Acidic copper-containing etching wastewater treatment system and method based on heat pump coupling regulation

Abstract

This invention discloses a system and method for treating acidic copper-containing etching wastewater based on heat pump coupling regulation, belonging to the field of industrial wastewater treatment and resource recovery technology. Addressing the shortcomings of existing PCB industry acidic copper chloride etching wastewater treatment processes, such as low resource recovery rates, high energy consumption, and the generation of hazardous waste and secondary pollution, this invention constructs a closed-loop system comprising pretreatment and reaction, humidification and concentration, dehumidification and absorption, and heat pump energy circulation. Through a metathesis reaction coupled with humidity regulation, combined with a closed-loop heat pump cycle, simultaneous recovery of copper, hydrochloric acid, and water is achieved. This invention improves copper and hydrochloric acid recovery rates, generates no hazardous waste, reduces power consumption per ton of water treated, and lowers operating costs compared to traditional processes, offering excellent environmental and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment and resource recovery technology, specifically to an acidic copper-containing etching wastewater treatment system and method based on heat pump coupling regulation. Background Technology

[0002] In the etching processes of the electronics industry, such as printed circuit boards (PCBs), acidic copper chloride etching solutions are widely used. This process generates large quantities of acidic copper-containing etching wastewater with high acidity, high copper ion content, and high chloride ion concentration. This wastewater has a complex composition, and direct discharge would cause serious pollution to water bodies and soil, threatening ecological security and human health. At the same time, the wastewater is rich in recyclable copper and hydrochloric acid resources; direct discharge without effective treatment would result in a significant waste of resources. Therefore, it is urgent to implement harmless treatment and resource recovery for this type of wastewater.

[0003] Currently, the mainstream treatment processes for acidic copper-containing etching wastewater in the industry all have significant shortcomings, failing to simultaneously achieve treatment effectiveness, resource recovery, energy consumption control, and environmental protection requirements. Specifically:

[0004] 1. Neutralization precipitation method: Copper ions are removed by adding alkaline solution to form copper hydroxide precipitate. The process is simple to operate, but it produces a large amount of copper-containing hazardous sludge, and copper resources cannot be effectively recovered. At the same time, it completely consumes the residual acid in the wastewater, resulting in a double waste of resources.

[0005] 2. Electrolytic recovery method: Copper can be recovered directly through electrolysis, but it has extremely high energy consumption and poor economic efficiency when treating wastewater with low copper concentration. In addition, it cannot recover hydrochloric acid from the wastewater, and the resource recovery dimension is limited.

[0006] 3. Solvent extraction, ion exchange, and membrane separation: Although these processes can achieve a certain degree of resource recovery, they generally suffer from problems such as complex process flow, high equipment investment and operating costs, easy fouling and deactivation of membrane elements or resins, and easy generation of secondary pollution during the treatment process, making it difficult to promote and apply them on a large scale and stably.

[0007] In summary, there is an urgent need in the industry to develop a new technology and supporting equipment for treating acidic copper-containing etching wastewater that can simultaneously achieve the recovery of multiple components in wastewater, truly achieve the goals of wastewater reduction, harmlessness, and resource utilization, and also has low energy consumption, stable and economical operation, and no secondary pollution. Summary of the Invention

[0008] In view of this, in order to overcome the above-mentioned defects of the prior art, the present invention aims to provide an acidic copper-containing etching wastewater treatment system and method based on heat pump coupling regulation, which realizes the recovery of copper in the wastewater in the form of copper sulfate and chlorine in the form of hydrochloric acid, while achieving efficient internal recycling of system heat and significantly reducing energy consumption in the treatment process.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] In a first aspect, the present invention provides an acidic copper-containing etching wastewater treatment system based on heat pump coupling regulation, comprising a pretreatment and reaction unit, a humidification and concentration unit, a dehumidification and absorption unit, and a heat pump energy circulation unit.

[0011] The pretreatment and reaction unit includes a mixing tank, a feed pump, and a preheater connected in sequence by pipelines. The mixing tank is equipped with a wastewater inlet for receiving acidic copper-containing etching wastewater and a sulfuric acid inlet for receiving concentrated sulfuric acid. The discharge end of the preheater is connected to the humidification and concentration unit. The pretreatment and reaction unit is used to mix and preheat the acidic copper-containing etching wastewater and concentrated sulfuric acid, and trigger a metathesis reaction to generate copper sulfate and hydrogen chloride.

[0012] The humidification and concentration unit includes a humidification tower, a humidification circulation pump, a humidification heater, and a discharge pump. A spray device is installed at the top of the humidification tower. The liquid storage section at the bottom of the humidification tower is connected to the inlet of the humidification circulation pump. The outlet of the humidification circulation pump is connected to the spray device at the top of the humidification tower via the material side of the humidification heater, forming a humidification circulation loop. The liquid storage section at the bottom of the humidification tower is also connected to a solid-liquid separation device via the discharge pump. An air inlet is installed at the bottom of the humidification tower, and an air outlet is installed at the top. The humidification and concentration unit is used to achieve the evaporation and concentration of the copper sulfate solution by using countercurrent gas-liquid contact, allowing circulating air to carry away moisture and hydrogen chloride gas from the solution, while simultaneously completing the evaporation and concentration of the copper sulfate solution.

[0013] The dehumidification absorption unit includes a dehumidification tower, a dehumidification circulation pump, a dehumidification cooler, and a hydrochloric acid recovery tank. A spray device is installed at the top of the dehumidification tower. The liquid storage section at the bottom of the dehumidification tower is connected to the inlet of the dehumidification circulation pump. The outlet of the dehumidification circulation pump is connected to the spray device at the top of the dehumidification tower via the material side of the dehumidification cooler, forming a dehumidification absorption circulation loop. The lower air inlet of the dehumidification tower is connected to the air outlet of the humidification tower via a fan. An exhaust port is installed at the top of the dehumidification tower. The liquid storage section at the bottom of the dehumidification tower is connected to the hydrochloric acid recovery tank via a discharge pipe. The dehumidification absorption unit is used to condense and absorb hydrogen chloride and water vapor in humid and hot air, enriching it to obtain hydrochloric acid product, while simultaneously outputting low-temperature dry air.

