Technological method and production device for centrally recovering copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid

Abstract

The invention relates to a process method and a production device for centrally recovering copper sulfate from a sulfuric acid-hydrogen peroxide system micro-etching waste liquid, and the method comprises the following steps: discharging the micro-etching waste liquid into a reaction kettle, adding sulfuric acid, adjusting the hydrogen ion concentration to 4.3-4.5 mol / L, filtering, conveying to a crystallization kettle, cooling the micro-etching waste liquid in the crystallization kettle to 0-5 DEG C, and carrying out vacuum filtration to obtain the copper sulfate. And cleaning, separating and drying the solid obtained by solid-liquid separation to obtain copper sulfate pentahydrate, and recycling the liquid to a production line after blending. According to the method, efficient recycling of microetching waste liquid resources is achieved, a high-purity copper sulfate product is produced, and the recovery rate is high. In addition, a set of production device which is low in cost, low in energy consumption and high in automation degree is matched for the method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sulfuric acid-hydrogen peroxide system micro-etching waste liquid recovery processing, in particular to a process method and production device for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid. BACKGROUND

[0002] In the printed circuit board and semiconductor manufacturing industry, copper etching is one of the core processes, and the sulfuric acid-hydrogen peroxide system micro-etching waste liquid is widely used due to its fast etching rate, low copper surface roughness, and good environmental protection. However, as the etching process proceeds, the concentration of copper ions in the micro-etching liquid gradually increases, and the concentrations of sulfuric acid and hydrogen peroxide decrease, resulting in the decline of etching ability, and eventually becoming waste liquid. The sulfuric acid concentration in such micro-etching waste liquid is about 160 g / L, and direct discharge requires the use of a large amount of caustic soda for neutralization, about 130 kg of caustic soda per cubic micro-etching waste liquid. Not only does this cause waste of copper resources, but it also poses a serious environmental problem. Therefore, how to efficiently recover copper from waste liquid and achieve the recycling of micro-etching liquid has become a difficult problem that needs to be solved in the industry.

[0003] Currently, the main methods for treating sulfuric acid-hydrogen peroxide system micro-etching waste liquid include chemical precipitation, electrolytic recovery, solution extraction, and evaporation crystallization. Among them, the most common chemical precipitation method is to add sodium hydroxide or sodium sulfide to make copper ions form Cu(OH)2 or CuS precipitate. This method is simple to operate, but the precipitate sludge contains high impurities and needs further treatment, and it cannot recover sulfuric acid and hydrogen peroxide, which is economically poor. The electrolytic recovery method directly extracts copper from waste liquid by electrolysis, which has high copper purity, but high energy consumption and low efficiency, and hydrogen peroxide is easily decomposed during electrolysis, resulting in the inability to reuse the micro-etching liquid. Therefore, the existing recovery of such micro-etching waste liquid has the problems of resource waste and process limitations. Therefore, in view of the above problems, it is urgent to develop a method that can simultaneously recover copper resources and regenerate micro-etching liquid for reuse to maximize resource utilization. SUMMARY

[0004] The purpose of the present application is to provide a process method and production device for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid.

[0005] The purpose of the present application is achieved by the following technical solution: The present application provides a process method for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, comprising the following steps: S1, the micro-etching waste liquid after use by the production line is discharged into a reaction kettle, sulfuric acid is added, and the hydrogen ion concentration is adjusted to 4.3-4.5 mol / L; S2, the micro-etching waste liquid pre-adjusted by step S1 is filtered by a precision filter to a crystallization kettle; S3, cooling the micro-etching waste liquid in the crystallization kettle to 0-5℃; S4, after crystallization, the micro-etching waste liquid is subjected to solid-liquid separation by a high-speed centrifuge, the solid part is copper sulfate pentahydrate crystal, and the permeate is used as micro-etching recovery liquid; S5, adding hydrogen peroxide solution to the micro-etching recovery liquid obtained in step S4, so that the concentration of hydrogen peroxide in the micro-etching recovery liquid is 18-22 g / L, and then conveying to the production line for reuse; S6, cleaning the copper sulfate pentahydrate crystal obtained in step S4 and performing secondary centrifugal separation, and obtaining electroplating grade superior copper sulfate pentahydrate after vacuum drying.

