A process and system for preparing weakly acidic hypochlorous acid water from etching waste liquid

Abstract

The present invention relates to the field of environmental protection technology, in particular to a process for preparing weakly acidic hypochlorous acid water from etching waste liquid, comprising the following steps: S1 electrolyzing acidic copper chloride etching liquid waste liquid as electrolyte to obtain metallic copper on the cathode plate and impurity-containing chlorine on the anode plate; S2 collecting the impure chlorine in step S1, and passing the impure chlorine through a dilute sulfuric acid solution and pure water in sequence to remove copper ions and impurity gases in the chlorine, and to obtain effective chlorine; S3 passing the effective chlorine obtained in step S2 through a sodium hydroxide solution and a hydrochloric acid solution in sequence to obtain a sodium hypochlorite solution and weakly acidic hypochlorous acid water in sequence. At the same time, a system for preparing weakly acidic hypochlorous acid water from etching waste liquid is disclosed. The process and system for preparing weakly acidic hypochlorous acid water from etching waste liquid of the present invention can recycle acidic copper chloride etching waste liquid, and can obtain weakly acidic hypochlorous acid water for disinfection or sterilization.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a process and system for preparing weakly acidic hypochlorous acid water from etching waste liquid. Background Art

[0002] With the development of the electronics industry, printed circuit boards are widely used in the production process of electronic products, but the large amount of waste generated in the process has caused great harm to the environment. Among them, the generation and discharge of etching waste liquid has caused serious environmental pollution and waste of resources. Most of the etching waste liquid is acidic copper chloride etching waste liquid, mainly because of its fast etching rate, high copper dissolving capacity and easy control.

[0003] At present, the treatment of acid copper chloride etching waste liquid generally adopts electrolysis. While the etching liquid is regenerated at the anode, the copper is deposited and recovered at the cathode at the same time. In this process, the anode produces strong oxidizing gas chlorine, part of which is used again in the etching waste liquid, and part is not recycled, causing secondary air pollution and waste of resources. Existing chlorine treatment generally uses ferrous chloride solution to absorb chlorine, but the chlorine after such treatment carries a small amount of copper ions and impurities, such as water vapor, oxygen, etc., which is ultimately difficult to recycle and recycle, reducing the use value and high cost. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a process and system for preparing weakly acidic hypochlorous acid water from etching waste liquid, which can recycle acidic copper chloride etching waste liquid and obtain weakly acidic hypochlorous acid water for disinfection or sterilization.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is:

[0006] A process for preparing weakly acidic hypochlorous acid water from etching waste liquid comprises the following steps:

[0007] S1. Electrolysis of waste liquid: electrolyzing the waste liquid of electrolytic acid copper chloride etching solution as electrolyte to obtain metallic copper on the cathode plate and chlorine gas containing impurities on the anode plate;

[0008] S2, treatment of chlorine: collecting the impure chlorine in step S1, and passing the impure chlorine through a dilute sulfuric acid solution and pure water in sequence to remove copper ions and impurity gases in the chlorine, and to obtain effective chlorine;

[0009] S3. Preparation of weakly acidic hypochlorous acid water: The effective chlorine gas obtained in step S2 is passed through a sodium hydroxide solution and a hydrochloric acid solution in sequence to obtain a sodium hypochlorite solution and weakly acidic hypochlorous acid water in sequence.

[0010] Furthermore, in step S3, the mass fraction of sodium chlorate in the sodium hypochlorite solution is 10 wt%, the mass fraction of hydrochloric acid in the hydrochloric acid solution is 35 wt%, and the concentration of the weakly acidic hypochlorous acid water is 500 ppm.

[0011] Furthermore, in the step S3, 947.365 kg of water needs to be added to every 5 kg of sodium hypochlorite solution when preparing the weakly acidic hypochlorous acid water.

[0012] A system for preparing weakly acidic hypochlorous acid water from etching waste liquid, comprising a waste liquid treatment module, a gas treatment module and a preparation module.

