Method for removing hydrogen peroxide from electronic waste liquid by hydrogen peroxide remover

Abstract

This invention discloses a method for treating hydrogen peroxide in electronic waste liquid using a hydrogen peroxide removal agent. The preparation method of the hydrogen peroxide removal agent is as follows: a titanium oxysulfate solution is prepared and mixed with a PVP solution to obtain a mixed solution; polycrystalline silicon powder is immersed in the mixed solution and calcined to obtain tetravalent titanium-supported polycrystalline silicon nanoparticles; then, an aqueous rheology modifier, nonionic surfactants A and B are mixed and added to the tetravalent titanium-supported polycrystalline silicon powder to obtain a liquid metal active catalyst. The method for treating hydrogen peroxide is as follows: the hydrogen peroxide removal agent is added to the electronic waste liquid to be treated, heated, and a catalytic oxidation reaction is carried out to reduce the hydrogen peroxide concentration; then the treated electronic waste liquid is cooled and discharged. The amount of hydrogen peroxide removal agent added is 2-5 mg / L. The hydrogen peroxide removal agent of this invention requires a small amount when treating acidic cleaning solutions from wafer waste, and compared with other processes that add metal salts, the dosage is reduced by 15 to 200 times.

Description

[0001] This patent application is a divisional application. The original application was entitled: "A method for preparing a hydrogen peroxide removal agent for electronic waste liquid and a method for treating hydrogen peroxide"; the application date was September 1, 2022; and the application number was 2022110635301. Technical Field

[0002] This invention relates to a method for treating electronic waste liquid, and more particularly to a method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent. Background Technology

[0003] In the electronics industry, a mixture of sulfuric acid and hydrogen peroxide is used in wafer cleaning processes. The sulfuric acid concentration ranges from 40% to 75%, while the hydrogen peroxide concentration ranges from 1% to 10%, serving as a cleaning agent for surface organic matter and residual metal. After cleaning, the waste liquid still retains high concentrations of sulfuric acid and hydrogen peroxide. Due to their chemical properties, the sulfuric acid reacts with the hydrogen peroxide to form a persulfate structure. Hydrogen peroxide in this structure is difficult to degrade spontaneously and will slowly release oxygen when exposed to high temperatures, posing a risk of explosion.

[0004] To eliminate the aforementioned risks, acidic cleaning agents must destroy the structure of persulfate and reduce hydrogen peroxide to oxygen and water. Currently, the commonly used method is batch hydrochloric acid / nitric acid oxidation. High concentrations of hydrochloric acid / nitric acid are added to the acidic cleaning agent, and the solution is heated to produce highly oxidizing substances such as hypochlorous acid, chlorine, and nitrogen dioxide. These react with the hydrogen peroxide in the solution, ultimately reducing the hydrogen peroxide concentration to below 5000 mg / L to meet outsourced disposal standards.

[0005] The batch hydrochloric acid / nitric acid oxidation method has the following disadvantages: (1) The amount of hydrochloric acid / nitric acid added is large, requiring 10-50% of the hydrogen peroxide concentration to be added; (2) The hypochlorous acid and chlorine / nitric acid produced by hydrochloric acid / nitric acid are highly oxidizing substances, which are highly sensitive to equipment materials and construction quality, and often lead to leakage at the connection of equipment pipes; (3) The hydrochloric acid / nitric acid oxidation method leaves a large amount of chloride ions and nitrate ions in the waste liquid, causing secondary pollution of the waste liquid; (4) The batch method has low reaction efficiency, so the unit waste liquid treatment volume is much lower than that of the continuous treatment process under the same land area, and the treatment volume can be more than twice as high, which also increases the construction cost of the process system. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent.

[0007] Technical solution: The preparation method of the hydrogen peroxide removal agent in electronic waste liquid according to the present invention includes the following steps:

[0008] (1) Add titanium oxysulfate solid powder to hot concentrated sulfuric acid to obtain titanium oxysulfate solution;

[0009] (2) Add the titanium oxysulfate solution to the PVP solution to obtain a mixed solution for loading;

[0010] (3) Polycrystalline silicon powder was immersed in a mixed solution for loading and calcined to obtain tetravalent titanium-loaded polycrystalline silicon nanopowder.

[0011] (4) After mixing aqueous rheology modifier, nonionic surfactant A and nonionic surfactant B, tetravalent titanium-supported polycrystalline silicon powder is added and mixed to obtain liquid metal active catalyst.

[0012] The aqueous rheology modifier is hydroxyethyl cellulose ether, hydroxypropyl cellulose, or an alkali-swellable non-associated thickener; when the aqueous rheology modifier is an alkali-swellable non-associated thickener, it also includes ammonia or xanthan gum; the nonionic surfactant A is any one of octylphenol and ethylene oxide condensate, polyoxyethylene ether, fatty alcohol polyoxyethylene ether, or fatty alcohol and ethylene oxide condensate; the nonionic surfactant B is polyethylene glycol, Span 80, or Tween 60.

