A method and equipment for recycling fluorine-containing waste acid

Abstract

The present invention relates to the field of water treatment, and discloses a method for resource recycling and reuse of fluorine-containing waste acid and recovery equipment. The equipment includes a fluorine-containing waste acid regulating water tank, a mixing reactor, a fully automatic drum microfilter, an inorganic membrane separation device and a control module. The fluorine-containing waste acid is first pre-treated in the regulating water tank, and then sequentially processed through the mixing reactor reaction, the fully automatic drum microfilter solid-liquid separation, and the inorganic membrane separation device for deep treatment to achieve waste acid resource recycling; the method steps cover the waste acid pretreatment, reaction treatment, solid-liquid separation, and membrane separation treatment links, and are precisely controlled using a sequential control algorithm and a PID control algorithm. The dosage of the reagent and the pressure adjustment are calculated according to specific formulas, respectively, and the influence of historical data is fully considered, so that the treatment process can be controlled more accurately; the invention can efficiently remove fluorosilicic acid impurities, effectively solve the problem of fluorine-containing waste acid treatment, and provide strong support for related enterprises to reduce costs and achieve green production.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and in particular to a method for recycling fluorine-containing waste acid and recovery equipment. Background Art

[0002] At present, the chemical precipitation method is mainly used to treat fluorine-containing waste acid. This method is based on the solubility product principle and is carried out by adding calcium hydroxide ( ), calcium carbonate ( ) The precipitant reacts with the fluoride in the waste acid to form a precipitate. Taking the reaction of hydrofluoric acid and calcium hydroxide as an example, the chemical equation is: However, this method still has some defects when treating mixed waste acid containing fluorosilicic acid:

[0003] 1. Low separation efficiency: Due to its special chemical structure, fluorosilicic acid produces small and dispersed precipitates, which makes solid-liquid separation difficult and makes it difficult to achieve the ideal impurity removal effect;

[0004] 2. Poor stability: Fluctuations in the composition of the waste acid will affect the precipitation effect, and the process parameters are difficult to accurately control;

[0005] 3. Waste of resources: A large amount of valuable acid is discarded along with the precipitated waste residue, and the acid recovery rate is low;

[0006] 4. Risk of secondary pollution: Improper disposal of the sedimentation products, such as improper landfilling, can easily cause environmental pollution.

[0007] At the same time, with the rapid development of the electronic information industry, manufacturing processes such as glass thinning generate hundreds of thousands of tons of fluorine-containing mixed waste acids annually, including hydrofluoric acid, sulfuric acid, hydrochloric acid, and fluorosilicic acid. The demand for their treatment continues to grow. Traditional methods are no longer able to meet the stringent impurity content standards required for industrial reuse, necessitating the development of efficient, stable, and resource-efficient treatment technologies. Summary of the Invention

[0008] The purpose of the present invention is to provide a method and equipment for resource recycling of fluorine-containing waste acid to solve at least one of the above technical problems.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] A fluorine-containing waste acid recovery device, comprising:

[0011] Fluorine-containing waste acid regulating water tank: equipped with a cone-bottom sludge pump and a liquid level sensor for settling glass slag and monitoring the liquid level;

[0012] Mixing reactor: It consists of three parts that can work alternately. Each part is equipped with an automatic dosing device, a stirring device, and temperature and pH sensors to achieve precise dosing and reaction control.

[0013] Fully automatic drum microfiltration machine: built-in high-precision filter, pressure sensor and backwash device for solid-liquid separation and automatic filter cleaning;

[0014] Inorganic membrane separation equipment: equipped with concentration sensor, flow sensor, pressure regulator and concentrated water reflux device for filtration and parameter control;

[0015] Control module: controls the operation of fluorine-containing waste acid regulating water tank, mixing reactor, fully automatic drum microfiltration machine, and inorganic membrane separation equipment.

