A method for reducing the amount of brown solution waste liquid

Abstract

The present application relates to a kind of brown waste liquid reduction processing method, comprising the following steps: (1) removing hydrogen peroxide stabilizer;(2) decomposing hydrogen peroxide;(3) low-temperature evaporation concentration;(4) concentrated liquid solidification;(5) concentrated liquid directly makes price outsourcing disposal.The brown waste liquid reduction processing method provided by the present application can quickly, efficiently and safely treat the COD non-degradable brown waste liquid, has fewer processing steps, lower cost, less equipment investment, strong adaptability, especially suitable for small-scale treatment, and has high market potential.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste liquid treatment technology, and specifically relates to a method for reducing the volume of browning waste liquid. Background Technology

[0002] In the printed circuit board industry, browning treatment technology is used to prevent the inner copper surface of the inner circuit board from being oxidized and to enhance the bonding force between boards during the lamination process. This technology is used to improve the stability of the inner layer board. However, if the copper ion content in the browning solution exceeds the standard, it will lead to process failure and generate waste browning solution.

[0003] Browning wastewater is a brownish-green acidic wastewater with a pH value between 0.5 and 0.8. Because it is discharged before the original browning solution has completely lost its film-forming ability during the copper etching process, it not only possesses the properties of the original browning solution but is also a wastewater with high copper content and high concentrations of harmful organic matter, including large amounts of triazole, pyridine, and other compounds. The COD value in this wastewater can reach over 10,000 mg / L. It also retains the unique film-forming ability of the original browning solution, forming films on copper surfaces, semi-cured substrates, other metals, and membrane surfaces. Browning wastewater contains large amounts of harmful substances such as triazole, copper ions, and pyrrole. If treatment fails to meet discharge requirements, it will pose a significant threat to the ecological environment and human health.

[0004] In existing technologies, the treatment of browning wastewater mainly involves recovering copper from the browning waste liquid and meeting discharge requirements through certain treatment techniques. Browning waste liquid treatment technologies have evolved from simple chemical-biological combined treatment, vacuum distillation treatment, and electrolytic deposition methods.

[0005] Because browning waste liquid has strong film-forming ability, strong complexing ability, and is stable under strong acid and weak oxidant (hydrogen peroxide) conditions and is not easily oxidized and degraded, it has some problems with existing treatment methods, including: (1) Chemical precipitation requires stronger chelating agents to extract copper ions, and current methods have failed to effectively precipitate copper; (2) Due to the high content of inorganic salts such as copper sulfate in the waste browning liquid, it is not conducive to the growth and reproduction of microorganisms, so biological degradation is not suitable; (3) During the simple electrolysis of browning waste liquid, a brownish-black film is easily formed on the cathode surface, which increases the overpotential for copper precipitation, resulting in very low current efficiency and difficulty in precipitating copper at the cathode; (4) Evaporation and concentration technology can effectively reduce the amount of browning liquid, but due to the high hydrogen peroxide content, the hydrogen peroxide concentration increases during the evaporation process, and there is an explosion risk during the evaporation and transportation processes. In the "2015 Hazardous Chemicals List", hydrogen peroxide with >8% is classified as a hazardous chemical, while hydrogen peroxide with an effective hydrogen peroxide content of less than 8% can be transported as ordinary cargo. Therefore, hydrogen peroxide needs to be treated.

