A method for preparing anhydrous aluminum chloride by using a multi-stage countercurrent cyclone

Abstract

The application relates to a method for preparing anhydrous aluminum chloride by using a multistage countercurrent cyclone, and belongs to the technical field of anhydrous aluminum chloride preparation. The method is characterized in that: alumina or an aluminum-containing mineral is used as a raw material, mixed with a chlorinating agent and a carbon source under the action of a heat source, and a chlorination reaction is carried out between a solid phase and a gas phase in a heat exchange process in a multistage countercurrent cyclone in a countercurrent mode, so that high-purity aluminum chloride with a mass fraction of 99.9% is finally obtained. The method uses a clean energy utilization process, absorbs carbon dioxide in tail gas by using calcium-containing water, realizes zero carbon emission, has high heat utilization efficiency and high chlorination utilization efficiency, and provides a new idea for obtaining anhydrous aluminum chloride raw materials in a low-cost, green and low-carbon mode.

Description

Technical Field

[0001] This invention belongs to the field of anhydrous aluminum chloride preparation technology, and relates to a method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator. Background Technology

[0002] Anhydrous aluminum chloride is an important industrial raw material. Currently, the most common industrial method for producing anhydrous aluminum chloride is the direct chlorination of metallic aluminum ingots. Chlorine gas is passed into molten aluminum to initiate the chlorination reaction, and the resulting aluminum chloride is then condensed to obtain anhydrous aluminum chloride. This method produces anhydrous aluminum chloride at a high cost, resulting in a persistently high price for the product.

[0003] CN103708518A uses aqueous aluminum chloride and thionyl chloride as raw materials. Solid aluminum chloride hexahydrate and liquid thionyl chloride are added separately to a dehydration reactor at atmospheric or slightly negative pressure. The water of crystallization reacts with thionyl chloride to generate sulfur dioxide gas and hydrogen chloride gas, and the aluminum chloride hexahydrate is converted into anhydrous aluminum chloride. The slurry is filtered, and the filtrate - thionyl chloride - is returned for use. The filtered anhydrous aluminum chloride filter cake is distilled in a distiller to obtain pure anhydrous aluminum chloride. The finished anhydrous aluminum chloride is packaged and stored. The distilled thionyl chloride gas is cooled and returned as a raw material for use. The reaction byproducts, a mixture of hydrogen chloride and sulfur dioxide gas, are absorbed and treated.

[0004] CN103803622A discloses a method for preparing anhydrous aluminum chloride from aluminum chloride hexahydrate by dehydration, comprising: (1) drying aluminum chloride hexahydrate to remove most of the water of crystallization; (2) dissolving the dried aluminum chloride in alcohol to prepare an alcoholic solution of aluminum chloride, and removing the water from the alcoholic solution of aluminum chloride by vacuum distillation; (3) reacting the dehydrated aluminum chloride alcoholic solution with ammonia to crystallize AlCl3·NH3; (4) washing, filtering and drying to obtain AlCl3·NH3 crystals, and heating the dried crystals to decompose and deaminate to obtain anhydrous aluminum chloride; in each process, ammonia, detergent and crystallization mother liquor can be recycled.

[0005] The above reaction process uses aluminum chloride hexahydrate to dehydrate and prepare anhydrous aluminum chloride. The process is complex and the energy consumption of the dehydration process is high. How to obtain anhydrous aluminum chloride raw materials in a low-cost, green and low-carbon way has become a problem that is currently troubling the anhydrous aluminum chloride industry. Summary of the Invention

[0006] Currently, the methods for preparing anhydrous aluminum chloride, such as direct chlorination of aluminum ingots and dehydration of aluminum chloride hexahydrate, are costly, complex, and energy-intensive, failing to meet the requirements of low cost, green, and low-carbon production.

