Comprehensive recovery method and system for multiple components in chemical polishing waste liquid

Abstract

The invention discloses a comprehensive recovery method and system for multiple components in chemical polishing waste liquid, the chemical polishing waste liquid is obtained by mixing chemical polishing tank liquid and rinse water after chemical polishing so as to adjust the proportion of the chemical polishing waste liquid, and the method further comprises the following steps: carrying out microfiltration treatment on the chemical polishing waste liquid to remove impurities so as to obtain chemical polishing filtrate; carrying out nanofiltration treatment on the chemical throwing filtrate to obtain a percolation acid solution containing phosphoric acid and a concentrated salt solution containing aluminum ions; extracting free phosphoric acid in the concentrated salt solution through acid retardant resin to obtain an aluminum salt solution used for extracting water agent raw materials; and mixing the free phosphoric acid with the percolation acid liquor, and carrying out evaporation and concentration treatment to obtain recovered phosphoric acid. The specific gravity of the waste liquid is adjusted by mixing the chemical polishing tank liquid and the rinsing water, and zero discharge of the waste liquid is realized, phosphoric acid and aluminum salt are efficiently recycled, energy consumption and cost are reduced, environmental pollution is reduced, and the resource utilization rate and economic benefits are improved through microfiltration, nanofiltration, acid retardation resin and evaporation concentration treatment.

Description

Technical Field

[0001] The invention belongs to the field of chemical waste liquid treatment, and specifically relates to a method and system for comprehensive recovery of multiple components in chemical waste liquid. Background Art

[0002] Aluminum alloys are widely used in aerospace, automobile manufacturing, electronic products and household appliances due to their light weight, high strength, good electrical and thermal conductivity and excellent corrosion resistance. In order to improve its surface properties and glossiness, anodizing treatment is often carried out, which includes a chemical polishing (chemical polishing) step. Chemical polishing uses a chemical polishing liquid of "phosphoric acid + additives" to improve surface flatness and glossiness. However, after repeated chemical polishing, the accumulation of aluminum ions in the chemical polishing liquid will affect the chemical polishing performance. It is necessary to regularly clean the tank, discharge the waste liquid and add new acid to maintain the high quality of the chemical polishing products.

[0003] Due to the large output, strong corrosiveness, great environmental damage and high difficulty in treatment, chemical waste liquid is classified as a hazardous waste (HW17) in my country. In order to avoid its negative impact on the environment, this type of hazardous waste must be treated and safely disposed of.

[0004] At present, the main treatment technologies include neutralization, diffusion dialysis and solvent extraction. However, the traditional neutralization method consumes a lot of useful resources and produces a large amount of sludge containing metal ions, which is difficult to recycle and wastes resources. Neutralization and other traditional treatment methods are prone to secondary pollution, such as the generation of a large amount of hydroxide sludge, which increases the complexity and cost of subsequent treatment. Although the diffusion dialysis method has low energy consumption, the acid recovery rate is low and the treatment time is long; the solvent extraction method has a complicated process, the acid concentration after stripping is not high, and the utilization rate is low.

[0005] In addition, existing technologies mostly focus on the treatment of a single substance and fail to fully consider the comprehensive recovery of multiple valuable components, resulting in low economic benefits. Summary of the invention

[0006] The present invention provides a method and system for comprehensive recovery of multiple components in chemical waste liquid, so as to solve the problems of large resource consumption, low treatment efficiency, complex process, easy secondary pollution and failure to fully consider the comprehensive recovery of multiple valuable components in the existing treatment technology.

[0007] The technical solution adopted by the present invention is:

[0008] A method for comprehensive recovery of multiple components in chemical waste liquid, wherein the chemical waste liquid is obtained by mixing chemical waste tank liquid and post-chemical waste rinsing water to adjust the specific gravity of the chemical waste liquid, and the method further comprises:

[0009] S100: microfiltration treatment is performed on the chemical waste liquid to remove impurities and obtain chemical waste filtrate;

[0010] S200: performing nanofiltration treatment on the chemical filtrate to obtain a diafiltration acid solution containing phosphoric acid and a concentrated salt solution containing aluminum ions;

[0011] S300: extracting free phosphoric acid in the concentrated salt solution through an acid retardation resin to obtain an aluminum salt solution for refining a pure water agent raw material;

[0012] S400: The free phosphoric acid is mixed with the diafiltration acid solution, and the mixture is evaporated and concentrated to obtain recovered phosphoric acid.

[0013] The method for comprehensive recovery of multiple components in chemical waste liquid described in the present invention also includes the following additional technical features:

[0014] The chemical polishing waste liquid is obtained by mixing the chemical polishing tank liquid and the post-chemical polishing rinsing water to adjust the specific gravity of the chemical polishing waste liquid, specifically:

[0015] According to the specific gravity of the chemical throwing tank liquid in the chemical throwing tank, combined with the volume of the chemical throwing waste liquid storage tank, the volume of the chemical throwing tank liquid discharged in a single time is calculated;

[0016] Inject chemical polishing tank liquid into the chemical polishing waste liquid storage tank. When the injection amount of the chemical polishing tank liquid reaches the calculated value, switch to injecting post-chemical polishing rinsing water into the chemical polishing waste liquid storage tank.

[0017] According to the specific gravity of the chemical throwing tank liquid in the chemical throwing tank, combined with the volume of the chemical throwing waste liquid storage tank, the volume of the chemical throwing tank liquid discharged in a single time is calculated, specifically:

[0018] According to the specific gravity of the chemical throwing tank liquid and the specific gravity of water in the chemical throwing tank, the volume ratio of the chemical throwing tank liquid and the post-chemical throwing rinsing water is calculated by taking the middle value of the target specific gravity range of the chemical throwing waste liquid;

[0019] The volumes of the chemical polishing tank liquid and the post-chemical polishing rinsing water are calculated based on the volume of the chemical polishing waste liquid required in the chemical polishing waste liquid storage tank.

[0020] The free phosphoric acid is mixed with the diafiltration acid solution, and recovered phosphoric acid is obtained by evaporation and concentration, specifically:

[0021] The mixed solution formed by the free phosphoric acid and the diafiltration acid solution is subjected to evaporation and concentration treatment;

[0022] When the specific gravity of the mixed liquid reaches the preset specific gravity, recovered phosphoric acid is obtained, and the recovered phosphoric acid is returned to the chemical disposal tank.

[0023] The method further comprises:

[0024] Adjusting the pH of the aluminum salt solution, adding a flocculant and allowing the solution to stand to precipitate and obtain an aluminum phosphate product;

[0025] Ethanol was added to the remaining supernatant to separate the sulfate product.

[0026] The pH value of the aluminum salt solution is adjusted, specifically:

[0027] Adding ammonia water or dilute phosphoric acid solution to the aluminum salt solution to adjust the pH of the aluminum salt solution;

[0028] When the pH value of the aluminum salt solution is less than the set pH value interval value, adding ammonia water to the aluminum salt solution;

[0029] When the pH value of the aluminum salt solution is greater than the set pH value interval value, adding dilute phosphoric acid solution to the aluminum salt solution;

[0030] The dilute phosphoric acid solution comes from a mixture of the free phosphoric acid and the leaching acid solution.