[0006] Further, in step S1, the micro-etching waste liquid comprises the following components: copper sulfate pentahydrate 50-60 g / L, sulfuric acid 190-210 g / L, and hydrogen peroxide 18-22 g / L.

[0007] Further, in step S1, a flocculating agent is added to the reaction kettle, and the temperature of the micro-etching waste liquid is controlled at 32-38℃, and the stirring speed is 100-300 rpm.

[0008] Further, the flocculating agent is at least one of polymeric ferric sulfate, polydimethyl diallyl ammonium chloride, and polyepoxy chloropropane-dimethyl amine. Preferably, the flocculating agent is compounded by polymeric ferric sulfate and polydimethyl diallyl ammonium chloride at a mass ratio of 3-4:1.

[0009] In the present application, the polymeric ferric sulfate and polydimethyl diallyl ammonium chloride are compounded as a composite flocculating agent, which is suitable for flocculation reaction in a strong acidic environment, and significantly improves the impurity removal efficiency. In actual operation, the materials are added step by step, polymeric ferric sulfate is added first, reacted for 8-15 min, then polydimethyl diallyl ammonium chloride is slowly added, reacted for 15-20 min, and finally the flocs are allowed to settle naturally.

[0010] Further, in step S2, the precision filter adopts two-stage filtration, the first stage adopts 5 μm filter core for pre-filtration, and the second stage adopts 0.5-1 μm filter core for fine filtration. Among them, the 5 μm filter core is preferably a polytetrafluoroethylene filter core or a sintered titanium metal filter core; the 0.5-1 μm filter core is preferably a ceramic membrane or a polyvinylidene fluoride filter core, and the operating pressure is 0.1-0.15 MPa.

[0011] Further, after filtration by the precision filter in step S2, it is treated by an ion exchange resin column and then enters the crystallization kettle. The ion exchange resin column can selectively adsorb metal ion impurities in the micro-etching waste liquid.

[0012] Further, in step S3, the crystallization kettle adopts three-stage gradient cooling, the first stage is reduced from room temperature to about 15℃, the cooling rate is 0.5-1℃ / min, and the temperature is kept for 1h; the second stage is reduced from 15℃ to about 5℃, the temperature is kept for 1-2h, and the cooling rate is 0.5-1℃ / min; the third stage is reduced from 5℃ to 0-5℃, the temperature is kept for 1-2h, and the cooling rate is 0.2-0.5℃ / min.

[0013] Further, in step S3, 0-4wt% of ethylene glycol is added into the crystallization kettle.

[0014] Further, in step S5, the hydrogen ion concentration in the micro-etching recovery liquid is maintained at 4.3-4.5mol / L by adding sulfuric acid into the micro-etching recovery liquid in real time through online monitoring.

[0015] Further, in step S5, a stabilizer is added into the micro-etching recovery liquid, and the amount of the stabilizer is 0.1-0.3g / L. The stabilizer is preferably at least one of benzoic acid, trisodium phosphate, sodium stannate and ethylenediaminetetraacetic acid.

[0016] Further, in step S5, a non-ionic surfactant is added into the micro-etching recovery liquid, and the amount of the non-ionic surfactant is 0.05-0.1g / L. The non-ionic surfactant is preferably Triton X-100.

[0017] In the present application, by adding hydrogen peroxide, sulfuric acid, a stabilizer and a non-ionic surfactant into the micro-etching recovery liquid, the oxidative decomposition can be inhibited, the oxidation ability can be maintained, the activity of the micro-etching liquid can be recovered, and the service life of the micro-etching recovery liquid can be prolonged, and meanwhile, when the micro-etching recovery liquid is reused to the production line, the copper etching uniformity can be improved.

[0018] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned by using a saturated copper sulfate solution, the concentration of the saturated copper sulfate solution is 40-45℃, the mass ratio of the saturated copper sulfate solution to the copper sulfate pentahydrate crystals is 1:3, and the cleaning time is 5-8min.

[0019] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned by using deionized water, the mass ratio of the deionized water to the copper sulfate pentahydrate crystals is 1:2, and the time is 1-3min.

