A method for producing aluminum ammonium sulfate by using waste sulfuric acid and by-product hydrogen in chlor-alkali production

Abstract

The present application relates to chemical technology field, disclose a kind of method for producing aluminium ammonium sulfate using waste sulfuric acid and by-product hydrogen in chlor-alkali production, comprising the following steps: S1, waste sulfuric acid produced in chlor-alkali production is added to aluminium hydroxide feed liquid, to generate aluminium sulfate solution;S2, aluminium ammonium sulfate solution is generated by adding ammonium sulfate solution to aluminium sulfate solution;S3, the concentration and pH value of aluminium ammonium sulfate solution obtained in step S2 are adjusted;S4, aluminium ammonium sulfate solution is pumped into spray drying tower for crystallization drying, spray drying tower uses by-product hydrogen in chlor-alkali production as heat source, the temperature in tower is controlled at 260-280 ℃, and then aluminium ammonium sulfate product is obtained after separation treatment.The present application has the advantages of large production scale, high product quality, low pressure safety, environmental protection and energy saving, stable operation, high product purity, high whiteness, small fineness, round and uniform particles, etc.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and in particular to a method for producing ammonium aluminum sulfate using waste sulfuric acid and by-product hydrogen gas from chlor-alkali production. Background Technology

[0002] In the ion-exchange membrane caustic soda production process, the wet chlorine gas from the electrolytic cell is at a high temperature and carries a high amount of water vapor, making it extremely corrosive. To meet the process requirements of the next chlorine treatment step, the moisture in the chlorine gas must be removed (the water content must not exceed 0.005%). A common approach involves two steps: First, cooling measures are taken to lower the temperature of the wet chlorine gas, reducing the partial pressure of saturated water vapor and thus lowering the water content. Second, concentrated sulfuric acid is used to further absorb the small amount of moisture remaining after the chlorine gas has cooled.

[0003] When drying chlorine with sulfuric acid, two drying towers, #1 (packed tower) and #2 (bubble cap tower), are connected in series to ensure sufficient contact between the chlorine and sulfuric acid. The sulfuric acid concentration used in the packed tower is 75-90%, and that in the bubble cap tower is 95-98%. The dried chlorine is then pressurized using a chlorine compressor before being transported. 98% concentrated sulfuric acid is used as the desiccant for drying the chlorine, and the moisture content in the chlorine is controlled to ≤1.0*10 through the counter-current flow of drying towers #1 and #2. -5 The concentration of sulfuric acid is set at ppm to meet process requirements, but the concentration gradually decreases during the circulation process. When it drops to 75%, it must be replaced with new acid, and the replaced sulfuric acid is pumped into a waste acid storage tank as waste acid. In existing technologies, most waste acid is sold or recycled after the chlorine gas is released, or the waste sulfuric acid is concentrated and reused. However, this part of the waste acid is difficult to treat, and the recycling cost far exceeds the utilization value, so the above methods have little recycling value.

[0004] On the other hand, with technological advancements, the application of ammonium aluminum sulfate is becoming increasingly widespread. Currently, there are two main production processes for ammonium aluminum sulfate. The first involves natural crystallization and coarse crushing in an active crystallization tank, followed by removal of crystal water using the heat from burning coal and natural gas in an iron box. The second is an intermittent, open production process, utilizing a lead reactor to react bauxite with concentrated sulfuric acid under high pressure to produce aluminum sulfate. Ammonium sulfate is then added to generate ammonium aluminum sulfate, which is then heated on a steel plate for dehydration. After passing the dehydration test, it is crushed, packaged, and sold. Both of these production processes have the following drawbacks: long production cycles, intermittent and open processes, high impurity content in the finished product, irregular particle size, low purity, low yield, severe waste gas and wastewater pollution, and low safety.