[0013] In step (1), the concentration of the titanium oxysulfate solution is 50-70 wt%; the concentrated sulfuric acid is heated to 120-130°C; and the amount of titanium oxysulfate solid powder added is 600-1200 g / L H2SO4.

[0014] In step (2), the mass ratio of titanium oxysulfate solution to PVP solution is 3:20 to 5:22.

[0015] In step (3), the calcination temperature is 660-760℃, the time is 20-50min, and the heating rate is 100℃ / 30min.

[0016] In step (4), the mass ratio of the tetravalent titanium-supported polycrystalline silicon powder to the aqueous rheology modifier, nonionic surfactant A, and nonionic surfactant B is 70:8:10:10 to 90:15:20:30.

[0017] The method for treating hydrogen peroxide in electronic waste liquid using the hydrogen peroxide removal agent prepared by the above method includes the following steps: adding the hydrogen peroxide removal agent to the electronic waste liquid to be treated, heating to carry out a catalytic oxidation reaction to reduce the hydrogen peroxide concentration, and then cooling the treated recovery liquid and discharging it.

[0018] The hydrogen peroxide removal agent is added at a concentration of 2-5 mg / L. The heating temperature is 110-130℃, and the reaction time is 1-5 minutes. The treated electronic waste liquid is then concentrated to increase the sulfuric acid concentration. Specifically, the sulfuric acid concentration is increased from 50-55 wt% to 55-63 wt%.

[0019] The specific steps of the method for treating hydrogen peroxide in electronic waste liquid are as follows:

[0020] (1) The hydrogen peroxide removal agent and the electronic waste liquid to be treated are transported to the mixer and mixed thoroughly. The mixture in the mixer is heated by heat exchange, and a catalytic oxidation reaction occurs to reduce the concentration of hydrogen peroxide.

[0021] (2) The treated recycled liquid is subjected to heat exchange, which lowers the temperature of the recycled liquid and raises the temperature of the electronic waste liquid to be treated.

[0022] (3) Discharge the cooled recovery liquid.

[0023] The process involves testing the hydrogen peroxide concentration in the treated recycled liquid. If the concentration is within acceptable limits, the liquid is discharged; otherwise, it is recycled.

[0024] The treated recovered liquid is separated from the gas produced in the reaction. The gas produced in the reaction is discharged after washing.

[0025] As a further preferred embodiment, the apparatus used in the above-mentioned method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent includes a microchannel heat recovery reactor; the microchannel heat recovery reactor includes a reaction zone and heat recovery layers located on both sides of the reaction zone, the reaction zone is composed of multiple interconnected chambers, each chamber including nested inner and outer cavities, the area enclosed between the inner and outer cavities forming a channel for fluid flow, the fluid entering the chamber is split at the channel inlet and converges at the channel outlet.

[0026] The inner cavity has an arc-shaped outline at the channel outlet. The outer cavity has a rhombus-shaped outline; the inner cavity has an inverted triangle-shaped outline. The rhombus and the inverted triangle share a common vertex, forming the channel entrance, and the opposite side is the channel outlet.

[0027] The ratio of the lengths of the two diagonals of the rhombus is 1.8 to 2.2:1. The cross-sectional length of the inner cavity near the channel outlet is the ratio of the length of the shorter diagonal of the rhombus to 1.8 to 2.2:1. The ratio of the width of the channel outlet to the length of the straight line of the base of the inverted triangle is 1.8 to 2.2:1.

[0028] The microchannel heat recovery reactor is made of silicon carbide material.

[0029] The inlet of the microchannel heat recovery reaction device is connected to a waste liquid collection tank and a reaction agent, respectively. The outlet of the microchannel heat recovery reaction device is connected to a gas washing device for washing the gas generated during the heat recovery process, a concentration evaporation device for the generated gas, a cooling device, and a recovery liquid collection tank connected to the cooling device.

[0030] The specific steps of the method for treating hydrogen peroxide in electronic waste using the above-mentioned device are as follows:

[0031] (1) The hydrogen peroxide removal agent and the electronic waste liquid to be treated are transported to the reaction zone and mixed.

[0032] A heat medium is introduced into the heat recovery layer to heat the mixture in the reaction zone, causing a catalytic oxidation reaction.

[0033] (2) The recovered liquid after treatment is separated from the gas generated by the reaction. The recovered liquid is concentrated in a concentration evaporation device, and the gas is discharged after being treated by a gas washing device.