[0016] As a further technical solution, the fully automatic drum microfiltration machine is also provided with a washing device and a drying device; the washing device is used to wash the separated solids, and the washing water returns to the fluorine-containing waste acid regulating water tank through a reflux pipe, and a flow sensor is provided on the reflux pipe; the drying device is used to dry the washed solids to obtain a fluorosilicate by-product.

[0017] A method for recycling fluorine-containing waste acid, comprising the following steps:

[0018] S1. Waste acid pretreatment: Fluorine-containing waste acid is discharged from the production line into a fluorine-containing waste acid conditioning tank. After glass slag is settled, a cone-bottom sludge pump discharges slag according to a preset timer. The liquid level sensor monitors the liquid level in real time, and the control module issues an early warning when the liquid level reaches the warning value.

[0019] S2, reaction treatment: The precipitated waste acid is pumped into the mixing reactor, and the three reaction parts work alternately according to the sequential control algorithm; the control module uses the PID algorithm to control the automatic dosing device to add reagents based on the temperature and pH sensor data, and controls the stirring speed to make the reagents react with the waste acid to remove the fluosilicic acid impurities;

[0020] S3, solid-liquid separation: The waste acid after the reaction enters the fully automatic drum microfiltration machine. The pressure sensor monitors the pressure difference on both sides of the filter. When the warning value is reached, the control module activates the backwash device. The separated solid is washed and dried to obtain the fluorosilicate byproduct;

[0021] S4, membrane separation treatment: The waste acid after microfiltration enters the inorganic membrane separation equipment. The concentration and flow sensors monitor the data in real time. The control module adjusts the pressure on both sides of the membrane and the concentrated water return ratio through the PID algorithm to ensure that the produced water quality meets the standards.

[0022] S5. Resource recycling: After the produced water meets the standards through online testing, it will be recycled to the temporary water tank; the concentrated water will return to the fully automatic drum microfiltration machine for further treatment, achieving zero discharge of waste acid and recycling of resources.

[0023] As a further technical solution, the dosage of the reagent in S2 is based on the content of fluorosilicic acid in the waste acid, according to the formula: Calculated;

[0024] in, For the quality of the medicine, is the molar concentration of fluorosilicic acid, is the volume of waste acid, is the molar mass of the drug.

[0025] As a further technical solution, the pressure is regulated according to the formula: Perform calculations;

[0026] in, is the pressure difference, is the set water production flow rate, is the solution viscosity, is the thickness of the film, is the membrane permeability, is the filtration area of the membrane, For impact indicators.

[0027] As a further technical solution, the calculation formula of the impact index is:

[0028] ;

[0029] in, is the historical data influence coefficient, and its value range is [0,1]; 、 Respectively represent the maximum and minimum values in the historical pressure difference data; is the standard deviation of historical pressure difference data; is the adjustment coefficient, the value range is [−1,1], and it is adjusted according to the actual situation.

[0030] As a further technical solution, the standard deviation of the historical pressure difference data The expression is:

[0031] ;

[0032] in, is the number of samples of historical pressure difference data, For the Historical pressure difference data values, is the average value of historical pressure difference data.

[0033] As a further technical solution, the agent is potassium chloride, sodium chloride, sodium sulfate or sodium fluoride.

[0034] Beneficial effects of the present invention:

[0035] (1) Accurately remove fluorosilicic acid impurities from waste acid while effectively increasing the content of other useful acids, so that the recycled acid meets the production process requirements, significantly reducing the purchase of new acid and lowering production costs; at the same time, a specific agent reacts with fluorosilicic acid to generate fluorosilicate precipitates, which are then washed and dried to obtain high-value by-products, thus maximizing resource utilization and creating additional economic benefits for the company;

[0036] (2) The control module adopts sequential control algorithm and PID control algorithm to monitor and accurately control the operating parameters of each equipment in real time; in the mixing reactor, it ensures that the chemical reaction is always in the optimal conditions to avoid reaction failure or low efficiency due to parameter fluctuations; the fully automatic drum microfiltration machine and inorganic membrane separation equipment operate in a stable state, the pressure sensor and backwash device effectively prevent the filter from being blocked, the concentration, flow sensor and related control devices avoid membrane contamination, reduce equipment downtime maintenance time, ensure the continuity and stability of the entire process, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below with reference to the accompanying drawings.

