significant increase in raw material costs and poor economic benefits in production.

[0004] (2) Harsh production environment and insufficient safety assurance: The reactor of the aluminum ingot process needs to be maintained at a high temperature of over 800°C for a long time. At the same time, the open or semi-open aluminum liquid pool will generate intense heat dissipation, which will cause the temperature of the workshop production environment to rise significantly. Especially in summer, the workshop is unbearably hot, which not only seriously affects the comfort of the operators, but also reduces the safety of the operation.

[0005] (3) Low product purity and poor storage stability: Even when using A00 high-purity aluminum ingots as raw materials, they still contain ≤0.3% iron impurities. At chlorination reaction temperatures above 800℃, iron reacts rapidly with chlorine to form FeCl3. Since the sublimation point of FeCl3 is much lower than the working temperature of the reactor, it sublimates into the gas phase simultaneously with AlCl3, eventually co-condensing with AlCl3 in the collector, becoming the main impurity in the product. 3+The electronic transition optical properties, the co-crystallization dispersion effect of AlCl3 and FeCl3, and the light scattering amplification effect of solid crystals all influence the coloring of white AlCl3 crystals to pale yellow or yellow, even if the FeCl3 content in the product is only 0.01%. If the iron content in the aluminum ingot is high, or if the reaction furnace body is made of iron, the FeCl3 content in the product will be further increased, resulting in a gray or even brownish-yellow product. In addition, during the aluminum ingot production process, an excessive amount of chlorine gas needs to be introduced to ensure complete reaction of metallic aluminum. In industrial production, the molar ratio of chlorine gas to aluminum is usually controlled at 1.6~2.0:1. The excess chlorine gas will enter the collector along with the gaseous AlCl3. The temperature of the collector is usually controlled at 100~150℃. At this temperature, AlCl3 can quickly sublimate into a solid, and some chlorine gas cannot be discharged in time. It will be physically adsorbed on the surface of AlCl3 crystals or dissolved in a small amount in the AlCl3 lattice to form free chlorine. Meanwhile, excess chlorine gas can react with trace amounts of moisture on the surface of AlCl3 crystals to produce HCl (reaction equation: Cl2 + H2O → HCl + HClO). HCl, as an irritating gas, will cause the product to have a strong hydrochloric acid odor. The presence of free chlorine will enhance the chemical activity of the product, making it susceptible to moisture absorption and corrosion, significantly reducing its storage stability. In summary, it is difficult to obtain a white, high-purity product from anhydrous aluminum trichloride prepared by the aluminum ingot method. The product is generally pale yellow, yellow, or light gray, and has a high content of free chlorine and iron impurities, which cannot meet the requirements of high-end industrial applications.

[0006] Besides the aluminum ingot method, another industrial method for preparing anhydrous aluminum trichloride is the alumina method. This method uses alumina as the aluminum source, chlorine as the chlorinating agent, and carbon as the reducing agent. The three react at temperatures above 1000℃ to produce anhydrous aluminum trichloride. The reaction equation is as follows: Al2O3(solid) + (m+n)C(solid) + 3Cl2(gas) = ​​2AlCl3(gas) + mCO + nCO2; The raw material alumina used in this method is relatively inexpensive, and a fixed bed or fluidized bed reactor is generally used. However, it has obvious drawbacks such as high product impurity content and large investment in production equipment. The overall economic benefits are worse than those of the aluminum ingot method, so it is rarely used in actual industrial production.

[0007] Furthermore, industrial production generates a large amount of scrap aluminum, such as pure aluminum processing scraps, waste aluminum foil, aluminum alloy scraps, and machining chips. These scrap aluminum materials often contain valuable alloying elements such as tin, silver, copper, nickel, and lithium. If they could be used in the preparation of anhydrous aluminum trichloride and the valuable elements could be separated and recovered, raw material costs could be significantly reduced and resource utilization could be improved. However, existing aluminum ingot methods and alumina methods are not suitable for using scrap aluminum as raw material. This results in two problems: firstly, impurities in low-purity scrap aluminum can seriously affect product quality and render it unusable; secondly, valuable alloying elements in scrap aluminum cannot be effectively separated and recovered, leading to resource waste.

[0008] In summary, existing industrial methods for preparing anhydrous aluminum trichloride all have significant drawbacks. They either suffer from high raw material costs, harsh production environments, and low product purity, or high product impurities, large equipment investments, and poor economic efficiency. None of these methods can achieve efficient, low-cost, and high-purity preparation of anhydrous aluminum trichloride. Therefore, developing a novel method for preparing anhydrous aluminum trichloride that is economically efficient, produces high-purity products, operates at low reaction temperatures, consumes little energy, and is safe and environmentally friendly has become a crucial technical challenge that urgently needs to be addressed by those skilled in the art. Summary of the Invention

[0009] The present invention aims to provide a novel method and apparatus for preparing anhydrous aluminum trichloride, which features high product purity, low reaction temperature, low energy consumption, safety and environmental protection, and can utilize waste aluminum as raw material, thus balancing low cost and high returns.

[0010] In view of this, the present invention provides a method for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, comprising: At 185~650℃, chlorine gas is introduced into the molten medium material Me, so that the molten medium material Me reacts with chlorine gas to generate chloride. Then, AlCl3 is generated through the displacement reaction between solid Al and chloride. The aluminum chloride generated in the reaction sublimates into the collector and is collected to obtain anhydrous aluminum trichloride product. The medium material Me is a metal or alloy with a melting point between 185 and 650°C, capable of reacting with chlorine to generate chloride, and whose chloride can undergo a displacement reaction with aluminum to generate AlCl3.

[0011] Furthermore, the method for preparing anhydrous aluminum trichloride includes the following steps: S1, Material preparation: Prepare granular aluminum material for later use; S2, charging: add dielectric material Me into the reactor to form dielectric layer a, and then place solid aluminum material on top of dielectric layer a to form aluminum material layer b; S3, Preparation of aluminum trichloride by heating reaction: The temperature inside the reactor is heated to between 185 and 650°C, while ensuring that the aluminum material remains in a solid state. The medium material Me in the medium layer a melts into a medium liquid, and the melted medium liquid can contact the aluminum material layer b above it. Chlorine gas is introduced into the medium liquid, so that the medium material Me in the medium liquid reacts with the chlorine gas to generate the corresponding liquid chloride. The chloride comes into direct contact with the solid aluminum material and undergoes a displacement reaction. The liquid medium material Me generated by the displacement reaction returns to the medium liquid, and the generated gaseous aluminum trichloride rises into the collector. After crystallization, anhydrous aluminum trichloride is obtained.

[0012] Furthermore, the particle size range of the granular aluminum material is 0.1~200mm, and the granular aluminum material is aluminum ingot or scrap aluminum.

[0013] Furthermore, the aluminum material used is scrap aluminum material, which is pure aluminum scrap or scrap aluminum alloy material rich in one or more valuable metals.

[0014] Furthermore, before use, the waste aluminum material is pretreated to remove organic impurities and moisture.

[0015] Furthermore, before feeding the aluminum material into the reactor, it is preheated to above 150°C in an inert atmosphere before being fed into the reactor.

[0016] Furthermore, the dielectric material Me is tin, lead, bismuth, zinc, or an alloy thereof.

[0017] Furthermore, during the preparation of anhydrous aluminum trichloride, the aluminum material layer b is always kept at a height of more than 0.5 cm immersed in the medium liquid for reaction. As the reaction proceeds, the solid aluminum material at the bottom of the aluminum material layer b is gradually consumed, and the solid aluminum material at the top falls into the medium liquid, allowing the reaction to continue.

[0018] Furthermore, the medium material Me contains 0.5-1.5 wt% of low-melting-point metal elements.

[0019] The present invention also provides an apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, wherein the apparatus for preparing anhydrous aluminum trichloride is prepared by the above-described method.

[0020] Compared with existing technologies, the method and apparatus for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination described in this invention have the following advantages: (1) High product purity, capable of preparing high-purity anhydrous aluminum trichloride: This invention adopts an indirect chlorination mode, where chlorine gas first reacts with the medium liquid, and the residual chlorine gas can further react with the aluminum material, greatly reducing the free chlorine residue; the reaction temperature is low, and the impurity chlorides other than aluminum are basically in liquid state and cannot enter the crystallizer with the gaseous aluminum trichloride; at the same time, the valuable alloying elements in the waste aluminum can be separated by the difference in electronegativity, avoiding them from being mixed into the product as impurities. The final anhydrous aluminum trichloride is a white crystal with AlCl3 purity ≥99.2%, which is much higher than the existing process, and it has no hydrochloric acid odor, which can meet the needs of high-end industrial fields.