[0014] The heat pump energy cycle unit includes a heat pump unit, which incorporates a heat pump condenser and a heat pump evaporator. The heat pump condenser is connected to the heat exchange side of the humidification heater and the heat exchange side of the preheater via a hot water circulation assembly, forming a closed hot water circulation loop. The heat pump evaporator is connected to the heat exchange side of the dehumidification cooler via a chilled water circulation assembly, forming a closed chilled water circulation loop. The heat pump energy cycle unit is used to recover the low-temperature waste heat generated during the dehumidification absorption process, upgrade it into high-grade, high-temperature heat energy, and then supply it to the preheater and the humidification heater, realizing a closed-loop recycling of system heat.

[0015] As a further embodiment of the present invention, the tube side of the preheater is the material side and the shell side is the heat exchange side. The tube side inlet of the preheater is connected to the feed pump outlet, and the tube side outlet is connected to the bottom liquid storage section of the humidification tower. The shell side of the preheater is connected to hot water output from the heat pump condenser. The mixed liquid is heated to 40-60°C in the preheater, triggering a metathesis reaction. The reaction equation is: CuCl2 + H2SO4 → CuSO4 + 2HCl↑.

[0016] As a further embodiment of the present invention, the air outlet of the humidification tower is connected to the lower air inlet of the dehumidification tower via a centrifugal fan, and the upper exhaust port of the dehumidification tower is connected to the air inlet of the centrifugal fan via a pipe, forming a closed-loop air circulation circuit; inside the humidification tower, after the circulating air comes into countercurrent contact with the spray liquid, it forms humid and hot air rich in HCl with a temperature of 55-60℃ and a relative humidity of ≥95%, while the copper sulfate solution continues to evaporate and concentrate during the circulation process.

[0017] As a further embodiment of the present invention, the circulating medium of the dehumidification absorption circulation loop is dilute hydrochloric acid. The low-temperature dilute hydrochloric acid spray liquid output by the dehumidification cooler comes into countercurrent contact with the high-temperature, high-humidity HCl-containing hot and humid air, cools and condenses, and absorbs water vapor and hydrogen chloride in the air to achieve the enrichment of hydrochloric acid. At the same time, low-temperature dry air with a temperature ≤25℃ is obtained and returned to the humidification tower for recycling.

[0018] As a further embodiment of the present invention, the hot water circulation assembly includes a hot water tank, a hot water circulation pump, and a hot water circulation pipeline; the hot water outlet of the heat pump condenser is connected to the inlet of the hot water tank, and the outlet of the hot water tank is connected to the heat exchange side inlet of the humidifier heater and the preheater respectively via the hot water circulation pump. The heat exchange side outlets of the humidifier heater and the preheater both return to the hot water tank, and the hot water tank is then connected to the hot water inlet of the heat pump condenser via the pipeline to form a closed hot water circulation loop.

[0019] As a further embodiment of the present invention, the chilled water circulation assembly includes a chilled water tank, a chilled water circulation pump, and a chilled water circulation pipeline; the chilled water outlet of the heat pump evaporator is connected to the inlet of the chilled water tank, the outlet of the chilled water tank is connected to the heat exchange side inlet of the dehumidifier via the chilled water circulation pump, the heat exchange side outlet of the dehumidifier flows back to the chilled water tank, and the chilled water tank is then connected to the chilled water inlet of the heat pump evaporator via a pipeline, forming a closed chilled water circulation loop.

[0020] As a further embodiment of the present invention, the solid-liquid separation device is a centrifuge. The solid phase outlet of the centrifuge produces copper sulfate solid product, and the liquid phase outlet of the centrifuge is connected in sequence to the bottom storage section of the humidification tower via a mother liquor tank and a mother liquor pump for the reflux circulation of concentrated mother liquor.

[0021] As a further embodiment of the present invention, the heat pump unit is a screw-type heat pump unit, which is internally equipped with a compressor, a heat pump condenser, an expansion valve, and a heat pump evaporator connected in sequence to form a closed refrigerant circulation loop. The low-temperature, low-pressure gaseous refrigerant is transformed into a high-temperature, high-pressure gaseous refrigerant by the compressor, and then heats the circulating hot water by exchanging heat in the heat pump condenser. It is condensed into a high-temperature, high-pressure liquid refrigerant, and then depressurized by the expansion valve to become a low-temperature, low-pressure liquid refrigerant. It absorbs heat from the chilled water by exchanging heat in the heat pump evaporator, vaporizes into a low-temperature, low-pressure gaseous refrigerant, and then flows back to the compressor to complete the refrigerant cycle.

[0022] Secondly, the present invention provides a method for treating acidic copper-containing etching wastewater based on heat pump coupling regulation, which is implemented using the above-mentioned acidic copper-containing etching wastewater treatment system. The method includes the following steps:

[0023] S1 Mixing reaction: Acidic copper-containing etching wastewater and concentrated sulfuric acid are added to the mixing tank in a preset ratio and mixed thoroughly. The mixture is then pumped to the preheater for heating, where a metathesis reaction occurs to produce copper sulfate and hydrogen chloride, resulting in a mixed reaction solution.

[0024] S2 Humidification and Concentration: The mixed reaction solution is sent into the humidification tower. The solution in the tower is sent to the humidification heater by the humidification circulation pump and heated to the preset temperature. Then, it is sprayed down from the top of the humidification tower. At the same time, dry air enters from the bottom of the humidification tower and comes into countercurrent contact with the sprayed liquid. The water and hydrogen chloride in the solution are carried away by the air, forming high temperature and high humidity HCl-containing hot and humid air that is discharged from the top of the tower. The copper sulfate solution in the tower is continuously concentrated.

[0025] S3 Dehumidification and Absorption: The high-temperature, high-humidity, HCl-containing hot and humid air discharged from the humidification tower is sent to the bottom of the dehumidification tower. The low-temperature dilute hydrochloric acid circulating liquid is sprayed down from the top of the dehumidification tower and comes into countercurrent contact with the hot and humid air. The water vapor and hydrogen chloride in the air are condensed and absorbed into the circulating liquid, realizing the enrichment of hydrochloric acid. The cooled and dehumidified dry air is discharged from the top of the tower and flows back to the humidification tower for recycling.

[0026] S4 Energy Cycle: The low-temperature waste heat released during the dehumidification absorption process is recovered by the heat pump unit and converted into high-temperature heat energy after being upgraded. This heat energy is used to heat the materials in the preheater and humidification heater, realizing the closed-loop recycling of system heat.

[0027] S5 Product Recovery: When the copper sulfate solution in the humidification tower is concentrated to the preset concentration, a portion of the concentrate is discharged and separated into solid and liquid components to obtain solid copper sulfate product; when the hydrochloric acid concentration in the dehumidification tower reaches the preset value, a portion of the hydrochloric acid is discharged to the hydrochloric acid recovery tank to obtain hydrochloric acid byproduct.