[0038] Figure 1 It is a logical structure diagram of the present invention;

[0039] Figure 2 It is a schematic diagram of the equipment of the present invention.

[0040] Description of the accompanying drawings: 1. Fluorine-containing waste acid regulating water tank; 2. Mixing reactor; 3. Fully automatic drum microfiltration machine; 4. Inorganic membrane separation equipment; 5. Automatic dosing device. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] See also Figure 1-Figure 2 As shown, the present invention is a fluorine-containing waste acid recovery equipment, comprising:

[0043] A fluorine-containing waste acid regulating water tank 1 is provided with a cone-bottomed sludge pump and a liquid level sensor. The cone-bottomed sludge pump is used to discharge the sediment, and the liquid level sensor is used to monitor the liquid level and transmit the data to the control module.

[0044] The mixing reactor 2 consists of three identical and interchangeable parts, each of which is equipped with an automatic dosing device 5, a stirring device, a temperature sensor, and a pH sensor. The automatic dosing device 5 is used to accurately add the reagent, the stirring device is used to ensure that the reagent and the waste acid react fully, and the temperature sensor and pH sensor are used to collect real-time reaction environment data and transmit it to the control module. The control module controls the stirring speed and dosage based on the feedback.

[0045] The fully automatic drum microfilter 3 is equipped with a filter screen, a pressure sensor, and a backwashing device. The pressure sensor monitors the pressure difference on both sides of the filter screen in real time. When the pressure difference reaches the warning value, the backwashing device is activated under the control of the control module and purified water is used to flush the filter screen.

[0046] The inorganic membrane separation device 4 is equipped with a concentration sensor and a flow sensor for monitoring the flow rates of produced water and brine and controlling the liquid flow rate. It is also equipped with a pressure regulating device and a brine return control device connected to the control module. The control module adjusts the pressure on both sides of the membrane and the brine return ratio based on the monitoring data. It is also equipped with a produced water return pipe and a brine return pipe. The produced water return pipe is connected to the reuse acid temporary storage tank, and the brine return pipe is connected to the fully automatic drum microfiltration machine 3.

[0047] A control module for controlling the fluorine-containing waste acid regulating water tank 1, the mixing reactor 2, the fully automatic drum microfiltration machine 3, and the inorganic membrane separation equipment 4;

[0048] The fully automatic drum microfilter 3 is also provided with a washing device and a drying device. The washing device is used to wash the separated solids, and the drying device is used to dry the washed solids. The washing water return pipe of the washing device is connected to the fluorine-containing mixed waste acid regulating water tank. A flow sensor is provided on the washing water return pipe, and the flow sensor is electrically connected to the control system module.

[0049] A method for recycling fluorine-containing waste acid, comprising the following steps:

[0050] S1. Waste acid pretreatment: Fluorine-containing waste acid is discharged from the glass thinning production line into the fluorine-containing waste acid regulating water tank 1, where it is buffered and regulated. The volume of the fluorine-containing waste acid regulating water tank 1 is used to allow the glass slag in the waste acid to settle to the bottom of the cone. The cone bottom sludge pump discharges the precipitated slag according to a preset timing program. The liquid level sensor monitors the liquid level in real time and transmits the data to the control module. When the liquid level approaches the warning value, the control module automatically issues an early warning.

