Fluorine-containing waste acid resource recycling method and recycling equipment

Abstract

The invention relates to the field of water treatment, and discloses a fluorine-containing waste acid resource recycling method and recycling equipment, and the equipment comprises a fluorine-containing waste acid adjusting water tank, a mixing reactor, a full-automatic roller microfilter, inorganic membrane separation equipment and a control module. The waste acid is subjected to reaction in a mixing reactor, solid-liquid separation by a full-automatic roller microfilter and advanced treatment by inorganic membrane separation equipment in sequence, so that the waste acid is recycled; the method comprises the steps of waste acid pretreatment, reaction treatment, solid-liquid separation and membrane separation treatment, and accurate regulation and control are carried out by utilizing a sequence control algorithm and a PID control algorithm. The chemical dosage and the pressure regulation are respectively calculated according to a specific formula, and the influence of historical data is fully considered, so that the treatment process can be more accurately controlled; according to the method, fluosilicic acid impurities can be efficiently removed, the problem of fluorine-containing waste acid treatment is effectively solved, and powerful support is provided for related enterprises to reduce cost and realize 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 adds 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: 1. Low separation efficiency: Due to its special chemical structure, the precipitate particles generated by fluorosilicic acid are small and dispersed, which makes it difficult to separate the solid and liquid and it is difficult to achieve the ideal impurity removal effect; 2. Poor stability: Fluctuations in the composition of waste acid will affect the precipitation effect, and process parameters are difficult to accurately control; 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; 4. Risk of secondary pollution: If the precipitation products are not handled properly, such as improper landfill, it is easy to cause environmental pollution.

[0003] At the same time, with the rapid development of the electronic information industry, the manufacturing process represented by glass thinning produces hundreds of thousands of tons of fluorine-containing mixed waste acid every year, including hydrofluoric acid, sulfuric acid, hydrochloric acid and fluorosilicic acid, and the demand for its treatment continues to grow. Traditional methods can no longer meet the strict standards for impurity content in industrial reuse, and there is an urgent need to develop efficient, stable and resource-based treatment technologies. Summary of the invention

[0004] The object of the present invention is to provide a method and equipment for recycling fluorine-containing waste acid resources to solve at least one of the above technical problems.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A fluorine-containing waste acid recovery device, comprising: Fluorine-containing waste acid regulating water tank: equipped with a cone-bottom sludge pump and a liquid level sensor to precipitate glass slag and monitor the liquid level; Mixing reactor: It consists of three parts that can work alternately. Each part is equipped with an automatic dosing device, a stirring device, and a temperature and pH sensor to achieve precise dosing and reaction control. Fully automatic drum microfilter: built-in high-precision filter, pressure sensor and backwashing device for solid-liquid separation and automatic filter cleaning; Inorganic membrane separation equipment: equipped with concentration sensor, flow sensor, pressure regulator and concentrated water reflux device for filtration and parameter control; Control module: Controls the operation of the fluorinated waste acid adjustment water tank, mixing reactor, fully automatic drum microfilter, and inorganic membrane separation equipment.

[0006] As a further technical solution, the fully automatic drum microfilter 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 returns to the fluorinated waste acid adjustment water tank through a reflux pipeline, and a flow sensor is provided on the reflux pipeline; the drying device is used to dry the washed solids to obtain fluorosilicate by-products.

[0007] A method for resource recycling of fluorinated waste acid, the steps of which are as follows: S1. Waste acid pretreatment: The fluorinated waste acid is discharged from the production line into the fluorinated waste acid adjustment water tank, the glass slag is precipitated by static settlement, and the sludge discharge pump at the conical bottom 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 a warning when the liquid level reaches the warning value; 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 adjusts the dosing of the automatic chemical feeder and controls the stirring speed according to the data of the temperature and pH sensors by using the PID algorithm, so that the chemical agent reacts with the waste acid to remove fluorosilicic acid impurities; S3. Solid-liquid separation: The reacted waste acid enters the fully automatic drum microfilter, the pressure sensor monitors the pressure difference on both sides of the filter screen, and the control module starts the backwashing device when the warning value is reached; the separated solids are washed and dried to obtain fluorosilicate by-products; S4. Membrane separation treatment: The microfiltered waste acid enters the inorganic membrane separation equipment, 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 reflux ratio by using the PID algorithm to ensure that the water quality of the produced water meets the standards; S5. Resource recycling: After the produced water passes the on-line detection and meets the standards, it is recycled to the temporary storage water tank; the concentrated water returns to the fully automatic drum microfilter for re-treatment, realizing zero discharge of waste acid and resource recycling.