[0020] The application further provides a production device for recovering copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, which comprises a production line micro-etching waste liquid storage tank, a reaction kettle, a crystallization kettle, a high-speed centrifuge and a micro-etching recovery liquid adjusting tank, wherein the inlet end of the production line micro-etching waste liquid storage tank is communicated with a pipeline through which the production line discharges micro-etching waste liquid, the inlet end of the production line micro-etching waste liquid storage tank is communicated with the reaction kettle, the discharge end of the reaction kettle is communicated with the crystallization kettle, the discharge end of the crystallization kettle is communicated with the high-speed centrifuge, the liquid discharge port of the high-speed centrifuge is communicated with the inlet end of the micro-etching recovery liquid adjusting tank, and the outlet end of the micro-etching recovery liquid adjusting tank is connected with a pipeline through which micro-etching recovery liquid is transported to the production line for recycling.

[0021] Further, a filtering system is arranged between the discharge end of the reaction kettle and the crystallization kettle. Specifically, the filtering system comprises two-stage precision filters arranged in sequence, the first stage adopts a 5-micron filter core for pre-filtering, and the second stage adopts a 0.5-1-micron filter core for fine filtering. Preferably, the 5-micron filter core is a polytetrafluoroethylene filter core or a sintered titanium metal filter core; and the 0.5-1-micron filter core is preferably a ceramic membrane or a polyvinylidene fluoride filter core.

[0022] Still further, the filtering system further comprises an ion exchange resin column.

[0023] Further, the production device further comprises a crystal post-processing system, which is used for processing the solid material obtained after the solid-liquid separation of the high-speed centrifuge. The crystal post-processing system comprises a washing tank, a secondary centrifuge and a vacuum dryer. After the solid material is cleaned in the washing tank, it is placed in the secondary centrifuge for secondary separation, and the obtained wet cake is placed in the vacuum dryer for vacuum drying.

[0024] Further, the reaction kettle and the micro-etching recovery liquid adjusting tank are both provided with an on-line pH meter, which is used for monitoring the hydrogen ion concentration in the micro-etching waste liquid.

[0025] Further, the reaction kettle and the micro-etching recovery liquid adjusting tank are both provided with a copper ion concentration sensor, which is used for monitoring the copper ion concentration in the micro-etching waste liquid.

[0026] Further, the high-speed centrifuge is a horizontal screw centrifuge.

[0027] The application has the beneficial effects that: the application provides a process method for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, which realizes efficient recovery and recycling of the resource of the sulfuric acid-hydrogen peroxide system micro-etching waste liquid, wherein more than 90% of copper ions in the waste liquid are recovered through gradient cooling crystallization and centrifugal separation process, and the obtained copper sulfate pentahydrate has high purity and can be directly used for electroplating or PCB production without secondary processing. After the micro-etching recovery liquid is supplemented with hydrogen peroxide and sulfuric acid and is adjusted by adding an additive, the oxidation capacity and acidity can be restored to the required level for production, and the micro-etching recovery liquid can be recycled for more than 30 times, thereby reducing the discharge of a large amount of waste liquid. On the other hand, a production device matched with the method is designed, which can be adapted to the existing micro-etching liquid production line through modular design, has low modification difficulty, can be applied to large-scale continuous production, has high automation degree and low energy consumption, solves the common problems in the traditional process such as easy decomposition of hydrogen peroxide, low copper recovery rate and impurity accumulation, and provides a new solution and idea for micro-etching liquid treatment in the PCB / semiconductor industry. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a production process schematic diagram of the production device for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to the embodiment 4. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of those skilled in the art, the application will be further described below in conjunction with the embodiments, and the content mentioned in the embodiments is not a limitation on the application.