[0051] S2, reaction treatment: the precipitated waste acid is pumped into the mixing reactor 2 through a pneumatic diaphragm pump, and the three parts of the mixing reactor 2 work alternately according to a sequential control algorithm; the control module uses a proportional-integral-differential PID control algorithm to control the automatic dosing device 5 to accurately add the reagent based on the reaction environment data collected by the temperature sensor and the pH sensor, and at the same time controls the stirring speed of the stirring device to ensure that the reagent reacts fully with the waste acid and remove the fluorosilicic acid impurities in the waste acid;

[0052] S3, solid-liquid separation: The waste acid treated in the mixing reactor 2 is pumped into the fully automatic drum microfiltration machine 3. The pressure sensor monitors the pressure difference on both sides of the filter in real time. When the pressure difference reaches the warning value, the control module controls the backwash device to start and calls purified water to wash the filter. The separated solids enter the washing device, which washes the solids. The washing water flows back to the fluorine-containing waste acid regulating water tank 1 through the reflux pipe. The flow sensor monitors the washing water flow in real time and transmits the data to the control module. The washed solids enter the drying device for drying to obtain the by-product fluorosilicate.

[0053] S4, membrane separation treatment: The waste acid leaving the fully automatic drum microfiltration machine 3 enters the inorganic membrane separation device 4. The concentration sensor and flow sensor monitor the flow rate of produced water and concentrated water and the liquid flow rate in real time. Based on the monitoring data, the control module uses the proportional-integral-differential PID control algorithm to adjust the pressure regulating device and the concentrated water return control device to achieve appropriate pressures on both sides of the membrane and the concentrated water return ratio to ensure that the produced water quality meets the standards.

[0054] S5. When the flow rate, pH value and fluoride ion concentration of the produced water meet the production process requirements after being tested by the online monitoring equipment, the produced water is returned to the acid temporary storage tank through the produced water return pipe; the concentrated water is returned to the fully automatic drum microfiltration machine 3 through the concentrated water return pipe for centrifugal filtration again.

[0055] During the waste acid recovery process, fluorine-containing waste acid is discharged from the glass thinning production line into the fluorine-containing waste acid regulating water tank 1, which has the function of buffering and regulating the waste acid flow and concentration fluctuations. Since the waste acid contains glass slag, the waste acid is allowed to stand still in the regulating water tank due to its large volume, and most of the glass slag is precipitated to the bottom of the cone. The sludge pump at the bottom of the cone discharges the precipitated slag according to a preset timing program to ensure smooth operation of subsequent equipment. At the same time, the liquid level sensor installed in the water tank monitors the liquid level in real time, and the data is transmitted to the control module. Once the liquid level approaches the warning value, the system automatically issues an early warning to prompt the operator to pay attention to the discharge of waste acid to avoid overflow risks.

[0056] The precipitated waste acid is pumped into the mixing reactor 2 by a pneumatic diaphragm pump. The mixing reactor 2 consists of three identical and alternately operating parts A, B, and C;

[0057] Phase 1: Waste acid is pumped into mixing reactor 2-A. At this time, the stirring device in mixing reactor 2-B continues to stir, allowing the previously added reagent to fully react with the waste acid. Mixing reactor 2-C then discharges the reacted acid to the next device according to the instructions of the control module. In mixing reactor 2-A, the automatic doser 5 accurately adds specific chemical reagents according to the process parameters preset by the control module. The reagents react with the fluorosilicic acid impurities in the waste acid. The temperature and pH sensors in the reactor collect reaction environment data in real time and feed it back to the control module every second. Based on the feedback, the control module instantly calculates and automatically adjusts the stirring speed and dosage.

[0058] Phase 2: Waste acid is pumped into the emptied mixing reactor 2-C, while mixing reactor 2-A continues to stir the reaction and mixing reactor 2-B is responsible for acid removal. Each reactor accurately performs its tasks under the automated process, and the control module monitors and coordinates the entire process to ensure seamless connection of each link.

[0059] Phase 3: Waste acid is pumped into the emptied mixing reactor 2-B, mixing reactor 2-C is stirred for reaction, and mixing reactor 2-A is discharged. This cycle is repeated, and automated optimization is used to improve reaction efficiency and waste acid treatment capacity.