[0013] The waste liquid treatment module includes a storage area and an electrolytic cell, wherein the storage area is used to obtain electrolytic acid copper chloride etching liquid waste from the etching liquid production line, and the storage area is connected to the electrolytic cell;

[0014] The gas processing module comprises a copper ion removal device and a foreign gas removal device, wherein the copper ion removal device is provided with a dilute sulfuric acid solution, and the inlet end of the copper ion removal device is connected to the anode collection area of ​​the electrolytic cell, and the outlet end of the copper ion removal device is connected to the foreign gas removal device, and the foreign gas removal device is provided with pure water;

[0015] The preparation module includes a sodium hypochlorite solution generating device and a hypochlorous acid water generating device.

[0016] The sodium hypochlorite solution generating device is provided with a sodium hydroxide solution, and one end of the sodium hypochlorite solution generating device is conductively connected to the impurity gas removing device, and the other end is conductively connected to the hypochlorous acid water generating device;

[0017] The hypochlorous acid water generating device comprises a generating box, in which a hydrochloric acid solution is arranged, and the generating box is conductively connected to the sodium hypochlorite solution generating device.

[0018] Furthermore, the copper ion removal device and the impurity gas removal device are both provided with cooling devices, and the two cooling devices are respectively connected to the copper ion removal device and the impurity gas removal device.

[0019] Furthermore, the copper ion removal device, the impurity gas removal device and the generation box are all provided with monitoring devices, and the monitoring devices include ion concentration sensors, gas concentration sensors and temperature sensors.

[0020] Furthermore, the inlet end of the copper ion removal device is conductively connected to the electrolytic cell through a first pipe, and the outlet end of the copper ion removal device is conductively connected to the inlet end of the impurity gas removal device through a second pipe, and the outlet end of the impurity gas removal device is conductively connected to the sodium hypochlorite solution generating device through a third pipe, and the first pipe, the second pipe and the third pipe are respectively provided with a jet machine.

[0021] Furthermore, the sodium hypochlorite solution generating device includes a reaction box, a liquid storage tank, a solution tank and a jet mixer. The reaction box is conductively connected to one end of the third pipeline away from the impurity gas removal device. The liquid storage tank and the solution tank are both arranged outside the reaction box, and the liquid storage tank and the solution tank are respectively provided with water and sodium hydroxide solution; the jet mixer is arranged in the reaction box, and the jet mixer is conductively connected to the liquid storage tank and the solution tank respectively.

[0022] Furthermore, at least two preparation modules are provided, and the reaction boxes of the preparation modules are respectively conductively connected to the impurity gas removal device.

[0023] Furthermore, a reserve box and a blending box are provided outside the generation box, and the reserve box and the blending box are respectively connected to the generation box through a delivery pipeline, and each of the delivery pipelines is provided with a flow valve and a booster pump, and the flow valve is electrically connected to the booster pump.

[0024] The beneficial effects of the present invention are:

[0025] 1. In the electrolytic cell, the acid copper chloride etching waste liquid is electrolyzed, so that impure chlorine gas is generated on the anode plate. The copper ions contained in the impure chlorine gas can be washed by using dilute sulfuric acid, and the impurities in the washed chlorine gas are purified by using pure water to obtain chlorine gas with good purity. The obtained effective chlorine gas is passed through sodium hydroxide and hydrochloric acid in turn to obtain weakly acidic hypochlorous acid water for disinfection or sterilization. Moreover, the hypochlorous acid water in this application has good quality and basically does not contain copper ions, and can be directly used in the production system of weakly acidic hypochlorous acid water later. The recycling of resources in the electrolysis process of acid copper chloride etching waste liquid is realized to prevent chlorine gas from causing secondary pollution to the environment.

[0026] 2. By controlling the concentration of sodium hydroxide solution, the sodium chlorate in the sodium hypochlorite solution has a suitable quality. By controlling the concentration of hydrochloric acid solution, weakly acidic hypochlorous acid water with a concentration of 500ppm can be obtained. Weakly acidic hypochlorous acid water of this concentration is harmless and safe to the human body, and has functions of sterilization and deodorization. It is a more effective and safer chemical reagent than traditional disinfectant water.