[0008] As a further technical solution, the dosing amount of the chemical agent in S2 is calculated according to the content of fluorosilicic acid in the waste acid according to the formula: Calculated; Where, is the mass of the chemical agent, is the molar concentration of fluorosilicic acid, is the volume of the waste acid, is the molar mass of the chemical agent.

[0009] As a further technical solution, the pressure adjustment is calculated according to the formula: Calculated; Where, is the pressure difference, is the set water production flow rate, is the solution viscosity, is the thickness of the membrane, is the membrane permeability, is the membrane filtration area, is the influencing index.

[0010] As a further technical solution, the calculation formula of the influencing index is: ; wherein, 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 the historical pressure difference data; is the adjustment coefficient, and its value range is [−1, 1], which is adjusted according to the actual situation.

[0011] As a further technical solution, the standard deviation of the historical pressure difference data has the following expression: ; wherein, is the sample number of the historical pressure difference data, is the th historical pressure difference data value, is the average value of the historical pressure difference data.

[0012] As a further technical solution, the medicament is potassium chloride, sodium chloride, sodium sulfate or sodium fluoride.

[0013] Advantages of the present invention: (1) Accurately remove the fluorosilicic acid impurities in the waste acid, and at the same time effectively increase the content of other useful acids, so that the recycled acid meets the production process requirements, greatly reduce the purchase amount of new acid, and reduce the production cost; at the same time, through the reaction of a specific medicament with fluorosilicic acid to generate a fluorosilicate precipitate, after washing and drying, a high-value by-product is obtained, realizing the maximum utilization of resources and creating additional economic benefits for the enterprise; (2) The control module adopts a sequential control algorithm and a PID control algorithm to monitor and accurately regulate the operating parameters of each device in real time; in the mixing reactor, ensure that the chemical reaction is always in the best conditions, and avoid reaction failure or low efficiency caused by parameter fluctuations; the fully automatic drum microfilter and the inorganic membrane separation device operate in a stable state, the pressure sensor and the backwashing device effectively prevent the filter screen from being blocked, and the concentration, flow sensor and related control devices avoid membrane fouling, reduce the equipment downtime for maintenance, ensure the continuity and stability of the entire process, and improve the production efficiency. Brief Description of the Drawings

[0014] The present invention will be further described below in conjunction with the drawings.

[0015] Figure 1 It is a schematic diagram of the logic structure of the present invention; Figure 2 It is a schematic diagram of the equipment of the present invention.

[0016] Brief Description of the Drawings: 1. Fluoride-containing waste acid adjustment water tank; 2. Mixing reactor; 3. Full-automatic drum microfilter; 4. Inorganic membrane separation equipment; 5. Automatic chemical feeder. Detailed Embodiments

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figure 1 - Figure 2 As shown, the present invention is a fluoride-containing waste acid recovery equipment, including: Fluoride-containing waste acid adjustment water tank 1, in which a cone-bottom sludge discharge pump and a liquid level sensor are provided. The cone-bottom sludge discharge pump is used to discharge the sediment slag, and the liquid level sensor is used to monitor the liquid level height and transmit the data to the control module; Mixing reactor 2, which consists of three identical and alternately operating parts, each part is equipped with an automatic chemical feeder 5, a stirring device, a temperature sensor and a pH sensor; among them, the automatic chemical feeder 5 is used for accurate dosing, the stirring device is used to make the chemical agent react fully with the waste acid, the temperature sensor and the pH sensor are used to collect the reaction environment data in real time and transmit it to the control module, and the control module controls the stirring speed and the chemical dosing amount according to the feedback; Full-automatic drum microfilter 3, which is internally equipped with a filter screen and is provided with a pressure sensor and a backwashing device; among them, 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 started under the control of the control module, and the purified water is called to wash the filter screen; Inorganic membrane separation equipment 4, which is provided with a concentration sensor and a flow sensor for monitoring the flow rates of the produced water and the concentrated water and controlling the liquid flow rate. It is also provided with a pressure regulating device and a concentrated water reflux control device connected to the control module. The control module adjusts the pressure on both sides of the membrane and the concentrated water reflux ratio according to the monitored data; it is also provided with a produced water reflux pipeline and a concentrated water reflux pipeline. The produced water reflux pipeline is connected to the recycled acid temporary storage water tank, and the concentrated water reflux pipeline is connected to the full-automatic drum microfilter 3; A control module for controlling a fluorine-containing waste acid regulating water tank 1, a mixing reactor 2, a full-automatic drum microfilter 3, and an inorganic membrane separation device 4; The full-automatic drum microfilter 3 is further provided with a washing device and a drying device. The washing device is used for washing the separated solids, and the drying device is used for drying the washed solids. The washing water return pipe of the washing device is communicated with 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.