[0060] The waste acid treated in mixing reactor 2 is pumped into a fully automatic drum microfiltration machine 3. This microfiltration machine is equipped with a filter screen. During operation, the drum rotates at a constant speed, and the waste acid is subjected to centrifugal force, causing the liquid to pass through the filter screen and enter the subsequent process, while solids adhere to the filter screen surface. A pressure sensor monitors the pressure difference across the filter screen in real time. Once the warning value is reached, indicating that the filter screen is approaching clogging, the control module immediately and automatically initiates a backwash program, using purified water to flush the filter screen to ensure continuous and efficient filtration. After filtering the mixed acid from the microfiltration machine, it meets the filtration requirements, and the separated solids can be washed. The washing water, monitored by a flow sensor, flows back to the high-concentration fluorine-containing mixed waste acid conditioning tank according to the control module's instructions, thus achieving water resource recycling. The washed solids enter the drying stage, where the temperature control system automatically and precisely adjusts the temperature and drying time according to a preset drying curve to ensure the stable output of the byproduct fluorosilicate.

[0061] The waste acid leaving the fully automatic drum microfiltration machine 3 enters the inorganic membrane separation equipment 4, which uses ultrafiltration membrane technology to drive the cross-flow filtration of the waste acid with the help of pressure. During the process, the concentration sensor monitors the flow rate of produced water and concentrated water in real time, and the flow sensor controls the liquid flow rate. The data is transmitted to the control module in real time. The control module dynamically adjusts the pressure on both sides of the membrane and the concentrated water return ratio parameters according to the produced water, concentrated water flow rate and liquid flow rate. When the flow rate, pH value and fluoride ion concentration indicators of the produced water are tested by the online monitoring equipment and confirmed to meet the production process requirements, the control module automatically guides the produced water back to the reuse acid temporary storage tank. The concentrated water is then instructed by the control module to flow back to the fully automatic drum microfiltration machine 3 for centrifugal filtration again based on the concentration monitoring results, ensuring zero waste liquid discharge of the entire system, maximizing resource recovery, and fully automated operation, stable and reliable.

[0062] The dosage of the reagent in S2 is based on the content of fluorosilicic acid in the waste acid, according to the formula: Calculated;

[0063] in, For the quality of the medicine, is the molar concentration of fluorosilicic acid, is the volume of waste acid, is the molar mass of the drug.

[0064] In the treatment of fluorine-containing waste acid, removing fluorosilicic acid impurities is a key step; this formula accurately determines the mass of the required reagent based on the stoichiometric relationship of the chemical reaction; taking the reaction of potassium chloride and fluorosilicic acid as an example, from the chemical equation It can be seen that the ratio of the amount of substances reacted by the two is 1:2; the dosage calculated by the formula can ensure that the reagent and fluosilicic acid fully react, so that fluosilicic acid can be converted into precipitate as much as possible, thereby efficiently removing fluosilicic acid impurities, improving the quality of waste acid, and meeting the quality requirements of the production process for recycled acid; if the dosage is insufficient, fluosilicic acid cannot react completely, resulting in an excessively high amount of fluosilicic acid residue in the waste acid, and the recycled acid does not meet the standard; if the dosage is too much, it will cause waste of reagents and increase processing costs.

[0065] The pressure is regulated according to the formula: Perform calculations;

[0066] in, is the pressure difference, is the set water production flow rate, is the solution viscosity, is the thickness of the film, is the membrane permeability, is the filtration area of the membrane, For impact indicators.

[0067] The calculation formula of the impact index is:

[0068] ;

[0069] in, The historical data influence coefficient has a value range of [0,1] and is used to measure the influence of historical data on the current pressure difference calculation. The larger the value, the more significant the impact of historical data; when When , it means that the impact of historical data is not considered; 、 Respectively represent the maximum and minimum values in the historical pressure difference data; used to calculate the extreme value difference. By analyzing the extreme pressure difference values in the historical data, the fluctuation range of the pressure difference can be captured, reflecting the extreme pressure changes that may occur during the operation of the equipment. The standard deviation of the historical pressure difference data is used to measure the degree of dispersion of the historical pressure difference data. The larger the standard deviation, the more drastic the fluctuation of the pressure difference data and the relatively poor stability of the equipment operation. Conversely, the smaller the standard deviation, the more stable the pressure difference data. is the adjustment coefficient, the value range is [−1,1], and it is adjusted according to the actual situation; when When , the influence of extreme value difference and standard deviation on pressure difference is positive, i.e., the pressure difference adjustment amplitude is amplified; when When , the impact is negative, reducing the adjustment range; when The influence of extreme value difference and standard deviation is not considered.