[0027] 3. The waste liquid treatment module, gas treatment module and preparation module of the present invention have simple structures, which reduces the production cost of weakly acidic hypochlorous acid water. Since a jet machine is provided between the copper ion removal device and the electrolytic cell and between the copper ion removal device and the impurity gas removal device, the impurity removal efficiency and quality of chlorine can be improved under the action of the jet machine, ensuring the acquisition of chlorine of good quality; under the joint action of the jet machine on the third pipeline and the jet mixer of the reaction box, the chlorine can be fully contacted with the sodium hydroxide solution, thereby improving the processing capacity of chlorine. Since the jet mixer can obtain the water in the liquid storage tank and the sodium hydroxide solution in the solution tank, the concentration and rate of the sodium hydroxide spraying can be controlled by adjusting the jet mixer, thereby controlling the mass fraction of sodium hypochlorite in the sodium hypochlorite solution, so as to ensure that weakly acidic hypochlorous acid water with a suitable concentration is prepared in the subsequent preparation with the hypochlorous acid water generating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flowchart of a process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to a preferred embodiment of the present invention.

[0029] Figure 2 The present invention is a structural block diagram of a system for preparing weakly acidic hypochlorous acid water from etching waste liquid according to a preferred embodiment of the present invention.

[0030] In the figure, 1-waste liquid treatment module, 11-storage area, 12-electrolyzer, 2-gas treatment module, 21-copper ion removal device, 22-impurity gas removal device, 3-sodium hypochlorite solution generation device, 31-reaction box, 32-liquid storage tank, 33-solution tank, 34-jet mixer, 4-hypochlorous acid water generation device, 41-generation box, 42-reserve box, 43-blending box, 44-transport pipeline, 441-flow valve, 442-boosting pump, 5-cooling device, 61-first pipeline, 62-second pipeline, 63-third pipeline, 64-jet machine. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0034] Please also see Figure 1 and Figure 2 A system for preparing weakly acidic hypochlorous acid water from etching waste liquid according to a preferred embodiment of the present invention comprises a waste liquid treatment module 1, a gas treatment module 2 and a preparation module.

[0035] The waste liquid treatment module 1 comprises a storage area 11 and an electrolytic cell 12 . The storage area 11 is used to obtain electrolytic acid copper chloride etching liquid waste from the etching liquid production line, and the storage area 11 is connected to the electrolytic cell 12 .

[0036] The gas processing module 2 includes a copper ion removal device 21 and a foreign gas removal device 22. The copper ion removal device 21 is provided with a dilute sulfuric acid solution, and the inlet end of the copper ion removal device 21 is connected to the anode collection area of ​​the electrolytic cell 12, and the outlet end of the copper ion removal device 21 is connected to the foreign gas removal device 22. The foreign gas removal device 22 is provided with pure water. The copper ion removal device 21 and the foreign gas removal device 22 of this embodiment are reaction tanks, so that chlorine reacts in the copper ion removal device 21 and the foreign gas removal device 22.

[0037] The preparation module includes a sodium hypochlorite solution generating device 3 and a hypochlorous acid water generating device 4.

[0038] The sodium hypochlorite solution generating device 3 is provided with a sodium hydroxide solution, and one end of the sodium hypochlorite solution generating device 3 is conductively connected to the impurity gas removing device 22 , and the other end is conductively connected to the hypochlorous acid water generating device 4 .

[0039] The hypochlorous acid water generating device 4 comprises a generating box 41 . The generating box 41 contains a hydrochloric acid solution, and the generating box 41 is electrically connected to the sodium hypochlorite solution generating device 3 .

[0040] The copper ion removal device 21 and the impurity gas removal device 22 are both provided with a cooling device 5, and the two cooling devices 5 are respectively connected to the copper ion removal device 21 and the impurity gas removal device 22. Under the action of the cooling device 5, the heat generated during the chlorine reaction can be absorbed to ensure the safety of the chlorine impurities during removal. The cooling device 5 of this embodiment can be provided with a water cooling pipe in the copper ion removal device 21 and the impurity gas removal device 22, and the water cooling pipe is connected to the cooling water pool through a pump to perform heat exchange on the water cooling pipe.