[0021] (2) Raw material costs are significantly reduced and resource utilization is high: This invention can directly use waste aluminum as raw material without using high-purity A00 aluminum ingots. The price of waste aluminum is much lower than that of pure aluminum ingots, which significantly reduces raw material costs. At the same time, valuable alloying elements such as tin, silver, copper, nickel and lithium in waste aluminum can be efficiently separated and recycled, improving resource utilization and further enhancing comprehensive economic benefits.

[0022] (3) Low reaction energy consumption and environmentally friendly production: The reaction temperature of the present invention is controlled at 185~650℃, which is much lower than the existing aluminum ingot method and alumina method, thus greatly reducing energy consumption; the reactor is completely sealed to avoid direct heat dissipation, the workshop environment temperature is comfortable, and the working conditions can be improved; and the free chlorine content in the tail gas is extremely low (≤0.01%), the environmental protection treatment burden is light, and it meets the requirements of green production.

[0023] (4) The process is stable and reliable and easy to operate: The present invention adopts a segmented heating and constant temperature control mode, combined with the setting of micro-reaction zone to ensure that the reaction temperature is stable and controllable; on this basis, the internal and external temperature control structure avoids the reaction runaway and side reaction caused by local overheating; and the medium material can be recycled and does not need to be replenished frequently; the waste aluminum material pretreatment process is simple, and the overall process can realize continuous production, which is convenient for industrial promotion and application.

[0024] (5) Low equipment investment and significant economic benefits: The reaction temperature of this invention is low, which reduces the high temperature resistance requirements of the reactor and the equipment cost is relatively low; the raw material cost is low, the product added value is high, and the valuable elements can be recycled, forming a closed-loop industrial chain of "waste aluminum utilization - high-purity product preparation - valuable element recycling", achieving the production goal of low cost, low energy consumption, low investment and high returns.

[0025] In summary, this invention provides a green and energy-saving preparation method for high-purity anhydrous aluminum trichloride, which can achieve low-cost, low-energy-consumption, low-investment, and high-return preparation of high-purity anhydrous aluminum trichloride. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the production apparatus for preparing anhydrous aluminum trichloride as described in Embodiment 1 of the present invention; Figure 2 yes Figure 1 A magnified view of a portion of region A in the middle; Figure 3 This is a schematic diagram of the production apparatus for preparing anhydrous aluminum trichloride as described in Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of the production apparatus for preparing anhydrous aluminum trichloride as described in Embodiment 3 of the present invention; Figure 5 This is a schematic diagram of the production apparatus for preparing anhydrous aluminum trichloride as described in Embodiment 4 of the present invention; Figure 6 This is a schematic diagram of the production apparatus for preparing anhydrous aluminum trichloride as described in Embodiment 5 of the present invention; Figure 7 This is a three-dimensional structural schematic diagram of the reactor body described in Embodiment 6 of the present invention; Figure 8 This is a schematic cross-sectional view of the reactor body described in Embodiment 6 of the present invention; Figure 9 yes Figure 8 A magnified schematic diagram of the local structure of region B in the middle; Figure 10 yes Figure 8 Another enlarged schematic diagram of a local structure in region B; Figure 11 yes Figure 10 A three-dimensional structural diagram of the elastic element; Figure 12 This is a photograph of a representative anhydrous aluminum trichloride obtained by this invention. Figure 13 This is a second photograph of a representative anhydrous aluminum trichloride obtained by this invention; Figure 14 These are actual photos of anhydrous aluminum trichloride produced using the aluminum ingot method; The markings in the diagram are as follows: 1. Furnace body; 101. Aluminum receiving cavity; 1011. Guide plate; 102. Medium receiving cavity; 103. Orifice plate; 104. Micro-reaction zone; 105. Gaseous aluminum trichloride discharge port; 106. Waste discharge port; 1061. Control valve three; 107. Inner furnace body; 2. Aluminum feeding hopper; 201. Control valve one; 3. Medium feeding hopper; 301. Control valve two; 4. External temperature control device; 401. Semi-circular disc 402. Pipe; 5. Heat exchanger; 6. Chlorine conveying device; 7. Temperature detector; 8. Liquid phase temperature detector; 9. Gas phase temperature detector; 10. Internal temperature control device; 11. Mechanical lifting arm; 12. Magnet; 13. Adaptive spring-loaded height adjustment mechanism; 14. Receiving groove; 15. Elastic element; 16. Flanged edge; 17. Snap-fit ​​flange; 18. Limiting block; 19. Bolt. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0028] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0029] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] This invention first provides a method for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, comprising: At 185~650℃, chlorine gas is introduced into the molten medium material Me, so that the molten medium material Me reacts with chlorine gas to generate chloride. Then, AlCl3 is generated through the displacement reaction between solid Al and chloride. The aluminum chloride generated in the reaction sublimates into the collector and is collected to obtain anhydrous aluminum trichloride product. The medium material Me is a metal or alloy with a melting point between 185 and 650°C, capable of reacting with chlorine to generate chloride, and whose chloride can undergo a displacement reaction with aluminum to generate AlCl3.

[0032] Preferably, during the preparation of anhydrous aluminum trichloride, the reaction temperature is specifically adjusted according to the type of chloride generated, so that the temperature inside the reactor is not lower than the melting point of the medium material and the chloride, ensuring that the medium material and the chloride generated in the reaction remain in a molten liquid state inside the reactor.

[0033] As specific examples of the present invention, the method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination includes the following steps: S1, Material preparation: Prepare granular aluminum material for later use; S2, charging: add dielectric material Me into the reactor to form dielectric layer a, and then place solid aluminum material on top of dielectric layer a to form aluminum material layer b; S3, Preparation of aluminum trichloride by heating reaction: The temperature inside the reactor is heated to between 185 and 650°C to ensure that the aluminum material remains in a solid state. The medium material Me in the medium layer a melts into a medium liquid, and the melted medium liquid can contact the aluminum material layer b above it. Chlorine gas is introduced into the medium liquid, so that the medium material Me in the medium liquid undergoes a liquid chlorination reaction with the chlorine gas to generate the corresponding chloride. The chloride comes into direct contact with the solid aluminum material and undergoes a displacement reaction. The liquid medium material Me generated by the displacement reaction returns to the medium liquid, and the generated gaseous aluminum trichloride rises into the collector. After crystallization, anhydrous aluminum trichloride is obtained.

[0034] As some examples of the present invention, in step S1, in addition to using raw materials such as pure aluminum ingots as aluminum material, more importantly, the present invention can also use waste aluminum material as aluminum material.

[0035] As examples of the present invention, the selected waste aluminum materials include, but are not limited to: pure aluminum processing scraps, such as turning scraps, sawn scraps, etc.; waste aluminum foil; and aluminum alloy scraps and shavings rich in one or more valuable metals such as tin, silver, lithium, copper, nickel, etc.

[0036] As some examples of the present invention, recycled aluminum ingots can also be used as aluminum material. In this case, the recycled aluminum ingots need to be processed into scraps of appropriate size before use.

[0037] Specifically, when using scrap aluminum as the aluminum raw material for preparing anhydrous aluminum trichloride, the scrap aluminum can be pretreated to remove organic impurities and moisture before use.

[0038] As some examples of the present invention, different pretreatments are performed for different scrap aluminum materials: for pure aluminum scrap, such as scrap aluminum foil and pure aluminum shavings, and for alloy scrap aluminum, such as scrap aluminum alloy containing tin, silver, nickel and lithium, a differentiated pretreatment process is adopted to avoid over-cleaning or incomplete cleaning caused by uniform treatment.

[0039] Specifically, as some examples of the present invention, the pretreatment process for pure aluminum scrap is as follows: First, alkaline washing is performed using a 5-8 wt% NaOH aqueous solution to remove oil and organic impurities from the surface of the material. Then, it is placed in deionized water for ultrasonic cleaning for 10-15 minutes. Finally, it is rinsed in a 1-2 wt% dilute hydrochloric acid solution for 3-5 minutes to remove the surface oxide film and reduce the generation of impurities and slag during the reaction process.

[0040] As some examples of the present invention, the pretreatment process for waste aluminum alloy materials is as follows: First, alkaline washing is carried out in a NaOH aqueous solution with a concentration of 5-8wt% to remove oil and organic impurities from the surface of the material. Then, it is placed in deionized water for ultrasonic cleaning for 10-15 minutes. After cleaning, nitrogen is used to purge and assist in drying.