[0005] Therefore, based on the above technical problems, there is an urgent need for a method to produce high-purity ammonium aluminum sulfate using waste sulfuric acid and by-product hydrogen from chlor-alkali production. Summary of the Invention

[0006] To address the technical problems existing in the prior art, this invention provides a method for producing ammonium aluminum sulfate using waste sulfuric acid and by-product hydrogen gas from chlor-alkali production.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for producing ammonium aluminum sulfate using waste sulfuric acid and by-product hydrogen gas from chlor-alkali production, comprising the following steps:

[0008] S1. Add waste sulfuric acid produced in chlor-alkali production to aluminum hydroxide solution to generate aluminum sulfate solution;

[0009] S2. Adding ammonium sulfate solution to aluminum sulfate solution produces ammonium aluminum sulfate solution;

[0010] S3. Adjust the concentration and pH value of the aluminum ammonium sulfate solution obtained in step S2;

[0011] S4. The aluminum ammonium sulfate solution is pumped into a spray drying tower for spray granulation and crystallization drying. The spray drying tower uses hydrogen, a by-product of chlor-alkali production, as a heat source and controls the temperature inside the tower at 260-280℃. After dehydration and separation, anhydrous aluminum ammonium sulfate is obtained.

[0012] Preferably, in step S1, pure water and aluminum hydroxide powder with a purity of 92% to 96% are added to the reactor respectively, and aluminum hydroxide solution is obtained by stirring. The mass ratio of pure water to aluminum hydroxide is 0.82:1.

[0013] Preferably, in step S1, before the aluminum hydroxide solution and waste sulfuric acid react, steam is introduced into the jacket of the reactor to heat it to 80-120°C, and the steam pressure in the jacket of the reactor is maintained at 0.2-0.4 MPa; the concentration of waste sulfuric acid is 72-76%, and the mass ratio of aluminum hydroxide to sulfuric acid is 1:1.885; after the vigorous reaction, the mixture is kept at a constant temperature and pressure and stirred for 60 minutes to settle.

[0014] Preferably, in step S2, the ammonium sulfate solution has a concentration of 40-60% and is prepared using 98% industrial ammonium sulfate. When the aluminum sulfate solution and the ammonium sulfate solution react, steam is introduced into the reactor to heat it to 100-160°C, the pressure inside the reactor is maintained at 0.2-0.4 kPa, and the reaction is stirred for 60 minutes.

[0015] Preferably, in step S3, the concentration of the aluminum ammonium sulfate solution is adjusted to 38–46°Be, and the pH value is adjusted to between 3 and 4.

[0016] Preferably, in step S4, the powder is separated by a cyclone separator after the spray drying tower. The separated powder enters the silo and is then packaged into finished products by a packaging machine. The separated gas phase enters the tail gas absorption tower after passing through a bag filter.

[0017] This invention utilizes surplus hydrogen from chlor-alkali production as heat energy and effectively recycles all waste acid from chlor-alkali production, forming a circular economy industrial chain with chlor-alkali production. This makes the enterprise's product structure more rational, enhances its benefits, and effectively strengthens its ability to resist market risks. On the other hand, it enables continuous production of ammonium aluminum sulfate in a closed environment, breaking the existing discontinuous production model. It has advantages such as large production scale, high product quality, low-pressure safety, environmental protection and energy saving, stable operation, high product purity, high whiteness, small fineness, and round and uniform particles. At the same time, it can achieve zero discharge of "three wastes" (waste gas, wastewater, and solid waste), ensuring environmentally friendly and green production.

[0018] This invention discloses a novel process for producing industrial-grade aluminum ammonium sulfate. The process involves dechlorinating 72-76% dilute sulfuric acid produced during chlor-alkali production and then combining it with high-purity aluminum hydroxide to produce high-purity aluminum sulfate. This high-purity aluminum ammonium sulfate is then produced by adding ammonium sulfate. The concentration and pH of the aluminum ammonium sulfate solution are adjusted, and surplus hydrogen gas, a byproduct of chlor-alkali production, is used as heat energy in a spray drying system to produce high-quality anhydrous aluminum ammonium sulfate for industrial use. This method optimizes and modifies traditional production processes, enabling the production process to be fully enclosed. This not only shortens production time and reduces production costs but also avoids environmental pollution and improves product purity. The industrial-grade aluminum ammonium sulfate prepared using this method fully complies with national standards. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of this embodiment.