[0070] For example: In a fluorine-containing waste acid treatment process, the set water flow rate , solution viscosity , the thickness of the film , the membrane permeability , the filtration area of the membrane , historical data impact coefficient , adjustment coefficient , after analyzing the historical pressure difference data, we can get , , standard deviation , calculate the original pressure difference ;

[0071] Then calculate the optimized pressure difference:

[0072] ;

[0073] The optimized formula takes into account the fluctuations of historical data and can calculate the pressure difference more accurately, providing a more reliable basis for early judgment and control of the operation of inorganic membrane separation equipment. In actual applications, historical data can be continuously updated according to the real-time data of equipment operation, and relevant parameters can be recalculated to ensure the accuracy of pressure difference calculation and the stability of equipment operation.

[0074] The standard deviation of the historical pressure difference data The expression is:

[0075] ;

[0076] in, is the number of samples of historical pressure difference data, For the Historical pressure difference data values, is the average value of historical pressure difference data.

[0077] In actual calculations, first find the average value of the historical pressure difference data, then calculate the sum of the squares of the differences between each data and the average value, divide it by the number of samples, and take the square root to get the standard deviation; the larger the standard deviation, the more drastic the fluctuation of the historical pressure difference data, and the relatively poor stability of the equipment operation; conversely, the smaller the standard deviation, the more stable the pressure difference data.

[0078] The medicament is potassium chloride, sodium chloride, sodium sulfate or sodium fluoride.

[0079] Example 1: Using potassium chloride as a medicament;

[0080] Fluorine-containing waste acid from the glass thinning industry, with a fluosilicic acid concentration of approximately 5%, is first pumped into mixing reactor 2 at a flow rate of 2 tons / hour. Automatic dosing device 5 precisely doses solid potassium chloride (in a 2:1 molar ratio of potassium chloride to fluosilicic acid) into the reactor according to a pre-set program, with a dosing rate set at 1 kg / min. The potassium chloride reacts with the fluosilicic acid in the waste acid to form potassium fluosilicate precipitate, effectively removing the fluosilicic acid impurities.

[0081] The control module monitors the pH parameters within the mixing reactor 2 in real time. After one hour of full reaction, the waste acid is pumped into the fully automatic drum microfiltration unit 3. The potassium fluorosilicate precipitate is trapped by the filter. Subsequent washing and drying processes produce a potassium fluorosilicate byproduct with a purity of approximately 98%. The filtered waste acid enters the inorganic membrane separation unit 4. After filtration, the recycled acid meets the production process requirements, and the hydrochloric acid content is increased by 3%. The recycled acid is returned to the recycled acid temporary storage tank, and the concentrated water is refluxed for further processing according to the control module's instructions. Ultimately, the fluorosilicic acid content in the waste acid is reduced to 0.34%.

[0082] Example 2: Sodium chloride is used as the reagent;

[0083] Fluorine-containing waste acid from the Bengbu glass thinning industry, with a fluosilicic acid concentration of approximately 5%, is first pumped into mixing reactor 2 at a flow rate of 2 tons / hour. Automatic dosing device 5 precisely doses solid sodium chloride (the molar ratio of sodium chloride to fluosilicic acid is 2:1) into the reactor according to a preset program, with a dosing rate set at 1 kg / min. The sodium chloride reacts with the fluosilicic acid in the waste acid to form sodium fluosilicate precipitate, effectively removing the fluosilicic acid impurities.