[0041] The copper ion removal device 21, the impurity gas removal device 22 and the generating box 41 are all provided with a monitoring device 65, and the monitoring device 65 includes an ion concentration sensor, a gas concentration sensor and a temperature sensor. The gas concentration sensor of this embodiment is a chlorine concentration sensor, the ion concentration sensors of the copper ion removal device 21 and the impurity gas removal device 22 are copper ion concentration sensors, and the ion concentration sensors in the generating box 41 are sodium ion concentration sensors and chlorine ion concentration sensors. Under the action of the monitoring device 65, the conditions in the copper ion removal device 21, the impurity gas removal device 22 and the generating box 41 can be monitored in real time to ensure that the prepared weakly acidic hypochlorous acid water has a suitable concentration.

[0042] In this embodiment, the inlet end of the copper ion removal device 21 is conductively connected to the electrolytic cell 12 through the first pipe 61, and the outlet end of the copper ion removal device 21 is conductively connected to the inlet end of the impurity gas removal device 22 through the second pipe 62, and the outlet end of the impurity gas removal device 22 is conductively connected to the sodium hypochlorite solution generating device 3 through the third pipe 63. The first pipe 61, the second pipe 62 and the third pipe 63 are respectively provided with a jet machine 64.

[0043] Since jet machines 64 are provided between the copper ion removal device 21 and the electrolytic cell 12 and between the copper ion removal device 21 and the impurity gas removal device 22, the impurity removal efficiency and quality of the chlorine gas can be improved under the action of the jet machines 64, thereby ensuring that chlorine gas of good quality is obtained.

[0044] The sodium hypochlorite solution generating device 3 comprises a reaction box 31 , a liquid storage tank 32 , a solution tank 33 and a jet mixer 34 .

[0045] The reaction box 31 is conductively connected to one end of the third pipe 63 away from the impurity gas removal device 22, the liquid storage tank 32 and the solution tank 33 are both arranged outside the reaction box 31, and the liquid storage tank 32 and the solution tank 33 are respectively provided with water and sodium hydroxide solution; the injection mixer 34 is arranged in the reaction box 31, and the injection mixer 34 is conductively connected to the liquid storage tank 32 and the solution tank 33 respectively.

[0046] Under the joint action of the jet machine 64 on the third pipeline 63 and the jet mixer 34 of the reaction box 31, the chlorine gas can be fully contacted with the sodium hydroxide solution, thereby improving the chlorine treatment capacity. Since the jet mixer 34 can obtain the water in the liquid storage tank 32 and the sodium hydroxide solution in the solution tank 33, the concentration and rate of the sodium hydroxide spraying can be controlled by adjusting the jet mixer 34, thereby controlling the mass fraction of sodium hypochlorite in the sodium hypochlorite solution, so as to ensure that weakly acidic hypochlorous acid water with a suitable concentration is prepared in the subsequent preparation with the hypochlorous acid water generating device 4.

[0047] In this embodiment, a reserve tank 42 and a blending tank 43 are provided outside the generation tank 41, and the reserve tank 42 and the blending tank 43 are respectively connected to the generation tank 41 through a delivery pipe 44, and each delivery pipe 44 is provided with a flow valve 441 and a booster pump 442, and the flow valve 441 is electrically connected to the booster pump 442. Under the action of the flow valve 441 and the booster pump 442, the hydrochloric acid solution in the reserve tank 42 and the water in the blending tank 43 can enter the generation tank 41, and at the same time, under the cooperation of the monitoring device 65, the hydrochloric acid solution in the generation tank 41 can be configured so that the hydrochloric acid in the hydrochloric acid solution in the generation tank 41 has a suitable quality.

[0048] Preferably, the present embodiment is further provided with a control module, which is electrically connected to the flow valve 441, the booster pump 442 and the monitoring device 65, respectively, so as to control and remotely monitor the preparation of the weakly acidic hypochlorous acid water.