[0041] As some examples of the present invention, in step S1, large pieces of aluminum material can be crushed into suitable particle sizes for use. Preferably, the particle size range of the granular aluminum material is 0.1~200mm. Suitable particle size is beneficial for feeding, the chlorination reaction, and the smooth discharge of aluminum trichloride gas.

[0042] As some examples of the present invention, before feeding the raw aluminum material into the reactor, it can be preheated to above 150°C in an inert atmosphere, such as a nitrogen atmosphere, to eliminate the influence of moisture and air.

[0043] As a preferred example of the present invention, when using nitrogen preheating to remove moisture from aluminum material, 0.5-1% by volume of argon can be added to the nitrogen atmosphere, and the preheating time can be shortened to 10-15 minutes. In this way, moisture and adsorbed air can be completely eliminated, slight oxidation of the aluminum material surface can be inhibited, and the total consumption of inert gas can be reduced.

[0044] As some examples of the present invention, in step S2, a suitable amount of solid dielectric material Me can be added to the bottom layer of the reactor to form a dielectric layer a, and then the aluminum material is weighed and placed on top of the dielectric layer a.

[0045] Preferably, the appropriate height of the dielectric layer a is 50~500mm.

[0046] As some examples of the present invention, the dielectric material Me is tin, lead, bismuth, zinc or an alloy thereof.

[0047] It is important to note that when using tin as the medium, parameters such as the amount of chlorine added and the reaction temperature must be controlled so that the main product of the chlorination reaction is divalent tin.

[0048] As some other examples of the present invention, in step S2, a medium material Me preheated to a molten state may be added to the bottom of the reactor to form a medium layer a, and then the aluminum material may be weighed and placed on the top of the medium layer a with the help of a mechanical support structure.

[0049] As some examples of the present invention, in step S2, trace amounts, preferably 0.5-1.5 wt%, of low-melting-point metal elements, such as bismuth, indium, gallium, etc., can be added to the dielectric material Me to form a multi-component composite dielectric alloy, so as to reduce the melting point of the dielectric material Me, reduce the energy consumption during the heating stage, improve the fluidity of the dielectric liquid, promote the full contact between chlorine gas and the dielectric liquid, thereby increasing the gas-liquid chlorination reaction rate, suppressing the stratification phenomenon after long-term circulation of the dielectric liquid, extending the service life of the dielectric material Me, and reducing the replenishment cost of the dielectric material Me.

[0050] As a preferred example of the present invention, in step S2, the height of the suitable aluminum layer b is 100~5000mm.

[0051] As a preferred example of the present invention, in step S2, for a continuous production process, the suitable height of the aluminum layer b is 50~1000mm.

[0052] As a preferred example of the present invention, during the preparation of anhydrous aluminum trichloride, the aluminum material layer b is always maintained at a height of 0.5 cm or more, such as 1-5 cm, immersed in the medium liquid for reaction. As the reaction proceeds, the solid aluminum material at the bottom of the aluminum material layer b is gradually consumed, while the solid aluminum material at the top falls into the medium liquid to continue the reaction. In this way, continuous production of anhydrous aluminum trichloride is achieved. However, it should be noted that the height of the aluminum material layer b immersed in the medium liquid should not be too large; specifically, it is preferable that the height of the aluminum material layer b immersed in the medium liquid is less than 80% of the height of the medium liquid.

[0053] In the method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination described in this invention, by controlling the height of the aluminum material layer b immersed in the medium liquid, a small micro-reaction zone is formed between the aluminum material layer b and the medium liquid. Compared with the reaction zone of a traditional solid-liquid reaction, this micro-reaction zone is extremely small. Therefore, although the above-mentioned reaction process for preparing anhydrous aluminum trichloride proceeds rapidly and is accompanied by intense exothermic reactions, the preparation method described in this invention can easily control the reaction process within a relatively controllable range.

[0054] As some examples of the present invention, the chlorine gas introduction rate is 0.3~1L / min, but the present invention does not specifically limit the chlorine gas introduction rate, which can be adjusted according to the size of the furnace, the amount of material added, the reaction temperature, etc.

[0055] As a specific example of the present invention, in step S3, it is necessary to ensure that the temperature of the reactor is within a suitable range so that the reaction medium material Me is always in a liquid state, aluminum is always in a solid state, aluminum trichloride is always in a gaseous state, and the generated chloride is in a liquid state. The suitable range can be 185~650℃, such as 185℃, 190℃, 200℃, 220℃, 250℃, 270℃, 300℃, 350℃, 400℃, 450℃, 480℃, 520℃, 570℃, 600℃, 630℃, 650℃, etc.

[0056] As a preferred example of the present invention, in step S3, the heating and temperature control process of the reactor includes the following three stages: Phase 1: Rapid heating phase. In this phase, the heating rate of the reactor is controlled at 15~20℃ / min, and the temperature of the reactor is raised from room temperature to 50~100℃ below the target reaction temperature. Phase Two: Slow Heating Phase. In this phase, the heating rate of the reactor is controlled at 5~8℃ / min, and the temperature of the reactor continues to rise to the target reaction temperature. Phase 3: Constant Temperature Control Phase: After reaching the target reaction temperature, the temperature control device is used to maintain the reactor in a basically constant temperature state, ensuring that the temperature inside the reactor does not exceed ±10℃ of the target reaction temperature.

[0057] As some examples of the present invention, the tail gas generated during the reaction process can be washed and absorbed by an alkaline scrubbing tower before being discharged, so as to reduce the free chlorine content in the tail gas to ≤0.01%.

[0058] As some examples of the present invention, valuable alloying elements in scrap aluminum can be separated and recycled in the following ways: For valuable metals with low chloride thermal stability and low volatility, such as lithium, their chlorides are not easily vaporized and eventually float on the surface of the liquid medium as chloride solid scum. After accumulating to a certain amount, they are removed, filtered, separated, and then recovered through subsequent wet processing, such as acid leaching-extraction processes.

[0059] For valuable metals whose chlorides have a strong tendency to be reduced by aluminum under high-temperature conditions, their chlorides can undergo a reduction reaction with aluminum in the molten reaction system to generate the corresponding metallic state or metal-rich phase, which is then enriched in the molten medium. By periodically discharging a portion of the molten medium and then treating it through cooling, solid-liquid separation, electrochemical or physical separation, the corresponding valuable metal can be recovered; the separated liquid medium can be returned to the reactor for recycling after necessary purification.

[0060] The specific recycling and processing technology for valuable alloying elements has been extensively documented in the existing technology, and will not be elaborated upon here.

[0061] As a preferred example of the present invention, the reaction system is kept in an air-isolated state throughout the reaction process.

[0062] The principle of preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination provided by this invention is as follows: Me (liquid) + Cl2 (gas) → MeCl2 (liquid) Gas-liquid reaction; MeCl2 (liquid) + Al (solid) → Me (liquid) + AlCl3 (gas) Liquid-solid reaction; The furnace temperature of the reactor is controlled at 185~650℃. The reaction process is as follows: First, chlorine gas is introduced into the molten metal Me, so that the molten metal Me reacts with chlorine gas to generate liquid chloride MeCl2. Then, AlCl3 is generated through the displacement between solid Al and liquid chloride MeCl2. The aluminum chloride generated in the reaction sublimates into the collector and is collected to obtain anhydrous aluminum trichloride product.

[0063] In the process for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination proposed in this invention, the introduced chlorine gas first contacts the molten medium material and undergoes a chlorination reaction to generate MeCl2 (liquid). During this process, Me acts as the chlorine acceptor, combining with chlorine gas to generate MeCl2 (liquid), transferring chlorine from the gas phase to the liquid phase, achieving "liquid phase fixation" of gaseous chlorine. This avoids the problems of low gas-solid contact efficiency and uneven reaction that exist when gaseous chlorine directly contacts solid aluminum. Then, MeCl2 acts as the chlorine donor, contacting solid aluminum again and undergoing a displacement reaction to transfer chlorine to Al to generate gaseous AlCl3. At the same time, Me is reduced and regenerated, returning to its initial state to participate in the next round of reaction. Moreover, the reaction temperature required for the above two steps is not high. Finally, Me completes the low-temperature indirect reaction between Cl2 and Al through the cycle of "combining with Cl2 → releasing Cl2", achieving the purpose of preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination.

[0064] The novel process for preparing anhydrous aluminum trichloride described above can directly use waste aluminum as raw material, eliminating the need for high-purity A00 aluminum ingots. Furthermore, the reaction temperature can be controlled at 185~650℃, significantly lower than existing aluminum ingot and alumina methods, thus greatly reducing energy consumption. Simultaneously, the low reaction temperature ensures that impurities other than aluminum are essentially liquid, preventing them from entering the crystallizer with gaseous aluminum trichloride. The resulting anhydrous aluminum trichloride is a white crystalline solid with an AlCl3 purity ≥99.2%, far exceeding existing processes, and it has no hydrochloric acid odor, meeting the requirements of high-end industrial applications.