[0006] CN201611143447.X discloses a treatment process for browning waste liquid. Its purpose is to provide a method for recovering copper from browning waste liquid through organic matter degradation, hydrogen peroxide decomposition, and electrolytic copper extraction. This method can efficiently degrade organic matter in metal waste liquid, is simple to operate, and allows for waste liquid recycling, thus possessing good application value. The technical solution is as follows: 1) The brown waste liquid is placed in a digestion container to degrade organic matter, resulting in a first solution. The method for degrading organic matter is a Fenton-like oxidation method to obtain hydroxyl radicals to degrade COD. The degradation reaction time is 24-48 hours, and the reaction temperature is 50-60℃. The digestion container is sealed and has thermal insulation properties. The digestion container includes a cooling water device and a leak-proof device; 2) The first solution is filtered to obtain a second solution; 3) The first solution is pumped to an oxygen-degrading tank to deoxygenate and decompose hydrogen peroxide, resulting in a third solution. The oxygen-degrading time is 12-24 hours; 4) The third solution is pumped to a cyclone electrolytic cell for copper extraction to obtain a fourth solution; 5) The fourth solution is discharged into a comprehensive wastewater tank. Its shortcomings are: 1) The reaction time for degrading organic matter is long, heating is required, and energy consumption is high. It is not suitable for enterprises with large processing capacity and limited space. Moreover, most of the COD in the browning solution is difficult to degrade. They will be firmly bound to copper. Even if electrolysis is possible, the energy consumption of electrolysis is very large. Degrading COD in browning solution has always been a problem in the industry; 2) The oxygen decomposition time is long, and there are requirements for site space and processing capacity; 3) The copper ion concentration after treatment is still about 2g / L. It is firmly bound to the difficult-to-degrade organic chelating agent. Discharging into the comprehensive wastewater pond will increase the difficulty of wastewater treatment. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for reducing the volume of browning waste liquid. This method is highly adaptable, has fewer processing steps, lower cost, and requires less equipment investment. It is especially suitable for treating small volumes of difficult-to-treat browning waste liquid and has high market potential.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a method for reducing the volume of browning wastewater, characterized by comprising the following steps:

[0009] (1) Removal of hydrogen peroxide stabilizer: Pump the browning waste liquid into an activated carbon adsorption column for filtration;

[0010] (2) Decompose hydrogen peroxide: The brown waste liquid that has passed through the activated carbon adsorption column is pumped into the mixing tank, hydrogen peroxide decomposing agent is added, and the mixture is stirred at room temperature until the hydrogen peroxide concentration is <1g / L.

[0011] (3) Low-temperature evaporation and concentration: After adding defoamer to the brown waste liquid treated in step (2), it is evaporated and concentrated under vacuum to form a concentrated liquid;

[0012] (4) Concentrate curing: When the copper content in the concentrate produced in step (3) is ≤40g / L, the concentrate is cured using a curing agent;

[0013] (5) Direct pricing and outsourcing of concentrated solution: When the copper content in the concentrated solution produced in step (3) is >40g / L, it is directly priced and outsourced.

[0014] Preferably, the activated carbon adsorption column in step (1) has three adsorption columns, each with a different carbon powder pore size. The carbon powder in the three adsorption columns is arranged from top to bottom as small-pore carbon powder, medium-pore carbon powder, and large-pore carbon powder, and the height ratio of the adsorption layers formed by the three carbon powders is 1:1:1. The small-pore carbon powder has a diameter of <2nm, the medium-pore carbon powder has a diameter of 2-100nm, and the large-pore carbon powder has a diameter of 100-10000nm. The carbon powder is coconut shell activated carbon.

[0015] Preferably, the removal of hydrogen peroxide stabilizer in step (1) further includes:

[0016] (1.1) The activated carbon adsorption column is backwashed using a backwashing device so that fine particles in each layer of activated carbon are placed on the upper layer and coarse particles are placed on the bottom layer.

[0017] (1.2) After removing all the water from the activated carbon adsorption column, turn off the backwashing device, open the injection valve, and use a pump to pump the browning waste liquid from the upper layer of the activated carbon adsorption column at a speed of 50-150L / h, and the lower layer flows out. The filtered browning waste liquid enters the stirring tank.

[0018] (1.3) When the COD reduction in the browning waste liquid is within 1-5%, replace it with new coconut shell activated carbon, and then repeat steps (1.1) and (1.2) in sequence.

[0019] As a preferred embodiment: the hydrogen peroxide decomposing agent in step (2) is composed of 1-2 parts by weight of MnO2, 3-5 parts by weight of FeSO4, and 4-6 parts by weight of CaO; the amount of the decomposing agent added is 0.1-2.5 times the mass of hydrogen peroxide in the browning waste liquid, the particle size of the hydrogen peroxide decomposing agent is <45 micrometers, and the reaction time is 1-2 hours.

[0020] As a preferred embodiment, the hydrogen peroxide decomposing agent in step (2) is composed of 1.5 to 2 parts by weight of MnO2, 4 to 4.5 parts by weight of FeSO4, and 4 to 5 parts by weight of CaO.