[0028] As a further aspect of the present invention, in step S1, the acidic copper-containing etching wastewater is acidic copper chloride etching wastewater generated by the PCB and electronic component manufacturing industries, Cu 2+ The concentration is 20-100 g / L, pH < 1; the volume ratio of the acidic copper-containing etching wastewater to concentrated sulfuric acid is (5-20):1, and the mixture is heated to 40-60℃ by a preheater.

[0029] As a further aspect of the present invention, in step S2, the solution in the humidifying heater is heated to 55-65°C, the operating temperature in the humidifying tower is 50-60°C, the temperature of the humidified air discharged from the humidifying tower is 55-60°C, and the relative humidity is ≥95%.

[0030] As a further aspect of the present invention, in step S3, the temperature of the dilute hydrochloric acid circulating liquid output by the dehumidifier is 15-25°C, the operating temperature inside the dehumidifier tower is 20-30°C, the temperature of the dry air discharged from the dehumidifier tower is ≤25°C, and the preset concentration of hydrochloric acid enrichment is 10%-20%.

[0031] As a further aspect of the present invention, in step S4, the heat pump condenser of the heat pump unit produces hot water at 55-70°C, which is supplied to the humidifying heater and the preheater respectively. After heat exchange, the water is cooled to 50-55°C and returned to the heat pump condenser for reheating. The heat pump evaporator of the heat pump unit produces chilled water at 8-15°C, which is supplied to the dehumidifying cooler. After heat exchange, the water is heated to 18-22°C and returned to the heat pump evaporator for recooling.

[0032] As a further aspect of the present invention, in step S5, the preset concentration of the copper sulfate solution is such that the solution density reaches 1.3-1.5 g / cm³. 3 The solid-liquid separation is performed using a centrifuge to separate copper sulfate pentahydrate solid with a water content of ≤5%. The separated mother liquor is then returned to the humidification tower for further circulation and concentration.

[0033] As a further aspect of the present invention, the system consumes 250-300 kWh of electricity per ton of acidic copper-containing etching wastewater, with a copper recovery rate of ≥98% and a hydrochloric acid recovery rate of ≥98%.

[0034] Compared with the prior art, the acidic copper-containing etching wastewater treatment system and method based on heat pump coupling regulation of the present invention has the following beneficial effects:

[0035] 1. High degree of resource utilization and no hazardous waste generation: This invention uses a double decomposition reaction coupled with humidity control process to convert all pollutants in wastewater into high value-added products. Copper is recovered in the form of copper sulfate pentahydrate crystals, and chlorine is recovered in the form of industrial hydrochloric acid. The resource recovery rate can reach more than 98%. No copper-containing hazardous sludge is generated in the entire treatment process, truly realizing the transformation of waste into treasure and the full resource utilization of wastewater.

[0036] 2. Extremely low energy consumption and excellent operating economy: The innovative introduction of a heat pump energy circulation unit recovers all the condensation waste heat released during the dehumidification absorption process and improves its quality before using it to heat the materials in the humidification and concentration process. This achieves a closed-loop heat circulation in the system, greatly reducing the external energy consumption of the evaporation and concentration process. Actual measurements show that the electricity consumption per ton of wastewater treated is only 250-300 kWh, and the operating cost is more than 50% lower than that of traditional evaporation technology. Moreover, the economic value of the recovered products can fully cover the operating cost.

[0037] 3. Compact process and high processing efficiency: This invention integrates multiple processes such as chemical reaction, evaporation and concentration, gas absorption, and energy recovery into a closed-loop system. The process flow is smooth, the heat and mass transfer efficiency of gas-liquid countercurrent contact is high, the equipment has a high degree of integration and a small footprint, and it can achieve continuous and stable operation and convenient operation and maintenance management.

[0038] 4. Environmentally friendly and with a high level of clean production: The entire process is a purely physical and chemical process, without introducing new impurities or generating secondary pollution. The air in the system is in a closed loop, and there is no exhaust gas discharge. Only reusable / external copper sulfate and hydrochloric acid products are produced, which fully meet the environmental protection requirements of clean production.

[0039] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to specific embodiments. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the exemplary embodiments or related technologies will be briefly introduced below. The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 This is a schematic diagram of the equipment connection for the acidic copper-containing etching wastewater treatment method based on heat pump coupling regulation provided by the present invention.

[0042] Figure 2The diagram shows the heat pump cycle process in the acidic copper-containing etching wastewater treatment method based on heat pump coupling regulation provided by the present invention.

[0043] Explanation of the labels in the diagram:

[0044] 1-Mixing tank; 2-Feed pump; 3-Preheater; 4-Humidification tower; 5-Humidification circulation pump; 6-Humidification heater; 7-Discharge pump; 8-Centrifuge; 9-Centrifugal fan; 10-Dehumidification tower; 11-Dehumidification circulation pump; 12-Dehumidification cooler; 13-Hydrochloric acid recovery tank; 14-Heat pump unit; 14A-Heat pump condenser; 14B-Heat pump evaporator; 15-Hot water tank; 16-Hot water circulation pump; 17-Chilled water tank; 18-Chilled water circulation pump; 19-Mother liquor tank; 20-Mother liquor pump; W-Wastewater inlet; S-Sulfuric acid inlet. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] In some of the processes described in the specification, claims and accompanying drawings of this invention, there are multiple operations that appear in a specific order. However, it should be clearly understood that these operations may not be performed in the order they appear herein or may be performed in parallel. The sequence numbers of the operations, such as 11, 12, etc., are merely used to distinguish different operations and do not represent any execution order in themselves.

[0047] The technical solutions in the exemplary embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described exemplary embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] This invention addresses acidic copper chloride etching wastewater generated by the PCB and electronic component manufacturing industries. Through a system and method coupled with a metathesis reaction and heat pump regulation, it achieves simultaneous recovery and closed-loop resource utilization of copper, hydrochloric acid, and water resources in the wastewater. The system is designed to withstand strong corrosion and can operate stably for extended periods in harsh environments with high acidity and high chloride ion concentrations. See also... Figure 1 and Figure 2 As shown in the figure, this embodiment provides an acidic copper-containing etching wastewater treatment system based on heat pump coupling regulation, including a pretreatment and reaction unit, a humidification and concentration unit, a dehumidification and absorption unit, and a heat pump energy circulation unit.