[0034] (3) The concentrated recovery liquid enters the heat recovery layer as a heat medium to exchange heat with the electronic waste liquid to be treated in the reaction zone;

[0035] (4) The recovered liquid from the heat recovery layer is further cooled by the cooling device. If the hydrogen peroxide concentration in the recovered liquid is qualified, it is discharged; if it is not qualified, the recovered liquid is recycled.

[0036] Reaction Principle: Tetravalent titanium in the active metal undergoes a catalytic complex reaction with hydrogen peroxide, generating a large number of hydroxyl radicals and superoxide radicals. These free radicals attack the hydrogen peroxide, oxidizing it to water and producing hydroxyl superoxide radicals. The hydroxyl superoxide radicals, superoxide radicals, and hydroxyl radicals then reduce the tetravalent titanium to trivalent titanium. The trivalent titanium then reacts with hydrogen peroxide to produce a large number of free radicals and tetravalent titanium, and the hydroxyl superoxide radicals further react with the trivalent titanium to produce tetravalent titanium. The final products are oxygen and water; the tetravalent titanium is not consumed in the reaction. Compared to ordinary ionic titanium dissolved in solution and lost as the solution leaves the system after treatment, polycrystalline silicon-supported tetravalent titanium is a heterogeneous catalysis. Solid-state catalysis increases the residence time of the active metal in the reactor, resulting in less loss and significantly reducing the amount of active metal required.

[0037] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects: (1) Since tetravalent titanium is supported on polycrystalline silicon, less tetravalent titanium is lost, thus the amount of liquid metal active catalyst added is smaller, less than 5 mg / L, and can reach 2 mg / L. Compared with the metal salt addition amount of 30 mg / L to 400 mg / L in the prior art, the dosage is reduced by 15 to 200 times; at the same time, a good hydrogen peroxide removal rate can still be achieved; (2) Compared with the hydrochloric acid / nitric acid oxidation method in the prior art, residual chlorine, hypochlorous acid, nitric acid and other ions or free strong oxidizing substances in the acid can be avoided. (3) Secondary pollution caused by the recovered liquid can be avoided, and the recycling value is increased. Attached Figure Description

[0038] Figure 1 The X-ray diffraction pattern of the tetravalent titanium-supported polycrystalline silicon nanopowder prepared in Example 1;

[0039] Figure 2 This is a cross-sectional view of the microchannel heat recovery reactor of the present invention;

[0040] Figure 3 This is a side view of the microchannel heat recovery reactor of the present invention;

[0041] Figure 4 This is a schematic diagram of the chamber structure in the microchannel heat recovery reaction device of the present invention;

[0042] Figure 5 This is a schematic diagram of the apparatus for treating waste acidic cleaning solution from wafers according to the present invention. Detailed Implementation

[0043] The present invention will now be described in further detail.

[0044] Example 1

[0045] A method for preparing a hydrogen peroxide removal agent for electronic waste liquid includes the following steps:

[0046] Step 1: Heat 98wt% concentrated sulfuric acid to 120℃, add 150g of 99% pure titanium oxysulfate solid powder to 100g of concentrated sulfuric acid, and cool the resulting titanium oxysulfate solution to 25℃.

[0047] Step 2: Prepare a viscosity-average molecular weight of 6*10 5 Add 100g to 1000g of polyvinylpyrrolidone to 1000g of deionized water and stir until the polyvinylpyrrolidone is completely dissolved.

[0048] Step 3: Slowly add the titanium oxysulfate solution to the PVP solution and stir for 30 minutes. During the stirring process, the solution must be kept at 25°C to avoid the sulfuric acid dilution releasing heat too quickly, which could lead to danger. The resulting mixed solution is used for loading.

[0049] Step 4: Prepare 100g of 800nm ​​polycrystalline silicon powder with a purity of 99.99% or higher. Immerse it in a loading solution and stir for 60 minutes. Then place it in a calcination furnace and heat it to 700℃ at a rate of 100℃ every 30 minutes. Maintain this temperature for 30 minutes, then cool it to 25℃ to obtain tetravalent titanium-supported polycrystalline silicon nanoparticles. Figure 1 As shown, based on the scattering angles corresponding to the diffraction peak intensities of tetravalent titanium-loaded polycrystalline silicon nanopowder in the X-ray diffraction pattern, the crystal structure is inferred to contain polycrystalline silicon and tetravalent titanium using literature databases. Among them, silicon represents polycrystalline silicon, and rutile and anatase represent tetravalent titanium.

[0050] Step 5: Heat 1000g of deionized water to 50℃, then add 5g of hydroxyethyl cellulose ether and stir until the solution is viscous and transparent. Add 10g of octylphenol and ethylene oxide condensate OP-15, 10g of polyoxyethylene ether, 20g of polyethylene glycol with a viscosity-average molecular weight of 400, and then add 80g of tetravalent titanium-supported polycrystalline silicon. Stir the mixture at 8000rpm for 10 minutes using a vacuum homogenizer to obtain a viscous black metallic active catalyst, which is the hydrogen peroxide removal agent in electronic waste liquid.