[0030] Embodiment 1 The embodiment provides a process method for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, which comprises the following steps: S1, the micro-etching waste liquid after use by the production line is discharged into a reaction kettle, sulfuric acid is added, and the hydrogen ion concentration is adjusted to 4.3 mol / L; S2, the micro-etching waste liquid after the pre-adjustment in step S1 is filtered by a precision filter to a crystallization kettle; S3, the micro-etching waste liquid in the crystallization kettle is cooled to 0℃; S4, the micro-etching waste liquid after crystallization is subjected to solid-liquid separation by a high-speed centrifuge, the solid part is copper sulfate pentahydrate crystal, and the permeate is used as micro-etching recovery liquid; S5, hydrogen peroxide solution is added to the micro-etching recovery liquid obtained in step S4, so that the concentration of hydrogen peroxide in the micro-etching recovery liquid is 18 g / L, and then the micro-etching recovery liquid is transported to the production line for reuse; S6, the copper sulfate pentahydrate crystal obtained in step S4 is washed and subjected to secondary centrifugal separation, and after vacuum drying, an electroplating grade superior product of copper sulfate pentahydrate is obtained.

[0031] Further, in step S1, the micro-etching waste liquid comprises the following components: copper sulfate pentahydrate 50 g / L, sulfuric acid 200 g / L, hydrogen peroxide 18 g / L.

[0032] Further, in step S1, a flocculating agent is added to the reaction kettle, and the temperature of the micro-etching waste liquid is controlled at 32°C, and the stirring speed is 150 rpm.

[0033] Further, the flocculating agent is compounded by polyferric sulfate and polydimethyl diallyl ammonium chloride with a mass ratio of 3:1. In actual operation, step feeding is adopted, polyferric sulfate is first added and reacts for 8 min, then polydimethyl diallyl ammonium chloride is slowly added and reacts for 17 min, and finally the flocs are allowed to settle naturally.

[0034] Further, in step S2, the precision filter adopts two-stage filtration, the first stage adopts 5 μm filter core for pre-filtration, and the second stage adopts 1 μm filter core for fine filtration. Among them, the 5 μm filter core is preferably a sintered titanium metal filter core; the 1 μm filter core is preferably a ceramic membrane, and the operating pressure is 0.1 MPa.

[0035] Further, in step S2, after filtration by the precision filter, it is treated by an ion exchange resin column and then enters the crystallization kettle. Among them, the ion exchange resin column is Dowex M4195.

[0036] Further, in step S3, the crystallization kettle adopts three-stage gradient cooling, the first stage is reduced from room temperature to about 15°C at a cooling rate of 1°C / min, and the temperature is kept for 1 h; the second stage is reduced from 15°C to about 5°C at a cooling rate of 1°C / min, and the temperature is kept for 2 h; the third stage is reduced from 5°C to 0°C at a cooling rate of 0.5°C / min, and the temperature is kept for 2 h.

[0037] Further, in step S3, 2 wt% of ethylene glycol is added to the crystallization kettle.

[0038] Further, in step S5, sulfuric acid is added to the micro-etching recovery liquid in real time through online monitoring, so that the hydrogen ion concentration in the micro-etching recovery liquid is maintained at 4.3 mol / L.

[0039] Further, in step S5, a stabilizing agent is added to the micro-etching recovery liquid, and the amount of the stabilizing agent is 0.1 g / L. The stabilizing agent is preferably trisodium phosphate.

[0040] Further, in step S5, a non-ionic surfactant is added to the micro-etching recovery liquid, and the amount of the non-ionic surfactant is 0.05 g / L. The non-ionic surfactant is preferably Triton X-100.

[0041] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned with a saturated copper sulfate solution, the concentration of the saturated copper sulfate solution is 40℃, the mass ratio of the saturated copper sulfate solution to the copper sulfate pentahydrate crystals is 1:3, and the cleaning time is 8 min.

[0042] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned with deionized water, the mass ratio of the deionized water to the copper sulfate pentahydrate crystals is 1:2, and the time is 2 min.