[0049] In this embodiment, the pretreatment and reaction unit includes a mixing tank 1, a feed pump 2, and a preheater 3 connected sequentially by pipelines. The mixing tank 1 is equipped with a wastewater inlet W for receiving acidic copper-containing etching wastewater and a sulfuric acid inlet S for receiving concentrated sulfuric acid. The mixing tank 1 is made of vertical PPH or steel-lined polytetrafluoroethylene material, with a built-in frame-type stirring device at a speed of 60-120 r / min. The wastewater inlet W and sulfuric acid inlet S are located at the top, and the discharge port is located at the bottom. The side wall is equipped with a level gauge and an online pH monitor to accurately control the feed ratio of wastewater and concentrated sulfuric acid, ensuring complete reaction. The feed pump 2 is a fluoroplastic alloy centrifugal pump with a head of 20-30m. All flow parts are designed to be corrosion-resistant, suitable for stable delivery of high-acidity and high-chloride-ion media.

[0050] The discharge end of the preheater 3 is connected to the humidification and concentration unit. The pretreatment and reaction unit is used to mix and preheat the acidic copper-containing etching wastewater and concentrated sulfuric acid, and trigger a metathesis reaction to generate copper sulfate and hydrogen chloride. The tube side of the preheater 3 is the material side, and the shell side is the heat exchange side. The tube side inlet of the preheater 3 is connected to the outlet of the feed pump 2, and the tube side outlet is connected to the bottom storage section of the humidification tower 4. The shell side of the preheater 3 is connected to hot water output from the heat pump condenser 14A. The mixed liquid is heated to 40-60℃ in the preheater 3, triggering a metathesis reaction. The reaction equation is: CuCl2 + H2SO4 → CuSO4 + 2HCl↑.

[0051] Specifically, the preheater 3 adopts a shell-and-tube graphite heat exchanger, with the tube side being the material side and the shell side being the hot water heat exchange side. It is resistant to temperatures of 0-100℃ and is resistant to strong acids and chloride ion corrosion. The material is heated to 40-60℃ in the tube side by the hot water in the shell side, which simultaneously triggers a metathesis reaction. The volatility of HCl is used to achieve the reaction separation of copper and chlorine.

[0052] In this embodiment, the humidification and concentration unit includes a humidification tower 4, a humidification circulation pump 5, a humidification heater 6, and a discharge pump 7. A spray device is installed at the top of the humidification tower 4, and the liquid storage section at the bottom of the humidification tower 4 is connected to the inlet of the humidification circulation pump 5. In this embodiment, the humidification tower 4 is a vertical counter-current spray tower, with the tower body made of PPH or fluoropolymer-lined steel, and filled with polypropylene Pall ring packing. The packing layer height is 1.5-3m to improve gas-liquid contact efficiency. A spiral spray device is installed at the top of the tower, with a spray coverage rate ≥150%. An air inlet is opened at the bottom of the tower body, and an air outlet is opened at the top. The bottom of the tower is a liquid storage section, equipped with an online density meter, thermometer, and level gauge to monitor the concentration of the copper sulfate solution in real time. The humidification circulation pump 5 is a fluoroplastic alloy centrifugal pump with a head of 25-35m and a large flow rate design to meet the spray circulation requirements. The flow-through components are resistant to strong acid corrosion.

[0053] The outlet of the humidifying circulation pump 5 is connected to the spray device at the top of the humidifying tower 4 via the material side of the humidifying heater 6, forming a humidifying circulation loop. The liquid storage section at the bottom of the humidifying tower 4 is also connected to a solid-liquid separation device via the discharge pump 7. The humidifying tower 4 has an air inlet at the bottom and an air outlet at the top. The humidifying concentration unit is used to allow the circulating air to carry away the water and hydrogen chloride gas in the solution through countercurrent gas-liquid contact, while simultaneously completing the evaporation and concentration of the copper sulfate solution. The humidifying heater 6 can be a shell-and-tube graphite heat exchanger, with the tube side being the copper sulfate material side and the shell side being the hot water heat exchange side, which can heat the circulating material to 55-65℃ to provide heat for water evaporation and HCl desorption. The discharge pump 7 can be a fluoroplastic alloy centrifugal pump with a head of 20-30m, used to transport the concentrated copper sulfate solution to the solid-liquid separation unit.

[0054] The air outlet of the humidification tower 4 is connected to the lower air inlet of the dehumidification tower 10 via a centrifugal fan 9, and the upper exhaust port of the dehumidification tower 10 is connected to the air inlet of the centrifugal fan 9 via a pipe, forming a closed-loop air circulation circuit. Inside the humidification tower 4, after the circulating air comes into countercurrent contact with the spray liquid, it forms humid and hot air rich in HCl with a temperature of 55-60℃ and a relative humidity of ≥95%, while the copper sulfate solution continues to evaporate and concentrate during the circulation process.

[0055] In this embodiment, the solid-liquid separation device is a centrifuge 8. The solid phase outlet of the centrifuge 8 produces copper sulfate solid product, and the liquid phase outlet of the centrifuge 8 is connected to the bottom storage section of the humidification tower 4 via a mother liquor tank 19 and a mother liquor pump 20 in sequence for the reflux circulation of concentrated mother liquor.

[0056] The working process of the humidification and concentration unit is as follows: the preheated mixed reaction liquid enters the storage section of the humidification tower 4, and is sent to the humidification heater 6 by the humidification circulation pump 5 to be heated to the set temperature. Then, it is sprayed down from the top of the tower and comes into countercurrent contact with the dry air blown in from the bottom of the tower. The water and HCl gas in the high temperature solution quickly diffuse into the air, forming high temperature, high humidity, HCl-containing hot and humid air that is discharged from the top of the tower. The copper sulfate solution is continuously concentrated during the circulation process.

[0057] In this embodiment, the dehumidification absorption unit includes a dehumidification tower 10, a dehumidification circulation pump 11, a dehumidification cooler 12, and a hydrochloric acid recovery tank 13. The top of the dehumidification tower 10 is equipped with a spray device, and the bottom liquid storage section of the dehumidification tower 10 is connected to the inlet of the dehumidification circulation pump 11. The outlet of the dehumidification circulation pump 11 is connected to the spray device at the top of the dehumidification tower 10 via the material side of the dehumidification cooler 12, forming a dehumidification absorption circulation loop. The lower air inlet of the dehumidification tower 10 is connected to the air outlet of the humidification tower 4 via a fan, and the upper part of the dehumidification tower 10 is equipped with an exhaust port. The bottom liquid storage section of the dehumidification tower 10 is connected to the hydrochloric acid recovery tank 13 via a discharge pipe. The dehumidification absorption unit is used to condense and absorb hydrogen chloride and water vapor in humid and hot air, enrich hydrochloric acid product, and output low-temperature dry air at the same time.