[0051] Example 2

[0052] A method for preparing a hydrogen peroxide removal agent for electronic waste liquid includes the following steps:

[0053] Step 1: Heat 98wt% concentrated sulfuric acid to 130℃, add 200g of 99% pure titanium oxysulfate solid powder to 100g of concentrated sulfuric acid, and cool the resulting titanium oxysulfate solution to 25℃.

[0054] Step 2: Prepare a viscosity-average molecular weight of 6*10 5 Add 200g to 1800g of polyvinylpyrrolidone to 1800g of deionized water and stir until the polyvinylpyrrolidone is completely dissolved.

[0055] Step 3: Slowly add the titanium oxysulfate solution to the PVP solution and stir for 30 minutes. During the stirring process, the solution must be kept at 25°C to avoid the sulfuric acid dilution releasing heat too quickly, which could lead to danger. The resulting mixed solution is used for loading.

[0056] Step 4: Prepare 100g of 800nm ​​polycrystalline silicon powder with a purity of 99.99% or higher, soak it in a loading solution, stir for 60 minutes, place it in a calcination furnace, heat it to 760°C at a heating rate of 100°C every 30 minutes, maintain this temperature for 30 minutes, and then cool it down to 25°C to obtain tetravalent titanium-supported polycrystalline silicon nanoparticles.

[0057] Step 5: Heat 1000g of deionized water to 50℃, then add 5g of hydroxyethyl cellulose ether and stir until the solution is viscous and transparent. Add 10g of octylphenol and ethylene oxide condensate OP-15, 20g of polyoxyethylene ether, 30g of polyethylene glycol with a viscosity-average molecular weight of 400, and then add 70g of tetravalent titanium-supported polycrystalline silicon. Stir with a vacuum homogenizer at 8000rpm for 10 minutes to obtain a viscous black metallic active catalyst, which is the hydrogen peroxide removal agent in electronic waste liquid.

[0058] Example 3

[0059] A method for preparing a hydrogen peroxide removal agent for electronic waste liquid includes the following steps:

[0060] Step 1: Heat 98wt% concentrated sulfuric acid to 124℃, add 100g of 99% pure titanium oxysulfate solid powder to 100g of concentrated sulfuric acid, and cool the resulting titanium oxysulfate solution to 25℃.

[0061] Step 2: Prepare a viscosity-average molecular weight of 6*10 5 Add 80g to 800g of polyvinylpyrrolidone to deionized water and stir until the polyvinylpyrrolidone is completely dissolved.

[0062] Step 3: Slowly add the titanium oxysulfate solution to the PVP solution and stir for 30 minutes. During the stirring process, the solution must be kept at 25°C to avoid the sulfuric acid dilution releasing heat too quickly, which could lead to danger. The resulting mixed solution is used for loading.

[0063] Step 4: Prepare 100g of 800nm ​​polycrystalline silicon powder with a purity of 99.99% or higher, soak it in a loading solution, stir for 60 minutes, place it in a calcination furnace, heat it to 660°C at a heating rate of 100°C every 30 minutes, maintain this temperature for 30 minutes, and then cool it down to 25°C to obtain tetravalent titanium-supported polycrystalline silicon nanoparticles.

[0064] Step 5: Heat 1000g of deionized water to 50℃, then add 3g of hydroxyethyl cellulose ether and stir until the solution is viscous and transparent. Add 5g of octylphenol and ethylene oxide condensate OP-15, 10g of polyoxyethylene ether, 10g of polyethylene glycol with a viscosity-average molecular weight of 400, and then add 90g of tetravalent titanium-supported polycrystalline silicon. Stir with a vacuum homogenizer at 8000rpm for 10 minutes to obtain a viscous black metallic active catalyst, which is the hydrogen peroxide removal agent in electronic waste liquid.

[0065] Example 4

[0066] A waste acidic cleaning solution from a semiconductor factory in Shanghai: hydrogen peroxide concentration 5-6 wt%, sulfuric acid concentration 55-60 wt%, pH <0, density 1450-1500 kg / m³ 3The water flow rate is 1 ton / hour, and the operating time is 24 hours. The method for treating the above-mentioned waste acidic cleaning solution includes the following steps:

[0067] Step 1: Transfer the waste acidic cleaning solution to a 1m [unit of volume] at a flow rate of 4 tons / hour. 3 The conveying time in the reaction tank is 10 minutes. When the liquid level in the reaction tank reaches the liquid level control point, the conveying will stop.

[0068] The second step is to circulate the waste acidic cleaning solution to a heat exchanger for heating for 10 minutes, after which the waste acidic cleaning solution reaches 60°C.