[0065] In addition, the present invention also provides an apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, wherein the apparatus for preparing anhydrous aluminum trichloride is prepared by the above-described method.

[0066] The apparatus for preparing anhydrous aluminum trichloride according to the present invention will be described in detail below through specific embodiments: Example 1 like Figures 1-2 As shown, an apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method includes: The reactor body 1 has its internal space divided into an upper aluminum receiving cavity 101 and a lower medium receiving cavity 102 by a perforated plate 103; In use, solid aluminum material is placed in the upper aluminum receiving cavity 101, and molten medium material is placed in the lower medium receiving cavity 102. The filling amount of the medium material is greater than the volume of the medium receiving cavity 102, so that part of the molten medium material can overflow the perforated plate 103 and contact the solid aluminum material on the upper side to form a micro-reaction zone 104 on the upper side of the perforated plate 103. The height ratio of the micro-reaction zone 104 to the medium receiving cavity 102 is (0.1~0.8):1. And a chlorine gas delivery device 5, which is used to deliver chlorine gas into the medium receiving cavity 102.

[0067] It should be noted that the dielectric material can be filled by preheating it to a molten state before injecting it into the dielectric receiving cavity 102, or by directly adding the solid dielectric material into the dielectric receiving cavity 102 and then heating it to a molten state. Preferably, the dielectric material is heated to a molten state before being injected into the dielectric receiving cavity 102.

[0068] As a preferred example of the present invention, the height of the microreaction zone 104 is 0.5 cm or more.

[0069] As a preferred example of the present invention, the height of the medium receiving cavity 102 is 10~30cm.

[0070] As a preferred example of the present invention, the height ratio of the microreaction zone 104 to the medium accommodating cavity 102 is (0.1~0.5):1.

[0071] As a preferred example of the present invention, the aperture of the perforated plate 103 is 5~15mm.

[0072] As some examples of the present invention, the chlorine pipe in the chlorine conveying device 5 is made of alumina ceramic pipe or quartz pipe, and one or more chlorine pipes can be set for each furnace.

[0073] In the above reaction process, Me, as the reaction carrier / circulating medium, plays a core role in transferring chlorine and realizing the indirect reaction between Cl2 and Al. From the perspective of reaction stoichiometry, the total amount of Me will not decrease in theory. Although in actual production, its total amount will be slightly lost due to the occurrence of a small number of side reactions, the rate of decrease is extremely slow and can be maintained by periodic replenishment. Therefore, the total amount of medium material in the reactor body 1 can remain basically unchanged for a considerable period of time, ensuring the reliable existence of the micro-reaction zone 104 and realizing continuous production.

[0074] Furthermore, since the molten medium material in this invention acts as a carrier for chlorine, and its total amount can remain relatively constant, within the reactor body 1, as the solid aluminum material in the micro-reaction zone 104 is continuously consumed, the aluminum material at the top of the micro-reaction zone 104 will continuously collapse and enter the micro-reaction zone 104, achieving continuous reaction and continuous generation of gaseous aluminum trichloride. That is, in this invention, the micro-reaction zone 104 forms a relatively small micro-reaction area in terms of volume compared to the reaction zone of a traditional solid-liquid reaction. Therefore, although the above-mentioned reaction process proceeds rapidly and is accompanied by intense exothermic reactions, the production apparatus described in this invention can easily control the reaction process within a relatively controllable range.

[0075] As some examples of the present invention, such as Figure 2 As shown, a guide plate 1011 is provided at the lower part of the aluminum receiving cavity 101, forming a cross-section that gradually narrows from top to bottom. The guide plate 1011 prevents the aluminum material from accumulating or bridging at the top, allowing it to slide continuously and stably into the micro-reaction zone 104.

[0076] As some examples of the present invention, the reactor body 1 is provided with: A gaseous aluminum trichloride discharge port 105 is located at the top of the reactor body 1 and is connected to a collector. The gaseous aluminum trichloride generated in the reactor body 1 can enter the collector through the gaseous aluminum trichloride discharge port 105 and be collected to obtain anhydrous aluminum trichloride product. Waste discharge port 106 is located at the bottom of the reactor body 1 and communicates with the medium receiving cavity 102 for discharging waste from the medium receiving cavity 102.

[0077] As some examples of the present invention, the production apparatus for preparing anhydrous aluminum trichloride based on the low-temperature indirect chlorination method further includes: An aluminum feeding hopper 2 is disposed on the upper side of the reactor body 1 and communicates with the aluminum receiving cavity 101 for feeding aluminum material into the aluminum receiving cavity 101; The medium feeding hopper 3 is connected to the medium receiving cavity 102 and is used to feed molten medium material into the medium receiving cavity 102.

[0078] As a preferred example of the present invention, the installation height of the medium feeding hopper 3 is higher than that of the medium receiving cavity 102, so as to realize the automatic feeding of the medium feeding hopper 3 without power.

[0079] As a preferred example of the present invention, the aluminum feeding hopper 2 has nitrogen purging and preheating functions.

[0080] As a preferred example of the present invention, a control valve 201 is provided between the aluminum feeding hopper 2 and the reactor body 1 to control the feeding of aluminum material; a control valve 301 is provided between the medium feeding hopper 3 and the reactor body 1 to control the feeding of medium material; and a control valve 1061 is provided between the waste discharge port 106 and the reactor body 1 to control the waste discharge process.

[0081] As a preferred example of the present invention, the waste discharge port 106 is used to remove the medium liquid rich in impurity elements, and the medium liquid after the impurity elements are separated can be replenished back into the medium receiving cavity 102.

[0082] As some examples of the present invention, the production apparatus for preparing anhydrous aluminum trichloride based on the low-temperature indirect chlorination method further includes: The external temperature control device 4 is a coil arranged around the outside of the reactor body 1. A high-temperature medium or a low-temperature medium can be introduced into the coil as needed to control the temperature inside the reactor body 1.

[0083] As a preferred example of the present invention, the coil is a semi-circular coil 401, which can better fit the outer wall of the reactor body 1 and achieve good heat exchange and temperature control.

[0084] As a preferred example of the present invention, the external temperature control device 4 uses cold / hot air as the heat exchange medium. When the reactor body 1 needs to be kept warm, hot air is introduced for heating, and when the reactor body 1 needs to be cooled, cold air is introduced for heat dissipation.

[0085] As some examples of the present invention, the production apparatus for preparing anhydrous aluminum trichloride based on the low-temperature indirect chlorination method further includes: A plurality of temperature detectors 6, including a liquid phase temperature detector 601 for detecting liquid medium material in a medium containment cavity 102, and a gas phase temperature detector 602 for detecting generated gaseous aluminum trichloride, wherein the temperature detection unit in the liquid phase temperature detector 601 is inserted into the liquid medium material in the medium containment cavity 102, and the temperature detection unit in the gas phase temperature detector 602 is located at the top of the aluminum containment cavity 101.

[0086] As a preferred example of the present invention, the chlorine conveying device 5 may include components such as a chlorine source, a chlorine conveying pipeline, and a flow meter, wherein the outlet end of the chlorine conveying pipeline can be inserted into the medium receiving cavity 102.

[0087] Preferred, such as Figure 2 As shown, the outlet end of the chlorine gas conveying pipeline is inserted into the medium receiving cavity 102 at a downward angle. The present invention does not limit the angle α between the outlet end of the chlorine gas conveying pipeline and the horizontal line, but it is preferable that the medium liquid in the medium receiving cavity 102 will not flow back into the chlorine gas conveying device 5.

[0088] The chlorine gas delivery pipeline is designed to allow chlorine gas to enter at a downward angle. The resulting bubbles do not rise vertically and escape rapidly; instead, they form an oblique trajectory within the reaction liquid, prolonging their residence time in the liquid phase. Simultaneously, the oblique impact makes the bubbles more easily broken into smaller bubbles, significantly increasing the gas-liquid contact surface area. This allows for more complete mass transfer between chlorine and the reaction liquid, fundamentally improving the chlorine reaction conversion rate and reducing the loss of unreacted chlorine. Furthermore, the obliquely introduced chlorine gas flow creates an oblique impact and stirring effect on the reaction liquid, breaking up the static stratification of the liquid phase and eliminating dead zones at the bottom and sidewalls of the reactor body 1. The airflow disturbance also allows the reaction products to quickly detach from the gas-liquid interface and float to the surface, ensuring the continuous progress of the reaction.