[0049] In this embodiment, two preparation modules are provided, and the reaction boxes 31 of the preparation modules are respectively connected to the impurity gas removal device 22. By providing two preparation modules, the production of weakly acidic hypochlorous acid water can be ensured, and the reaction of chlorine and sodium hydroxide and the reaction of sodium hypochlorite and hydrochloric acid can be controlled to ensure the quality of sodium hypochlorite.

[0050] The process for preparing weakly acidic hypochlorous acid water from etching waste liquid in this embodiment includes the following steps:

[0051] S1. Electrolysis of waste liquid: electrolyze the waste liquid of electrolytic acid copper chloride etching solution as electrolyte to obtain metallic copper on the cathode plate and chlorine gas containing impurities on the anode plate.

[0052] S2. Treatment of chlorine: collect the impure chlorine in step S1, and pass the impure chlorine through a dilute sulfuric acid solution and pure water in sequence to remove copper ions and impurity gases in the chlorine, and obtain effective chlorine.

[0053] S3. Preparation of weakly acidic hypochlorous acid water: The effective chlorine gas obtained in step S2 is passed through a sodium hydroxide solution and a hydrochloric acid solution in sequence to obtain a sodium hypochlorite solution and weakly acidic hypochlorous acid water in sequence.

[0054] In this embodiment, acidic copper chloride etching waste liquid is electrolyzed to generate impure chlorine gas on the anode plate, and copper ions contained in the impure chlorine gas can be washed with dilute sulfuric acid, and impurities in the washed chlorine gas can be purified with pure water to obtain chlorine gas with better purity.

[0055] The obtained effective chlorine gas is passed through sodium hydroxide and hydrochloric acid in sequence to obtain weakly acidic hypochlorous acid water for disinfection or sterilization. Moreover, the hypochlorous acid water in the present application has good quality and basically does not contain copper ions, and can be directly used in the subsequent weakly acidic hypochlorous acid water production system. The recycling of resources in the electrolysis process of acidic copper chloride etching waste liquid is realized, and the secondary pollution of the environment caused by chlorine gas is prevented.

[0056] In step S3, the mass fraction of sodium chlorate in the sodium hypochlorite solution is 10 wt%, the mass fraction of hydrochloric acid in the hydrochloric acid solution is 35 wt%, and the concentration of weakly acidic hypochlorous acid water is 500 ppm. In step S3, 947.365 kg of water needs to be added to every 5 kg of sodium hypochlorite solution when preparing weakly acidic hypochlorous acid water.

[0057] In this embodiment, in order to provide guarantee for the continuous and large-volume production of high-quality sodium hypochlorite, the generated mass is controlled to be 5 kg of sodium hypochlorite solution with a mass fraction of 10 wt%, wherein the chlorine content is 238.08 g and the water content is 4500 g.

[0058] Therefore, when preparing weakly acidic hypochlorous acid water with a concentration of 500 ppm, 0.7 kg of hydrochloric acid solution with a mass fraction of 35 wt% of hydrochloric acid is added to the sodium hypochlorite solution generating device 3, wherein the chlorine content is 238.08 g and the water content is 445 g.

[0059] According to NaOCl+HCl+H2O=NaCl+HOCl+H2O, the actual chlorine content of the weakly acidic hypochlorous acid water with a concentration of 500ppm is 476.16g, and the actual amount of water required is 952.32kg. Therefore, 947.365kg of pure water should be added to the hypochlorous acid water generating device 4.