[0031] The free phosphoric acid in the concentrated salt solution is extracted by an acid retardation resin to obtain an aluminum salt solution for refining a pure water agent raw material, specifically:

[0032] The concentrated salt solution is fed into the acid retardation resin from top to bottom, wherein the free phosphoric acid is adsorbed on the acid retardation resin and the aluminum salt solution is filtered out from the acid retardation resin;

[0033] When the acid retardation resin is saturated, reverse osmosis water is passed through the acid retardation resin from bottom to top to desorb the free phosphoric acid to form elution acid.

[0034] The method for determining whether the acid retardant resin is saturated is as follows:

[0035] The acid retardation resin is determined to be saturated when the pH change of the aluminum salt solution reaches a preset pH change limit.

[0036] The present invention also discloses a multi-component comprehensive recovery system in chemical waste liquid, comprising: a chemical waste liquid storage tank, a microfiltration membrane, a waste tank liquid storage tank, and a filtrate storage tank. After the chemical waste liquid in the chemical waste liquid storage tank is microfiltered by the microfiltration membrane, impurities are discharged into the waste tank liquid storage tank, and the chemical waste filtrate is discharged into the filtrate storage tank;

[0037] Nanofiltration membrane, concentrated salt solution storage tank a, purified acid storage tank, after the chemical filtrate in the filtrate storage tank passes through the nanofiltration membrane, the separated diafiltration acid is discharged into the purified acid storage tank, and the concentrated salt solution is discharged into the concentrated salt solution storage tank a;

[0038] Acid retardation resin tank, reverse osmosis water storage tank, concentrated salt solution storage tank b, the concentrated salt solution in the concentrated salt solution storage tank a passes through the acid retardation resin tank, discharges the aluminum salt solution to the concentrated salt solution storage tank b, flushes the free phosphoric acid in the acid retardation resin tank with the reverse osmosis water storage tank and discharges it into the purified acid storage tank;

[0039] A finished acid storage tank, wherein the phosphoric acid solution in the purified acid storage tank is evaporated and concentrated to obtain finished acid, and the finished acid is discharged into the finished acid storage tank;

[0040] Phosphate storage tank and sulfate storage tank. The aluminum phosphate product obtained by treating the aluminum salt solution in the concentrated salt solution storage tank b is discharged into the phosphate storage tank, and the sulfate product is discharged into the sulfate storage tank.

[0041] The purified acid storage tank is connected to the concentrated salt solution storage tank b to discharge the purified acid solution in the purified acid storage tank into the concentrated salt solution storage tank b, so as to adjust the pH value of the aluminum salt solution in the concentrated salt solution storage tank b;

[0042] The finished acid storage tank is connected to the chemical disposal tank so that the recovered finished acid can be used for chemical disposal operations.

[0043] Due to the adoption of the above technical solution, the beneficial effects achieved by the present invention are as follows:

[0044] 1. In the present invention, the chemical polishing waste liquid is obtained by mixing the chemical polishing tank liquid and the post-chemical polishing rinse water to adjust the specific gravity of the chemical polishing waste liquid. This method utilizes the chemical polishing tank liquid and the post-chemical polishing rinse water, fully utilizes the waste liquid generated by the chemical polishing process, realizes zero discharge of the chemical polishing waste liquid, and reduces the impact on the environment. Usually, the chemical polishing tank liquid has a higher concentration of acid and metal ions, and the post-chemical polishing rinse water contains a lower concentration of residues. The chemical polishing tank liquid and the post-chemical polishing rinse water are mixed to adjust the specific gravity of the chemical polishing waste liquid, thereby avoiding the energy consumption of high-energy consumption processing steps such as the increase in the amount of additional chemicals added to achieve a specific pH value or other process requirements when the specific gravity of the chemical polishing waste liquid is too low, and the evaporation concentration caused by the increase in the amount of treated water.

[0045] It can also prevent the equipment from corroding faster when the acidity of the waste liquid is too high, thereby increasing the service life of the equipment.

[0046] 2. In the present invention, the chemical waste liquid is subjected to microfiltration treatment to remove impurities and obtain a chemical waste filtrate; the chemical waste filtrate is subjected to nanofiltration treatment to obtain a diafiltration acid solution containing phosphoric acid and a concentrated salt solution containing aluminum ions. The chemical waste liquid is preferentially subjected to microfiltration treatment. By removing impurities such as large particles, the processing load of the subsequent nanofiltration module can be significantly reduced, the impact of macromolecular substances and organic matter on the nanofiltration membrane can be reduced, and membrane pollution can be prevented, thereby improving the performance and service life of the nanofiltration membrane. The liquid entering the nanofiltration module is purer, which helps to improve the efficiency and stability of the entire treatment system.

[0047] Nanofiltration can efficiently separate phosphoric acid from other components in chemical waste liquid, obtain leaching acid rich in phosphoric acid, and produce concentrated salt solution containing a high concentration of aluminum ions. The aluminum ions in the concentrated salt solution are effectively intercepted, reducing its potential pollution risk to the environment. Moreover, through nanofiltration treatment, phosphoric acid and aluminum salts can be effectively recovered and reused as valuable chemicals, saving resources and reducing costs.

[0048] The combined treatment method of microfiltration and nanofiltration can significantly reduce the emission of harmful substances, meeting the requirements of clean production and environmental protection. Through the efficient recovery of multiple valuable components in the waste liquid, it helps to achieve the goal of zero discharge of chemical waste liquid and reduce the impact on the environment. The recovered phosphoric acid can be directly reused in the chemical tank, reducing production costs, and the concentrated salt solution produced can be further processed into other useful products (such as water purification agent raw materials), bringing additional economic benefits.

[0049] 3. In the present invention, the free phosphoric acid in the concentrated salt solution is extracted by an acid retardation resin to obtain an aluminum salt solution for purifying the raw material of the pure water agent. The acid retardation resin can effectively adsorb most of the free phosphoric acid, ensuring that it is fully separated from the concentrated salt solution, thereby improving the recovery rate of phosphoric acid and facilitating the subsequent resource recycling. The resin itself can be regenerated and reused, reducing processing costs and reducing the generation of waste. Through the resin adsorption and desorption process, the secondary pollution that may be generated by traditional chemical methods is avoided, meeting environmental protection requirements.

[0050] After being treated with the acid retardant resin, the discharged concentrated salt solution contains a high concentration of aluminum ions. These aluminum salt solutions can be further purified and used as raw materials for the production of water purifiers. Aluminum-based water purifiers are widely used in the market. Through this process, valuable by-products can be obtained, increasing economic benefits. In general, converting aluminum salt solutions that were originally regarded as waste into useful products realizes the recycling of resources and reduces resource waste.

[0051] 4. In the present invention, the free phosphoric acid is mixed with the leached acid solution and subjected to evaporation and concentration treatment to obtain recovered phosphoric acid. The evaporation and concentration process can remove water and other volatile substances to obtain high-purity recovered phosphoric acid, which is suitable for a variety of industrial applications. The recovered phosphoric acid can be directly reused in the chemical throwing tank, reducing the need for replenishment of new acid and saving resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0053] Figure 1 The present invention is a schematic flow diagram of a method for comprehensive recovery of multiple components in chemical waste liquid according to one embodiment of the present invention;

[0054] Figure 2 The present invention is a schematic structural diagram of a multi-component comprehensive recovery system for chemical waste liquid according to one embodiment of the present invention.