[0089] Example 2 It should be noted that in this invention, it is generally only necessary to preheat the reactor body 1 using a heating device before loading. After the furnace temperature rises to the reaction temperature and the reaction starts, the reaction can be sustained by the self-exothermic reaction process. Simultaneously, a temperature control device is required to strictly regulate the temperature inside the furnace to prevent the temperature inside the reactor body 1 from continuously rising and exceeding the set temperature, leading to reaction runaway. Therefore, in practical applications, the heating function of the external temperature control device 4 is not critical. To simplify the structure of the external temperature control device 4 and avoid switching the heat exchange medium, an electric heating device can also be installed on the reactor body 1. In this case, the external temperature control device 4 only needs to perform cooling and heat dissipation functions. The following Example 2 provides an external temperature control device 4 with only cooling and heat dissipation functions for use in the production apparatus for preparing anhydrous aluminum trichloride according to this invention.

[0090] like Figure 3 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method differs from the production apparatus described in Example 1 above mainly in that: An electric heating device (not shown in the figure) is installed on the reactor body 1 to preheat the reactor body 1 and the materials inside it before the reaction begins. The external temperature control device 4 is used to cool and dissipate heat from the reaction furnace body 1 during the reaction process. The external temperature control device 4 uses water or other refrigerants as the heat exchange medium.

[0091] As some specific examples of the present invention, the external temperature control device 4 includes: A coil, such as a semi-circular coil 401, is arranged around the outer wall of the reactor body 1; The heat exchanger 402 is connected to both ends of the semi-circular coil 401 through pipes, forming a circulating cooling loop.

[0092] As some examples of the present invention, the heat exchanger 402 can perform heat exchange by means of air cooling, water cooling, etc.

[0093] Example 3 like Figure 4 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination includes an external temperature control device 4 and an internal temperature control device 7, wherein the structure of the external temperature control device 4 can be any one of the above embodiments 1 to 3.

[0094] The internal temperature control device 7 is a cooling and heat dissipation device installed in the middle of the reactor body 1. The internal temperature control device 7 includes a cooling cavity located in the middle of the reactor body 1 and a phase change material filled in the cooling cavity. The cooling cavity is partially located inside the reactor body 1 and partially exposed outside the reactor body 1. In use, heat is absorbed by the internal temperature control device 7 located inside the reactor body 1, and then released by heat transfer and the internal temperature control device 7 located outside the reactor body 1.

[0095] As some examples of the present invention, the phase change material is a liquid-solid phase change material.

[0096] As some examples of the present invention, the phase change temperature of the phase change material is lower than the reaction temperature, preferably, the phase change temperature of the phase change material is 15~25°C lower than the reaction temperature.

[0097] As some specific examples of the present invention, this production apparatus for anhydrous aluminum trichloride, which includes both an external temperature control device 4 and an internal temperature control device 7, is particularly suitable for the preparation of anhydrous aluminum trichloride in large reaction furnaces 1 and at higher reaction temperatures, such as above 450°C.

[0098] Of course, the cooling chamber in the internal temperature control device 7 can also be filled with heat exchange medium, and cooling and heat dissipation can be achieved through the circulation of heat exchange medium. However, relatively speaking, using phase change material for heat dissipation can avoid large temperature changes in the reactor body 1, making the temperature control process more stable and making better use of the stability and continuity of the reaction.

[0099] For the rapid and intense exothermic reaction in the preparation of anhydrous aluminum trichloride, this embodiment addresses the core process challenges of localized thermal runaway, uneven temperature field, and difficulty in controlling the reaction rhythm through spatialized and precise thermal control. As is known to those skilled in the art, the most challenging problem in rapid and intense exothermic reactions is the accumulation of reaction heat from the outside to the center of the furnace. At this point, the furnace wall cooling structure can only remove heat near the wall surface. Due to the long heat transfer path and low mass and heat transfer efficiency, a high-temperature hotspot forms in the center of the furnace, with temperatures far exceeding the process setpoint. In this invention, an internal temperature control device 7 is installed in the central region of the furnace body 1. This device acts as a built-in heat dissipation source for the core heat accumulation area, directly removing heat from the high-temperature reaction zone in the center of the furnace. This significantly reduces the temperature gradient from the wall surface to the center, achieving uniform temperature control across the entire radial and axial domains. The improved temperature field uniformity alleviates the surge in side reactions and decreased product selectivity caused by localized high temperatures, thus improving product quality while better controlling the reaction process.

[0100] Example 4 like Figure 5 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method includes: The reactor body 1 has an inner furnace body 107 inside it. The inner furnace body 107 is a cylindrical structure that can be slidably installed inside the reactor body 1. An internal temperature control device 7 is installed in the inner furnace body 107. The internal temperature control device 7 is a circular columnar structure. A perforated plate 103 is formed by drilling holes in the bottom plate of the inner furnace body 107. The inner furnace body 107 and the internal temperature control device 7 are integrated into one unit. The mechanical lifting arm 8 is connected to the inner furnace body 107 and can drive the inner furnace body 107 and the inner temperature control device 7 to rise or fall. Thus, an aluminum receiving cavity 101 is formed in the upper part of the orifice plate 103, and a medium receiving cavity 102 is formed in the lower part of the orifice plate 103; In use, solid aluminum material is placed in the aluminum receiving cavity 101, that is, in the space formed by the cylinder wall of the inner furnace body 107, the perforated plate 103 and the outer wall of the inner temperature control device 7. Molten medium is filled in the medium receiving cavity 102, that is, the bottom of the reaction furnace body 1. The height of the inner furnace body 107 is adjusted by the mechanical lifting arm 8 so that at least part of the molten medium can overflow the perforated plate 103 and contact the solid aluminum material. In this way, a micro-reaction zone 104 can be formed on the upper side of the perforated plate 103. And a chlorine delivery device 5, which is used to deliver chlorine gas 9 into the micro-reaction zone 104 or the medium receiving cavity 102.

[0101] As some examples of the present invention, an external temperature control device 4 is provided on the outside of the reactor body 1.

[0102] The specific composition and working method of the mechanical lifting mechanism have been widely disclosed in the prior art. The present invention does not limit the specific structure of the mechanical lifting arm 8, as long as it can drive the inner furnace body 107 and the inner temperature control device 7 to rise or fall.

[0103] In addition, it should be noted that when implementing this embodiment, attention should also be paid to the sealing problem between the reactor body 1 and the inner furnace body 107. Since the actual lifting range of the inner furnace body 107 is small, mostly <3~5cm, sealing can be achieved by setting a sealing ring at the connection between the two, or by connecting the top surface of the reactor body 1 and the inner furnace body 107 through a retractable corrugated pipe.

[0104] In the production apparatus for anhydrous aluminum trichloride disclosed in this embodiment, by setting up a liftable inner furnace body 107, the area of ​​the micro-reaction zone 104 can be adjusted, thereby adjusting the reaction rate, making it more flexible, safe and controllable.

[0105] Example 5 like Figure 6 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method differs from Example 4 above mainly in that: The internal temperature control device 7 is filled with a composite material consisting of a solid-liquid phase change material and a thermosensitive magnetic material. At the same time, a magnet 9 is set below the reaction furnace body 1. The Curie point temperature of the thermosensitive magnetic material is 15~25℃ lower than the reaction temperature, and the temperature of the phase change material is 10~15℃ lower than the reaction temperature. During operation, the phase change material located at the lower part of the internal temperature control device 7 first absorbs heat and becomes liquid. At the same time, the thermistor magnetic material located at the lower part of the internal temperature control device 7 loses its magnetism and is no longer attracted by the magnetic force of the magnet 9 because its temperature has reached above the Curie point. Meanwhile, the composite material located at the upper part of the internal temperature control device 7 remains solid because its temperature is lower. At the same time, the thermistor magnetic material at the upper part still retains its magnetism. Thus, after the lower composite material melts, the composite material at the upper part of the internal temperature control device 7 can move downward under the magnetic attraction of the magnet 9, while squeezing the melted composite material at the lower part to the upper part of the internal temperature control device 7, where it dissipates heat and re-solidifies. This cycle, using magnetic attraction, achieves the non-powered circulation of the phase change material within the internal temperature control device 7, promoting heat dissipation.

[0106] As a preferred example of the present invention, considering the influence of the internal temperature control device 7, the medium in the central area of ​​the reactor body 1 cannot make good contact with the solid aluminum material. Therefore, an upwardly recessed groove can be provided at the bottom of the reactor body 1, and the magnet 9 can be embedded in the groove. In this way, the distance between the magnet 9 and the internal temperature control device 7 can be shortened, the effect of the magnet 9 on the thermosensitive magnetic material can be more fully utilized, and the molten medium can be better distributed in the area corresponding to the solid aluminum material.