[0007] To address the above problems, this invention provides a method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator, comprising the following steps:

[0008] Step 1. Using alumina or aluminum-containing minerals as raw materials, mix them with a chlorinating agent and a carbon source under the action of a heat source to obtain a mixture;

[0009] Step 2. The mixture undergoes a chlorination reaction in a multi-stage countercurrent cyclone separator to generate high-temperature flue gas and slag; wherein, the multi-stage countercurrent cyclone separator consists of one or more cyclone heat exchangers, and the solid phase and gas phase undergo a chlorination reaction in a countercurrent manner during the heat exchange process;

[0010] Step 3. The high-temperature flue gas is condensed and separated in a screw propeller condenser to obtain anhydrous aluminum chloride and residual flue gas; the residual flue gas is compressed and separated to obtain liquid chlorine and carbon dioxide.

[0011] Step 4. Remove iron from anhydrous aluminum chloride using aluminum powder to obtain high-purity aluminum chloride;

[0012] The working mechanism of the multi-stage countercurrent cyclone separator is as follows: the mixture obtained in step 1 is added to the countercurrent cyclone heat exchanger, and high-temperature flue gas is introduced into it to carry out heat exchange and chlorination reaction. The filter residue obtained from the reaction is discharged or carried by the high-temperature flue gas into the next stage countercurrent cyclone heat exchanger, realizing the recycling of heat and carbon source until the chlorination efficiency of alumina or aluminum-containing raw materials in the filter residue is greater than 95%, and the heat exchange and chlorination reaction ends. During the heat exchange and chlorination reaction, biomass carbon is added to the reactor as a supplementary carbon source.

[0013] In step 1, the mass fraction of alumina is greater than 98.5%, and the aluminum-containing mineral is one or more of the following: gibbsite, boehmite, diaspore, kaolin, illite, pyrophyllite, red mud, fly ash, aluminum ash, coal gangue, and coal gasification slag; the chlorinating agent is chlorine gas; the carbon source and heat source are high-temperature carbon-containing flue gas generated by "oxygen-rich and oxygen-deficient" combustion in a gas-fired boiler; the mass ratio of alumina or aluminum-containing raw material to carbon source is carbon monoxide: alumina or aluminum-containing raw material = 0.2 to 4:1.

[0014] The "oxygen-enriched and oxygen-deficient" combustion refers to the oxygen-deficient combustion of carbon monoxide and oxygen in a gas-fired boiler, producing high-temperature carbon-containing flue gas containing carbon monoxide and carbon dioxide. The resulting flue gas does not contain nitrogen or sulfur products and does not require desulfurization or denitrification treatment.

[0015] In step 2, carbon and oxygen are added to the feed inlet and air inlet of the multi-stage countercurrent cyclone separator, respectively. The heat released after the added carbon and oxygen react is 5% to 15% of the heat required by the system. The chlorination reaction temperature is 300 to 1000°C, and the time is 10 to 90 minutes. Biomass carbon needs to be added during the chlorination reaction. The chlorination efficiency of aluminum-containing raw materials in the chlorination reaction is greater than 95%. The high-temperature flue gas temperature is 300 to 400°C, the system heat utilization rate reaches more than 70%, and the chlorine utilization efficiency reaches more than 99%.

[0016] In step 3, the spiral propulsion condenser is connected to the flue gas recovery device via a pipeline. The spiral propulsion condenser utilizes a hollow spiral scraper propeller with a central shaft. Solid components in the high-temperature flue gas condense and adhere to the inner wall of the condenser. The spiral scraper propeller rotates at 5-100 rpm, stripping away the condensed solids from the inner wall and discharging them into the condenser tank. The remaining flue gas is discharged through the central shaft of the spiral scraper propeller and sent to the flue gas recovery device for recycling. The separation efficiency between the high-temperature flue gas and anhydrous aluminum chloride is greater than 99%, and the moisture content of the anhydrous aluminum chloride is less than 0.1%.