[0021] Preferably, the decomposition of hydrogen peroxide in step (2) further includes:

[0022] (2.1) Component analysis: The concentrations of hydrogen peroxide, copper and COD in the browning waste liquid before and after passing through the activated adsorption column are analyzed and detected. The degree of hydrogen peroxide decomposition is determined based on the COD concentration, and an appropriate amount of hydrogen peroxide decomposition agent is selected.

[0023] (2.2) Decomposition reaction: using 1-3m 3 The mixing tank is stirred, and hydrogen peroxide decomposing agent is added at 0.1 to 2.5 times the mass of hydrogen peroxide under slow stirring. The reaction time is 1 to 2 hours at room temperature until the hydrogen peroxide concentration is <1g / L.

[0024] Preferably, the defoamer in step (3) is an alcohol-based defoamer, and the dosage is 0.5–2 kg / m³. 3 The vacuum pressure is -0.092MPa to -0.099MPa, the evaporation temperature is 35℃ to 39℃, and the volumetric evaporation concentration ratio is 4 to 8 times.

[0025] Preferably, the low-temperature evaporation concentration in step (3) further includes:

[0026] (3.1) The dosage is 0.5~2kg / m 3 Add an alcohol-based defoamer to the browning waste liquid after hydrogen peroxide decomposition and stir well;

[0027] (3.2) By using a circulating pump and a vacuum pump, a negative pressure is created inside the evaporator, which automatically sends the browning waste liquid into the low-temperature evaporation equipment;

[0028] (3.3) Control the vacuum pressure to -0.092MPa to -0.099MPa so that the browning waste liquid is evaporated and concentrated at 35 to 39℃;

[0029] (3.4) Control the volume evaporation concentration ratio to 4 to 8 times so that the COD, copper and other pollutant indicators in the condensate formed by the evaporation of water vapor are lower than the comprehensive wastewater indicators, so that the concentrate is close to saturation but does not crystallize out.

[0030] Preferably, the curing agent in step (4) is solidified dry sludge produced by adding lime in other wastewater treatment processes in the plant, and the mass ratio of the solidified dry sludge to the concentrate is 0.5:1 to 3:1, and the copper content in the solidified dry sludge is 2% to 3%.

[0031] Preferably, the solidification of the concentrate in step (4) further includes:

[0032] (4.1) Analyze the copper content in the concentrate produced in step (3). When the copper content is ≤40g / L, use a solidification method for treatment.

[0033] (4.2) Use solidified dry mud produced by adding lime in other wastewater treatment processes in the plant, with a copper content of 2% to 3%, and grind the dry mud to a particle size of <150μm using a ball mill;

[0034] (4.3) Add solidified dry mud at a mass ratio of 0.5:1 to 3:1 of solidified dry mud to concentrated liquid. Add the concentrated liquid and the ball-milled solidified dry mud to the concentrated liquid solidifier in sequence. After thorough mixing in the concentrated liquid solidifier, powdered granular dry mud is obtained.

[0035] (4.4) The solidified sludge can be outsourced for treatment.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) The method for reducing the volume of browning waste liquid provided by the present invention can quickly, efficiently and safely treat COD-recalcitrant browning waste liquid. The treatment process has fewer steps, lower treatment costs, less equipment investment, and strong adaptability. It is especially suitable for batch treatment of small amounts of browning liquid and has high market potential.

[0038] (2) This invention does not require large-scale COD degradation. It only requires removing a small amount of hydrogen peroxide stabilizer from the browning waste liquid to disrupt the stability of the hydrogen peroxide, and then decomposing the hydrogen peroxide. Therefore, it can solve the problem of difficult-to-treat browning waste liquid, especially the treatment of browning waste liquid with difficult COD degradation.

[0039] (3) Achieve volume reduction treatment of browning waste liquid. The volume of browning waste liquid can be reduced by 75-87.5%. The treatment of browning waste liquid has been changed from high-priced outsourcing (>2000 yuan / ton) to priced outsourcing. Excluding the revenue, the treatment cost of one ton of waste liquid is <300 yuan / ton, saving enterprises at least 1700 yuan / ton, thereby saving enterprises the amount of outsourcing treatment and treatment costs.