[0069] The third step is to add 1.5 mg / L of active metal to the reaction tank, for a total addition of 1500 mg.

[0070] Step 4: After the active metal has been added, start the circulation pump to circulate the reaction for 60 minutes.

[0071] Step 5: After the reaction time is reached, the treated waste acidic cleaning solution is circulated to a heat exchanger to begin circulating cooling. The cooling time is about 30 minutes, and the waste acidic cleaning solution is below 30°C after cooling.

[0072] Step 6: Transfer the cooled waste acidic cleaning solution to the treated storage tank over approximately 10 minutes. At this point, the residual hydrogen peroxide concentration in the waste acidic cleaning solution inside the storage tank is approximately 500 mg / L, and the hydrogen peroxide removal rate reaches 99.44%.

[0073] Step 8: The treated waste acidic cleaning solution is outsourced for further processing.

[0074] Example 5

[0075] like Figure 2-3 As shown, an apparatus for treating waste acidic cleaning solution from wafers includes a microchannel heat recovery reactor 1, comprising a reaction zone 2 and heat recovery layers 3 located on both sides of the reaction zone 2. The reaction zone 2 is composed of multiple interconnected chambers. Figure 4As shown, each chamber includes an outer cavity 4 and an inner cavity 5 disposed within the outer cavity 4. The area between the inner cavity 5 and the outer cavity 4 forms a channel for liquid flow. One end of the inner cavity 5 coincides with one end of the outer cavity 4, and the coincident end is the inlet 6 of the channel. Liquid entering the chamber is divided at the inlet 6 of the channel and converges at the outlet 7 of the channel. In this embodiment, the outer cavity 4 has a rhombus shape, with one vertex of the rhombus being the inlet 6 of the channel and the opposite vertex being the outlet of the channel. In this embodiment, the inner cavity 5 has an inverted triangle shape, with the base of the inverted triangle being arc-shaped and the apex of the inverted triangle being the inlet 6 of the channel. In this embodiment, the length ratio of the two diagonals of the rhombus is 2:1, and this ratio can be 1.8 to 2.2:1. The cross-sectional length of the inner cavity 5 near the outlet of the channel is 2:1 of the length of the shorter diagonal of the rhombus, and this ratio can be 1.8 to 2.2:1. The ratio of the width of the passage exit to the length of the straight line of the base of the inverted triangle is 2:1, and this ratio can be 1.8 to 2.2:1.

[0076] like Figure 5 As shown, the inlet of the microchannel heat recovery reactor 1 is connected to the waste liquid collection tank 8 and the reaction reagent 9, respectively. The outlet of the microchannel heat recovery reactor 1 is connected to a gas scrubbing device 10 for scrubbing the gas generated during the heat recovery process, a concentration evaporation device 11 for evaporating the generated gas, and a cooling device 12. The cooling device 12 is connected to the recovery liquid collection tank 13. The cooling device 13 is connected to an H2O2 analyzer 14. A non-conforming tank 15 is also connected between the cooling device 12 and the recovery liquid collection tank for storing non-conforming recovery liquid with a residual hydrogen peroxide concentration greater than 500 mg / L.

[0077] Example 6

[0078] A semiconductor factory in Fujian Province produced a waste acidic cleaning solution with the following composition: hydrogen peroxide concentration of 8-9 wt%, sulfuric acid concentration of 50-55 wt%, pH <0, and density of 1400-1450 kg / m³. 3 The water flow rate is 0.5 tons / hour, and the operating time is 24 hours. The method for treating the above-mentioned waste acidic cleaning solution using the apparatus of Example 5 includes the following steps:

[0079] Step 1: Send the waste acidic cleaning solution to the inlet of the microchannel heat recovery reactor at a flow rate of 0.5 tons / hour.

[0080] Step 2: Add 3 mg / L of the ferrous metal active catalyst from Example 1 as a catalytic medium at the inlet of the microchannel heat recovery reactor. The waste acid cleaning solution and the active metal mixture enter the reaction zone of the microchannel heat recovery reactor.

[0081] Step 3: Pass 0.4MPa steam at 58kg / h into the heat recovery layer of the heat recovery reactor to heat the waste acidic cleaning solution. At this time, the active metal will produce a common chain catalytic oxidation reaction with sulfuric acid and hydrogen peroxide. The mixed liquid is heated from 25℃ to 125℃ and stays in the reaction zone for 2 minutes. At this time, the concentration of hydrogen peroxide is less than 500mg / L.

[0082] Step 4: After treatment, the recovered liquid is separated from the oxygen produced by the reaction and concentrated by evaporation. Due to the evaporation of water vapor in the recovered liquid, the temperature of the recovered liquid will decrease from 125°C to 110°C, while the sulfuric acid concentration will increase from 50-55 wt% to 55-63 wt%.