[0017] In step 3, when alumina is used as the raw material, a single-stage spiral propulsion condenser is used, and the temperature is controlled at 155-175℃ to obtain aluminum chloride product. When the raw material is one of the following: gibbsite, boehmite, diaspore, kaolin, illite, pyrophyllite, red mud, fly ash, coal gangue, or coal gasification slag, a three-stage spiral propulsion condenser is set up. The first stage controls the temperature range of 200-250℃ to obtain crude ferric chloride, the second stage controls the temperature at 155-175℃ to obtain crude aluminum chloride, and the third stage controls the temperature at 10-30℃ to obtain crude silicon tetrachloride.

[0018] In step 4, aluminum chloride is purified by removing iron from aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%, and silicon tetrachloride is purified by distillation to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%.

[0019] The present invention provides a method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator, which, compared with the prior art, has the following advantages:

[0020] (1) High-temperature carbon monoxide flue gas generated by "oxygen-rich and oxygen-deficient" combustion in a gas-fired boiler is used as a heat source and carbon source. At the same time, appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system, without the need for additional heating. The resulting flue gas contains no nitrogen or sulfur products, and the generated flue gas does not require desulfurization and denitrification treatment, which is a clean energy utilization process.

[0021] (2) The system has high heat utilization efficiency and high chlorination utilization efficiency: Using a multi-stage countercurrent cyclone separator as a reaction device, the high-temperature flue gas preheats the material through the multi-stage countercurrent setting. The temperature of the high-temperature flue gas of anhydrous aluminum chloride obtained after passing through the multi-stage countercurrent cyclone separator is less than 300℃, and the system heat utilization rate reaches more than 70%; the chlorine utilization efficiency reaches more than 99%.

[0022] (3) The spiral propeller condenser is equipped with an internal spiral propeller. The condensed solids are discharged from the condenser tank via spiral propeller scrapers. The central shaft of the spiral propeller has a hollow structure, through which flue gas is discharged, achieving continuous discharge of anhydrous aluminum chloride. The condensation recovery efficiency of aluminum chloride is greater than 99%, and the water absorption rate is less than 0.1%.

[0023] (4) Zero emissions, clean production, and high added value of products. Carbon dioxide in the exhaust gas is absorbed by calcium-containing water, achieving zero carbon emissions. Attached Figure Description

[0024] Figure 1 A schematic diagram of the process and apparatus for preparing anhydrous aluminum chloride.

[0025] Figure 2 This is a schematic diagram of a spiral propulsion condenser device.

[0026] Among them, 1-stirring motor; 2-spiral propulsion scraper; 3-flue gas inlet; 4-airlock; 5-tank body. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the embodiments.

[0028] The alumina used in the embodiments of the present invention has the following main component contents: Al-98.6%, SiO2%-0.01%, Fe2O3%-0.02%, and Na2O-0.5%;

[0029] The bauxite used in the embodiments of the present invention has the following main components: Al2O3 63.85%, SiO2 12.84%, TiO2 2.93%, Fe2O3 3.64%, Ga2O3-40ppm, Sc2O3-30ppm, Li2O-120ppm, and the remainder are trace elements.

[0030] The red mud used in the embodiments of the present invention has the following main components: Al2O3-23.85%, SiO2-19.84%, TiO2-2.93%, Fe2O3-6.64%, Ga2O3-30ppm, Sc2O3-80ppm, Li2O-60ppm, with the balance being impurities.

[0031] The aluminum ash used in the embodiments of the present invention has the following main components: Al-45.3%, MgO-10%, F-2.3%, Cl-15.3%, with the remainder being impurities.

[0032] The fly ash used in the embodiments of the present invention has the following main components: Al2O3-47.8%, SiO2-42.3%, MgO-1.21%, Fe2O3-3.51%, TiO2-2.3%, Ga2O3-80ppm, Sc2O3-30ppm, Li2O-400ppm, GeO2-32ppm, with the balance being impurities.

[0033] The main components of the coal gangue used in the embodiments of the present invention are shown in the table below: C-14.9%, O-48.3%, Al-11%, Si-19.3%, K-0.75%, Ca-1.07%, Fe-2.29%, with the balance being impurities;

[0034] The main components of the coal gasification slag used in the embodiments of the present invention are Al2O3-8.72%, SiO2-35.24%, MgO-1.54%, Fe2O3-5.73%, with the remainder being impurities;

[0035] The production process described in this invention is not limited to using this type of raw material; any raw material with aluminum as its main component can be produced using this technology.