[0040] (4) Hydrogen peroxide can exist in browning liquid containing a large amount of copper ions mainly because hydrogen peroxide stabilizers are added. The stabilizing principle is that the stabilizers can form chelates with copper ions, thereby reducing or eliminating the decomposition of copper ions by hydrogen peroxide. Therefore, one of the keys to decomposing hydrogen peroxide is to remove the hydrogen peroxide stabilizers. The main components of hydrogen peroxide stabilizers are benzenesulfonic acid, ethylenediaminetetraacetic acid, mercaptoacetic acid, sodium silicate, etc. Some organic stabilizers can be removed by activated carbon adsorption. Therefore, this invention first utilizes activated carbon adsorption to remove this part of the organic stabilizers, thereby disrupting the stability of hydrogen peroxide in browning waste liquid and making it more conducive to the subsequent decomposition of hydrogen peroxide. Attached Figure Description

[0041] Figure 1 This is a process flow diagram of a method for reducing the volume of browning waste liquid according to the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings:

[0043] Please see Figure 1 As shown, the method for reducing the volume of browning wastewater provided by the present invention includes the following steps:

[0044] (1) Removal of hydrogen peroxide stabilizer: Pump the browning waste liquid into an activated carbon adsorption column for filtration;

[0045] (2) Decompose hydrogen peroxide: The brown waste liquid that has passed through the activated carbon adsorption column is pumped into the mixing tank, hydrogen peroxide decomposing agent is added, and the mixture is stirred at room temperature until the hydrogen peroxide concentration is <1g / L.

[0046] (3) Low-temperature evaporation and concentration: After adding defoamer to the brown waste liquid treated in step (2), it is evaporated and concentrated under vacuum to form a concentrated liquid;

[0047] (4) Concentrate curing: When the copper content in the concentrate produced in step (3) is ≤40g / L, the concentrate is cured using a curing agent;

[0048] (5) Direct pricing and outsourcing of concentrated solution: When the copper content in the concentrated solution produced in step (3) is >40g / L, it is directly priced and outsourced.

[0049] Preferably, the activated carbon adsorption column in step (1) has three adsorption columns, each with a different carbon powder pore size. The carbon powder in the three adsorption columns is arranged from top to bottom as small-pore carbon powder, medium-pore carbon powder, and large-pore carbon powder, and the height ratio of the adsorption layers formed by the three carbon powders is 1:1:1. The small-pore carbon powder has a diameter of <2nm, the medium-pore carbon powder has a diameter of 2-100nm, and the large-pore carbon powder has a diameter of 100-10000nm. The carbon powder is coconut shell activated carbon.

[0050] Preferably, the removal of hydrogen peroxide stabilizer in step (1) further includes:

[0051] (1.1) The activated carbon adsorption column is backwashed using a backwashing device so that fine particles in each layer of activated carbon are placed on the upper layer and coarse particles are placed on the bottom layer.

[0052] (1.2) After removing all the water from the activated carbon adsorption column, turn off the backwashing device, open the injection valve, and use a pump to pump the browning waste liquid from the upper layer of the activated carbon adsorption column at a speed of 50-150L / h, and the lower layer flows out. The filtered browning waste liquid enters the stirring tank.

[0053] (1.3) When the COD reduction in the browning waste liquid is within 1-5%, replace it with new coconut shell activated carbon, and then repeat steps (1.1) and (1.2) in sequence.

[0054] As a preferred embodiment: the hydrogen peroxide decomposing agent in step (2) is composed of 1-2 parts by weight of MnO2, 3-5 parts by weight of FeSO4, and 4-6 parts by weight of CaO; the amount of the decomposing agent added is 0.1-2.5 times the mass of hydrogen peroxide in the browning waste liquid, the particle size of the hydrogen peroxide decomposing agent is <45 micrometers, and the reaction time is 1-2 hours.

[0055] As a preferred embodiment, the hydrogen peroxide decomposing agent in step (2) is composed of 1.5 to 2 parts by weight of MnO2, 4 to 4.5 parts by weight of FeSO4, and 4 to 5 parts by weight of CaO.

[0056] Preferably, the decomposition of hydrogen peroxide in step (2) further includes:

[0057] (2.1) Component analysis: The concentrations of hydrogen peroxide, copper and COD in the browning waste liquid before and after passing through the activated adsorption column are analyzed and detected. The degree of hydrogen peroxide decomposition is determined based on the COD concentration, and an appropriate amount of hydrogen peroxide decomposition agent is selected.