[0019] A method for resource recycling of fluorine-containing waste acid, the steps of which are as follows: S1. Waste acid pretreatment: The fluorine-containing waste acid is discharged from the glass thinning production line into the fluorine-containing waste acid regulating water tank 1, and buffer regulation is carried out in the fluorine-containing waste acid regulating water tank 1. The glass slag in the waste acid is precipitated to the cone bottom by using the volume of the fluorine-containing waste acid regulating water tank 1, and the sludge discharge pump at the cone bottom discharges the precipitated slag according to a preset timing program; the liquid level sensor monitors the liquid level height in real time and transmits the data to the control module. When the liquid level approaches the warning value, the control module automatically issues a warning; S2. Reaction treatment: The precipitated waste acid is pumped into the mixing reactor 2 by a pneumatic diaphragm pump. The three parts of the mixing reactor 2 work alternately according to the sequential control algorithm; the control module controls the precise dosing of the automatic dosing device 5 by using the proportional-integral-derivative PID control algorithm according to 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 make the medicament and the waste acid react fully to remove the fluorosilicic acid impurities in the waste acid; S3. Solid-liquid separation: The waste acid treated by the mixing reactor 2 is pumped into the full-automatic drum microfilter 3. 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 control module controls the backwashing device to start and calls the purified water to wash the filter screen; the separated solids enter the washing device, and the washing device washes the solids. The washing water is returned to the fluorine-containing waste acid regulating water tank 1 through the return 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; S4. Membrane separation treatment: The waste acid leaving the full-automatic drum microfilter 3 enters the inorganic membrane separation device 4. The concentration sensor and the flow sensor monitor the flow rates of the produced water and the concentrated water and the liquid flow rate in real time. The control module adjusts the pressure regulating device and the concentrated water return control device by using the proportional-integral-derivative PID control algorithm according to the monitored data to make the pressure on both sides of the membrane and the concentrated water return ratio reach appropriate values to ensure that the quality of the produced water meets the standards; S5. After the flow rate, pH value, and fluoride ion concentration of the produced water are detected by the on-line monitoring equipment and meet the requirements of the production process, the produced water returns to the recycled acid temporary storage water tank through the produced water return pipeline; the concentrated water returns to the fully automatic drum microfilter 3 through the concentrated water return pipeline for centrifugal filtration again.

[0020] In the process of this waste acid recovery, the 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 flow rate and concentration fluctuation of the waste acid; due to the glass slag in the waste acid, relying on the large volume of the regulating water tank, the waste acid is left standing in it, and most of the glass slag precipitates to the conical bottom; the sludge discharge pump at the conical bottom discharges the precipitated slag according to the preset timing program to ensure the smooth operation of the subsequent equipment; at the same time, the liquid level sensor installed in the water tank monitors the liquid level height in real time, and the data is transmitted to the control module. Once the liquid level approaches the warning value, the system automatically issues a warning to prompt the operator to pay attention to the discharge of the waste acid and avoid the risk of overflow.

[0021] 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. Stage 1: The waste acid is pumped into the mixing reactor 2-A. At this time, the stirring device in the mixing reactor 2-B keeps stirring to make the previously added chemical agent react fully with the waste acid. The mixing reactor 2-C discharges the reacted acid to the next equipment according to the instructions of the control module; in the mixing reactor 2-A, the automatic chemical dosing device 5 accurately adds a specific chemical agent according to the process parameters preset by the control module. The chemical agent reacts with the fluorosilicic acid impurities in the waste acid; the temperature and pH sensors in the reactor collect the reaction environment data in real time and feedback to the control module every second. The control module instantly calculates and automatically adjusts the stirring speed and chemical dosing amount according to the feedback. Stage 2: The waste acid is pumped into the emptied mixing reactor 2-C. The mixing reactor 2-A keeps stirring and reacting, and the mixing reactor 2-B is responsible for discharging the acid; each reactor accurately executes tasks under the automated process, and the control module monitors and coordinates the whole process to ensure seamless connection of each link.