[0020] Figure 2 This is a particle appearance diagram of ammonium aluminum sulfate produced by mechanical pulverization using existing methods.

[0021] Figure 3 This is a particle appearance diagram of ammonium aluminum sulfate produced using the method described in this embodiment. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example

[0026] See Figures 1-3 A method for producing ammonium aluminum sulfate using waste sulfuric acid and byproduct hydrogen from chlor-alkali production includes the following steps:

[0027] S1. Add pure water and aluminum hydroxide powder with a purity of 92% to 96% to the reactor respectively. Stir to obtain aluminum hydroxide solution. The mass ratio of pure water to aluminum hydroxide is 0.82:1. Open the steam valve of the reactor jacket and introduce steam into the reactor jacket to heat to 80 to 120°C. Maintain the steam pressure in the reactor jacket at 0.2 to 0.4 MPa. Slowly add waste sulfuric acid with a concentration of 72% to 76% produced in chlor-alkali production through the pipeline to react. The mass ratio of aluminum hydroxide to sulfuric acid is 1:1.885. After the vigorous reaction, keep the temperature and pressure maintained and stir for 60 minutes to generate aluminum sulfate solution.

[0028] S2. Add ammonium sulfate solution to aluminum sulfate solution. The concentration of ammonium sulfate solution is 40-60% and it is prepared using 98% industrial ammonium sulfate. Steam is introduced into the reaction vessel to heat to 100-160°C. The pressure inside the reaction vessel is maintained at 0.2-0.4 kPa. The reaction is stirred for 60 minutes to generate ammonium aluminum sulfate solution.

[0029] S3. Add pure water to adjust the concentration of the aluminum ammonium sulfate solution obtained in step S2 to 38-46°Be (Bome degree) and the pH value to between 3 and 4.

[0030] S4. The aluminum ammonium sulfate solution is pumped into the spray drying tower by a screw pump for crystallization drying. The spray drying tower uses hydrogen, a by-product of chlor-alkali production, as a heat source and controls the temperature inside the tower at 260-280℃ to ensure that the 12 water molecules of crystallization in the aluminum ammonium sulfate particles are removed and dried. Then, it is separated by a cyclone separator. The separated powder is aluminum ammonium sulfate. The aluminum ammonium sulfate powder enters the silo and is then packaged into finished product by a packaging machine. The separated gas phase enters the tail gas absorption tower after passing through a bag filter.

[0031] The above method for producing ammonium aluminum sulfate has the following technical advantages:

[0032] Taking the recovery and treatment of 5095 kg of waste sulfuric acid in this project as an example, the other ingredients are: 2128 kg of aluminum hydroxide powder with a purity of 94%, 1727 kg of industrial ammonium sulfate with a purity of 98% (prepared into a 40-60% ammonium sulfate solution in the preparation tank), 1643 kg of bottom water, 1385 kg of initial replenishment water, and 3118 kg of water for adjusting the Baume concentration. The specific production steps are as follows.

[0033] 1. Feeding

[0034] (1) First, add 1643 kg of water to the bottom, then turn on the steam and stir;

[0035] (2) Add 2128 kg of aluminum hydroxide powder with a purity of 94%;

[0036] (3) Open the steam inlet valve of the reactor jacket and introduce steam into the reactor jacket to raise the temperature to 80-120°C, and maintain the steam pressure in the reactor jacket at 0.2-0.4 MPa;

[0037] (4) Add 5095 kg of sulfuric acid, determine the time of violent reaction according to the pressure gauge of the reactor, and after the reaction, introduce steam into the reactor to control the pressure inside the reactor at 0.2-0.4 kPa;

[0038] (5) Maintain sedimentation for 60 minutes, and control the pressure inside the reactor at 0.2-0.4 kPa;

[0039] (6) Add 1385 kg of water to the reactor for dilution and maintain the temperature at 100℃;

[0040] (7) Add the prepared 40-60% ammonium sulfate solution;

[0041] (8) Take a sample after 30 minutes of reaction, and measure the pH value as 3-4 and the temperature as 80-120℃.