[0058] The circulating medium of the dehumidification absorption circulation loop is dilute hydrochloric acid. The low-temperature dilute hydrochloric acid spray liquid output by the dehumidifier 12 comes into countercurrent contact with the high-temperature, high-humidity HCl-containing hot and humid air, cools and condenses, and absorbs water vapor and hydrogen chloride in the air to achieve the enrichment of hydrochloric acid. At the same time, low-temperature dry air with a temperature ≤25℃ is obtained and returned to the humidification tower 4 for recycling.

[0059] The dehumidification tower 10 can be a vertical counter-current spray tower with a PPH or fluoropolymer-lined steel body. It is filled with polypropylene Pall ring packing with a packing layer height of 1.5-3m. A spiral spray device is installed at the top of the tower, with a spray coverage rate of ≥150%. The air inlet at the bottom of the tower is connected to the air outlet of the humidification tower 4 via a centrifugal fan 9, and the exhaust outlet at the top flows back to the air inlet of the centrifugal fan 9 through a pipeline, forming a closed-loop air circulation circuit with no exhaust gas discharge. The bottom of the tower is a liquid storage section, equipped with an online hydrochloric acid concentration meter, thermometer, and level gauge to monitor the degree of hydrochloric acid enrichment in real time. The dehumidification circulating pump 11 can be a fluoroplastic alloy centrifugal pump with a head of 25-35m, a large flow rate design, and flow-through components resistant to hydrochloric acid corrosion; the dehumidification cooler 12 can be a shell-and-tube graphite heat exchanger with the tube side being the hydrochloric acid circulating liquid side and the shell side being the chilled water heat exchange side, with a temperature resistance of 10-60℃, which can cool the hydrochloric acid circulating liquid to 15-25℃, providing low-temperature conditions for water vapor condensation and HCl absorption; the hydrochloric acid recovery tank 13 can be made of PE or fluoropolymer-lined steel, equipped with a level gauge and a breather valve, for storing qualified hydrochloric acid products.

[0060] The working process of the dehumidification and absorption unit is as follows: the high-temperature, high-humidity, HCl-containing hot and humid air discharged from the humidification tower 4 is sent to the bottom of the dehumidification tower 10 by the centrifugal fan 9, and comes into countercurrent contact with the low-temperature dilute hydrochloric acid circulating liquid sprayed down from the top of the tower. The hot and humid air is rapidly cooled, and the water vapor in it condenses into liquid water. The HCl gas is efficiently absorbed, realizing the continuous enrichment of hydrochloric acid. The cooled and dehumidified low-temperature dry air is discharged from the top of the tower and flows back to the humidification tower 4 for recycling, completing the closed-loop regeneration of the air.

[0061] In this embodiment, the heat pump energy circulation unit includes a heat pump unit 14, which houses a heat pump condenser 14A and a heat pump evaporator 14B. The heat pump condenser 14A is connected to the heat exchange side of the humidifier heater 6 and the heat exchange side of the preheater 3 via a hot water circulation assembly, forming a closed hot water circulation loop. The heat pump evaporator 14B is connected to the heat exchange side of the dehumidifier cooler 12 via a chilled water circulation assembly, forming a closed chilled water circulation loop. The heat pump energy circulation unit is used to recover the low-temperature waste heat generated during the dehumidification absorption process, upgrade it into high-grade high-temperature heat energy, and supply it to the preheater 3 and the humidifier heater 6, thereby realizing the closed-loop recycling of system heat.

[0062] The heat pump unit 14 is a screw-type water source heat pump unit 14, which integrates a compressor, a heat pump condenser 14A, an expansion valve, and a heat pump evaporator 14B, forming a closed refrigerant circulation loop. The refrigerant used is environmentally friendly R134a / R245fa refrigerant, and the unit's COP value is ≥4.5, with an energy efficiency ratio far exceeding that of traditional electric heating and steam heating. The internal working process of the unit is as follows: the low-temperature, low-pressure gaseous refrigerant is adiabatically compressed by the compressor to form a high-temperature, high-pressure gaseous refrigerant; the high-temperature, high-pressure gaseous refrigerant enters the heat pump condenser 14A, exchanges heat with the circulating water to release heat, and condenses itself into a high-temperature, high-pressure liquid refrigerant; the high-temperature, high-pressure liquid refrigerant is throttled and depressurized by the expansion valve, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant; the low-temperature, low-pressure refrigerant enters the heat pump evaporator 14B, absorbs heat from the chilled water, vaporizes itself into a low-temperature, low-pressure gaseous refrigerant, and flows back to the compressor, completing the reverse Carnot cycle.

[0063] The hot water circulation assembly includes a hot water tank 15, a hot water circulation pump 16, and a hot water circulation pipeline. The hot water outlet of the heat pump condenser 14A is connected to the inlet of the hot water tank 15. The outlet of the hot water tank 15 is connected to the heat exchange side inlets of the humidifier heater 6 and the preheater 3 via the hot water circulation pump 16. The heat exchange side outlets of the humidifier heater 6 and the preheater 3 both return to the hot water tank 15. The hot water tank 15 is then connected to the hot water inlet of the heat pump condenser 14A via a pipeline, forming a closed hot water circulation loop.

[0064] The chilled water circulation assembly includes a chilled water tank 17, a chilled water circulation pump 18, and chilled water circulation pipelines. The chilled water outlet of the heat pump evaporator 14B is connected to the inlet of the chilled water tank 17. The outlet of the chilled water tank 17 is connected to the heat exchange side inlet of the dehumidifier 12 via the chilled water circulation pump 18. The heat exchange side outlet of the dehumidifier 12 returns to the chilled water tank 17. The chilled water tank 17 is then connected to the chilled water inlet of the heat pump evaporator 14B via pipelines, forming a closed chilled water circulation loop.

[0065] The heat pump unit 14 is a screw-type heat pump unit 14, which is internally equipped with a compressor, a heat pump condenser 14A, an expansion valve, and a heat pump evaporator 14B connected in sequence to form a closed refrigerant circulation loop. The low-temperature, low-pressure gaseous refrigerant is transformed into a high-temperature, high-pressure gaseous refrigerant by the compressor, and then heats the circulating hot water by exchanging heat in the heat pump condenser 14A. It condenses into a high-temperature, high-pressure liquid refrigerant, and then depressurizes through the expansion valve to become a low-temperature, low-pressure liquid refrigerant. It then absorbs heat from the chilled water by exchanging heat in the heat pump evaporator 14B, vaporizes into a low-temperature, low-pressure gaseous refrigerant, and then flows back to the compressor to complete the refrigerant cycle.