[0107] As a preferred example of the present invention, the internal temperature control device 7 is particularly suitable for the production of anhydrous aluminum trichloride with a reaction temperature of <400°C.

[0108] As some examples of the present invention, the content of phase change material in the composite material is 75-90 wt%.

[0109] Example 6 like Figures 7-9 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method differs from Example 5 above mainly in that: The anhydrous aluminum trichloride production apparatus further includes an adaptive spring-loaded height adjustment mechanism 10, which is located at the connection between the reactor body 1 and the inner furnace body 107, and is used to automatically adjust the height of the reactor body 1 according to the pressure exerted by the inner furnace body 107 on the reactor body 1.

[0110] Specifically, the adaptive spring-loaded height adjustment mechanism 10 includes: The receiving groove 1001 is an annular groove provided on the top of the side wall of the reactor body 1; An elastic element 1002 is disposed in the receiving groove 1001; Flanged edge 1003 is an annular flange provided on the lower side of the top surface of the inner furnace body 107; After the inner furnace body 107 is installed inside the reaction furnace body 1, the elastic element 1002 is located inside the receiving groove 1001, the top surface of the inner furnace body 107 is pressed against the elastic element 1002, and the flange 1003 surrounds the outside of the receiving groove 1001.

[0111] Thus, the inner furnace body 107 will be installed on the reaction furnace body 1 mainly by the pressure it exerts on the elastic element 1002. The degree of elastic deformation of the elastic element 1002 will be directly determined by the pressure of the inner furnace body 107. That is, when the pressure of the inner furnace body 107 on the elastic element 1002 increases, the height of the elastic element 1002 under pressure decreases, thereby reducing the height of the inner furnace body 107; conversely, the height of the inner furnace body 107 will increase.

[0112] Based on this, the downward force on the inner furnace body 107 mainly consists of two parts: one is its own gravity. During continuous production, solid aluminum material is constantly consumed while new aluminum material is continuously added to the furnace body, thus its own gravity can remain basically constant. The other part is the magnetic attraction force generated by the magnet 9 on the composite material in the inner temperature control device 7. During the reaction process, when the reaction temperature rises, a large amount of phase change material in the lower part of the inner temperature control device 7 melts, and at the same time, a large amount of thermistor magnetic material loses its magnetism. At this time, the magnetic attraction force generated by the magnet 9 on the composite material in the inner temperature control device 7... The total amount of solid composite material that is magnetically attracted within the internal temperature control device 7 is small and far from the magnet 9. Therefore, the magnetic attraction force from the magnet 9 on the internal temperature control device 7 is small, and consequently, the pressure exerted by the inner furnace body 107 on the elastic member 1002 is also small. At this time, the elastic member 1002 recovers its deformation and increases in height, which will drive the inner furnace body 107 to move upward, so that less solid aluminum material comes into contact with the molten medium, the volume of the micro-reaction zone 104 decreases, the reaction rate slows down, and the released reaction heat decreases. Conversely, when the reaction temperature decreases, the smaller amount of phase change material in the lower part of the internal temperature control device 7 melts, and simultaneously, a smaller amount of thermistor magnetic material loses its magnetism. At this time, because the total amount of solid composite material that can be magnetically attracted within the internal temperature control device 7 is large and close to the magnet 9, the overall magnetic attraction force from the magnet 9 on the internal temperature control device 7 increases. Consequently, the pressure exerted by the inner furnace body 107 on the elastic element 1002 also increases. At this time, the elastic element 1002 is compressed and its height decreases, which can drive the inner furnace body 107 to move downward, allowing more solid aluminum material to come into contact with the molten medium. This increases the volume of the micro-reaction zone 104, improves the reaction rate, and increases the released heat of reaction. Thus, the adaptive spring-loaded height adjustment mechanism 10 achieves automatic adjustment of the height of the inner furnace body 107 and the reaction rate based on changes in the reaction temperature.

[0113] As some examples of the present invention, at room temperature, the magnetic attraction force on the internal temperature control device 7 is 0.5 to 3 times its own weight.

[0114] It should be noted that, in this invention, the height variation of the inner furnace body 107 is generally less than 5 cm, mostly less than 3 cm. The change in height leading to a change in the distance between the inner furnace body 107 and the magnet 9, and consequently a weakening of the magnetic force of the magnet 9 on the same object, has a very small effect and can be essentially ignored. Therefore, the magnetic force affecting the inner temperature control device 7 is mainly determined by the change in reaction temperature.

[0115] As some examples of the present invention, the elastic deformation capability of the elastic element 1002 is set according to the adjustment stroke of the inner furnace body 107. Specifically, it is preferable that the height of the micro-reaction zone 104 formed by the contact between the solid aluminum material and the molten medium material when the inner furnace body 107 is in its highest and lowest positions meets the set value. In addition, the magnitude of the magnetic force generated by the magnet 9 on the inner temperature control device 7, as well as the type and content of the phase change material and thermistor magnetic material in the inner temperature control device 7, can also be set as needed. Specifically, it is preferable that at the set reaction temperature, the adaptive spring-loaded height adjustment mechanism 10 can achieve height adjustment of the inner furnace body 107 to the set stroke.

[0116] As a preferred example of the present invention, such as Figure 9 As shown, the elastic element 1002 is an elastic structure with a circular or elliptical cross-section, such as an internally inflated industrial air spring. Thus, while achieving height adjustment, the elastic element 1002 can also maintain close contact with the top surface of the inner furnace body 107, achieving a good seal.

[0117] As a preferred example of the present invention, such as Figure 9 As shown, the adaptive spring-loaded height adjustment mechanism 10 further includes: The snap-fit ​​flange 1004 is an inwardly extending protrusion that is circumferentially spaced on the underside of the flange 1003; A notch is provided on the receiving groove 1001 to allow the snap-fit ​​flange 1004 to pass through. After the snap-fit ​​flange 1004 passes through the notch, the top surface of the inner furnace body 107 is rotated so that the snap-fit ​​flange 1004 is misaligned with the notch and located on the lower side of the receiving groove 1001. A gap is reserved between the snap-fit ​​flange 1004 and the lower side of the receiving groove 1001. When the inner furnace body 107 moves upward to the set highest position, the snap-fit ​​flange 1004 can snap onto the receiving groove 1001 to lock the upward movement of the inner furnace body 107.

[0118] As some examples of the present invention, a gap is reserved between the side wall of the receiving groove 1001 and the top surface of the inner furnace body 107. The height of this gap is the maximum stroke of the height adjustment of the inner furnace body 107. When the inner furnace body 107 moves downward to the set lowest position, the side wall of the receiving groove 1001 contacts the top surface of the inner furnace body 107. In this way, the receiving groove 1001 can provide receiving space and limit the elastic member 1002 while providing redundant support for the elastic member 1002, so as to avoid the elastic member 1002 being over-compressed.

[0119] As some examples of the present invention, in order to further strengthen the sealing connection between the inner furnace body 107 and the reaction furnace body 1, a sealing ring or other device may be provided between the outer side wall of the flange 1003 and the receiving groove 1001. It should be noted that the sealing device should be made of soft material, specifically so as not to affect the height adjustment of the inner furnace body 107.

[0120] Example 7 like Figures 10-11 As shown, a production apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method differs from Example 6 above mainly in that: The elastic element 1002 in the adaptive spring-loaded height adjustment mechanism 10 is as follows: Figure 11 The W-shaped elastic structure shown has a bolt 1006 threadedly connected to the inner furnace body 107, which passes through the gap in the middle of the elastic element 1002 and is inserted into a blind hole preset in the receiving groove 1001. The main function of the bolt 1006 is to limit the inner furnace body 107, the elastic element 1002 and the receiving groove 1001 in the vertical direction.

[0121] Similarly, the inner furnace body 107 is installed on the reaction furnace body 1 mainly by the pressure it exerts on the elastic element 1002, and the degree of elastic deformation of the elastic element 1002 will be directly determined by the magnitude of the pressure of the inner furnace body 107.

[0122] As some examples of the present invention, a limiting block 1005 is provided in the receiving groove 1001. The lower end of the limiting block 1005 is inserted into the receiving groove 1001, the upper end is U-shaped, and a groove adapted to the shape of one side of the elastic member 1002 is formed on the bottom surface of the limiting block 1005. In this way, the elastic member 1002 can be further limited by the limiting block 1005, and the elastic member 1002 can be allowed to deform appropriately.