Claims

1. A process for preparing weakly acidic hypochlorous acid water from etching waste liquid, characterized in that: The following steps are included: S1, electrolysis of waste liquid: electrolyzing the electrolytic acid copper chloride etching liquid waste liquid as an electrolyte through the waste liquid treatment module (1) to obtain metallic copper on the cathode plate and chlorine gas containing impurities on the anode plate; S2, chlorine treatment: the impure chlorine in step S1 is collected by the gas treatment module (2), and the impure chlorine is passed through a dilute sulfuric acid solution and pure water in sequence to remove copper ions and impurity gases in the chlorine, so as to obtain effective chlorine; S3, preparation of weakly acidic hypochlorous acid water: the effective chlorine gas obtained in step S2 is sequentially passed through a sodium hydroxide solution and a hydrochloric acid solution by a preparation module to obtain a sodium hypochlorite solution and weakly acidic hypochlorous acid water in sequence; in step S3, the mass fraction of sodium chlorate in the sodium hypochlorite solution is 10wt%, the mass fraction of hydrochloric acid in the hydrochloric acid solution is 35wt%, and the concentration of the weakly acidic hypochlorous acid water is 500ppm; The waste liquid treatment module (1) comprises a storage area (11) and an electrolytic cell (12), wherein the storage area (11) is used to obtain electrolytic acid copper chloride etching liquid waste liquid from an etching liquid production line, and the storage area (11) is connected to the electrolytic cell (12); The gas processing module (2) comprises a copper ion removal device (21) and a foreign gas removal device (22), wherein the copper ion removal device (21) is provided with a dilute sulfuric acid solution, and the inlet end of the copper ion removal device (21) is connected to the anode collection area of ​​the electrolytic cell (12), and the outlet end of the copper ion removal device (21) is connected to the foreign gas removal device (22), and the foreign gas removal device (22) is provided with pure water; The preparation module comprises a sodium hypochlorite solution generating device (3) and a hypochlorous acid water generating device (4), The sodium hypochlorite solution generating device (3) is provided with a sodium hydroxide solution, and one end of the sodium hypochlorite solution generating device (3) is electrically connected to the impurity gas removing device (22), and the other end is electrically connected to the hypochlorous acid water generating device (4); The hypochlorous acid water generating device (4) comprises a generating box (41), a hydrochloric acid solution is provided in the generating box (41), and the generating box (41) is electrically connected to the sodium hypochlorite solution generating device (3); The inlet end of the copper ion removal device (21) is conductively connected to the electrolytic cell (12) via a first pipeline (61), and the outlet end of the copper ion removal device (21) is conductively connected to the inlet end of the impurity gas removal device (22) via a second pipeline (62), and the outlet end of the impurity gas removal device (22) is conductively connected to the sodium hypochlorite solution generating device (3) via a third pipeline (63), and the first pipeline (61), the second pipeline (62) and the third pipeline (63) are each provided with a jet machine (64); A reserve box (42) and a blending box (43) are provided outside the generation box (41); the reserve box (42) and the blending box (43) are respectively connected to the generation box (41) through a delivery pipeline (44); and each delivery pipeline (44) is provided with a flow valve (441) and a booster pump (442); the flow valve (441) is electrically connected to the booster pump (442).

2. The process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to claim 1, characterized in that: In the step S3, 947.365 kg of water needs to be added to every 5 kg of sodium hypochlorite solution when preparing the weakly acidic hypochlorous acid water.

3. The process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to claim 1, characterized in that: The copper ion removal device (21) and the impurity gas removal device (22) are both provided with a cooling device (5), and the two cooling devices (5) are respectively connected to the copper ion removal device (21) and the impurity gas removal device (22).

4. The process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to claim 1, characterized in that: The copper ion removal device (21), the impurity gas removal device (22) and the generation box (41) are all provided with a monitoring device (65), and the monitoring device (65) includes an ion concentration sensor, a gas concentration sensor and a temperature sensor.

5. The process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to claim 1, characterized in that: The sodium hypochlorite solution generating device (3) comprises a reaction box (31), a liquid storage tank (32), a solution tank (33) and a jet mixer (34); the reaction box (31) is conductively connected to an end of the third pipe (63) away from the impurity gas removing device (22); the liquid storage tank (32) and the solution tank (33) are both arranged outside the reaction box (31), and the liquid storage tank (32) and the solution tank (33) are respectively provided with water and a sodium hydroxide solution; the jet mixer (34) is arranged inside the reaction box (31), and the jet mixer (34) is conductively connected to the liquid storage tank (32) and the solution tank (33) respectively.

6. The process for preparing weakly acidic hypochlorous acid water from etching waste liquid according to claim 5, characterized in that: At least two preparation modules are provided, and the reaction boxes (31) of the preparation modules are respectively connected to the impurity gas removal device (22).

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