[0066] For example, in the treatment of acidic copper-containing etching wastewater generated by a PCB factory, the acidic copper chloride etching wastewater treatment system based on heat pump coupling regulation of the present invention, Cu 2+ If the concentration is about 50g / L and the pH is <1, the wastewater and concentrated sulfuric acid are added to the mixing tank 1 at a volume ratio of 10:1. The mixture is then transported by the feed pump 2 to the preheater 3 and preheated to 50°C before entering the humidification tower 4.

[0067] In the humidification unit, the solution is drawn out by the humidification circulation pump 5, heated to 60°C by the humidification heater 6 which has 65°C hot water flowing through its shell side, and then sent to the top of the humidification tower 4 for spraying. Air is blown in from the bottom of the humidification tower 4 by the centrifugal fan 9, and becomes 60°C, high-humidity, HCl-rich hot and humid air after contacting the sprayed liquid.

[0068] The hot, humid air is fed into the bottom of the dehumidification tower 10. In the dehumidification unit, dilute hydrochloric acid is drawn from the bottom of the tower by the dehumidification circulation pump 11, cooled to 20°C by the dehumidification cooler 12 (with 15°C chilled water flowing through its shell side), and then sprayed onto the top of the dehumidification tower 10. The hot, humid air comes into contact with the cold acid solution, is cooled and dehumidified, and moisture and HCl are absorbed. After the temperature drops below 25°C, the air is discharged from the top of the tower and enters the centrifugal fan 9, forming a closed-loop cycle. The concentration of the hydrochloric acid solution at the bottom of the dehumidification tower 10 gradually increases. The heat pump unit 14, such as a screw-type heat pump, is the energy hub of the entire system.

[0069] The normal operation of a heat pump can be analyzed primarily by examining the energy state of the circulating medium within the pump. The low-temperature, low-pressure gaseous refrigerant is transformed into a high-temperature, high-pressure gaseous state by the compressor. This high-temperature, high-pressure gaseous refrigerant then passes through the condenser, exchanging heat with the substance requiring heating, releasing energy, and transforming into a high-temperature, high-pressure liquid refrigerant. This high-temperature, high-pressure liquid refrigerant then passes through the expansion valve, releasing pressure and transforming into a low-temperature, low-pressure liquid refrigerant. This low-temperature, low-pressure liquid refrigerant then passes through the evaporator, exchanging heat with the substance requiring heat release, absorbing energy, and transforming into a low-temperature, low-pressure gaseous refrigerant.

[0070] In the hot water circulation system, the heat pump condenser 14A produces hot water at 65°C. Part of the hot water enters the shell side of the humidifier heater 6, and the other part enters the shell side of the preheater 3. After releasing heat, the water cools down to about 55°C and flows back to the hot water tank 15 for storage. Then, the hot water circulation pump 16 transports the hot water to the heat pump condenser 14A for reheating, thus forming a hot water circulation.

[0071] The heat pump evaporator 14B of the chilled water circulation system produces chilled water at 10°C, which enters the shell side of the dehumidifier 12, absorbs heat, and is heated to about 20°C. The water then flows back to the chilled water tank 17 for storage, and is then transported by the chilled water circulation pump 18 to the heat pump evaporator 14B for further cooling, thus forming a chilled water circulation.

[0072] The air circulation system is mainly based on the different saturation humidity of air at different temperatures. Inside the humidification tower 4, the air is hot and humid, which carries away moisture and high-temperature volatile substances (HCl). After passing through the dehumidification tower 10, the moisture and high-temperature volatile substances in the air are condensed and turned into low-temperature, relatively dry air before entering the humidification tower 4, thus forming the air circulation system.

[0073] During continuous operation, when the solution density at the bottom of humidification tower 4 reaches 1.4 g / cm³... 3 The discharge pump 7 is turned on, and part of the concentrated liquid is sent to the centrifuge 8 for separation to obtain copper sulfate solid (CuSO4·5H2O) with a water content of less than 5%. The mother liquor enters the mother liquor tank 19 and is then transported back to the humidification tower 4 by the mother liquor pump 20. The copper sulfate solid can be prepared into a saturated solution or further dried to obtain copper sulfate crystals for sale or reuse. At the same time, when the hydrochloric acid concentration H at the bottom of the dehumidification tower 10 reaches the set concentration, such as 15%, the valve is opened to discharge part of the hydrochloric acid into the hydrochloric acid recovery tank 13 as a by-product for sale.

[0074] Calculations show that the system consumes approximately 250-300 kWh of electricity to process each ton of wastewater, demonstrating significant energy savings. Furthermore, the recovered copper sulfate and hydrochloric acid can cover the operating costs, resulting in excellent economic and environmental benefits.

[0075] This invention also provides a method for treating acidic copper-containing etching wastewater based on heat pump coupling regulation, implemented using the aforementioned acidic copper-containing etching wastewater treatment system. The method includes the following steps:

[0076] S1 Mixing reaction: Acidic copper-containing etching wastewater and concentrated sulfuric acid are added to mixing tank 1 in a preset ratio and mixed thoroughly. The mixture is then pumped to preheater 3 by feed pump 2 and heated to undergo a metathesis reaction to produce copper sulfate and hydrogen chloride, thus obtaining a mixed reaction solution.

[0077] In step S1, the acidic copper-containing etching wastewater is acidic copper chloride etching wastewater generated by the PCB and electronic component manufacturing industries. 2+The concentration is 20-100 g / L, pH < 1; the volume ratio of the acidic copper-containing etching wastewater to concentrated sulfuric acid is (5-20):1, and the mixture is heated to 40-60℃ by preheater 3.

[0078] S2 Humidification and Concentration: The mixed reaction solution is sent into the humidification tower 4. The solution in the tower is sent to the humidification heater 6 through the humidification circulation pump 5 and heated to the preset temperature. Then, it is sprayed down from the top of the humidification tower 4. At the same time, dry air enters from the bottom of the humidification tower 4 and comes into countercurrent contact with the sprayed liquid. The water and hydrogen chloride in the solution are carried away by the air, forming high temperature and high humidity HCl-containing hot and humid air that is discharged from the top of the tower. The copper sulfate solution in the tower is continuously concentrated.

[0079] In step S2, the solution in the humidifying heater 6 is heated to 55-65°C, the operating temperature in the humidifying tower 4 is 50-60°C, the temperature of the humidified air discharged from the humidifying tower 4 is 55-60°C, and the relative humidity is ≥95%.