[0055] Among them, 1 chemical waste liquid storage tank; 2 high-pressure pump a; 3 security filter; 4 microfiltration membrane; 5 waste tank liquid storage tank; 6 filtrate storage tank; 7 high-pressure pump b; 8 nanofiltration membrane; 9 concentrated salt solution storage tank a; 10 high-pressure pump c; 11 acid retardation resin tank; 12 concentrated salt solution storage tank b; 13 reverse osmosis water storage tank; 14 booster pump a; 15 purified acid storage tank; 16 booster pump b; 17 evaporation concentrator; 18 finished acid storage tank; 19 pH adjustment medicine box; 20 flocculant medicine box; 21 sludge pump a; 22 phosphate storage tank; 23 sludge pump b; 24 filter press; 25 drum dryer; 26 phosphate storage tank; 27 booster pump c; 28 sulfate storage tank; 29 ethanol medicine box; 30 sludge pump c; 31 sulfate storage tank. DETAILED DESCRIPTION

[0056] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0057] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0058] like Figure 1 As shown, a method for comprehensive recovery of multiple components in chemical polishing waste liquid is provided, wherein the chemical polishing waste liquid is obtained by mixing chemical polishing tank liquid and post-chemical polishing rinsing water to adjust the specific gravity of the chemical polishing waste liquid.

[0059] It can be understood that the chemical polishing tank liquid and the post-chemical polishing rinse water are two different liquids produced during the surface treatment process of aluminum alloy.

[0060] Among them, the chemical polishing bath is an active liquid used in the chemical polishing process, containing a high concentration of acid (such as phosphoric acid) and other additives to improve the gloss and flatness of the aluminum alloy surface. As the use time increases, the aluminum ion concentration in the bath will gradually increase.

[0061] Rinsing water after chemical polishing is the water used to clean the workpiece after chemical polishing to remove the polishing liquid and other impurities remaining on the workpiece surface. The rinsing water may contain a certain amount of free acid, metal ions and other soluble substances.

[0062] The method utilizes the chemical polishing tank liquid and the rinsing water after chemical polishing, fully utilizes the waste liquid generated by the chemical polishing process, realizes zero discharge of chemical polishing waste liquid, and reduces the impact on the environment.

[0063] The chemical waste liquid obtained by mixing these two liquids needs to have its specific gravity adjusted to a specific range, usually 1.1 to 1.2. When the specific gravity of the chemical waste liquid is too low, the phosphoric acid content is too low, resulting in a larger amount of treated water. When the specific gravity is too high, the acidity of the chemical waste liquid is too high, which accelerates the corrosion rate of the equipment.

[0064] This method mixes the chemical throwing tank liquid and the rinse water after chemical throwing to adjust the specific gravity of the chemical throwing waste liquid, thereby avoiding the energy consumption of high-energy consumption treatment steps such as the increase in the amount of additional chemicals added to achieve a specific pH value or other process requirements when the specific gravity of the chemical throwing waste liquid is too low, and the evaporation concentration caused by the increase in the amount of treated water. It can also avoid the accelerated corrosion rate of equipment when the acidity of the chemical throwing waste liquid is too high, thereby increasing the service life of the equipment.

[0065] The method further comprises:

[0066] S100: microfiltration is performed on the chemical waste liquid to remove impurities and obtain chemical waste filtrate.

[0067] Microfiltration (MF) uses a filtration membrane with a pore size of about 0.1 to 10 microns, which can effectively remove larger particle impurities such as colloids, insoluble solid particles and microorganisms in the waste liquid. Through microfiltration treatment, the content of suspended particles in the waste liquid can be significantly reduced, ensuring the quality of the water in the subsequent treatment steps.

[0068] Microfiltration, as a pretreatment step, can remove most macromolecular substances and organic matter, thereby reducing the processing load of the subsequent nanofiltration module. This reduces the impact of macromolecular substances and organic matter on the nanofiltration membrane, prevents membrane contamination, extends the service life of the nanofiltration membrane, and improves the operating efficiency of the entire system.

[0069] It should be noted that according to the characteristics of chemical waste liquid, acid-resistant and corrosion-resistant microfiltration membrane materials, such as PTFE membrane, should be selected to ensure its long-term stable performance in harsh environments.

[0070] This method can effectively remove impurities by microfiltration of chemical waste liquid, obtain purer chemical filtrate, and provide high-quality water inlet conditions for subsequent treatment steps, thereby ensuring efficient and stable operation of the entire treatment process.

[0071] S200: performing nanofiltration treatment on the chemical filtrate to obtain a diafiltration acid solution containing phosphoric acid and a concentrated salt solution containing aluminum ions.

[0072] Nanofiltration (NF) uses a semipermeable membrane with a pore size of about 1 nanometer to 10 nanometers to selectively retain polyvalent metal cations (such as aluminum ions) under high pressure, while allowing acidic anions (such as phosphate ions) to pass through. Through nanofiltration treatment, phosphoric acid in the filtrate can be efficiently separated from other components to obtain a diafiltration acid solution rich in phosphoric acid, while producing a concentrated salt solution containing a higher concentration of aluminum ions.

[0073] Nanofiltration membranes usually have an isoelectric point between pH=3 and 6, so at low pH values, the membrane is positively charged. In an acidic environment, nanofiltration membranes can effectively intercept polyvalent metal cations while allowing acidic anions to pass freely, thereby achieving the concentration of free phosphoric acid in the waste liquid. The purity of phosphoric acid in the diafiltration acid solution is significantly improved, which is conducive to subsequent resource recovery and reuse.

[0074] Through nanofiltration treatment, aluminum ions can be effectively separated from waste liquid, reducing its potential pollution risk to the environment. Aluminum ions in concentrated salt solution are effectively intercepted, reducing the emission of harmful substances and meeting environmental protection requirements.

[0075] Nanofiltration treatment can not only separate valuable phosphoric acid, but also convert aluminum ions in the concentrated salt solution into useful by-products (such as water purifier raw materials) by further processing it. This achieves the recycling of resources, reduces the need for new acid replenishment, saves resources and reduces costs.

[0076] It should be noted that according to the characteristics of the chemical filtrate, an acid-resistant separation membrane is selected to ensure its long-term stable performance in harsh environments.

[0077] This method can efficiently separate the leaching acid solution containing phosphoric acid and the concentrated salt solution containing aluminum ions by nanofiltration treatment of the chemical waste liquid, which not only improves the purity and recovery rate of phosphoric acid, but also significantly reduces the emission of pollutants and realizes the recycling of resources. This key step provides a solid foundation for the comprehensive recovery process of the entire chemical waste liquid multi-component.

[0078] S300: extracting free phosphoric acid in the concentrated salt solution through an acid retardation resin to obtain an aluminum salt solution for purifying a raw material of a pure water agent.

[0079] Acid retarding resin is a strong alkaline anion exchange resin. When a concentrated salt solution (containing free phosphoric acid) passes through a column containing this resin, the free acid is adsorbed by the resin, while the salt solution flows out from the other end. Acid retarding resin can effectively adsorb most of the free phosphoric acid, ensuring that it is fully separated from the concentrated salt solution, thereby improving the recovery rate of phosphoric acid.