[0022] Stage 3: The waste acid is pumped into the emptied mixing reactor 2-B. The mixing reactor 2-C stirs and reacts, and the mixing reactor 2-A discharges the acid. In this way, it circulates alternately, and the reaction efficiency and waste acid treatment capacity are improved by means of automation optimization. The waste acid treated by the mixing reactor 2 is pumped into the fully automatic drum microfilter 3; this microfilter is equipped with a filter screen. When the drum rotates at a constant speed during operation, the waste acid is affected by centrifugal force, and the liquid passes through the filter screen and enters the subsequent process, while the solids adhere to the surface of the filter screen; the pressure sensor monitors the pressure difference on both sides of the filter screen in real time. Once the warning value is reached, it indicates that the filter screen is approaching blockage, and the control module immediately automatically starts the backwashing program, calling the purified water to wash the filter screen to ensure continuous and efficient filtration; the mixed acid filtered from the microfilter meets the conditions for entering the filtration, and the separated solids can be washed. Under the monitoring of the flow sensor, the washing water returns to the high-concentration fluorine-containing mixed waste acid adjustment water tank according to the instructions of the control module, realizing the recycling of water resources. The washed solids enter the drying process, and the temperature control system automatically and precisely controls the temperature and duration according to the preset drying curve to ensure the stable quality of the by-product fluorosilicate produced.

[0023] The waste acid leaving the fully automatic drum microfilter 3 enters the inorganic membrane separation equipment 4. This equipment uses ultrafiltration membrane technology and drives the cross-flow filtration of the waste acid with pressure; during the process, the concentration sensor monitors the flow rates of the produced water and the concentrated water in real time, and the flow sensor controls the liquid flow rate, and 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 reflux ratio parameters according to the flow rates of the produced water and the concentrated water and the liquid flow rate; when the flow rate, pH value, and fluoride ion concentration indicators of the produced water are detected by the on-line monitoring equipment and confirmed to meet the production process requirements, the control module automatically guides the produced water back to the reused acid temporary storage water tank; the concentrated water is refluxed to the fully automatic drum microfilter 3 for centrifugal filtration again according to the concentration monitoring results under the instruction of the control module, ensuring zero discharge of waste liquid in the whole system, maximizing resource recovery, and the whole process is automatically operated, stable and reliable.

[0024] The dosage of the agent in S2 is calculated according to the content of fluorosilicic acid in the waste acid according to the formula: Calculated; Among them, is the mass of the agent, is the molar concentration of fluorosilicic acid, is the volume of the waste acid, is the molar mass of the agent.

[0025] In the process of treating fluorine-containing waste acid, removing fluorosilicic acid impurities is a key link; this formula accurately determines the mass of the required agent according to the stoichiometric relationship of chemical reactions; taking the reaction between potassium chloride and fluorosilicic acid as an example, from the chemical equation It can be seen that the molar ratio of the two reactions is 1:2; calculating the dosage through the formula can ensure that the agent reacts fully with fluorosilicic acid, making fluorosilicic acid as much as possible converted into precipitation, so as to efficiently remove fluorosilicic acid impurities, improve the quality of waste acid, and meet the quality requirements of the reused acid for the production process; if the dosage is insufficient, fluorosilicic acid cannot react completely, resulting in too high a residual amount of fluorosilicic acid in the waste acid, and the reused acid does not meet the standard; if the dosage is too much, it will cause waste of the agent and increase the treatment cost.

[0026] The pressure 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, For impact indicators.

[0027] The calculation formula of the impact index is: ; in, is the historical data influence coefficient, with a value range of [0,1], which 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 , 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 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; is the standard deviation of historical pressure difference data; it is used to measure the degree of dispersion of historical pressure difference data; the larger the standard deviation, the more drastic the fluctuation of pressure difference data, and the relatively poor stability of equipment operation; on the contrary, 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, that is, 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.

[0028] For example: In a fluorine-containing waste acid treatment process, the set water production 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 ; Then calculate the optimized pressure difference: ; Through the optimized formula, the fluctuation of historical data is comprehensively considered, and the pressure difference can be calculated 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.

[0029] 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, It is the average value of historical pressure difference data.

[0030] 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 fluctuations in 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.

[0031] The medicament is potassium chloride, sodium chloride, sodium sulfate or sodium fluoride.