[0083] Step 5: The 110°C recovery liquid is transported to the heat recovery layer of the microchannel heat recovery reactor, where the temperature of the recovery liquid drops from 110°C to 35°C. At the same time, the acidic cleaning liquid to be treated in the cold flow pipe is heated from 25°C to 100°C.

[0084] Step 6: The recovered liquid is further cooled to 36°C by the heat recovery layer of the microchannel heat recovery reactor and the cooling device.

[0085] Step 7: Check the hydrogen peroxide concentration in the cooled recovery solution. If the residual hydrogen peroxide concentration is less than 500 mg / L, the recovery solution is transferred to a recovery solution collection tank for storage. If the residual concentration is greater than 500 mg / L, the recovery solution is transferred to a non-conforming tank for storage. Simultaneously, calculate the additional amount of active metal to be added based on the residual concentration and add it to the reaction apparatus.

[0086] Step 8: When the liquid level in the recovery liquid collection tank reaches 50% or more, drain it from the system for recycling or outsourced disposal. At this point, the sulfuric acid concentration in the recovery liquid reaches 55-63 wt%, the hydrogen peroxide residual concentration is less than 1 mg / L, and the hydrogen peroxide removal rate reaches 99.999%.

[0087] Step 9: Hydrogen peroxide is used to transport the substandard recovery liquid to the inlet of the microchannel heat recovery reactor at a flow rate of 1 / 20 of the original water flow rate. After the substandard recovery liquid undergoes secondary reaction treatment and the residual concentration of hydrogen peroxide is lower than 500 mg / L, it is transported together with the recovery liquid from the first treatment to the recovery liquid collection tank for storage.

[0088] Example 7

[0089] A waste acidic cleaning solution from a semiconductor factory in Shanghai: hydrogen peroxide concentration 5-6 wt%, sulfuric acid concentration 55-60 wt%, pH <0, density 1450-1500 kg / m³ 3 The water flow rate is 1 ton / hour, and the operating time is 24 hours.

[0090] The method for treating the above-mentioned waste acidic cleaning solution using the apparatus of Example 5 includes the following steps:

[0091] Step 1: Send the waste acidic cleaning solution to the inlet of the microchannel heat recovery reactor at a flow rate of 0.5 tons / hour.

[0092] Step 2: Add 2 mg / L of the ferrous metal active catalyst from Example 1 as a catalytic medium at the inlet of the microchannel heat recovery reactor. The waste acid cleaning solution and the active metal mixture enter the reaction zone of the silicon carbide microchannel heat recovery reactor.

[0093] Step 3: 0.4MPa steam 100kg / h is introduced into the heat recovery layer of the heat recovery reaction device to heat the waste acidic cleaning solution. At this time, the active metal will produce a common chain catalytic oxidation reaction with sulfuric acid and hydrogen peroxide. The mixed liquid is heated from 25℃ to 125℃ and stays in the reaction zone for 2 minutes. At this time, the concentration of hydrogen peroxide is less than 500mg / L.

[0094] Step 4: After treatment, the recovered liquid is separated from the oxygen produced by the reaction and concentrated by evaporation. Due to the evaporation of water vapor in the recovered liquid, the temperature of the recovered liquid will decrease from 125°C to 110°C, while the sulfuric acid concentration will increase from 55-60 wt% to 60-67 wt%.

[0095] Step 5: The 110°C recovery liquid is transported to the heat recovery layer of the microchannel heat recovery reactor, where the temperature of the recovery liquid drops from 110°C to 35°C. At the same time, the acidic cleaning liquid to be treated in the cold flow pipe is heated from 25°C to 100°C.

[0096] Step 6: The recovered liquid passes through the heat recovery layer of the microchannel heat recovery reactor and is further cooled to 36°C by the cooling device.

[0097] Step 7: Detect the hydrogen peroxide concentration in the cooled recovery solution. If the residual hydrogen peroxide concentration is less than 500 mg / L, transfer the recovery solution to a collection tank for storage. If the residual concentration is greater than 500 mg / L, transfer the recovery solution to a non-conforming tank for storage. Simultaneously, calculate the additional amount of active metal to be added based on the residual concentration and add it to the reaction apparatus.

[0098] Step 8: When the liquid level in the recovery liquid collection tank reaches 50% or more, drain it from the system for recycling or outsourced disposal. At this point, the sulfuric acid concentration in the recovery liquid reaches 60-67 wt%, the hydrogen peroxide residual concentration is less than 1 mg / L, and the hydrogen peroxide removal rate reaches 99.998%.

[0099] Step 9: Hydrogen peroxide is used to transport the substandard recovery liquid to the inlet of the microchannel heat recovery reactor at a flow rate of 1 / 20 of the original water flow rate. After the substandard recovery liquid undergoes secondary reaction treatment and the residual concentration of hydrogen peroxide is lower than 500 mg / L, it is transported together with the recovery liquid from the first treatment to the recovery liquid collection tank for storage.