[0080] After the acid retardation resin treatment, the discharged concentrated salt solution contains a higher concentration of aluminum ions, which can be further purified. The obtained aluminum salt solution contains almost no free acid and is suitable as a raw material for the production of water purifiers, such as aluminum-based water purifiers, increasing the economic value of by-products.

[0081] Through the resin adsorption and desorption process, the secondary pollution that may be caused by traditional chemical methods is avoided. It meets environmental protection requirements, reduces the emission of harmful substances, and realizes the recycling of resources.

[0082] It should be noted that, according to the specific composition of the concentrated salt solution, a suitable strong alkaline anion exchange resin should be selected to ensure its effective adsorption capacity for free phosphoric acid.

[0083] This method uses an acid-retarded resin to extract free phosphoric acid from a concentrated salt solution, which can not only efficiently separate and recover valuable phosphoric acid, but also obtain a high-purity aluminum salt solution for the purification of pure water agent raw materials. This key step not only improves resource utilization and reduces environmental pollution, but also brings significant economic benefits. It is an important link in the comprehensive recovery process of multi-component chemical waste liquid.

[0084] S400: The free phosphoric acid is mixed with the diafiltration acid solution, and the mixture is evaporated and concentrated to obtain recovered phosphoric acid.

[0085] By mixing the free phosphoric acid desorbed from the acid retardant resin with the diafiltration acid (rich in phosphoric acid) obtained after nanofiltration treatment, the phosphoric acid components from the two sources can be integrated. This mixing method ensures the concentration of phosphoric acid and provides stable feed conditions for subsequent evaporation and concentration treatment.

[0086] Evaporation concentration is the process of increasing the concentration of solutes in a solution by evaporating the water in the liquid through heating. In this step, the mixed acid solution is sent to the evaporation concentration module and processed under negative pressure. The evaporation concentration process can remove water and other volatile substances to obtain high-purity recycled phosphoric acid, which is suitable for a variety of industrial applications. The recovered phosphoric acid can be directly reused in the chemical throwing tank, reducing the need for new acid replenishment and saving resources. After evaporation concentration treatment, the specific gravity of the recovered phosphoric acid can be increased to above 1.7, which meets the standards for reuse.

[0087] The negative pressure evaporation concentration device is used to provide a negative pressure environment through a vacuum pump unit to reduce the boiling point of the waste acid, thereby reducing energy consumption. Under negative pressure conditions, the boiling point of the waste acid is reduced, which reduces the temperature required for evaporation and reduces energy consumption. The lower evaporation temperature is also conducive to reducing the damage to the equipment by high-temperature corrosive gases and extending the service life of the equipment. The negative pressure environment is conducive to the separation of substances and further improves the purity of the recovered phosphoric acid.

[0088] Through evaporation and concentration treatment, useful components can be recovered to the maximum extent and waste liquid discharge can be reduced. The goal of zero discharge of chemical waste liquid is achieved, the impact on the environment is reduced, and the standards of clean production are met.

[0089] The method obtains recovered phosphoric acid by mixing free phosphoric acid with leaching acid and subjecting the mixture to evaporation and concentration treatment. The method can not only efficiently recover and purify valuable phosphoric acid components, but also significantly improve resource utilization, reduce processing costs and environmental impact, and bring considerable economic benefits and technical reliability.

[0090] In general, this method integrates nanofiltration and resin technology, including four modules: microfiltration, nanofiltration, acid retardation resin and evaporation concentration. After the chemical throwing tank liquid is mixed with the post-chemical throwing rinse water, it is first pretreated by the microfiltration module to remove impurities such as colloids, insoluble solid particles and microorganisms, reduce the load of the nanofiltration module and extend the life of the nanofiltration membrane. Then, the chemical throwing filtrate passes through the nanofiltration module to remove aluminum ions and improve the purity of phosphoric acid. The concentrated salt solution produced by nanofiltration is adsorbed by the acid retardation resin module to remove free phosphoric acid, and the produced aluminum salt solution is used for purification as a raw material for water purifiers. Finally, the free phosphoric acid and the leached acid reach a specific gravity of more than 1.7 after the evaporation concentration module and are returned to the chemical throwing tank. This method realizes the recovery of phosphoric acid and aluminum salt solution, achieves zero discharge of chemical throwing waste liquid, and meets the clean production standards.

[0091] This comprehensive recovery method of multiple components in chemical waste liquid not only optimizes resource utilization and reduces environmental pollution, but also brings significant economic benefits and technical reliability. It is an important means to achieve the goal of zero discharge of chemical waste liquid.

[0092] As a preferred embodiment of the present invention, the chemical polishing waste liquid is obtained by mixing the chemical polishing tank liquid and the post-chemical polishing rinsing water to adjust the specific gravity of the chemical polishing waste liquid, specifically:

[0093] According to the specific gravity of the chemical throwing tank liquid in the chemical throwing tank, combined with the volume of the chemical throwing waste liquid storage tank, the volume of the chemical throwing tank liquid discharged in a single time is calculated;

[0094] Inject chemical polishing tank liquid into the chemical polishing waste liquid storage tank. When the injection amount of the chemical polishing tank liquid reaches the calculated value, switch to injecting post-chemical polishing rinsing water into the chemical polishing waste liquid storage tank.

[0095] In order to ensure that the specific gravity of the chemical polishing waste liquid in the chemical polishing waste liquid storage tank is adjusted to the target range, usually 1.1-1.2, it is necessary to accurately calculate the volume of the chemical polishing tank liquid discharged at a single time, and combine the volume of the chemical polishing waste liquid storage tank to reasonably arrange the injection sequence of the chemical polishing tank liquid and the post-chemical polishing rinse water.

[0096] Use the specific gravity sensor to obtain the current specific gravity of the chemical polishing tank liquid. Assume that the specific gravity of the chemical polishing tank liquid is ρ 槽液 . Assume that the total volume of the chemical waste liquid storage tank is V 总 . According to the specific gravity of the chemical throwing tank liquid and the volume of the chemical throwing waste liquid storage tank, calculate the volume of the chemical throwing tank liquid discharged in a single time.

[0097] Specifically, according to the specific gravity of the chemical throwing tank liquid and the specific gravity of water in the chemical throwing tank, the volume ratio of the chemical throwing tank liquid and the post-chemical throwing rinsing water is calculated by taking the middle value of the target specific gravity range of the chemical throwing waste liquid;

[0098] The volumes of the chemical polishing tank liquid and the post-chemical polishing rinsing water are calculated based on the volume of the chemical polishing waste liquid required in the chemical polishing waste liquid storage tank.

[0099] The specific gravity of the rinse water after chemical polishing is usually close to that of pure water, which is set as ρ 漂洗水 =1.0. The middle value of the target specific gravity range of the chemical waste liquid is taken as the target specific gravity.

[0100] According to the principle of mass conservation, the volume ratio of chemical polishing tank liquid and post-chemical polishing rinse water can be calculated using the following formula:

[0101]

[0102] Among them, V 槽液 is the volume of the chemical polishing tank liquid;

[0103] V 漂洗水 is the volume of rinse water after chemical polishing, and V 总 =V 槽液 +V 漂洗水 .