[0036] The process flow and apparatus for preparing anhydrous aluminum chloride in the examples are as follows: Figure 1 As shown, the spiral propulsion condenser device is as follows: Figure 2 As shown.

[0037] Example 1

[0038] A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator mainly includes the following steps:

[0039] (1) High-temperature carbon monoxide flue gas generated by the "oxygen-rich and oxygen-deficient" combustion of the gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to aluminum oxide in the flue gas is 0.2:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system. The heat released after the added carbon and oxygen react is 9% of the heat required by the system.

[0040] (2) A two-stage countercurrent cyclone separator is used. Alumina is added to the second-stage cyclone separator. The reaction temperature of the chlorination process is 500℃ and the reaction time is 90min. Alumina reacts with chlorine to produce anhydrous aluminum chloride.

[0041] (3) A single-stage spiral propeller condenser is used, the temperature is controlled at 155℃, the stirring speed of the spiral propeller is 50rpm, and the condensed product is pushed out through the discharge airlock and sealed. The separation efficiency of flue gas and anhydrous aluminum chloride is 99%, and the water content of the obtained anhydrous aluminum chloride is 0.08%.

[0042] (4) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0043] After treatment by this method, the chlorination efficiency of alumina is 96%; the gas phase products are separated and iron is removed by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0044] Example 2

[0045] A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator mainly includes the following steps:

[0046] (1) High-temperature carbon monoxide flue gas generated by the "oxygen-rich and oxygen-deficient" combustion of the gas boiler is used as the heat source and carbon source. The ratio of carbon monoxide to aluminum oxide in the flue gas is 1:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system. The heat released after the added carbon and oxygen react is 5% of the heat required by the system.

[0047] (2) A three-stage countercurrent cyclone separator is used to add alumina into the third stage cyclone separator. The chlorination process is carried out at a reaction temperature of 600℃ and a reaction time of 90min. Alumina reacts with chlorine to produce anhydrous aluminum chloride.

[0048] (3) A single-stage spiral propulsion condenser is used to control the temperature to 175℃. The condenser is condensed by the spiral propulsion condenser. The stirring speed of the spiral propulsion condenser is 5rpm. The condensed product is pushed out through the discharge airlock and sealed. The separation efficiency of flue gas and anhydrous aluminum chloride is 99%. The water content of the obtained anhydrous aluminum chloride is 0.09%.

[0049] (4) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0050] After treatment by this method, the chlorination efficiency of alumina is 98%; the gas phase products are separated and iron is removed by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0051] Example 3

[0052] A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator mainly includes the following steps:

[0053] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to aluminum oxide in flue gas is 2:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 10% of the heat required by the system.

[0054] (2) A 4-stage countercurrent cyclone separator was used. Alumina was added to the 4th stage cyclone separator. The chlorination process was carried out at a reaction temperature of 800℃ and a reaction time of 80min. Alumina reacted with chlorine to produce anhydrous aluminum chloride.

[0055] (3) A single-stage spiral propulsion condenser is used to control the temperature to 160℃. The condenser is condensed by the spiral propulsion condenser. The stirring speed of the spiral propulsion condenser is 100rpm. The condensed product is pushed out through the discharge airlock and sealed. The separation efficiency of flue gas and anhydrous aluminum chloride is 99%. The moisture content of the obtained anhydrous aluminum chloride is 0.08%.

[0056] (4) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0057] (5) The anhydrous aluminum chloride obtained is purified by a purification process to obtain anhydrous aluminum chloride product.

[0058] After treatment by this method, the chlorination efficiency of alumina is 97%; the gas phase products are separated and iron is removed by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0059] Example 4

[0060] A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator mainly includes the following steps:

[0061] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to aluminum oxide in flue gas is 4:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 8% of the heat required by the system.