[0032] Embodiment 1: Using potassium chloride as a medicament; The fluorine-containing waste acid from the glass thinning industry has a fluorosilicic acid concentration of about 5%. The precipitated waste acid is first pumped into the mixing reactor 2 at a flow rate of 2t / h. The automatic doser 5 accurately adds potassium chloride solid (the molar ratio of potassium chloride to fluorosilicic acid is 2:1) to the reactor according to the preset program, and the dosing rate is set to 1kg / min. Potassium chloride reacts with the fluorosilicic acid in the waste acid to form potassium fluorosilicate precipitate, which effectively removes fluorosilicic acid impurities.

[0033] The control module monitors the pH parameters in the mixing reactor 2 in real time. After 1 hour of full reaction, the waste acid is pumped into the fully automatic drum microfilter 3, and the potassium fluorosilicate precipitate is intercepted by the filter. After subsequent washing and drying processes, a potassium fluorosilicate byproduct with a purity of about 98% is obtained. The filtered waste acid enters the inorganic membrane separation equipment 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 and reprocessed according to the instructions of the control module. Finally, the fluorosilicic acid content in the waste acid is reduced to 0.34%.

[0034] Example 2: Using sodium chloride as the reagent; The fluorine-containing waste acid from the glass thinning industry in Bengbu has a fluorosilicic acid concentration of about 5%. First, the precipitated waste acid is pumped into the mixing reactor 2 at a flow rate of 2 t / h. The automatic dosing device 5 accurately adds solid sodium chloride to the reactor according to a preset program (the molar ratio of sodium chloride to fluorosilicic acid is 2:1), and the dosing rate is set at 1 kg / min. Sodium chloride reacts with the fluorosilicic acid in the waste acid to form sodium fluorosilicate precipitate, effectively removing fluorosilicic acid impurities.

[0035] The control module monitors the pH parameter in the mixing reactor 2 in real time. After 1 hour of sufficient reaction, the waste acid is pumped into the fully automatic drum microfilter 3. The sodium fluorosilicate precipitate is intercepted by the filter screen. After subsequent washing and drying processes, a by-product of sodium fluorosilicate with a purity of about 98% is obtained. The filtered waste acid enters the inorganic membrane separation device 4. After filtration, the recycled acid meets the production process requirements. The hydrochloric acid content increases by 3.1%. The recycled acid returns to the recycled acid temporary storage tank, and the concentrated water is refluxed for reprocessing according to the instructions of the control module. Finally, the fluorosilicic acid content in the waste acid is reduced to 0.41%.

[0036] Example 3: Using sodium sulfate as the reagent; The fluorine-containing waste acid from the glass thinning industry in Bengbu has a fluorosilicic acid concentration of about 5%. First, the precipitated waste acid is pumped into the mixing reactor 2 at a flow rate of 2 t / h. The automatic dosing device 5 accurately adds solid sodium sulfate to the reactor according to a preset program (the molar ratio of sodium sulfate to fluorosilicic acid is 1:1), and the dosing rate is set at 1 kg / min. Sodium sulfate reacts with the fluorosilicic acid in the waste acid to form sodium fluorosilicate precipitate, effectively removing fluorosilicic acid impurities.

[0037] The control module monitors the pH parameter in the mixing reactor 2 in real time. After 1 hour of sufficient reaction, the waste acid is pumped into the fully automatic drum microfilter 3. The sodium fluorosilicate precipitate is intercepted by the filter screen. After subsequent washing and drying processes, a by-product of sodium fluorosilicate with a purity of about 98% is obtained. The filtered waste acid enters the inorganic membrane separation device 4. After filtration, the recycled acid meets the production process requirements. The sulfuric acid content increases by 4.5%. The recycled acid returns to the recycled acid temporary storage tank, and the concentrated water is refluxed for reprocessing according to the instructions of the control module. Finally, the fluorosilicic acid content in the waste acid is reduced to 0.47%.

[0038] Example 4: Using sodium fluoride as the reagent; The fluorine-containing waste acid from the glass thinning industry in Bengbu has a fluorosilicic acid concentration of about 5%. First, the precipitated waste acid is pumped into the mixing reactor 2 at a flow rate of 2 t / h. The automatic dosing device 5 accurately adds solid sodium fluoride to the reactor according to a preset program (the molar ratio of sodium fluoride to fluorosilicic acid is 2:1), and the dosing rate is set at 1 kg / min. Sodium fluoride reacts with the fluorosilicic acid in the waste acid to form sodium fluorosilicate precipitate, effectively removing fluorosilicic acid impurities.