[0100] Example 8

[0101] A semiconductor factory in Shandong province produced a waste acidic cleaning solution with the following composition: hydrogen peroxide concentration of 2-3 wt%, sulfuric acid concentration of 55-60 wt%, pH <0, and density of 1450-1500 kg / m³. 3 The water flow rate is 1 ton / hour, and the operating time is 24 hours.

[0102] The method for treating the above-mentioned waste acidic cleaning solution using the apparatus of Example 5 includes the following steps:

[0103] Step 1: Send the waste acidic cleaning solution to the inlet of the microchannel heat recovery reactor at a flow rate of 0.5 tons / hour.

[0104] Step 2: Add 1.5 mg / L of the ferrous metal active catalyst from Example 1 as a catalytic medium at the inlet of the microchannel heat recovery reactor. The waste acid cleaning solution and the active metal mixture enter the reaction zone of the silicon carbide microchannel heat recovery reactor.

[0105] Step 3: 0.4MPa steam 100kg / h is introduced into the heat recovery layer of the heat recovery reaction device to heat the waste acidic cleaning solution. At this time, the active metal will produce a common chain catalytic oxidation reaction with sulfuric acid and hydrogen peroxide. The mixed liquid is heated from 25℃ to 125℃ and stays in the reaction zone for 2 minutes. At this time, the concentration of hydrogen peroxide is less than 500mg / L.

[0106] Step 4: After treatment, the recovered liquid is separated from the oxygen produced by the reaction and concentrated by evaporation. Due to the evaporation of water vapor in the recovered liquid, the temperature of the recovered liquid will decrease from 125°C to 110°C, while the sulfuric acid concentration will increase from 55-60 wt% to 60-67 wt%.

[0107] Step 5: The 110°C recovery liquid is transported to the heat recovery layer of the microchannel heat recovery reactor, where the temperature of the recovery liquid drops from 110°C to 35°C. At the same time, the acidic cleaning liquid in the cold flow pipe is heated from 25°C to 100°C.

[0108] Step 6: The recovered liquid passes through the heat recovery layer of the microchannel heat recovery reactor and is further cooled to 36°C.

[0109] Step 7: Detect the hydrogen peroxide concentration in the cooled recovery solution. If the residual hydrogen peroxide concentration is less than 500 mg / L, transfer the recovery solution to a collection tank for storage. If the residual concentration is greater than 500 mg / L, transfer the recovery solution to a non-conforming tank for storage. Simultaneously, calculate the additional amount of active metal to be added based on the residual concentration and add it to the reaction apparatus.

[0110] Step 8: When the liquid level in the recovery liquid collection tank reaches 50% or more, drain it from the system for recycling or outsourced disposal. At this point, the sulfuric acid concentration in the recovery liquid reaches 60-67 wt%, the hydrogen peroxide residual concentration is less than 1 mg / L, and the hydrogen peroxide removal rate reaches 99.995%.

[0111] Step 9: Hydrogen peroxide is used to transport the substandard recovery liquid to the inlet of the microchannel heat recovery reactor at a flow rate of 1 / 20 of the original water flow rate. After the substandard recovery liquid undergoes secondary reaction treatment and the residual concentration of hydrogen peroxide is lower than 500 mg / L, it is transported together with the recovery liquid from the first treatment to the recovery liquid collection tank for storage.

[0112] Comparative Example

[0113] A waste acidic cleaning solution from a semiconductor factory in Shanghai: hydrogen peroxide concentration 5-6 wt%, sulfuric acid concentration 55-60 wt%, pH <0, density 1450-1500 kg / m³ 3 The water flow rate is 1 ton / hour, and the operating time is 24 hours. The method for treating the above-mentioned waste acidic cleaning solution includes the following steps:

[0114] Step 1: Transfer the waste acidic cleaning solution at a flow rate of 4 tons / hour to a 1m... 3 The conveying time in the reaction tank is 10 minutes. When the liquid level in the reaction tank reaches the liquid level control point, the conveying will stop.

[0115] The second step is to circulate the waste acidic cleaning solution to a heat exchanger for heating for 10 minutes, after which the waste acidic cleaning solution reaches 60°C.

[0116] The third step is to add 68wt% nitric acid to the reaction tank at a rate of 2.2L per batch over a period of 10 minutes.

[0117] Step 4: After the nitric acid is added, start the circulation pump to circulate the reaction for 60 minutes.

[0118] Step 5: After the reaction time is reached, the waste acidic cleaning solution is circulated to the heat exchanger to begin cooling. The cooling time is about 30 minutes, and the waste acidic cleaning solution is below 30°C after cooling.