[0043] Embodiment 2 The embodiment provides a process method for recovering copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, and the process method comprises the following steps: S1, the micro-etching waste liquid after use by a production line is discharged into a reaction kettle, sulfuric acid is added, and the hydrogen ion concentration is adjusted to 4.4 mol / L; S2, the micro-etching waste liquid pre-adjusted through step S1 is filtered through a precision filter to a crystallization kettle; S3, the micro-etching waste liquid in the crystallization kettle is cooled to 2℃; S4, the micro-etching waste liquid after crystallization is subjected to solid-liquid separation through a high-speed centrifuge, the solid part is copper sulfate pentahydrate crystals, and the permeate is used as a micro-etching recovery liquid; S5, hydrogen peroxide solution is added to the micro-etching recovery liquid obtained through step S4, so that the hydrogen peroxide concentration in the micro-etching recovery liquid is 20 g / L, and then the micro-etching recovery liquid is conveyed to a production line for reuse; S6, the copper sulfate pentahydrate crystals obtained through step S4 are cleaned and subjected to secondary centrifugal separation, and after vacuum drying, an electroplating grade superior product of copper sulfate pentahydrate is obtained.

[0044] Further, in step S1, the micro-etching waste liquid comprises the following components: copper sulfate pentahydrate 58 g / L, sulfuric acid 205 g / L, and hydrogen peroxide 20 g / L.

[0045] Further, in step S1, a flocculating agent is added to the reaction kettle, and the temperature of the micro-etching waste liquid is controlled at 35℃, and the stirring speed is 200 rpm.

[0046] Further, the flocculating agent is compounded by polymeric ferric sulfate and polydimethyl diallyl ammonium chloride with a mass ratio of 3:1. In the actual operation process, the polymeric ferric sulfate is first added, reacted for 10 min, then the polydimethyl diallyl ammonium chloride is slowly added, reacted for 20 min, and finally the flocs are naturally settled.

[0047] Further, in step S2, the precision filter adopts two-stage filtration, the first stage adopts 5 μm filter core for pre-filtration, and the second stage adopts 0.5 μm filter core for fine filtration. The 5 μm filter core is preferably sintered titanium metal filter core, and the 0.5 μm filter core is preferably ceramic membrane, and the operating pressure is 0.15 MPa.

[0048] Further, after the filtration by the precision filter in step S2, the solution is treated by an ion exchange resin column and then enters a crystallization kettle. The ion exchange resin column is Dowex M4195.

[0049] Further, in step S3, the crystallization kettle adopts three-stage gradient cooling, the first stage is cooled from room temperature to about 15℃ at a cooling rate of 0.5℃ / min and is kept for 1 h; the second stage is cooled from 15℃ to about 5℃ at a cooling rate of 0.5℃ / min and is kept for 1 h; and the third stage is cooled from 5℃ to 2℃ at a cooling rate of 0.2℃ / min and is kept for 2 h.

[0050] Further, in step S3, 3wt% of ethylene glycol is added to the crystallization kettle.

[0051] Further, in step S5, the micro-etching recovery solution is supplemented with sulfuric acid in real time through online monitoring, so that the hydrogen ion concentration in the micro-etching recovery solution is maintained at 4.4 mol / L.

[0052] Still further, in step S5, a stabilizer is added to the micro-etching recovery solution, and the amount of the stabilizer is 0.2 g / L. The stabilizer is preferably ethylenediaminetetraacetic acid.

[0053] Still further, in step S5, a non-ionic surfactant is added to the micro-etching recovery solution, and the amount of the non-ionic surfactant is 0.08 g / L. The non-ionic surfactant is preferably Triton X-100.

[0054] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned with a saturated copper sulfate solution, the concentration of the saturated copper sulfate solution is 45℃, the mass ratio of the saturated copper sulfate solution to the copper sulfate pentahydrate crystals is 1:3, and the cleaning time is 6 min.

[0055] Still further, in step S6, the copper sulfate pentahydrate crystals are cleaned with deionized water, the mass ratio of the deionized water to the copper sulfate pentahydrate crystals is 1:2, and the time is 3 min.