[0058] (2.2) Decomposition reaction: using 1-3m 3 The mixing tank is stirred, and hydrogen peroxide decomposing agent is added at 0.1 to 2.5 times the mass of hydrogen peroxide under slow stirring. The reaction time is 1 to 2 hours at room temperature until the hydrogen peroxide concentration is <1g / L.

[0059] Preferably, the defoamer in step (3) is an alcohol-based defoamer, and the dosage is 0.5–2 kg / m³. 3 The vacuum pressure is -0.092MPa to -0.099MPa, the evaporation temperature is 35℃ to 39℃, and the volumetric evaporation concentration ratio is 4 to 8 times.

[0060] Preferably, the low-temperature evaporation concentration in step (3) further includes:

[0061] (3.1) The dosage is 0.5~2kg / m 3 Add an alcohol-based defoamer to the browning waste liquid after hydrogen peroxide decomposition and stir well;

[0062] (3.2) By using a circulating pump and a vacuum pump, a negative pressure is created inside the evaporator, which automatically sends the browning waste liquid into the low-temperature evaporation equipment;

[0063] (3.3) Control the vacuum pressure to -0.092MPa to -0.099MPa so that the browning waste liquid is evaporated and concentrated at 35 to 39℃;

[0064] (3.4) Control the volume evaporation concentration ratio to 4 to 8 times so that the COD, copper and other pollutant indicators in the condensate formed by the evaporation of water vapor are lower than the comprehensive wastewater indicators, so that the concentrate is close to saturation but does not crystallize out.

[0065] Preferably, the curing agent in step (4) is solidified dry sludge produced by adding lime in other wastewater treatment processes in the plant, and the mass ratio of the solidified dry sludge to the concentrate is 0.5:1 to 3:1, and the copper content in the solidified dry sludge is 2% to 3%.

[0066] Preferably, the solidification of the concentrate in step (4) further includes:

[0067] (4.1) Analyze the copper content in the concentrate produced in step (3). When the copper content is ≤40g / L, use a solidification method for treatment.

[0068] (4.2) Use solidified dry mud produced by adding lime during the wastewater treatment process in the plant, with a copper content of 2% to 3%, and use a ball mill to grind the dry mud to a particle size of <150μm;

[0069] (4.3) Add solidified dry mud at a mass ratio of 0.5:1 to 3:1 of solidified dry mud to concentrated liquid. Add the concentrated liquid and the ball-milled solidified dry mud to the concentrated liquid solidifier in sequence. After thorough mixing in the concentrated liquid solidifier, powdered granular dry mud is obtained.

[0070] (4.4) The solidified sludge can be outsourced for treatment.

[0071] The present invention will be further described in detail below with reference to embodiments:

[0072] Example 1: A method for treating browning wastewater.

[0073] Composition of browning waste liquid: Cu: 20.3 g / L, H2O2: 23.1 g / L, COD: 26640 mg / L, pH: 0.7.

[0074] Brown leaching wastewater treatment capacity: 1m³ 3 / d.

[0075] Includes the following steps:

[0076] (1) Removal of hydrogen peroxide stabilizer: The browning waste liquid is pumped from top to bottom into an activated carbon adsorption column containing carbon powder of different pore sizes at a speed of 100L / h, and then enters a stirring tank; the activated carbon adsorption column has three layers of adsorption columns, each of which has a different carbon powder pore size. The carbon powder in the three layers of adsorption columns is, from top to bottom, small pore carbon powder, medium pore carbon powder and large pore carbon powder, and the height ratio of the adsorption column layers is 1:1:1; the small pore carbon powder has a diameter of <2nm, the medium pore carbon powder has a diameter of 2-100nm, and the large pore carbon powder has a diameter of 100-10000nm; the carbon powder is coconut shell activated carbon;