[0042] (9) Add 3118 kg of water (in three batches to avoid the solution concentration being too low), adjust the Beaume concentration to 44°Be, and at the same time introduce steam to maintain the temperature of the liquid at 100-160°C, and wait for the spray drying to be supplied.

[0043] 2. Spray drying

[0044] The drying temperature control is based on the following: it loses 10 molecules of water of crystallization at 120℃, becomes anhydrous at approximately 250℃, and decomposes above 280℃. Specifically...

[0045] (1) Turn on the hydrogen burner, adjust the gas intake, and supply heat to the drying tower through the air duct;

[0046] (2) After the inlet temperature of the drying tower rises to 220℃, open the bag dust collector pulse control valve and the air inlet valve in sequence, adjust the back-blowing pressure to 0.35Mpa, turn on the bag dust collector induced draft fan, bag dust collector star valve and cyclone lower star valve, adjust the inlet temperature of the drying tower, and control the temperature of the top of the drying tower to 240~280℃, the temperature of the middle part to 250~260℃, and the temperature of the bottom part to 220~240℃.

[0047] (3) After confirming that the drying system is operating normally, contact the reaction station to start feeding. The initial feeding amount is 0.7m. 3 After feeding material at a rate of / hour and adjusting the feed flow meter, and after the system has been running stably for 30 minutes, gradually adjust the feed rate to 0.9–1.2 m³ / h. 3 Continue to ensure stable system operation per hour until feeding is completed;

[0048] (4) After feeding, conduct a patrol inspection every 30 minutes and package the material according to the particle size of the output.

[0049] (5) After feeding is completed, notify the dispatcher to stop the hydrogen supply to the hot air furnace, reduce the inlet temperature of the dryer, and stop the vibrating hammer, star valve and feed pump in sequence. After 5 minutes, first close the crushing valve and then close the feeding valve.

[0050] (6) Always pay attention to the internal temperature of the bag filter. The temperature should not exceed 180℃. If it exceeds 180℃, the cold air intake should be adjusted immediately to cool down the equipment to avoid damage.

[0051] (8) Operators should wear complete protective clothing and strictly follow the operating procedures.

[0052] Process data records and required index tests during the spray drying feeding process should be provided in a timely manner to facilitate the adjustment of temperature control indicators.

[0053] The working principle of a spray dryer is as follows: air is heated by passing through a filter and a hydrogen burner, and then enters the hot air distributor at the top of the drying chamber. The hot air, after passing through the hot air distributor, enters the drying chamber evenly and rotates in a spiral shape. At the same time, liquid aluminum ammonium sulfate is sprayed into the spray drying tower through a high-speed centrifugal atomizer at the top of the tower. The liquid is sprayed out in a mist form through the high-speed centrifugal nozzle at the top of the tower. The liquid is sprayed into extremely small mist droplets, which greatly increases the surface area of ​​contact between the liquid and the hot air. The mist material and the hot air exchange in parallel, and the moisture and some structural water on the surface of the material evaporate rapidly. In a very short time, it is dried into anhydrous aluminum ammonium sulfate product. The coarser finished product is collected by the collection cylinder at the bottom of the drying tower, while the finer finished product is transported by a pipe located in the conical part to a cyclone separator and a bag dust collector, and is collected by the collection cylinder at the bottom of the cyclone separator. The dried anhydrous aluminum ammonium sulfate product is cooled by the air conveying pipe and sent to the silo, where it is directly discharged from the packaging machine outlet for packaging and weighing. The exhaust gas then enters a bag filter for further dust removal before being discharged by a centrifugal fan.

[0054] The characteristics of a spray dryer are:

[0055] (1) The drying speed is very fast: After the liquid is centrifuged and sprayed, the surface area is greatly increased. In the high temperature airflow, 95-98% of the water can be evaporated instantly, and the drying time only takes a few minutes.