[0039] The control module monitors the pH parameter in the mixing reactor 2 in real time. After 1 hour of sufficient reaction, the waste acid is pumped into the fully automatic drum microfilter 3, and the sodium fluorosilicate precipitate is intercepted by the filter screen. Subsequently, after the washing and drying processes, a by-product of sodium fluorosilicate with a purity of approximately 98% is obtained. The filtered waste acid enters the inorganic membrane separation device 4. After filtration, the recycled acid meets the production process requirements, and the content of hydrofluoric acid increases from [X]% to 1.3%. The recycled acid returns to the recycled acid temporary storage water tank, and the concentrated water is refluxed for reprocessing according to the instructions of the control module. Finally, the content of fluosilicic acid in the waste acid is reduced to 0.47%.

[0040] It should be noted that: the calculation formulas and each parameter participating in the operation in the present invention are all pre-processed by dimensionless processing, and the process of dimensionless processing is well known in the industry and will not be described here.

[0041] The above has described in detail an embodiment of the present invention, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. Any equivalent changes and improvements made according to the scope of the application of the present invention shall still fall within the scope covered by the patent of the present invention. Please note that there is a missing value in the description of the increase in hydrofluoric acid content in the original text (it says "from [X]% to 1.3%"), which is filled with [X] in the translation for the sake of integrity. You may need to check and correct it according to the actual situation.

Claims

1. A fluorine-containing waste acid recovery equipment, characterized in that, include: Fluorine-containing waste acid regulating water tank (1): equipped with a conical 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 accurate dosing and reaction control; Fully automatic drum microfilter (3): with built-in high-precision filter, pressure sensor and backwashing device for solid-liquid separation and automatic filter cleaning; Inorganic membrane separation equipment (4): equipped with a concentration sensor, a flow sensor, a pressure regulator and a 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 microfilter (3), and the inorganic membrane separation equipment (4).

2. The fluorine-containing waste acid recovery equipment according to claim 1, 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 byproduct.

3. A method for resource recycling of fluorine-containing waste acid realized by the fluorine-containing waste acid recovery equipment described in claim 1, characterized in that, The steps of this method are as follows: S1. Waste acid pretreatment: The fluorine-containing waste acid is discharged from the production line into the fluorine-containing waste acid regulating water tank (1), and the glass slag is precipitated by static precipitation, and 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 according to 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 screen, and when the warning value is reached, the control module starts the backwashing 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 produced water quality meets the standard; S5. Resource recycling: After the produced water meets the standards through online testing, it is recycled to the temporary water storage tank; the concentrated water returns to the fully automatic drum microfiltration machine (3) for further treatment, thus achieving zero discharge of waste acid and recycling of resources.

4. The method for resource recycling of fluorine-containing waste acid according to claim 3, characterized in that, The dosage of the medicament in S2 is calculated according to the content of fluosilicic acid in the waste acid according to the formula: It is calculated as follows; Among them, is the mass of the reagent, is the molar concentration of fluosilicic acid, is the volume of waste acid, is the molar mass of the reagent.

5. The method for resource recycling of fluorine-containing waste acid according to claim 3 or 4, characterized in that, The pressure regulation is calculated according to the formula: for calculation; Among them, is the pressure difference, is the set water production flow rate, is the solution viscosity, is the membrane thickness, is the membrane permeability, is the membrane filtration area, is the influencing index.

6. The method for resource recycling of fluorine-containing waste acid according to claim 5, wherein, The calculation formula of the impact index is: ； Among them, is the historical data influence coefficient, and its value range is [0, 1]; and respectively represent the maximum and minimum values in the historical pressure difference data; is the standard deviation of the historical pressure difference data; is the adjustment coefficient, and its value range is [−1, 1], which is adjusted according to the actual situation.

7. The method for resource utilization and recycling of fluorine-containing waste acid according to claim 6, characterized in that, The standard deviation of the historical pressure difference data is expressed as: ； Among them, is the sample number of historical pressure difference data, is the th historical pressure difference data value, is the average value of historical pressure difference data.

8. The method for resource recycling of fluorine-containing waste acid according to claim 3, characterized in that, The medicament is potassium chloride, sodium chloride, sodium sulfate or sodium fluoride.

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