[0077] (2) Decomposition of hydrogen peroxide: The composition of the browning waste liquid after adsorption column analysis was found to be 23.00 g / L hydrogen peroxide, 19.35 g / L copper, and 24001 mg / L COD. When COD ≥ 20000 mg / L, the amount of hydrogen peroxide decomposing agent added should be 0.5–2.5 times the mass concentration of hydrogen peroxide; when COD < 20000 mg / L, the amount of hydrogen peroxide decomposing agent added should be 0.1–0.5 times the mass concentration of hydrogen peroxide. The copper and COD contents in this browning liquid are very high, and hydrogen peroxide is difficult to degrade; therefore, the amount of hydrogen peroxide decomposing agent added should be 0.5–2.5 times the amount of hydrogen peroxide. The browning waste liquid was pumped into a mixing tank, and hydrogen peroxide decomposing agent was added. The amount of decomposing agent added was 15g / L, which was composed of 1.5 parts MnO2, 4.5 parts FeSO4, and 4 parts CaO with a particle size of <45 micrometers. The mixture was stirred at room temperature for 1-2 hours until the hydrogen peroxide concentration dropped to 0.5g / L.

[0078] (3) Low-temperature evaporation and concentration: The browning waste liquid treated in step (2) is concentrated at a rate of 1 kg / m³. 3 An alcohol-based defoamer was added and stirred evenly. The mixture was then evaporated and concentrated under a vacuum pressure of -0.092 MPa to -0.099 MPa and an evaporation temperature of 35°C to 39°C. The concentrate was discharged after being concentrated to near saturation in the evaporation equipment. The concentration volume ratio was 6.

[0079] (4) The copper content in the concentrate was 76 g / L, which is >40 g / L. It was directly priced and outsourced for disposal.

[0080] Example 2: A method for treating browning wastewater.

[0081] Composition of browning waste liquid: Cu: 7.6 g / L, H2O2: 8 g / L, COD: 17560 mg / L, pH: 0.6.

[0082] Brown leaching wastewater treatment capacity: 1m³ 3 / d.

[0083] Example 2 is basically the same as Example 1, except that the amount of decomposition agent added is different and the concentrated liquid after evaporation is solidified.

[0084] Includes the following steps:

[0085] (1) Removal of hydrogen peroxide stabilizer: The browning waste liquid is pumped from top to bottom into an activated carbon adsorption column with different pore sizes at a speed of 100L / h, and then enters a stirring tank; the activated carbon adsorption column has three layers of adsorption columns, each layer of adsorption column has a different carbon powder pore size, and the carbon powder in the three layers of adsorption columns is, from top to bottom, small pore carbon powder, medium pore carbon powder and large pore carbon powder, with an adsorption layer height ratio of 1:1:1; the small pore carbon powder has a diameter of <2nm, the medium pore carbon powder has a diameter of 2-100nm, and the large pore carbon powder has a diameter of 100-10000nm; the carbon powder is coconut shell activated carbon.

[0086] (2) Decomposition of hydrogen peroxide: The composition of the browning waste liquid after adsorption column analysis was found to be 7.92 g / L hydrogen peroxide, 7.34 g / L copper, and 15452.8 mg / L COD. When COD ≥ 20000 mg / L, the amount of hydrogen peroxide decomposing agent added should be 0.5–2.5 times the mass concentration of hydrogen peroxide; when COD < 20000 mg / L, the amount of hydrogen peroxide decomposing agent added should be 0.1–0.5 times the mass concentration of hydrogen peroxide. The copper and COD content in this browning liquid is relatively low, making hydrogen peroxide relatively easy to decompose; therefore, the amount of hydrogen peroxide decomposing agent added should be 0.1–0.5 times the amount of hydrogen peroxide. The browning waste liquid was pumped into a mixing tank, and a decomposing agent was added. The amount of the decomposing agent added was 3g / L, which consisted of 1.5 parts MnO2, 4.5 parts FeSO4, and 4 parts CaO with a particle size of <45 micrometers. The mixture was stirred at room temperature for 1-2 hours until the hydrogen peroxide concentration dropped to 0.5g / L.

[0087] (3) Low-temperature evaporation and concentration: The browning waste liquid treated in step (2) is concentrated at a rate of 1 kg / m³. 3 Add alcohol-based defoamer, stir evenly, and then evaporate and concentrate under vacuum pressure of -0.092MPa to -0.099MPa and evaporation temperature of 35℃ to 39℃. After evaporating to near crystallization in the evaporation equipment, the concentrate is discharged. The concentration volume ratio is 5.