[0104] Then the specific volume of the chemical polishing tank liquid and the rinse water after chemical polishing is:

[0105]

[0106] V 漂洗水 =V 总 -V 槽液

[0107] In one embodiment, the specific gravity of the polishing tank liquid is 槽液 =1.3; specific gravity of rinse water ρ 漂洗水 =1.0; target weight ρ 目标 =1.15; total volume of storage tank V 总 =1000L.

[0108] Calculate the volume of the chemical polishing tank liquid and the rinse water after chemical polishing according to the formula:

[0109]

[0110] V 漂洗水 =1000-500=5500L

[0111] Therefore, when the chemical waste liquid storage tank needs 1000 liters of chemical waste liquid, 500 liters of chemical waste liquid and 500 liters of post-chemical waste rinsing water should be injected respectively.

[0112] Taking the middle value of the target specific gravity range of the chemical waste liquid as the calculation basis can ensure that the specific gravity of the final mixed chemical waste liquid is stable at the center of the target range, avoid processing deviations caused by too high or too low specific gravity, and make subsequent processing steps more stable.

[0113] In addition, by taking the middle value of the target specific gravity range of the chemical waste liquid, the calculation formula and operation process can be simplified and the complexity can be reduced. The middle value serves as a fixed reference point, making the calculation process simpler and facilitating the design and implementation of the automated control system.

[0114] Inject the chemical waste liquid tank into the chemical waste liquid storage tank and monitor the injection volume at the same time. When the injection volume of the chemical waste liquid tank reaches the calculated value, stop injecting the chemical waste liquid tank immediately. After stopping the injection of the chemical waste liquid tank, immediately switch to injecting the post-chemical waste rinse water. Continue to inject the post-chemical waste rinse water until the storage tank reaches the required total volume.

[0115] By installing a real-time monitoring system, the volume changes in the tank can be monitored at any time to achieve precise control of the injection process and ensure that the injection amount is accurate. Through the monitoring system and quantitative calculation, it is easier to achieve high-precision control and reduce the possibility of human error.

[0116] As a preferred embodiment of the present invention, the free phosphoric acid is mixed with the diafiltration acid solution, and the recovered phosphoric acid is obtained by evaporation and concentration, specifically:

[0117] The mixed solution formed by the free phosphoric acid and the diafiltration acid solution is subjected to evaporation and concentration treatment;

[0118] When the specific gravity of the mixed liquid reaches the preset specific gravity, recovered phosphoric acid is obtained, and the recovered phosphoric acid is returned to the chemical disposal tank.

[0119] It is understood that evaporation concentration is the process of increasing the concentration of solutes in a solution by evaporating the water in the liquid through heating. In this step, the mixed acid solution is sent to the evaporation concentration module and processed under negative pressure.

[0120] The evaporation and concentration process can remove water and other volatile substances to obtain high-purity recycled phosphoric acid, which is suitable for a variety of industrial applications. After evaporation and concentration, the specific gravity of the recovered phosphoric acid can be increased to a preset value (usually above 1.7), which meets the standards for reuse.

[0121] In addition, under negative pressure conditions, the boiling point of waste acid is reduced, which reduces the temperature required for evaporation and reduces energy consumption. The lower evaporation temperature is also conducive to reducing the damage to equipment caused by high-temperature corrosive gases and extending the service life of equipment. The negative pressure environment is conducive to the separation of substances and further improves the purity of the recovered phosphoric acid.

[0122] A preset specific gravity value, such as 1.7, is set according to actual needs to ensure the quality and applicability of the recovered phosphoric acid. During the evaporation and concentration process, a specific gravity sensor is used to monitor the change in the specific gravity of the mixed solution in real time. The specific gravity of the mixed solution reaching the preset value is used as a judgment condition to ensure that the specific gravity of the recovered phosphoric acid is stable within the target range.

[0123] The recovered phosphoric acid obtained through evaporation and concentration is directly fed back to the chemical polishing tank for use in the chemical polishing process. In this way, the need for new acid replenishment is reduced, resources are saved, and production costs are reduced. At the same time, the recycling of phosphoric acid is achieved, waste emissions are reduced, and the requirements of clean production and environmental protection are met.

[0124] As a preferred embodiment of the present invention, the method further comprises:

[0125] Adjusting the pH of the aluminum salt solution, adding a flocculant and allowing the solution to stand to precipitate and obtain an aluminum phosphate product;

[0126] Ethanol was added to the remaining supernatant to separate the sulfate product.

[0127] In this embodiment, by adjusting the pH value, aluminum ions can be separated from the salt solution to form aluminum phosphate precipitation. Ammonia water or dilute phosphoric acid is used to adjust the pH value to ensure that it is stable between 3 and 4. If the pH is too low, the aluminum ions in the salt solution cannot be fully separated, and if the pH is too high, other hydroxides may precipitate, affecting the purity of the aluminum phosphate.

[0128] Adding flocculants can accelerate the precipitation rate of aluminum phosphate and increase the particle size of aluminum phosphate nucleation, which helps to achieve effective separation of mud and water. The commonly used flocculant is polyacrylamide (PAM), and its dosage is generally 0.01% to 1% of the weight of the waste liquid. Add the flocculant to the aluminum salt solution and stir it thoroughly to make it evenly dispersed. After stirring, let it stand for 1 to 2 hours to allow the aluminum phosphate precipitate to settle fully.

[0129] Through static precipitation, aluminum phosphate will gradually settle to the bottom of the container to form solid precipitation. Water is removed by filter press 24 and drum dryer 25 to finally obtain a dry aluminum phosphate product, which can be used for the production of water purifiers and other purposes.

[0130] The supernatant contains a certain concentration of sulfate, which can be precipitated by adding ethanol. Depending on the volume of the sulfate solution, add ethanol at a ratio of 1:1 to 4:1. For example, if the volume of the sulfate solution is 100 liters, add 100 to 400 liters of ethanol. Stir well to mix the ethanol and sulfate solution evenly. Since the solubility of ethanol in water is greater than the solubility of sulfate in water, sulfate will precipitate during the addition of ethanol.

[0131] After the sulfate is precipitated, it can be separated from the solution by solid-liquid separation techniques (such as centrifugation, filtration, etc.). Water is removed by a filter press 24 and a drum dryer 25 to finally obtain a dry sulfate product that can be used for industrial applications.

[0132] By adjusting the pH of the aluminum salt solution and adding a flocculant for precipitation, the aluminum phosphate product can be effectively separated; and by adding ethanol to the remaining supernatant for separation, the sulfate product can be obtained. This series of steps not only achieves efficient recovery of multiple valuable components, but also significantly improves resource utilization.

[0133] Specifically, the pH of the aluminum salt solution is adjusted as follows:

[0134] Adding ammonia water or dilute phosphoric acid solution to the aluminum salt solution to adjust the pH of the aluminum salt solution;

[0135] When the pH value of the aluminum salt solution is less than the set pH value interval value, adding ammonia water to the aluminum salt solution;

[0136] When the pH value of the aluminum salt solution is greater than the set pH value interval value, adding dilute phosphoric acid solution to the aluminum salt solution;

[0137] The dilute phosphoric acid solution comes from a mixture of the free phosphoric acid and the leaching acid solution.