[0084] The control module monitors the pH parameters within the mixing reactor 2 in real time. After one hour of full reaction, the waste acid is pumped into the fully automatic drum microfiltration unit 3, where the sodium fluorosilicate precipitate is trapped by the filter. After washing and drying, the sodium fluorosilicate byproduct with a purity of approximately 98% is obtained. The filtered waste acid enters the inorganic membrane separation unit 4, where it is filtered until the recycled acid meets the production process requirements, with the hydrochloric acid content increased by 3.1%. The recycled acid is then returned to the recycled acid temporary storage tank, and the concentrated water is recirculated and processed according to the control module's instructions. Ultimately, the fluosilicic acid content in the waste acid is reduced to 0.41%.

[0085] Example 3: Sodium sulfate is used as the reagent;

[0086] Fluorine-containing waste acid from the Bengbu glass thinning industry, with a fluosilicic acid concentration of approximately 5%, is first pumped into mixing reactor 2 at a flow rate of 2 tons / hour. Automatic dosing device 5 precisely doses solid sodium sulfate (at a 1:1 molar ratio of sodium sulfate to fluosilicic acid) into the reactor according to a pre-set program, with a dosing rate set at 1 kg / min. The sodium sulfate reacts with the fluosilicic acid in the waste acid to form sodium fluosilicate precipitate, effectively removing the fluosilicic acid impurities.

[0087] The control module monitors the pH parameters within the mixing reactor 2 in real time. After one hour of full reaction, the waste acid is pumped into the fully automatic drum microfiltration unit 3, where the sodium fluorosilicate precipitate is trapped by the filter. Subsequent washing and drying processes produce a sodium fluorosilicate byproduct with a purity of approximately 98%. The filtered waste acid enters the inorganic membrane separation unit 4, where it is filtered until the recycled acid meets the production process requirements, with the sulfuric acid content increased by 4.5%. The recycled acid is then returned to the recycled acid temporary storage tank, and the concentrated water is recirculated and processed according to the control module's instructions. Ultimately, the fluorosilicic acid content in the waste acid is reduced to 0.47%.

[0088] Example 4: Sodium fluoride is used as the agent;

[0089] Fluorine-containing waste acid from the Bengbu glass thinning industry, with a fluosilicic acid concentration of approximately 5%, is first pumped into mixing reactor 2 at a flow rate of 2 tons / hour. Automatic dosing device 5 precisely doses sodium fluoride solid (the molar ratio of sodium fluoride to fluosilicic acid is 2:1) into the reactor according to a preset program, with a dosing rate set at 1 kg / min. The sodium fluoride reacts with the fluosilicic acid in the waste acid to form sodium fluosilicate precipitate, effectively removing the fluosilicic acid impurities.

[0090] The control module monitors the pH parameters within the mixing reactor 2 in real time. After one hour of full reaction, the waste acid is pumped into the fully automatic drum microfiltration unit 3, where the sodium fluorosilicate precipitate is trapped by the filter. Subsequent washing and drying processes produce a sodium fluorosilicate byproduct with a purity of approximately 98%. The filtered waste acid then enters the inorganic membrane separation unit 4. After filtration, the recycled acid meets the production process requirements, with the hydrofluoric acid content increased by 1.3%. The recycled acid is then returned to the recycled acid temporary storage tank, and the concentrated water is recirculated and processed according to the control module's instructions. Ultimately, the fluorosilicic acid content in the waste acid is reduced to 0.47%.

[0091] It should be noted that the calculation formulas and various parameters involved in the calculations in the present invention have been dimensionally processed in advance, and the process of dimensionless processing is well known in the industry and will not be described here.