[0062] (2) A three-stage countercurrent cyclone separator was used to add alumina into the third stage cyclone separator. The chlorination process was carried out at a reaction temperature of 450℃ and a reaction time of 60min. Alumina reacted with chlorine to produce anhydrous aluminum chloride.

[0063] (3) A single-stage spiral propulsion condenser is used, the temperature is controlled at 170℃, and condensation is carried out through the spiral propulsion condenser. The stirring speed of the spiral propulsion condenser is 60rpm, which pushes the condensed product out through the discharge airlock and seals it. The separation efficiency of flue gas and anhydrous aluminum chloride is 99%, and the water content of the obtained anhydrous aluminum chloride is 0.07%.

[0064] (4) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0065] (5) The anhydrous aluminum chloride obtained is purified by a purification process to obtain anhydrous aluminum chloride product.

[0066] After treatment by this method, the chlorination efficiency of alumina is 97%; the gas phase products are separated and iron is removed by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0067] Example 5

[0068] A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator mainly includes the following steps:

[0069] (1) High-temperature carbon monoxide flue gas generated by the "oxygen-rich and oxygen-deficient" combustion of the gas boiler is used as the heat source and carbon source. The ratio of carbon monoxide to aluminum oxide in the flue gas is 3:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system. The heat released after the added carbon and oxygen react is 12% of the heat required by the system.

[0070] (2) A five-stage countercurrent cyclone separator was used. Alumina was added to the five-stage cyclone separator. The chlorination process was carried out at a reaction temperature of 1000℃ and a reaction time of 40min. Alumina reacted with chlorine to produce anhydrous aluminum chloride.

[0071] (3) A single-stage spiral propulsion condenser is used, the temperature is controlled at 160℃, and condensation is carried out through the spiral propulsion condenser. The stirring speed of the spiral propulsion condenser is 80rpm, which pushes the condensed product out through the discharge airlock and seals it. The separation efficiency of flue gas and anhydrous aluminum chloride is 99%, and the water content of the obtained anhydrous aluminum chloride is 0.06%.

[0072] (4) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0073] (5) The anhydrous aluminum chloride obtained is purified by a purification process to obtain anhydrous aluminum chloride product.

[0074] After treatment by this method, the chlorination efficiency of alumina is 98%; the gas phase products are separated and iron is removed by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0075] Example 6

[0076] The raw material used in this invention is bauxite, and the main steps include:

[0077] (1) High-temperature carbon monoxide flue gas generated by the "oxygen-rich and oxygen-deficient" combustion of the gas boiler is used as the heat source and carbon source. The ratio of carbon monoxide to bauxite in the flue gas is 4:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system. The heat released after the added carbon and oxygen react is 8% of the heat required by the system.

[0078] (2) A three-stage countercurrent cyclone separator is used to add bauxite into the third stage cyclone separator. The chlorination process is carried out at a reaction temperature of 850℃ and a reaction time of 80min. Bauxite reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare metal chlorides.

[0079] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 250°C to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 170°C to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to 30°C to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.07%.

[0080] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0081] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0082] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in bauxite is 96%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0083] Example 7

[0084] The raw material used in this invention is red mud, and the main steps include:

[0085] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to red mud in flue gas is 4:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 8% of the heat required by the system.

[0086] (2) A three-stage countercurrent cyclone separator is used. Red mud is added to the third-stage cyclone separator. The chlorination process is carried out at a reaction temperature of 900℃ and a reaction time of 70min. Red mud reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare dispersed metal chlorides.

[0087] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 200℃ to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 160℃ to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to -10℃ to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.08%.

[0088] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0089] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0090] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in the red mud is 97%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0091] Example 8

[0092] The raw material used in this invention is aluminum ash, and the main steps include:

[0093] (1) High-temperature carbon monoxide flue gas generated by the "oxygen-rich and oxygen-deficient" combustion of the gas boiler is used as the heat source and carbon source. The ratio of carbon monoxide to aluminum ash in the flue gas is 3:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of the chlorination reaction in the system. The heat released after the added carbon and oxygen react is 10% of the heat required by the system.