[0123] Similarly, a gap is reserved between the limiting block 1005 and the top surface of the inner furnace body 107. This gap can serve the same purpose as the gap reserved between the side wall of the receiving groove 1001 and the top surface of the inner furnace body 107 in the above embodiment 10, which will not be described in detail here.

[0124] As some examples of the present invention, a plurality of the adaptive spring-loaded height adjustment mechanisms 10 are provided at circumferential intervals in the reactor body 1 and the inner furnace body 107.

[0125] It should be noted that, since the elastic element 1002 cannot play a sealing role at this time, a reliable sealing structure must be set at the connection between the reaction furnace body 1 and the inner furnace body 107.

[0126] As some examples of the present invention, a sealing ring with a cylindrical cross-section or a sealing material that is attached and fixed to the connecting surface can be provided between the flange 1003 and the receiving groove 1001, which can achieve a rolling seal between the two while allowing the inner furnace body 107 to make a small range of height adjustments.

[0127] As some examples of the present invention, during production, the gas pressure inside the reactor body 1 can be adjusted so that it operates under a slightly negative pressure, thereby reducing the requirements for the sealing level of the reactor body.

[0128] The process for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination provided by this invention is as follows: (1) After pretreatment, the waste aluminum material is metered and loaded into the hopper, and then sent into the reactor. At the same time, the medium material Me is loaded into the reactor to form the medium layer a. (2) After heating the reactor to the set temperature, chlorine gas is introduced into the reactor so that the medium material Me in the medium liquid reacts with the chlorine gas to generate the corresponding chloride. The chloride comes into direct contact with the solid aluminum material and undergoes a displacement reaction. The liquid medium generated by the displacement reaction returns to the bottom medium liquid, while the generated gaseous aluminum trichloride rises to the upper layer of the furnace and enters the collector. After crystallization, anhydrous aluminum trichloride is obtained.

[0129] (3) During the reaction, the valuable metals in the raw materials will gradually accumulate in the medium liquid. After the valuable metals in the medium liquid accumulate to a certain content, the medium liquid is discharged, the valuable metals are separated and extracted, and the valuable metal products are obtained. The separated and purified medium liquid can also be returned to the reactor.

[0130] The following specific examples illustrate the method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to the present invention: Example 8 Preparation of anhydrous aluminum trichloride: The preparation process is divided into three stages: furnace start-up, normal production, and furnace shutdown.

[0131] Production preparation: Collect scrap aluminum materials such as pure aluminum processing scraps, waste aluminum foil, aluminum alloy scraps, and machined scraps. Remove organic impurities from the surface by alkaline washing and ultrasonic cleaning. Then dry and crush to a particle size of 0.1~200mm for later use. Furnace start-up: Install the perforated plate, furnace cover, gas inlet and outlet, and charging hopper located inside the reactor body to support the aluminum charge layer b. Install the insulation blanket and preheat the aluminum charge through the external cooler (heat exchange tube) preheating system. Add the calculated amount of preheated medium material Me to molten state through the medium inlet on the reactor body, and add the aluminum charge preheated to 260°C.

[0132] Normal production: Connect the chlorine gas pipe, supply chlorine gas, and turn on the cooling crystallizer. Once the furnace temperature rises to the reaction temperature of 310℃, remove the insulation blanket and adjust the cooling airflow until the reaction gas outlet temperature reaches the rated value. Then stabilize the chlorine gas flow rate and normal production can begin. The AlCl3 purity was tested to be 99.6%.

[0133] Shutdown: When the system malfunctions or there are too many impurities in the furnace, such as LiCl and Al2O3, that need to be cleaned, the furnace should be shut down. When shutting down, first turn off the chlorine gas, add an insulation blanket, and continue the reaction by turning on the hot air to keep it warm until no aluminum chloride gas is produced. Then turn on the nitrogen gas and cool it to room temperature through the cooling system. Then open the furnace cover and remove the impurities.

[0134] Example 9 Preparation of anhydrous aluminum trichloride: The preparation process is divided into three stages: furnace start-up, normal production, and furnace shutdown.

[0135] Production preparation: Collect scrap aluminum materials such as pure aluminum processing scraps, waste aluminum foil, aluminum alloy scraps, and machining chips. Remove organic impurities from the surface by alkaline washing and ultrasonic cleaning. Then dry and crush to a particle size of 100~200mm for later use. Furnace start-up: Install the perforated plate, furnace cover, gas inlet and outlet, and charging hopper located inside the reactor body to support the aluminum material layer b, and the insulation blanket. Preheat the aluminum material through the external cooler (heat exchange tube) preheating system. Add the calculated amount of preheated to molten medium material Me through the medium inlet on the reactor body, and add the aluminum material preheated to 180°C.

[0136] Normal production: Connect the chlorine gas pipe, supply chlorine gas, and turn on the cooling crystallizer. Once the furnace temperature rises to the reaction temperature of 360℃, remove the insulation blanket and adjust the cooling airflow until the reaction gas outlet temperature reaches the rated value. Then stabilize the chlorine gas flow rate and normal production can begin. The AlCl3 purity was tested to be 99.4%.

[0137] Shutdown: When the system malfunctions or there are too many impurities in the furnace, such as LiCl and Al2O3, that need to be cleaned, the furnace should be shut down. When shutting down, first turn off the chlorine gas, add an insulation blanket, and continue the reaction by turning on the hot air to keep it warm until no aluminum chloride gas is produced. Then turn on the nitrogen gas and cool it to room temperature through the cooling system. Then open the furnace cover and remove the impurities.

[0138] Example 10 Preparation of anhydrous aluminum trichloride: The preparation process is divided into three stages: furnace start-up, normal production, and furnace shutdown.

[0139] Production preparation: Collect scrap aluminum materials such as pure aluminum processing scraps, waste aluminum foil, aluminum alloy scraps, and machined scraps. Remove organic impurities from the surface by alkaline washing and ultrasonic cleaning. Then dry and crush to a particle size of 10~50mm for later use. Furnace start-up: Install the perforated plate, furnace cover, gas inlet and outlet, and charging hopper located inside the reactor body to support the aluminum charge layer b, and the insulation blanket. Preheat the aluminum charge through the external cooler (heat exchange tube) preheating system. Add the calculated amount of preheated to molten medium material Me through the medium inlet on the reactor body, and add the aluminum charge preheated to 220°C.

[0140] Normal production: Connect the chlorine gas pipe, supply chlorine gas, and turn on the cooling crystallizer. Once the furnace temperature rises to the reaction temperature of 410℃, remove the insulation blanket and adjust the cooling airflow until the reaction gas outlet temperature reaches the rated value. Then stabilize the chlorine gas flow rate and normal production can begin. The AlCl3 purity was tested to be 99.6%.

[0141] Shutdown: When the system malfunctions or there are too many impurities in the furnace, such as LiCl and Al2O3, that need to be cleaned, the furnace should be shut down. When shutting down, first turn off the chlorine gas, add an insulation blanket, and continue the reaction by turning on the hot air to keep it warm until no aluminum chloride gas is produced. Then turn on the nitrogen gas and cool it to room temperature through the cooling system. Then open the furnace cover and remove the impurities.

[0142] Performance testing: The anhydrous aluminum trichloride prepared in Example 8 was tested, and the results are shown in Table 1 below: Table 1. Quality Inspection Results of Anhydrous Aluminum Trichloride Products Comparative Example 1 The specific steps for preparing anhydrous aluminum trichloride using the existing aluminum ingot method are as follows: 1. Material preparation: Select A00 grade pure aluminum ingots (aluminum content ≥99.7%) as raw materials and crush them into blocks; 2. Heating and melting: Place the block aluminum ingots into the reactor and heat them to 800°C to completely melt the aluminum ingots into molten aluminum; 3. Chlorination reaction: Chlorine gas is introduced into the molten aluminum (at a rate of 1.2 L / min). The chlorine gas reacts directly with the molten aluminum to produce gaseous AlCl3. 4. Condensation and crystallization: Gaseous AlCl3 enters the collector and naturally condenses and crystallizes to obtain anhydrous aluminum trichloride. 5. Exhaust gas treatment: The exhaust gas is discharged after being washed and absorbed by dilute alkali.

[0143] The anhydrous aluminum trichloride prepared in this comparative example is a pale yellow crystal, and the actual product is as follows: Figure 14As shown, it has a slight hydrochloric acid odor. After testing, the purity of AlCl3 is 98.6%, the free chlorine content is 0.05%, and the iron impurity content is 0.02%.