[0056] (2) Parallel-flow spray drying is adopted, ensuring uniform heating of the droplets during the drying process and resulting in high product quality. Inside the spray drying chamber, the droplets flow in the same direction as the hot air. Although the hot air temperature is high, the chamber temperature drops immediately upon entering the drying chamber and contacting the spray droplets, preventing the aluminum ammonium sulfate particles from overheating and melting. Simultaneously, the drying tower has a diameter of 10 meters and a height of 12 meters, providing a long travel distance between the aluminum ammonium sulfate crystals and the hot air, effectively removing their water of crystallization and achieving an anhydrous product.

[0057] (3) Wide range of applications: Spray drying is usually used for solutions with a moisture content of 40-60%. Even special materials with a moisture content of up to 90% or more can be dried into powder products in one step without concentration. After drying, the product does not need to be crushed and screened, which reduces production steps, simplifies the production process, and improves the purity of the product. For the particle size, precision, and moisture content of the product within a certain range, the operating conditions can be changed to adjust them, making control and management very convenient.

[0058] Table 1 compares the production of ammonium aluminum sulfate using existing methods (the methods mentioned in the background art) with the method of the present invention.

[0059] Table 1

[0060]

[0061] In the production of caustic soda using an ion-exchange membrane, the sulfuric acid consumption for chlorine drying is 18 kg / t, and the liquid chlorine production is 17,000 tons / month. The annual consumption of 98% concentrated sulfuric acid is: 17,000 tons / month * 0.014 tons / ton * 12 months = 3,672 tons. The annual production of 75% waste acid is: 3,672 * 98% / 75% = 4,798 tons. Since this waste acid is produced solely from concentrated sulfuric acid used for chlorine drying, it contains very few impurities. Using the method of this invention, it can be dechlorinated and used as a raw material for the production of high-purity ammonium aluminum sulfate. A 10,000-ton / year industrial high-purity ammonium aluminum sulfate production line can be constructed, consuming 0.69 tons / ton of waste acid, and 7,000 tons of industrial waste acid can be recycled annually.

[0062] In addition, the 200,000-ton ion-exchange membrane caustic soda project will generate 57 million Nm³ of nitrogen oxides during the production process. 3 Hydrogen, of which 5.74 million Nm 3 Hydrogen was used to synthesize 60,000 tons of high-purity hydrochloric acid, with an actual surplus of 51.26 million Nm³. 3 This translates to 6408 Nm per hour. 3 / h. Venting large amounts of excess hydrogen would result in a huge waste of resources. The method of this invention uses a hydrogen burner to provide heat energy, recovering and utilizing 2300 Nm³ per hour. 3 Hydrogen not only avoids the environmental pollution caused by using coal as a heat source in the existing aluminum ammonium sulfate production process, but also makes full use of energy, ultimately achieving energy conservation, emission reduction, recycling and efficiency improvement, and reducing production costs, thus creating huge economic benefits for enterprises.

[0063] Referring to Table 1, it can be seen from the above that the method of the present invention for producing ultrafine high-purity aluminum ammonium sulfate has advantages such as low investment cost of production equipment, safe and stable operation, and advanced technology. It fully realizes the complete recovery and reuse of waste sulfuric acid and by-product hydrogen generated in caustic soda production, which is conducive to enterprises to extend the industrial chain, achieve the goals of energy saving, emission reduction and efficiency improvement, and reduction of production costs, thereby bringing huge economic benefits.

[0064] The chemical reaction equation for this method is as follows:

[0065] 2Al(OH)3+3H2SO4+(NH4)2SO4·18H2O=2NH4Al(SO4)2·12H2O

[0066]

[0067] All the above data are calculated based on 100% content. If the content is lower than 100%, divide by the actual content for calculation. For example, if the reaction uses aluminum hydroxide powder with a purity of 94%, the amount of aluminum hydroxide required for the reaction divided by 0.94 is the amount of aluminum hydroxide powder to be added during the reaction. In addition, in actual production, to ensure complete reaction of aluminum hydroxide, 0.5% to 1% excess waste sulfuric acid can be added.

[0068] The purpose of this invention is to provide a method for the continuous and efficient production of high-purity ammonium aluminum sulfate in a closed system. The ammonium aluminum sulfate produced by the method of this invention has a purity of over 99.5% and can be used to manufacture artificial gemstones, laser crystals, high-purity alumina, electronic components, computer components, and high-pressure sodium lamps, etc.