[0094] (2) A three-stage countercurrent cyclone separator is used. Aluminum ash is added to the third-stage cyclone separator. The chlorination process is carried out at a reaction temperature of 950℃ and a reaction time of 60min. Aluminum ash reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare dispersed metal chlorides.

[0095] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 220°C to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 155°C to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to 10°C to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.08%.

[0096] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.6%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.99%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0097] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0098] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in aluminum ash is 96%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0099] Example 9

[0100] The raw material used in this invention is fly ash, and the main steps include:

[0101] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to fly ash in flue gas is 3:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 10% of the heat required by the system.

[0102] (2) A three-stage countercurrent cyclone separator is used to add fly ash into the third stage cyclone separator. The chlorination process is carried out at a reaction temperature of 1000℃ and a reaction time of 90min. Fly ash reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare dispersed metal chlorides.

[0103] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 220°C to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 165°C to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to 20°C to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.08%.

[0104] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0105] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0106] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in fly ash is 96%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0107] Example 10

[0108] The raw material used in this invention is coal gangue, and the main steps include:

[0109] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to coal gangue in flue gas is 3.5:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 10% of the heat required by the system.

[0110] (2) A four-stage countercurrent cyclone separator is used. Fly ash is added to the fourth stage cyclone separator. The chlorination process is carried out at a reaction temperature of 900℃ and a reaction time of 90min. Coal gangue reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare dispersed metal chlorides.

[0111] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 230°C to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 165°C to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to 15°C to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.09%.

[0112] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0113] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0114] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in coal gangue is 96%; carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

[0115] Example 11

[0116] The raw material used in this invention is coal gasification slag, and the main steps include:

[0117] (1) High-temperature carbon monoxide flue gas generated by “oxygen-rich and oxygen-deficient” combustion of gas boiler is used as heat source and carbon source. The ratio of carbon monoxide to coal gasification slag in flue gas is 3.5:1. Appropriate amounts of carbon and oxygen are added at the feed port and air inlet of the multi-stage countercurrent cyclone separator to maintain the thermal balance of chlorination reaction in the system. The heat released after the added carbon and oxygen react is 15% of the heat required by the system.

[0118] (2) A three-stage countercurrent cyclone separator is used to add coal gasification slag into the third stage cyclone separator. The chlorination process is carried out at a reaction temperature of 800℃ and a reaction time of 90min. The coal gasification slag reacts with chlorine and carbon monoxide to produce aluminum chloride, ferric chloride, silicon chloride and rare dispersed metal chlorides.

[0119] (3) A three-stage spiral propulsion condenser is used for condensation separation. The spiral propulsion agitator is driven at a speed of 70 rpm, which pushes the condensed product out through the discharge airlock. First, the first-stage spiral propulsion condenser cools down to 240°C to obtain crude ferric chloride product. Then, the second-stage spiral propulsion condenser cools down to 160°C to obtain crude aluminum chloride. Finally, the third-stage spiral propulsion condenser cools down to 20°C to obtain crude silicon tetrachloride. Through the spiral propulsion condenser, the separation efficiency of flue gas and chloride is 99%, and the water content of the obtained chloride is 0.08%.

[0120] (4) The silicon tetrachloride produced by chlorination can be continuously discharged in liquid form through a condenser. The aluminum chloride is de-ironized by aluminum powder to obtain high-purity aluminum chloride with a mass fraction of 99.9%. The silicon tetrachloride is distilled to obtain high-purity silicon tetrachloride with a mass fraction of 99.9%. The enriched rare and dispersed metal chlorides can be further separated and purified.

[0121] (5) The remaining carbon dioxide in the exhaust gas is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate;

[0122] After treatment by this method, the chlorination efficiency of aluminum, silicon, and rare metals in the coal gasification slag is 96%; the carbon dioxide in the tail gas is absorbed by calcium-containing wastewater to obtain light calcium carbonate product.