[0056] Example 3 The embodiment provides a process method for recovering copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, which comprises the following steps: S1, the micro-etching waste liquid after use by the production line is discharged into a reaction kettle, sulfuric acid is added, and the hydrogen ion concentration is adjusted to 4.5 mol / L; S2, the micro-etching waste liquid pre-adjusted by step S1 is filtered by a precision filter to a crystallization kettle; S3, the micro-etching waste liquid in the crystallization kettle is cooled to 0℃; S4, the micro-etching waste liquid after crystallization is subjected to solid-liquid separation by a high-speed centrifuge, the solid part is copper sulfate pentahydrate crystal, and the permeate is used as micro-etching recovery liquid; S5, hydrogen peroxide solution is added to the micro-etching recovery liquid obtained by step S4, so that the concentration of hydrogen peroxide in the micro-etching recovery liquid is 22 g / L, and then the micro-etching recovery liquid is transported to the production line for reuse; S6, the copper sulfate pentahydrate crystal obtained by step S4 is washed and subjected to secondary centrifugal separation, and after vacuum drying, an electroplating grade superior product of copper sulfate pentahydrate is obtained.

[0057] Further, in step S1, the micro-etching waste liquid comprises the following components: copper sulfate pentahydrate 60 g / L, sulfuric acid 210 g / L, and hydrogen peroxide 21 g / L.

[0058] Further, in step S1, a flocculating agent is added to the reaction kettle, and the temperature of the micro-etching waste liquid is controlled at 38℃, and the stirring speed is 300 rpm.

[0059] Further, the flocculating agent is compounded by polymeric ferric sulfate and polydimethyl diallyl ammonium chloride with a mass ratio of 4:1. In actual operation, the materials are added step by step, polymeric ferric sulfate is added first, reacted for 12 min, then polydimethyl diallyl ammonium chloride is slowly added, reacted for 18 min, and finally the flocs are allowed to settle naturally.

[0060] Further, in step S2, the precision filter adopts two-stage filtration, the first stage adopts 5 μm filter core for pre-filtration, and the second stage adopts 0.5 μm filter core for fine filtration. Among them, the 5 μm filter core is preferably a polytetrafluoroethylene filter core; the 0.5-1 μm filter core is preferably a polyvinylidene fluoride filter core, and the operating pressure is 0.15 MPa.

[0061] Further, after filtration by the precision filter in step S2, the micro-etching waste liquid is treated by an ion exchange resin column and then enters the crystallization kettle. The ion exchange resin column is Dowex M4195.

[0062] Further, in step S3, the crystallization kettle adopts three-stage gradient cooling, the first stage is reduced from room temperature to about 15℃ at a cooling rate of 0.5℃ / min, and the temperature is kept for 1 h; the second stage is reduced from 15℃ to about 5℃ at a cooling rate of 0.5-1℃ / min, and the temperature is kept for 1 h; the third stage is reduced from 5℃ to 0℃ at a cooling rate of 0.2℃ / min, and the temperature is kept for 2 h.

[0063] Further, in step S3, 4wt% of ethylene glycol is added to the crystallization kettle.

[0064] Further, in step S5, sulfuric acid is added to the micro-etching recovery liquid in real time through online monitoring, so that the hydrogen ion concentration in the micro-etching recovery liquid is maintained at 4.5mol / L.

[0065] Further, in step S5, a stabilizer is added to the micro-etching recovery liquid, and the amount of the stabilizer is 0.3g / L. The stabilizer is preferably ethylenediaminetetraacetic acid.

[0066] Further, in step S5, a non-ionic surfactant is added to the micro-etching recovery liquid, and the amount of the non-ionic surfactant is 0.1g / L. The non-ionic surfactant is preferably Triton X-100.

[0067] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned with a saturated copper sulfate solution, the concentration of the saturated copper sulfate solution is 45℃, the mass ratio of the saturated copper sulfate solution to the copper sulfate pentahydrate crystals is 1:3, and the cleaning time is 8min.

[0068] Further, in step S6, the copper sulfate pentahydrate crystals are cleaned with deionized water, the mass ratio of the deionized water to the copper sulfate pentahydrate crystals is 1:2, and the time is 1min.

[0069] Example 4 The embodiment provides a production device for recovering copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid, which comprises a production line micro-etching waste liquid storage tank, a reaction kettle, a crystallization kettle, a high-speed centrifuge and a micro-etching recovery liquid adjusting tank. The inlet end of the production line micro-etching waste liquid storage tank is in communication with a pipeline through which the production line discharges micro-etching waste liquid. The inlet end of the production line micro-etching waste liquid storage tank is in communication with the reaction kettle. The discharge end of the reaction kettle is in communication with the crystallization kettle. The discharge end of the crystallization kettle is in communication with the high-speed centrifuge. The liquid discharge port of the high-speed centrifuge is in communication with the inlet end of the micro-etching recovery liquid adjusting tank. The outlet end of the micro-etching recovery liquid adjusting tank is connected through a pipeline to a production line for recycling micro-etching recovery liquid.