[0138] It should be noted that the pH value of the aluminum salt solution is usually adjusted to between 3 and 4. This range helps to separate aluminum ions from the salt solution to form aluminum phosphate precipitation.

[0139] Ammonia is used to raise the pH (make the solution more alkaline). Dilute phosphoric acid is used to lower the pH (make the solution more acidic).

[0140] If the pH value of the aluminum salt solution is detected to be lower than the set target range (e.g. pH < 3), it indicates that the solution is over-acidic. At this time, ammonia water is added to the aluminum salt solution to increase the pH value. According to the difference between the actual pH value and the target pH value, ammonia water is added gradually until the pH value reaches the target range. After each addition, the pH change is monitored in real time using a pH sensor to ensure that it does not exceed the target range.

[0141] If the pH value of the aluminum salt solution is detected to be higher than the set target range (e.g. pH>4), it indicates that the solution is too alkaline. Add dilute phosphoric acid to the aluminum salt solution to lower the pH value. According to the difference between the actual pH value and the target pH value, gradually add dilute phosphoric acid until the pH value reaches the target range. After each addition, use a pH sensor to monitor the pH change in real time to ensure that it does not exceed the target range.

[0142] In this embodiment, an automated control system is introduced, combined with real-time monitoring equipment (such as a pH sensor, a flow meter, etc.), to achieve precise control of the pH value.

[0143] By precisely adjusting the pH of the aluminum salt solution, not only can the subsequent processing steps be smoothly carried out, but also the valuable aluminum phosphate and sulfate products can be effectively separated. This method not only optimizes resource utilization and reduces environmental pollution, but also brings significant economic benefits and technical reliability.

[0144] By mixing free phosphoric acid (desorbed from the acid retardant resin) with leaching acid (phosphoric acid-rich acid obtained after nanofiltration treatment) to form dilute phosphoric acid solution, waste can be reused. Recycled phosphoric acid is used to replace new acid, reducing the demand for new acid replenishment, and reducing the procurement cost and resource consumption of new acid. At the same time, the valuable components in the chemical waste liquid are fully utilized to avoid resource waste, which is in line with the concept of circular economy.

[0145] As a preferred embodiment of the present invention, free phosphoric acid in the concentrated salt solution is extracted by an acid retardation resin to obtain an aluminum salt solution for purifying a water purification agent raw material, specifically:

[0146] The concentrated salt solution is fed into the acid retardation resin from top to bottom, wherein the free phosphoric acid is adsorbed on the acid retardation resin and the aluminum salt solution is filtered out from the acid retardation resin;

[0147] When the acid retardation resin is saturated, reverse osmosis water is passed through the acid retardation resin from bottom to top to desorb the free phosphoric acid to form elution acid.

[0148] Among them, the acid-retarding resin is a strong alkaline anion exchange resin that can selectively adsorb free acids (such as phosphoric acid) while allowing other components (such as aluminum salt solution) to pass through. The concentrated salt solution is slowly fed from top to bottom into the column filled with the acid-retarding resin. This flow pattern ensures that the liquid is in full contact with the resin and improves the adsorption efficiency. The free phosphoric acid is adsorbed by the acid-retarding resin, while the aluminum salt solution containing a higher concentration of aluminum ions is filtered out from the resin to obtain a relatively pure aluminum salt solution.

[0149] As the concentrated salt solution continues to pass through, the acid-retardant resin will gradually reach adsorption saturation, and regeneration is required to restore its adsorption capacity.

[0150] Specifically, the method for determining whether the acid retardant resin is saturated is as follows: measuring the pH of the aluminum salt solution filtered out from the lower end of the acid retardant resin, and when the pH change value of the aluminum salt solution rises to a preset pH change limit, the acid retardant resin is determined to be saturated.

[0151] When the concentrated salt solution passes through the acid retardation resin, the free phosphoric acid is adsorbed by the resin, resulting in a decrease in the phosphoric acid content in the outflowing aluminum salt solution. As the adsorption proceeds, the free acid concentration in the aluminum salt solution gradually decreases, and the pH value rises accordingly.

[0152] When the acid retardant resin approaches or reaches saturation, its adsorption capacity weakens and it can no longer effectively adsorb free phosphoric acid. As a result, more free phosphoric acid will pass through the resin column, causing the free acid concentration in the outflowing aluminum salt solution to increase and the pH value to decrease.

[0153] According to actual operation experience and experimental data, a reasonable pH change limit is set (for example, ΔpH = 0.5). When the pH change of the aluminum salt solution exceeds this limit, it is considered that the acid retardation resin is close to saturation.

[0154] A pH sensor is installed at the lower end of the acid retardation resin column to monitor the pH value of the outflowing aluminum salt solution in real time. An automated control system is used to record the changing trend of the pH value to ensure that the data is accurate and reliable.

[0155] At the beginning of the treatment, the initial pH value of the aluminum salt solution is recorded (e.g., pH=3.5). As the concentrated salt solution continues to pass through, the pH value change of the aluminum salt solution is monitored in real time. When the pH change value (ΔpH) rises to the preset pH change limit (e.g., ΔpH≥0.5), the acid retardation resin is determined to be saturated.

[0156] This embodiment measures the pH of the aluminum salt solution filtered out from the lower end of the acid retardant resin, and determines whether the acid retardant resin is saturated based on the pH change value rising to a preset pH change limit, thereby ensuring the efficiency and stability of the treatment process.

[0157] By passing reverse osmosis water (RO water) from bottom to top through a saturated acid-retarding resin, the adsorbed free phosphoric acid can be effectively desorbed to form an elution acid. High-purity reverse osmosis water is passed from bottom to top through a saturated acid-retarding resin column. This reverse flow helps to maximize the desorption of free phosphoric acid.

[0158] The water molecules in the reverse osmosis water gradually replace the phosphate ions on the resin, desorb them and form elution acid. The desorbed free phosphoric acid is collected to form high-purity elution acid, which can be used for subsequent treatment or reuse.

[0159] After desorption, the acid retardant resin regains its adsorption capacity and can be used again to adsorb free phosphoric acid. The resin itself can be regenerated and reused, reducing processing costs and reducing waste generation. The recovered eluted acid can be directly reused in the chemical tank or other processes after treatment, reducing the need for new acid replenishment.

[0160] The adsorption of the resin is monitored in real time by online monitoring equipment (such as pH sensors, etc.) to determine whether it is close to saturation.