Claims

1. A method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator, characterized in that, It mainly includes the following steps, Step 1. Using alumina or aluminum-containing minerals as raw materials, mix them with a chlorinating agent and a carbon source under the action of a heat source to obtain a mixture; Step 2. The mixture undergoes a chlorination reaction in a multi-stage countercurrent cyclone separator to generate high-temperature flue gas and slag; wherein, the multi-stage countercurrent cyclone separator consists of one or more cyclone heat exchangers, and the solid phase and gas phase undergo a chlorination reaction in a countercurrent manner during the heat exchange process; Step 3. The high-temperature flue gas is condensed and separated in a spiral propeller condenser to obtain anhydrous aluminum chloride and residual flue gas. The residual flue gas is compressed and separated to obtain liquid chlorine and carbon dioxide. The spiral propeller condenser is connected to a flue gas recovery device. The spiral propeller condenser uses a hollow spiral scraper propeller with a central shaft. Solid components in the high-temperature flue gas condense and adhere to the inner wall of the condenser. The spiral scraper propeller rotates at 5-100 rpm, peeling off the condensed solids from the inner wall and discharging them into the condenser tank. The residual flue gas is discharged through the central shaft of the spiral scraper propeller and sent to the flue gas recovery device for recovery. The separation efficiency between the high-temperature flue gas and anhydrous aluminum chloride is greater than 99%; the moisture content of the anhydrous aluminum chloride is less than 0.1%. Step 4. Remove iron from anhydrous aluminum chloride using aluminum powder to obtain high-purity aluminum chloride; In step 1, the mass fraction of alumina is greater than 98.5%, and the aluminum-containing mineral is one or more of the following: gibbsite, boehmite, diaspore, illite, pyrophyllite, red mud, fly ash, aluminum ash, coal gangue, and coal gasification slag. The chlorinating agent is chlorine gas; the carbon source and heat source are high-temperature carbon-containing flue gas generated by "oxygen-rich and oxygen-deficient" combustion in a gas-fired boiler; the mass ratio of alumina and carbon source is carbon monoxide: alumina or aluminum-containing raw materials = (0.2~4):1; The "oxygen-enriched and oxygen-deficient" combustion refers to the oxygen-deficient combustion of carbon monoxide and oxygen in a gas-fired boiler, producing high-temperature carbon-containing flue gas containing carbon monoxide and carbon dioxide. The resulting flue gas does not contain nitrogen or sulfur products. Carbon and oxygen are added to the feed inlet and air inlet of the multi-stage countercurrent cyclone separator, respectively. The heat released after the reaction of the added carbon and oxygen is 5% to 15% of the heat required by the system. In step 2, biomass carbon needs to be added during the chlorination reaction; the chlorination reaction time is 10~90min; the chlorination efficiency of aluminum-containing raw materials in the chlorination reaction is greater than 95%; the high-temperature flue gas temperature is 300~400℃, the system heat utilization rate reaches more than 70%, and the chlorine utilization efficiency reaches more than 99%.

2. The method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator according to claim 1, characterized in that, In step 2, the chlorination reaction temperature is 300~1000℃.

3. The method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator according to claim 1, characterized in that, Alumina is used as raw material, and a single-stage spiral propulsion condenser is used to control the temperature at 155~175℃ to obtain aluminum chloride product. Using aluminum-containing minerals as raw materials, the spiral propulsion condenser is a three-stage spiral propulsion condenser. The first stage controls the temperature range of 200~250℃ to obtain crude ferric chloride, the second stage controls the temperature of 155~175℃ to obtain crude aluminum chloride, and the third stage controls the temperature of 10~30℃ to obtain crude silicon tetrachloride. The liquid chlorine is returned to the chlorination stage for use, and carbon dioxide is absorbed by a calcium-containing aqueous solution to prepare light calcium carbonate.

4. The method for preparing anhydrous aluminum chloride using a multi-stage countercurrent cyclone separator according to claim 1, characterized in that, In step 4, the mass fraction of high-purity aluminum chloride is greater than 99.99%.

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