[0119] Step 6: Transfer the waste acidic cleaning solution in the reaction tank to the post-treatment storage tank. The transfer time is about 10 minutes.

[0120] Step 7: At this point, the residual concentration of hydrogen peroxide in the waste acid cleaning solution inside the storage tank is approximately 5000 mg / L, and the hydrogen peroxide removal rate reaches 94.44%.

[0121] Step 8: Outsource the treatment of the waste acidic cleaning solution.

[0122] This invention achieves the resource utilization of sulfuric acid by catalytically decomposing hydrogen peroxide in waste acidic cleaning solutions and concentrating it to produce sulfuric acid recovery solution. This solution can be used for water treatment acid-base neutralization or, where permitted by standards, can replace industrial-grade sulfuric acid. Furthermore, the short processing time further reduces construction and operating costs, and requires minimal additives to the recovery solution, resulting in high recycling and application value.

Claims

1. A method for treating hydrogen peroxide in electronic waste liquid using a hydrogen peroxide removal agent, characterized in that, The hydrogen peroxide removal agent is added to the electronic waste liquid to be treated, heated, and a catalytic oxidation reaction is carried out to reduce the hydrogen peroxide concentration. Then the treated electronic waste liquid is cooled and discharged. The amount of hydrogen peroxide removal agent added is 2~5 mg / L. The preparation method of the hydrogen peroxide removal agent includes the following steps: (1) Add titanium oxysulfate solid powder to hot concentrated sulfuric acid to obtain titanium oxysulfate solution; (2) Add the titanium oxysulfate solution to the PVP solution to obtain a mixed solution for loading; the mass ratio of the titanium oxysulfate solution to the PVP solution is 3:20~5:22; (3) Polycrystalline silicon powder was immersed in a mixed solution for loading and calcined to obtain tetravalent titanium-loaded polycrystalline silicon nanopowder; (4) After mixing the aqueous rheology modifier, nonionic surfactant A, and nonionic surfactant B, tetravalent titanium-supported polycrystalline silicon powder is added and mixed to obtain a liquid metal active catalyst, which is the hydrogen peroxide removal agent in the electronic waste liquid; the mass ratio of the tetravalent titanium-supported polycrystalline silicon powder to the aqueous rheology modifier, nonionic surfactant A, and nonionic surfactant B is 70:8:10:10~90:15:20:30; The aqueous rheology modifier is hydroxyethyl cellulose ether, hydroxypropyl cellulose, or an alkali-swellable non-associated thickener; when the aqueous rheology modifier is an alkali-swellable non-associated thickener, it also includes ammonia or xanthan gum; the nonionic surfactant A is any one of octylphenol and ethylene oxide condensate, polyoxyethylene ether, fatty alcohol polyoxyethylene ether, or fatty alcohol and ethylene oxide condensate; the nonionic surfactant B is polyethylene glycol, Span 80, or Tween 60.

2. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 1, characterized in that, The apparatus used in the method includes a microchannel heat recovery reactor; the microchannel heat recovery reactor includes a reaction zone and heat recovery layers located on both sides of the reaction zone. The reaction zone is composed of multiple interconnected chambers. Each chamber includes nested inner and outer cavities. The area enclosed between the inner and outer cavities forms a channel for fluid flow. Fluid entering the chamber is split at the channel inlet and converges at the channel outlet.

3. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 2, characterized in that, The inner cavity has an arc-shaped profile at the channel outlet.

4. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 2, characterized in that, The outer cavity has a rhombus-shaped outline; the inner cavity has an inverted triangle-shaped outline. The rhombus and the inverted triangle share a common vertex, forming a channel entrance, and the opposite side is the channel exit.

5. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 2, characterized in that, The inlet of the microchannel heat recovery reaction device is connected to the waste liquid collection tank and the reaction reagent, respectively. The outlet of the microchannel heat recovery reaction device is connected to a gas washing device for washing the gas generated during the heat recovery process, a concentration evaporation device for concentrating and evaporating the generated recovery liquid, and a cooling device for cooling the generated recovery liquid. The recovery liquid collection tank is connected to the cooling device.

6. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 4, characterized in that, The ratio of the lengths of the two diagonals of the rhombus is 1.8 to 2.2:1; the ratio of the cross-sectional length of the inner cavity near the channel outlet to the length of the shorter diagonal of the rhombus is 1.8 to 2.2:

1.

7. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 4, characterized in that, The ratio of the width of the channel exit to the length of the straight line of the base of the inverted triangle is 1.8 to 2.2:

1.

8. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 1, characterized in that, In step (3), the calcination temperature is 660~760℃ and the time is 20~50min.

9. The method for treating hydrogen peroxide in electronic waste liquid using hydrogen peroxide removal agent according to claim 1, characterized in that, In step (1), the amount of titanium oxysulfate solid powder added is 600~1200g / L H2SO4.

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