[0144] A comparison is made between anhydrous aluminum trichloride produced by the traditional aluminum ingot process and the preparation process provided by this invention: (1) From the perspective of product quality: Products produced by aluminum ingot processing are mostly yellow or gray; see attached for details. Figure 14 The product contains high levels of impurities such as free chlorine and iron, and can only be used to produce ordinary industrial-grade products. This is because chlorine reacts directly with molten aluminum. Insufficient chlorine can easily produce aluminum powder, aluminum monochloride, and aluminum dichloride, while excessive chlorine can produce free chlorine. High temperatures can also cause chlorides, which are impurities in the raw materials, to enter the product.

[0145] The product obtained by this invention is white, as shown in the attached document. Figure 12 and 13 High purity aluminum trichloride can be prepared by using materials with low levels of chlorine, free chlorine, and other impurities. This is because chlorine reacts first with the liquid medium, and the residual chlorine reacts with aluminum again. Therefore, there is no free chlorine in the product. Due to the low temperature of the process, chlorides other than aluminum are essentially liquid. Elements with a lower electronegativity than aluminum (such as lithium) are ultimately separated and recovered as chlorides. Chlorides of elements with a higher electronegativity than aluminum (such as silver, tin, and copper) undergo a displacement reaction with aluminum and ultimately enter the molten metal medium in metallic form. They are then released through a siphon and separated.

[0146] (2) Comparison based on the raw materials used: The aluminum ingot process requires the use of metallic aluminum ingots, generally A00 aluminum ingots (≥99.7%), which are more expensive.

[0147] This invention can use pure aluminum scrap or alloy scrap, including aluminum shavings, aluminum chips, aluminum blocks, aluminum ingots, aluminum foil, etc., which are inexpensive and have good economic benefits.

[0148] (3) Comparison in terms of preparation process and environmental pressure: The aluminum ingot process involves high reaction temperatures (above 800℃), and the molten aluminum pools are directly exposed to air, resulting in very high ambient temperatures in the production workshop. The exhaust gas contains residual chlorine, further increasing the processing burden.

[0149] This invention features a low reaction temperature (mainly around 300℃), a completely sealed reactor, and a more comfortable ambient temperature. The exhaust gas contains virtually no free chlorine, reducing the processing burden.

[0150] (4) From an economic perspective: The high price of raw materials for aluminum ingot processing and the poor quality of products result in poor economic benefits.

[0151] This invention uses aluminum scrap, which is much cheaper, and can easily separate and recycle valuable elements in aluminum alloys, such as tin, copper, silver, and lithium. The product quality is also good, resulting in higher economic benefits.

[0152] Through multiple experiments and measurements, it was found that the purity of the product prepared by this process is AlCl3 ≥ 99.2%, while the purity of the product prepared by other existing methods is AlCl3 ≥ 98.5%.

[0153] In summary, this invention provides a green and energy-saving preparation method and apparatus for high-purity anhydrous aluminum trichloride, which has the following advantages: (1) High product purity, capable of producing high-purity anhydrous aluminum trichloride: This invention adopts an indirect chlorination mode, where chlorine gas first reacts with the medium liquid, and the residual chlorine gas can further react with the aluminum material, greatly reducing the free chlorine residue; the reaction temperature is low (185~650℃), and the impurity chlorides other than aluminum are basically in liquid state and cannot enter the crystallizer with the gaseous aluminum trichloride; at the same time, the valuable alloying elements in the waste aluminum can be separated by the difference in electronegativity, avoiding them from being mixed into the product as impurities. The final anhydrous aluminum trichloride is a white crystal with AlCl3 purity ≥99.2%, which is much higher than the existing process (the purity of the product of the existing process is ≥98.5%), and it has no hydrochloric acid odor, which can meet the needs of high-end industrial fields.

[0154] (2) Raw material costs are significantly reduced and resource utilization is high: This invention can directly use waste aluminum as raw material without using high-purity A00 aluminum ingots. The price of waste aluminum is much lower than that of pure aluminum ingots, which significantly reduces raw material costs. At the same time, valuable alloying elements such as tin, silver, copper, nickel and lithium in waste aluminum can be efficiently separated and recycled, improving resource utilization and further enhancing comprehensive economic benefits.

[0155] (3) Low reaction energy consumption and environmentally friendly production: The reaction temperature of the present invention is controlled at 185~650℃, which is much lower than that of the existing aluminum ingot method (above 800℃) and alumina method (above 1000℃), which greatly reduces energy consumption; the reactor is completely sealed to avoid direct heat dissipation, the workshop environment temperature is comfortable, and the working conditions can be improved; and the free chlorine content in the tail gas is extremely low (≤0.01%), the environmental protection burden is light, and it meets the requirements of green production.

[0156] (4) The process is stable and reliable and easy to operate: The present invention adopts a segmented heating and constant temperature control mode, combined with the setting of micro-reaction zone to ensure that the reaction temperature is stable and controllable; on this basis, the internal and external temperature control structure avoids the reaction runaway and side reaction caused by local overheating; and the medium material can be recycled and does not need to be replenished frequently; the waste aluminum material pretreatment process is simple, and the overall process can realize continuous production, which is convenient for industrial promotion and application.

[0157] (5) Low equipment investment and significant economic benefits: The reaction temperature of this invention is low, which reduces the high temperature resistance requirements of the reactor and the equipment cost is relatively low; the raw material cost is low, the product added value is high, and the valuable elements can be recycled, forming a closed-loop industrial chain of "waste aluminum utilization - high-purity product preparation - valuable element recycling", achieving the production goal of low cost, low energy consumption, low investment and high returns.

[0158] In summary, the method and apparatus for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination described in this invention can achieve low-cost, low-energy consumption, low-investment, and high-return preparation of high-purity anhydrous aluminum trichloride.

[0159] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination, characterized in that, include: At 185~650℃, chlorine gas is introduced into the molten medium material Me, so that the molten medium material Me reacts with chlorine gas to generate chloride. Then, AlCl3 is generated through the displacement reaction between solid Al and chloride. The aluminum chloride generated in the reaction sublimates into the collector and is collected to obtain anhydrous aluminum trichloride product. The medium material Me is a metal or alloy with a melting point between 185 and 650°C, capable of reacting with chlorine to generate chloride, and whose chloride can undergo a displacement reaction with aluminum to generate AlCl3.

2. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 1, characterized in that, The method for preparing anhydrous aluminum trichloride includes the following steps: S1, Material preparation: Prepare granular aluminum material for later use; S2, charging: add dielectric material Me into the reactor to form dielectric layer a, and then place solid aluminum material on top of dielectric layer a to form aluminum material layer b; S3, Preparation of aluminum trichloride by heating reaction: The temperature inside the reactor is heated to between 185 and 650°C to ensure that the aluminum material remains in a solid state. The medium material Me in the medium layer a melts into a medium liquid, and the melted medium liquid can contact the aluminum material layer b above it. Chlorine gas is introduced into the medium liquid, so that the medium material Me in the medium liquid reacts with the chlorine gas to generate the corresponding liquid chloride. The chloride comes into direct contact with the solid aluminum material and undergoes a displacement reaction. The liquid medium material Me generated by the displacement reaction returns to the medium liquid, and the generated gaseous aluminum trichloride rises into the collector. After crystallization, anhydrous aluminum trichloride is obtained.

3. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 2, characterized in that, The particle size range of the granular aluminum material is 0.1~200mm, and the granular aluminum material is aluminum ingot or scrap aluminum.

4. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 1, 2, or 3, characterized in that, The aluminum material used is scrap aluminum, which is either pure aluminum scrap or scrap aluminum alloy rich in one or more valuable metals.

5. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 4, characterized in that, Before use, the waste aluminum material should be pretreated to remove organic impurities and moisture.

6. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 1, characterized in that, Before feeding the aluminum material into the reactor, it is preheated to above 150°C in an inert atmosphere.

7. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 1, characterized in that, The dielectric material Me is tin, lead, bismuth, zinc, or an alloy thereof.

8. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 2, characterized in that, During the preparation of anhydrous aluminum trichloride, the aluminum material layer b is always kept at a height of more than 0.5 cm immersed in the medium liquid for reaction. As the reaction proceeds, the solid aluminum material at the bottom of the aluminum material layer b is gradually consumed, and the solid aluminum material at the top falls into the medium liquid, so that the reaction continues.

9. The method for preparing anhydrous aluminum trichloride based on low-temperature indirect chlorination according to claim 2, characterized in that, The medium material Me contains 0.5-1.5 wt% of low-melting-point metal elements.

10. An apparatus for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, characterized in that, The apparatus for preparing anhydrous aluminum trichloride is used to prepare anhydrous aluminum trichloride according to any one of claims 1 to 9.

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