[0092] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for recycling fluorine-containing waste acid, characterized in that: The method steps are as follows: S1. Pretreatment of waste acid: Fluorine-containing waste acid is discharged from the production line into a fluorine-containing waste acid regulating water tank (1). After glass slag is settled, the conical bottom sludge pump discharges the slag according to a preset timing program. The liquid level sensor monitors the liquid level in real time, and the control module issues an early warning when the liquid level reaches the warning value. S2, reaction treatment: the waste acid after precipitation is pumped into the mixing reactor (2), and the three reaction parts work alternately according to the sequential control algorithm; the control module uses the PID algorithm to control the automatic dosing device (5) to add the reagent based on the temperature and pH sensor data, and controls the stirring speed so that the reagent reacts with the waste acid to remove the fluorosilicic acid impurities; S3, solid-liquid separation: the waste acid after the reaction enters the fully automatic drum microfiltration machine (3), the pressure sensor monitors the pressure difference on both sides of the filter, and when the warning value is reached, the control module starts the backwash device; the separated solid is washed and dried to obtain a fluorosilicate byproduct; S4, membrane separation treatment: The waste acid after microfiltration enters the inorganic membrane separation equipment (4), the concentration and flow sensors monitor the data in real time, and the control module adjusts the pressure on both sides of the membrane and the concentrated water return ratio through the PID algorithm to ensure that the water quality meets the standards; S5. Resource recycling: After the produced water meets the standards through online testing, it is recycled to the temporary water tank; the concentrated water returns to the fully automatic drum microfiltration machine (3) for further treatment, achieving zero discharge of waste acid and resource recycling; The pressure on both sides of the S4 membrane is regulated according to the formula: Perform calculations; in, is the pressure difference, is the set water production flow rate, is the solution viscosity, is the thickness of the film, is the membrane permeability, is the filtration area of the membrane, is the impact indicator; The calculation formula of the impact index is: ； in, is the historical data influence coefficient, and its value range is [0,1]; 、 Respectively represent the maximum and minimum values in the historical pressure difference data; is the standard deviation of historical pressure difference data; is the adjustment coefficient, the value range is [−1,1], and it is adjusted according to the actual situation.

2. The method for recycling fluorine-containing waste acid according to claim 1, characterized in that: The dosage of the reagent in S2 is based on the content of fluorosilicic acid in the waste acid, according to the formula: Calculated; in, For the quality of the medicine, is the molar concentration of fluorosilicic acid, is the volume of waste acid, is the molar mass of the drug.

3. The method for recycling fluorine-containing waste acid according to claim 1, characterized in that: The standard deviation of the historical pressure difference data The expression is: ； in, is the number of samples of historical pressure difference data, For the Historical pressure difference data values, is the average value of historical pressure difference data.

4. The method for recycling fluorine-containing waste acid according to claim 1, characterized in that: The medicament is potassium chloride, sodium chloride or sodium fluoride.

5. A fluorine-containing waste acid recovery device for implementing the fluorine-containing waste acid resource recycling method according to claim 1, characterized in that: include: Fluorine-containing waste acid regulating water tank (1): equipped with a cone-bottom sludge pump and a liquid level sensor for settling glass slag and monitoring the liquid level; Mixing reactor (2): It consists of three parts that can work alternately. Each part is equipped with an automatic dosing device (5), a stirring device, and a temperature and pH sensor to achieve precise dosing and reaction control. Fully automatic drum microfiltration machine (3): built-in high-precision filter, pressure sensor and backwash device for solid-liquid separation and automatic filter cleaning; Inorganic membrane separation equipment (4): equipped with a concentration sensor, flow sensor, pressure regulator and concentrated water return device for filtration and parameter control; Control module: controls the operation of the fluorine-containing waste acid regulating water tank (1), the mixing reactor (2), the fully automatic drum microfiltration machine (3), and the inorganic membrane separation equipment (4).

6. The fluorine-containing waste acid recovery equipment according to claim 5, characterized in that: The fully automatic drum microfilter (3) is further provided with a washing device and a drying device; the washing device is used to wash the separated solids, and the washing water is returned to the fluorine-containing waste acid regulating water tank (1) through a reflux pipe, and a flow sensor is provided on the reflux pipe; the drying device is used to dry the washed solids to obtain a fluorosilicate by-product.

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