[0161] like Figure 2 As shown, the present invention also provides a multi-component comprehensive recovery system in chemical waste liquid, comprising: a chemical waste liquid storage tank 1, a microfiltration membrane 4, a waste tank liquid storage tank 5, and a filtrate storage tank 6. After the chemical waste liquid in the chemical waste liquid storage tank 1 is microfiltered by the microfiltration membrane 4, impurities are discharged into the waste tank liquid storage tank 5, and the chemical waste filtrate is discharged into the filtrate storage tank 6;

[0162] Nanofiltration membrane 8, concentrated salt solution storage tank a 9, purified acid storage tank 15, after the filtrate in the filtrate storage tank 6 passes through the nanofiltration membrane 8, the separated diafiltration acid is discharged into the purified acid storage tank 15, and the concentrated salt solution is discharged into the concentrated salt solution storage tank a 9;

[0163] Acid retardation resin tank 11, reverse osmosis water storage tank 13, concentrated salt solution storage tank b 12, the concentrated salt solution in the concentrated salt solution storage tank a9 passes through the acid retardation resin tank 11, discharges the aluminum salt solution to the concentrated salt solution storage tank b 12, and flushes the free phosphoric acid in the acid retardation resin tank 11 with the reverse osmosis water storage tank 13 and discharges it into the purified acid storage tank 15;

[0164] Finished acid storage tank 18, which obtains finished acid by evaporating and concentrating the phosphoric acid solution in the purified acid storage tank 15, and discharges the finished acid into the finished acid storage tank 18;

[0165] Phosphate storage tank 26, sulfate storage tank 31, the aluminum phosphate product obtained by treating the aluminum salt solution in the concentrated salt solution storage tank b12 is discharged into the phosphate storage tank 26, and the sulfate product is discharged into the sulfate storage tank 31.

[0166] Specifically, the chemical throwing tank liquid and the post-chemical throwing rinse water are mixed in the chemical throwing waste liquid storage tank 1, the specific gravity of the chemical throwing waste liquid is adjusted to 1.1-1.2, and it is transported to the security filter 3 through the pipeline by the high-pressure pump a2 to remove some insoluble solid particles, and then the colloid and insoluble solid particles in the chemical throwing waste liquid are removed by the microfiltration membrane 4, and the concentrated water is discharged into the waste tank liquid storage tank 5 for concentrated water circulation. When the conductivity of the concentrated water reaches the set value, the concentrated water is discharged to the comprehensive sewage treatment in the factory area, and the chemical throwing filtrate is discharged into the filtrate storage tank 6 through the pipeline.

[0167] In one embodiment, the concentrations of the components in the chemical waste liquid are as follows:

[0168]

[0169] Among them, the microfiltration module adopts the external pressure PTFE microfiltration membrane component DDPT-2880, with a membrane area of ​​35m 2 / piece, the number of membrane components is 3, and the working pressure is 5MPa.

[0170] The chemical waste liquid is transported to the nanofiltration membrane 8 through the pipeline by the high pressure pump b7 to remove the aluminum ions in the filtrate, thereby improving the quality of phosphoric acid in the chemical waste liquid. The concentrated salt solution is discharged to the concentrated salt solution storage tank a9, and the purified acid produced is stored in the purified acid storage tank 15.

[0171] Among them, the component concentrations after treatment by the nanofiltration module are shown in the following table:

[0172]

[0173] Among them, the nanofiltration membrane 8 uses an acid-resistant separation membrane with a working pressure of 5 MPa.

[0174] The concentrated salt solution is sent to the acid retardation resin tank 11 through the pipeline by the high-pressure pump c10, so that the free acid therein is adsorbed by the resin, and the aluminum salt solution is filtered out at the same time. The aluminum salt solution is discharged to the concentrated salt solution storage tank b12 through the pipeline. When the resin is saturated with adsorption, that is, when the pH of the filtered aluminum salt solution rises to the set value, the inlet pipeline valve of the acid retardation resin tank 11 is closed, and the RO pipeline valve is opened at this time. The RO water in the reverse osmosis water storage tank 13 is passed from top to bottom into the acid retardation resin tank 11 through the pipeline by the booster pump a14. Through the octopus water distributor, the RO is uniformly passed through the acid retardation resin, and the free acid blocked by the resin is desorbed to form a purified acid recovery liquid. The purified acid is discharged to the purified acid storage tank 15 through the pipeline.

[0175] Among them, the component concentrations after treatment with the acid retardation resin module are shown in the following table:

[0176]

[0177] The diameter / height ratio of the adsorption column in the acid retardation resin tank 11 is (1.5-3.5): 1. The acid retardation resin is a strongly basic anion exchange resin, and its particle size is 0.2-0.4 mm.

[0178] Among them, the filtrate countercurrent flow rate is 5 to 10 BV / h.

[0179] Among them, the downstream flow rate of RO water is 5-8BV / h, and the RO water consumption is 1-2BV.

[0180] Among them, the negative pressure in the resin separation column is -0.1-0.2MPa. Under negative pressure conditions, the resin residual liquid can be more fully filtered out, reducing the use of RO water, thereby reducing the amount of evaporation liquid, and reducing the energy loss during the evaporation process.

[0181] The purified acid and the flushing acid are mixed in the purified acid storage tank 15 and transported to the evaporation concentrator 17 through the pipeline by the booster pump b 16. After multiple liquid replenishment and concentration, the specific gravity is increased to 1.7, and the aluminum ion concentration is lower than 5g / L, meeting the customer's phosphoric acid reuse requirements.

[0182] Among them, the pressure of the evaporation concentrator 17 is -60 to -80 MPa, the temperature of the solution in the tank is 60 to 80°C, and the steam temperature is 110 to 130°C.

[0183] The filtered aluminum salt solution is placed in the concentrated salt solution storage tank b12, and ammonia water or dilute phosphoric acid solution is added through the pH adjustment box 19 to adjust the pH to 3-4, and then flocculants are added through the flocculant box 20, stirred and mixed, and then left to stand for 1-2 hours. The precipitated solids are passed into the phosphate storage tank 22 through the pipeline through the sludge pump a21, and sent to the filter press 24 through the pipeline through the sludge pump b23. The filter cake is transported to the drum dryer 25 through the conveyor belt. High-temperature air is passed into the lower end of the drum dryer 25 to dry the moisture contained in the incoming material. The dried material is stored in the phosphate storage tank 26 through the discharge port, and is used as the raw material for producing aluminum-based water purifiers.

[0184] At the same time, the supernatant is passed through the booster pump c 27 through the pipeline into the sulfate storage tank 28, and a certain amount of ethanol is added through the ethanol medicine box 29. The amount of ethanol added should be controlled so that the volume ratio of ethanol to sulfate solution is between 1:1 and 4:1. After stirring and mixing, it is sent to the filter press 24 through the sludge pump c 30 through the pipeline. The filter cake is transported to the drum dryer 25 for drying through the conveyor belt. After drying, the material is stored in the sulfate storage tank 31 through the discharge port.

[0185] Wherein, the drying temperature of the drum dryer 25 is 100-105°C.

[0186] As a preferred embodiment of the present invention, the purified acid storage tank 15 is connected to the concentrated salt solution storage tank b12 to discharge the purified acid solution in the purified acid storage tank 15 into the concentrated salt solution storage tank b12, so as to adjust the pH of the aluminum salt solution in the concentrated salt solution storage tank b12;

[0187] The finished acid storage tank 18 is connected to the chemical disposal tank so that the recovered finished acid can be used for chemical disposal operations.