[0070] Further, a filtration system is arranged between the discharge end of the reaction kettle and the crystallization kettle. Specifically, the filtration system comprises two-stage precision filters arranged in sequence. The first-stage filter adopts a 5μm filter core for pre-filtration, and the second-stage filter adopts a 0.5μm filter core for fine filtration. The 5μm filter core is preferably a sintered titanium metal filter core, and the 0.5μm filter core is preferably a ceramic membrane.

[0071] Further, the filtration system further comprises an ion exchange resin column.

[0072] Further, the production device further comprises a crystal post-treatment system for treating the solid material obtained after the solid-liquid separation of the high-speed centrifuge, wherein the crystal post-treatment system comprises a washing tank, a secondary centrifuge and a vacuum dryer, the solid material is washed in the washing tank, then is placed in the secondary centrifuge for secondary separation, and the obtained wet cake is placed in the vacuum dryer for vacuum drying.

[0073] Further, the reaction kettle and the micro-etching recovery liquid adjusting tank are both provided with an on-line pH meter for monitoring the hydrogen ion concentration in the micro-etching waste liquid.

[0074] Further, the reaction kettle and the micro-etching recovery liquid adjusting tank are both provided with a copper ion concentration sensor for monitoring the copper ion concentration in the micro-etching waste liquid.

[0075] Further, the high-speed centrifuge is a horizontal screw centrifuge.

[0076] Comparative Example 1 The difference between the present comparative example and Example 2 is that the present comparative example provides a process method for recovering copper sulfate from the sulfuric acid-hydrogen peroxide system micro-etching waste liquid, wherein in step S1, no flocculating agent is added; in step S2, no ion exchange resin column treatment is performed; in step S3, the crystallization kettle is directly cooled from the initial temperature to 0℃ at a cooling rate of 1℃ / min, and is kept at 0℃ for 3h; and in step S5, only hydrogen peroxide is added to the micro-etching recovery liquid, so that the concentration of hydrogen peroxide in the micro-etching recovery liquid is 20g / L.

[0077] The structures of the process methods of Examples 1-3 and Comparative Example 1 are calculated, and the results are shown in the following table:

[0078] In the present application, Examples 1-3 effectively remove impurities by stepwise addition of flocculating agents and fine filtration, significantly improve the copper recovery rate and the purity of copper sulfate pentahydrate, and can make the micro-etching recovery rate circulate multiple times by adjusting the concentration of hydrogen peroxide and inhibiting the decomposition of hydrogen peroxide by adding an auxiliary agent. Therefore, Examples 1-3 reduce waste liquid discharge and sulfuric acid / hydrogen peroxide addition amount by high recovery rate and recycling, and have lower long-term operation cost.

[0079] The specific embodiments described above are further illustrations of the technical solutions and beneficial effects of the present application, and are not limitations on the embodiments. Any obvious substitutions for those skilled in the art without departing from the concept of the present application are within the protection scope of the present application.

Claims

1. A process for centralized recovery of copper sulfate from waste liquid microetching in a sulfuric acid-hydrogen peroxide system, characterized by: The steps include: S1. The micro-etching waste liquid used in the production line is discharged into the reactor, sulfuric acid is added, and the hydrogen ion concentration is adjusted to 4.3-4.5 mol / L; S2, the micro-etching waste liquid pre-conditioned in step S1 is filtered through a precision filter and then discharged into a crystallization kettle; S3, cooling the micro-etching waste liquid in the crystallization kettle to 0-5°C; S4. The micro-etching waste liquid after crystallization is separated into solid and liquid by a high-speed centrifuge. The solid part is copper sulfate pentahydrate crystals, and the permeate is used as the micro-etching recovery liquid; S5. Add hydrogen peroxide solution to the micro-etching recovery liquid obtained in step S4 to make the hydrogen peroxide concentration in the micro-etching recovery liquid 18-22 g / L, and then transport it to the production line for reuse; S6. The copper sulfate pentahydrate crystals obtained in step S4 are cleaned and centrifuged a second time, and then vacuum-dried to obtain electroplating-grade superior copper sulfate pentahydrate.