[0069] This invention differs significantly from traditional processes in drying high-purity aluminum ammonium sulfate solutions. Traditional processes use detachable crystallization tanks for crystallization and crushing, followed by heating and drying on iron plates. This invention, however, employs a closed-loop spray drying tower, resolving issues such as air pollution, long crystallization times, and problems with mother liquor recovery, treatment, and discharge. Furthermore, the high-purity aluminum ammonium sulfate powder produced after flash drying has a smooth surface, better flowability, and significantly higher purity than products manufactured using other processes. Additionally, traditional crystallization methods involve natural cooling, taking 7-14 days, resulting in a long production cycle. After crystallization, the mother liquor is discharged, and the crystals are manually broken up using an electric pick, conveyed to a crusher, and then placed on an iron plate for dehydration using coal as heat. This process is physically demanding and poses safety hazards. This invention directly combines the crystallization and drying processes, completing the drying process in just a few minutes, greatly shortening production time, significantly improving efficiency, and effectively reducing production costs.

[0070] The embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for producing ammonium aluminum sulfate using waste sulfuric acid and byproduct hydrogen gas from chlor-alkali production, characterized in that, Includes the following steps: S1. Add waste sulfuric acid produced in chlor-alkali production to aluminum hydroxide solution to generate aluminum sulfate solution; S2. Adding ammonium sulfate solution to aluminum sulfate solution produces ammonium aluminum sulfate solution; S3. Adjust the concentration and pH value of the aluminum ammonium sulfate solution obtained in step S2; S4. Pump the aluminum ammonium sulfate solution into the spray drying tower for spray granulation and crystallization drying. The spray drying tower uses hydrogen gas, a by-product of chlor-alkali production, as a heat source and controls the temperature inside the tower at 260~280℃. Then, after dehydration and separation, anhydrous aluminum ammonium sulfate is obtained. In step S1, pure water and aluminum hydroxide powder with a purity of 92%~96% are added to the reactor separately, and an aluminum hydroxide solution is obtained by stirring. The mass ratio of pure water to aluminum hydroxide is 0.82:

1. Before the aluminum hydroxide solution reacts with waste sulfuric acid, steam is introduced into the reactor jacket to heat it to 80~120℃, and the steam pressure in the reactor jacket is maintained at 0.2~0.4 MPa. The concentration of waste sulfuric acid is 72~76%, and the mass ratio of aluminum hydroxide to sulfuric acid is 1:1.

885. In step S2, the ammonium sulfate solution has a concentration of 40-60% and is prepared using 98% industrial ammonium sulfate. When the aluminum sulfate solution and the ammonium sulfate solution react, steam is introduced into the reactor to heat it to 100-160°C, the pressure inside the reactor is maintained at 0.2-0.4 kPa, and the reaction is stirred for 60 minutes. In the S3 step, the concentration of the aluminum ammonium sulfate solution is adjusted to 38-46 o Be, the pH value is adjusted to between 3 and 4; In step S4, the temperature at the top of the spray drying tower is controlled to be 240-280°C, the temperature in the middle part is controlled to be 250-260°C, the temperature at the bottom is controlled to be 220-240°C, the initial feeding amount is 0.7 m 3 / hour, and after the system is stabilized, it is adjusted to 0.9-1.2 m 3 / hour.

2. The method for producing ammonium aluminum sulfate using waste sulfuric acid and byproduct hydrogen gas from chlor-alkali production according to claim 1, characterized in that, In step S1, after the vigorous reaction has passed, maintain the temperature and pressure and stir for 60 minutes to allow the mixture to settle.

3. The method for producing ammonium aluminum sulfate using waste sulfuric acid and byproduct hydrogen gas from chlor-alkali production according to claim 1, characterized in that, In step S4, the powder is separated by a cyclone separator after the spray drying tower. The separated powder enters the silo and is then packaged into finished products by a packaging machine. The separated gas phase enters the tail gas absorption tower after passing through a bag filter.

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