[0080] S3 Dehumidification and Absorption: The high-temperature, high-humidity, HCl-containing hot and humid air discharged from the humidification tower 4 is sent to the bottom of the dehumidification tower 10. The low-temperature dilute hydrochloric acid circulating liquid is sprayed down from the top of the dehumidification tower 10 and comes into countercurrent contact with the hot and humid air. The water vapor and hydrogen chloride in the air are condensed and absorbed into the circulating liquid, realizing the enrichment of hydrochloric acid. The cooled and dehumidified dry air is discharged from the top of the tower and returned to the humidification tower 4 for recycling.

[0081] In step S3, the temperature of the dilute hydrochloric acid circulating liquid output by the dehumidifier 12 is 15-25℃, the operating temperature inside the dehumidifier 10 is 20-30℃, the temperature of the dry air discharged from the dehumidifier 10 is ≤25℃, and the preset concentration of hydrochloric acid enrichment is 10%-20%.

[0082] S4 Energy Cycle: The low-temperature waste heat released during the dehumidification absorption process is recovered by the heat pump unit 14, and after being upgraded, it is converted into high-temperature heat energy, which is used for material heating in the preheater 3 and the humidifier heater 6, realizing the closed-loop recycling of system heat.

[0083] In step S4, the heat pump condenser 14A of the heat pump unit 14 produces hot water at 55-70°C, which is supplied to the humidifier heater 6 and the preheater 3 respectively. After heat exchange, the water is cooled to 50-55°C and returned to the heat pump condenser 14A for reheating. The heat pump evaporator 14B of the heat pump unit 14 produces chilled water at 8-15°C, which is supplied to the dehumidifier cooler 12. After heat exchange, the water is heated to 18-22°C and returned to the heat pump evaporator 14B for cooling.

[0084] S5 Product Recovery: When the copper sulfate solution in the humidification tower 4 is concentrated to the preset concentration, a portion of the concentrate is discharged and separated into solid and liquid components to obtain solid copper sulfate product; when the hydrochloric acid concentration in the dehumidification tower 10 reaches the preset value, a portion of the hydrochloric acid is discharged to the hydrochloric acid recovery tank 13 to obtain hydrochloric acid by-product.

[0085] In step S5, the copper sulfate solution is concentrated to a preset concentration where the solution density reaches 1.3-1.5 g / cm³. 3 The solid-liquid separation is performed using centrifuge 8 to separate copper sulfate pentahydrate solid with a water content of ≤5%. The separated mother liquor is returned to humidification tower 4 for further circulation and concentration.

[0086] The system of this invention consumes 250-300 kWh of electricity per ton of acidic copper-containing etching wastewater, with a copper recovery rate of ≥98% and a hydrochloric acid recovery rate of ≥98%. This invention utilizes a coupled process of metathesis reaction and humidity control to convert all pollutants in the wastewater into high-value-added products. Copper is recovered in the form of copper sulfate pentahydrate crystals, and chlorine is recovered in the form of industrial hydrochloric acid, achieving a resource recovery rate of over 98%. The entire treatment process generates no copper-containing hazardous sludge, truly realizing the transformation of waste into treasure and the full resource utilization of wastewater.

[0087] This invention introduces a heat pump energy circulation unit to recover all the condensation waste heat released during the dehumidification absorption process and improve its quality before using it to heat the materials in the humidification and concentration process. This achieves a closed-loop heat circulation in the system, greatly reducing the external energy consumption of the evaporation and concentration process. Actual measurements show that the power consumption per ton of wastewater treated is only 250-300 kWh, and the operating cost is more than 50% lower than that of traditional evaporation technology. Moreover, the economic value of the recovered products can fully cover the operating cost.

[0088] This invention integrates multiple processes, including chemical reaction, evaporation and concentration, gas absorption, and energy recovery, into a closed-loop system. The process flow is smooth, with high heat and mass transfer efficiency due to gas-liquid countercurrent contact. The equipment boasts high integration, a small footprint, and can achieve continuous and stable operation, making maintenance and management convenient. The entire process is purely physicochemical, introducing no new impurities and generating no secondary pollution. The system features closed-loop air circulation, resulting in no waste gas emissions. Only reusable / sellable copper sulfate and hydrochloric acid are produced, fully complying with clean production environmental requirements.

[0089] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A heat pump coupling adjustment-based acidic copper-containing etching wastewater treatment system, characterized in that, The system comprises a pretreatment and reaction unit, a humidification and concentration unit, a dehumidification and absorption unit and a heat pump energy circulation unit. The pretreatment and reaction unit comprises a mixing tank, a feed pump and a preheater connected in sequence by pipelines, the mixing tank is provided with a wastewater feed port for accessing acidic copper-containing etching wastewater and a sulfuric acid feed port for accessing concentrated sulfuric acid, and the outlet end of the preheater is communicated with the humidification and concentration unit. The humidification and concentration unit comprises a humidification tower, a humidification circulating pump, a humidification heater and a discharge pump, the top of the humidification tower is provided with a spraying device, the bottom storage section of the humidification tower is communicated with the inlet of the humidification circulating pump, the outlet of the humidification circulating pump is communicated with the spraying device at the top of the humidification tower through the material side of the humidification heater, forming a humidification circulation loop; the bottom storage section of the humidification tower is also connected with a solid-liquid separation device through the discharge pump, the lower part of the humidification tower is provided with an air inlet, and the upper part is provided with an air outlet. The dehumidification and absorption unit comprises a dehumidification tower, a dehumidification circulating pump, a dehumidification cooler and a hydrochloric acid recovery tank, the top of the dehumidification tower is provided with a spraying device, the bottom storage section of the dehumidification tower is communicated with the inlet of the dehumidification circulating pump, the outlet of the dehumidification circulating pump is communicated with the spraying device at the top of the dehumidification tower through the material side of the dehumidification cooler, forming a dehumidification and absorption circulation loop; the air inlet of the lower part of the dehumidification tower is communicated with the air outlet of the humidification tower through a fan, the upper part of the dehumidification tower is provided with an exhaust port, and the bottom storage section of the dehumidification tower is communicated with the hydrochloric acid recovery tank through a discharge pipeline. The heat pump energy circulation unit comprises a heat pump unit, and the heat pump unit is internally provided with a heat pump condenser and a heat pump evaporator. The heat pump condenser is communicated with the heat exchange side of the humidification heater and the heat exchange side of the preheater through a hot water circulation assembly, forming a closed hot water circulation loop; and the heat pump evaporator is communicated with the heat exchange side of the dehumidification cooler through a chilled water circulation assembly, forming a closed chilled water circulation loop.

2. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 1, wherein, The tube side of the preheater is the material side, and the shell side is the heat exchange side, the inlet of the tube side of the preheater is communicated with the outlet of the feed pump, and the outlet of the tube side is communicated with the bottom storage section of the humidification tower; the shell side of the preheater is connected with the hot water output by the heat pump condenser, and the mixed liquid is heated to 40-60℃ in the preheater, triggering a metathesis reaction, and the reaction equation is: CuCl2+H2SO4→CuSO4+2HCl↑.

3. The heat pump coupled adjusted acidic copper-containing etching wastewater treatment system according to claim 2, wherein, The air outlet of the humidification tower is communicated with the lower air inlet of the dehumidification tower through a centrifugal fan, and the upper exhaust port of the dehumidification tower is communicated with the air inlet end of the centrifugal fan through a pipeline, forming a closed air circulation loop.

4. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 3, characterized in that, The circulating medium of the dehumidification and absorption circulation loop is dilute hydrochloric acid, the low-temperature dilute hydrochloric acid spraying liquid output by the dehumidification cooler is countercurrently contacted with high-temperature and high-humidity HCl-containing wet hot air, to cool, condense and absorb water vapor and hydrogen chloride in the air, while obtaining low-temperature dry air, which is returned to the humidification tower for circulation.

5. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 2, wherein, The hot water circulation assembly includes a hot water tank, a hot water circulation pump, and a hot water circulation pipeline. The hot water outlet of the heat pump condenser is connected to the inlet of the hot water tank. The outlet of the hot water tank is connected to the heat exchange side inlet of the humidifier and the preheater via the hot water circulation pump. The heat exchange side outlets of the humidifier and the preheater return to the hot water tank. The hot water tank is then connected to the hot water inlet of the heat pump condenser via a pipeline, forming a closed hot water circulation loop.

6. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 5, wherein, The chilled water circulation assembly includes a chilled water tank, a chilled water circulation pump, and chilled water circulation pipelines. The chilled water outlet of the heat pump evaporator is connected to the inlet of the chilled water tank. The outlet of the chilled water tank is connected to the heat exchange side inlet of the dehumidifier via the chilled water circulation pump. The heat exchange side outlet of the dehumidifier returns to the chilled water tank. The chilled water tank is then connected to the chilled water inlet of the heat pump evaporator via pipelines, forming a closed chilled water circulation loop.

7. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 1, wherein, The solid-liquid separation equipment is a centrifuge. The solid phase outlet of the centrifuge produces copper sulfate solid product, and the liquid phase outlet of the centrifuge is connected to the bottom storage section of the humidification tower via a mother liquor tank and a mother liquor pump for the reflux circulation of concentrated mother liquor.

8. The heat pump coupled based adjusted acidic copper containing etching wastewater treatment system according to claim 3, wherein, The heat pump unit is a screw-type heat pump unit, which is internally equipped with a compressor, heat pump condenser, expansion valve and heat pump evaporator connected in sequence to form a closed refrigerant circulation loop.

9. A method for treating acidic copper-containing etching wastewater based on heat pump coupling adjustment, characterized in that, Based on the acidic copper-containing etching wastewater treatment system according to any one of claims 1-8, the wastewater treatment method includes the following steps: S1 Mixing reaction: Acidic copper-containing etching wastewater and concentrated sulfuric acid are added to the mixing tank in a preset ratio and mixed thoroughly. The mixture is then pumped to the preheater for heating, where a metathesis reaction occurs to produce copper sulfate and hydrogen chloride, resulting in a mixed reaction solution. S2 Humidification and Concentration: The mixed reaction solution is sent into the humidification tower. The solution in the tower is sent to the humidification heater by the humidification circulation pump and heated to the preset temperature. Then, it is sprayed down from the top of the humidification tower. At the same time, dry air enters from the bottom of the humidification tower and comes into countercurrent contact with the sprayed liquid. The water and hydrogen chloride in the solution are carried away by the air, forming high temperature and high humidity HCl-containing hot and humid air that is discharged from the top of the tower. The copper sulfate solution in the tower is continuously concentrated. S3 Dehumidification and Absorption: The high-temperature, high-humidity, HCl-containing hot and humid air discharged from the humidification tower is sent to the bottom of the dehumidification tower. The low-temperature dilute hydrochloric acid circulating liquid is sprayed down from the top of the dehumidification tower and comes into countercurrent contact with the hot and humid air. The water vapor and hydrogen chloride in the air are condensed and absorbed into the circulating liquid, realizing the enrichment of hydrochloric acid. The cooled and dehumidified dry air is discharged from the top of the tower and flows back to the humidification tower for recycling. S4 Energy Cycle: The low-temperature waste heat released during the dehumidification absorption process is recovered by the heat pump unit and converted into high-temperature heat energy after grade improvement, which is used for material heating in the preheater and humidification heater; S5 Product Recovery: When the copper sulfate solution in the humidification tower is concentrated to the preset concentration, a portion of the concentrate is discharged and separated into solid and liquid components to obtain solid copper sulfate product; when the hydrochloric acid concentration in the dehumidification tower reaches the preset value, a portion of the hydrochloric acid is discharged to the hydrochloric acid recovery tank to obtain hydrochloric acid byproduct.

10. The heat pump coupled adjusted acidic copper-containing etching wastewater treatment method according to claim 9, wherein, In step S2, the solution in the humidifying heater is heated to 55-65℃, the operating temperature in the humidifying tower is 50-60℃, the temperature of the humidified air discharged from the humidifying tower is 55-60℃, and the relative humidity is ≥95%. In step S3, the temperature of the dilute hydrochloric acid circulating liquid output by the dehumidifying cooler is 15-25℃, the operating temperature in the dehumidifying tower is 20-30℃, the temperature of the dry air discharged from the dehumidifying tower is ≤25℃, and the preset concentration of hydrochloric acid enrichment is 10%-20%. In step S4, the heat pump condenser of the heat pump unit produces hot water at 55-70℃, which is supplied to the humidifying heater and the preheater respectively. After heat exchange, the water is cooled to 50-55℃ and returned to the heat pump condenser for reheating. The heat pump evaporator of the heat pump unit produces chilled water at 8-15℃, which is supplied to the dehumidifying cooler. After heat exchange, the water is heated to 18-22℃ and returned to the heat pump evaporator for recooling.

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