2. The process for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to claim 1, characterized in that: In step S1 , the micro-etching waste liquid includes the following components: 50-60 g / L of copper sulfate pentahydrate, 190-210 g / L of sulfuric acid, and 18-22 g / L of hydrogen peroxide.

3. The process for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to claim 1, characterized in that: In step S1, a flocculant is added to the reaction kettle, and the temperature of the micro-etching waste liquid is controlled at 32-38° C., and the stirring speed is 100-300 rpm.

4. The process for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to claim 1, characterized in that: In step S2, the precision filter adopts two-stage filtration, the first stage adopts a 5 μm filter element for pre-filtration, and the second stage adopts a 0.5-1 μm filter element for fine filtration.

5. The process for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to claim 1, characterized in that: In step S3, the crystallization kettle adopts a three-stage gradient cooling method, wherein the first stage is cooled from room temperature to about 15°C, the cooling rate is 0.5-1°C / min, and the temperature is kept for 1 hour; the second stage is cooled from 15°C to about 5°C, and the temperature is kept for 1-2 hours, the cooling rate is 0.5-1°C / min; the third stage is cooled from 5°C to 0-5°C, and the temperature is kept for 1-2 hours, the cooling rate is 0.2-0.5°C / min.

6. The process for centralized recovery of copper sulfate from sulfuric acid-hydrogen peroxide system micro-etching waste liquid according to claim 1, characterized in that: In step S6, the copper sulfate pentahydrate crystals are cleaned with a saturated copper sulfate solution, the concentration of the saturated copper sulfate solution is 40-45° C., the mass ratio of the saturated copper sulfate solution to the copper sulfate pentahydrate crystals is 1:3, and the cleaning time is 5-8 min.

7. A production device for centralized recovery of copper sulfate from waste liquid microetching in a sulfuric acid-hydrogen peroxide system, characterized by: It includes a micro-etching waste liquid storage tank for the production line, a reactor, a crystallization kettle, a high-speed centrifuge, and a micro-etching recovery liquid regulating tank, wherein the inlet end of the micro-etching waste liquid storage tank of the production line is connected to a pipeline for discharging micro-etching waste liquid from the production line, the inlet end of the micro-etching waste liquid storage tank of the production line is connected to the reactor, the discharge end of the reactor is connected to the crystallization kettle, the discharge end of the crystallization kettle is connected to the high-speed centrifuge, the discharge port of the high-speed centrifuge is connected to the inlet end of the micro-etching recovery liquid regulating tank, and the outlet end of the micro-etching recovery liquid regulating tank transports the micro-etching recovery liquid to the production line through a pipeline for reuse.

8. The production device for centralized recovery of copper sulfate from waste liquid micro-etching in a sulfuric acid-hydrogen peroxide system according to claim 7, characterized in that: A filtering system is also provided between the discharge end of the reactor and the crystallization kettle.

9. The production device for centralized recovery of copper sulfate from waste liquid micro-etching in a sulfuric acid-hydrogen peroxide system according to claim 7, characterized in that: The production device also includes a crystal post-processing system, which is used to process the solid material obtained after solid-liquid separation in a high-speed centrifuge. The crystal post-processing system includes a washing tank, a secondary centrifuge and a vacuum dryer. After the object material is cleaned in the washing tank, it is placed in the secondary centrifuge for secondary separation, and the obtained wet cake is placed in the vacuum dryer for vacuum drying.

10. The production device for centralized recovery of copper sulfate from waste liquid microetching in a sulfuric acid-hydrogen peroxide system according to claim 7, characterized in that: The reactor and the micro-etching recovery liquid regulating tank are both provided with an online pH meter, and the online pH meter is used to monitor the hydrogen ion concentration in the micro-etching waste liquid.

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