[0188] By adding an appropriate amount of purified acid, the pH value of the aluminum salt solution in the concentrated salt solution storage tank b12 can be effectively adjusted to ensure the optimal operating conditions of the subsequent processing steps. The purified acid is derived from the recovered free phosphoric acid, which realizes the reuse of waste, reduces the need for the replenishment of new acid, and reduces the procurement cost and resource consumption of new acid. By returning the recovered finished acid in the finished acid storage tank 18 to the chemical polishing tank for chemical polishing operations, the closed-loop recycling of the acid is realized, the production cost is reduced, and the economic benefits of the enterprise are increased.

[0189] By connecting the purified acid storage tank 15 with the concentrated salt solution storage tank b 12, and connecting the finished acid storage tank 18 with the chemical disposal tank, effective recycling of the acid solution can be achieved, which not only optimizes resource utilization and reduces environmental pollution, but also brings significant economic benefits and technical reliability.

[0190] In addition, the above-mentioned multi-component comprehensive recovery system in chemical waste liquid can achieve any effect in the multi-component comprehensive recovery method in chemical waste liquid, which will not be elaborated here.

[0191] Anything not described in the present invention can be achieved by adopting or drawing on existing technologies.

[0192] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0193] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for comprehensive recovery of multiple components in chemical waste liquid, characterized in that: The chemical polishing waste liquid is obtained by mixing the chemical polishing tank liquid and the post-chemical polishing rinsing water to adjust the specific gravity of the chemical polishing waste liquid. The method further comprises: The chemical waste liquid is subjected to microfiltration treatment to remove impurities and obtain a chemical filtrate; The filtrate is subjected to nanofiltration treatment to obtain a diafiltration acid solution containing phosphoric acid and a concentrated salt solution containing aluminum ions; Extracting free phosphoric acid in the concentrated salt solution by an acid retardation resin to obtain an aluminum salt solution for refining a raw material for a purified water agent; The free phosphoric acid is mixed with the diafiltration acid solution, and then subjected to evaporation and concentration treatment to obtain recovered phosphoric acid.

2. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 1, characterized in that: The chemical polishing waste liquid is obtained by mixing the chemical polishing tank liquid and the post-chemical polishing rinsing water to adjust the specific gravity of the chemical polishing waste liquid, specifically: According to the specific gravity of the chemical throwing tank liquid in the chemical throwing tank, combined with the volume of the chemical throwing waste liquid storage tank, the volume of the chemical throwing tank liquid discharged in a single time is calculated; Inject chemical polishing tank liquid into the chemical polishing waste liquid storage tank. When the injection amount of the chemical polishing tank liquid reaches the calculated value, switch to injecting post-chemical polishing rinsing water into the chemical polishing waste liquid storage tank.

3. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 2, characterized in that: According to the specific gravity of the chemical throwing tank liquid in the chemical throwing tank, combined with the volume of the chemical throwing waste liquid storage tank, the volume of the chemical throwing tank liquid discharged in a single time is calculated, specifically: According to the specific gravity of the chemical throwing tank liquid and the specific gravity of water in the chemical throwing tank, the volume ratio of the chemical throwing tank liquid and the post-chemical throwing rinsing water is calculated by taking the middle value of the target specific gravity range of the chemical throwing waste liquid; The volumes of the chemical polishing tank liquid and the post-chemical polishing rinsing water are calculated based on the volume of the chemical polishing waste liquid required in the chemical polishing waste liquid storage tank.

4. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 1, characterized in that: The free phosphoric acid is mixed with the diafiltration acid solution, and recovered phosphoric acid is obtained by evaporation and concentration, specifically: The mixed solution formed by the free phosphoric acid and the diafiltration acid solution is subjected to evaporation and concentration treatment; When the specific gravity of the mixed liquid reaches the preset specific gravity, recovered phosphoric acid is obtained, and the recovered phosphoric acid is returned to the chemical disposal tank.

5. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 1, characterized in that: The method further comprises: Adjusting the pH of the aluminum salt solution, adding a flocculant and allowing the solution to stand to precipitate and obtain an aluminum phosphate product; Ethanol was added to the remaining supernatant to separate the sulfate product.

6. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 5, characterized in that: The pH value of the aluminum salt solution is adjusted, specifically: Adding ammonia water or dilute phosphoric acid solution to the aluminum salt solution to adjust the pH of the aluminum salt solution; When the pH value of the aluminum salt solution is less than the set pH value interval value, adding ammonia water to the aluminum salt solution; When the pH value of the aluminum salt solution is greater than the set pH value interval value, adding dilute phosphoric acid solution to the aluminum salt solution; The dilute phosphoric acid solution comes from a mixture of the free phosphoric acid and the leaching acid solution.

7. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 1, characterized in that: The free phosphoric acid in the concentrated salt solution is extracted by an acid retardation resin to obtain an aluminum salt solution for refining a pure water agent raw material, specifically: The concentrated salt solution is fed into the acid retardation resin from top to bottom, wherein the free phosphoric acid is adsorbed on the acid retardation resin and the aluminum salt solution is filtered out from the acid retardation resin; When the acid retardation resin is saturated, reverse osmosis water is passed through the acid retardation resin from bottom to top to desorb the free phosphoric acid to form elution acid.

8. The method for comprehensive recovery of multiple components in chemical waste liquid according to claim 7, characterized in that: The method for determining whether the acid retardant resin is saturated is as follows: The acid retardation resin is determined to be saturated when the pH change of the aluminum salt solution reaches a preset pH change limit.

9. A multi-component comprehensive recovery system for chemical waste liquid, characterized in that: include: A chemical waste liquid storage tank, a microfiltration membrane, a waste tank liquid storage tank, and a filtrate storage tank. After the chemical waste liquid in the chemical waste liquid storage tank is microfiltered by the microfiltration membrane, impurities are discharged into the waste tank liquid storage tank, and the chemical waste filtrate is discharged into the filtrate storage tank; Nanofiltration membrane, concentrated salt solution storage tank a, purified acid storage tank, after the chemical filtrate in the filtrate storage tank passes through the nanofiltration membrane, the separated diafiltration acid is discharged into the purified acid storage tank, and the concentrated salt solution is discharged into the concentrated salt solution storage tank a; Acid retardation resin tank, reverse osmosis water storage tank, concentrated salt solution storage tank b, the concentrated salt solution in the concentrated salt solution storage tank a passes through the acid retardation resin tank, discharges the aluminum salt solution to the concentrated salt solution storage tank b, flushes the free phosphoric acid in the acid retardation resin tank with the reverse osmosis water storage tank and discharges it into the purified acid storage tank; A finished acid storage tank, wherein the phosphoric acid solution in the purified acid storage tank is evaporated and concentrated to obtain finished acid, and the finished acid is discharged into the finished acid storage tank; Phosphate storage tank and sulfate storage tank. The aluminum phosphate product obtained by treating the aluminum salt solution in the concentrated salt solution storage tank b is discharged into the phosphate storage tank, and the sulfate product is discharged into the sulfate storage tank.

10. A multi-component comprehensive recovery system in chemical waste liquid according to claim 9, characterized in that: The purified acid storage tank is connected to the concentrated salt solution storage tank b to discharge the purified acid solution in the purified acid storage tank into the concentrated salt solution storage tank b, so as to adjust the pH value of the aluminum salt solution in the concentrated salt solution storage tank b; The finished acid storage tank is connected to the chemical disposal tank so that the recovered finished acid can be used for chemical disposal operations.

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