[0088] (4) The copper content in the concentrate was 38 g / L, <40 g / L, and solidification was adopted. Solidified dry sludge produced by adding lime during the wastewater treatment process in the plant was used, with a copper content of 2%–3%. The dry sludge was ground to a particle size <150 μm using a ball mill. Dry sludge was added at a mass ratio of 2:1 to the concentrate. The concentrate and the ball-milled dry sludge were then added to a concentrate solidification machine and thoroughly mixed to obtain powdered dry sludge. The solidified sludge can be outsourced for further treatment.

[0089] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A method for reducing the volume of browning wastewater, characterized in that, Includes the following steps: (1) Removal of hydrogen peroxide stabilizer: Pump the browning waste liquid into an activated carbon adsorption column for filtration; (2) Decomposing hydrogen peroxide: The brown waste liquid that has passed through the activated carbon adsorption column is pumped into a mixing tank, hydrogen peroxide decomposing agent is added, and the mixture is stirred at room temperature until the hydrogen peroxide concentration is <1g / L. The hydrogen peroxide decomposing agent is composed of 1-2 parts by weight of MnO2, 3-5 parts by weight of FeSO4, and 4-6 parts by weight of CaO; the amount of hydrogen peroxide decomposing agent added is 0.1-2.5 times the mass of hydrogen peroxide in the browning waste liquid; the particle size of the hydrogen peroxide decomposing agent is <45 micrometers; and the reaction time is 1-2 hours. (3) Low-temperature evaporation and concentration: After adding defoamer to the brown waste liquid treated in step (2), it is evaporated and concentrated at low temperature under vacuum to form a concentrated liquid; (4) Concentrate curing: When the copper content in the concentrate produced in step (3) is ≤40g / L, the concentrate is cured using a curing agent; (5) Direct pricing and outsourcing of concentrated solution: When the copper content in the concentrated solution produced in step (3) is >40g / L, it is directly priced and outsourced.

2. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, The activated carbon adsorption column in step (1) has three adsorption columns, each with a different carbon powder pore size. The carbon powder in the three adsorption columns, from top to bottom, consists of small-pore carbon powder, medium-pore carbon powder, and large-pore carbon powder. The height ratio of the adsorption layers formed by the three carbon powder layers is 1:1:

1. The small-pore carbon powder has a diameter of <2nm, the medium-pore carbon powder has a diameter of 2-100nm, and the large-pore carbon powder has a diameter of 100-10000nm. The carbon powder is coconut shell activated carbon.

3. The method for reducing the volume of browning wastewater according to claim 2, characterized in that, The removal of hydrogen peroxide stabilizer in step (1) further includes: (1.1) The activated carbon adsorption column is backwashed using a backwashing device so that fine particles in each layer of activated carbon are placed on the upper layer and coarse particles are placed on the bottom layer. (1.2) After removing all the water from the activated carbon adsorption column, turn off the backwashing device, open the injection valve, and use a pump to pump the browning waste liquid from the upper layer of the activated carbon adsorption column at a speed of 50-150 L / h, and let the lower layer flow out. The filtered browning waste liquid enters the stirring tank. (1.3) When the COD reduction in the browning waste liquid is within 1 to 5%, replace it with new coconut shell activated carbon, and then repeat steps (1.1) and (1.2) in sequence.

4. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, The hydrogen peroxide decomposing agent mentioned in step (2) is composed of 1.5 to 2 parts by weight of MnO2, 4 to 4.5 parts by weight of FeSO4, and 4 to 5 parts by weight of CaO.

5. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, Step (2) further includes the following steps: (2.1) Component analysis: The concentrations of hydrogen peroxide, copper and COD in the browning waste liquid before and after passing through the activated adsorption column are analyzed and detected. The degree of hydrogen peroxide decomposition is determined based on the COD concentration, and an appropriate amount of hydrogen peroxide decomposition agent is selected. (2.2) Decomposition reaction: using 1-3 m 3 The mixing tank is stirred, and hydrogen peroxide decomposing agent is added at 0.1 to 2.5 times the mass of hydrogen peroxide under slow stirring. The reaction time is 1 to 2 hours at room temperature until the hydrogen peroxide concentration is <1g / L.

6. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, The defoamer mentioned in step (3) is an alcohol-based defoamer, and the dosage is 0.5–2 kg / m³. 3 The vacuum pressure is -0.092MPa to -0.099MPa, the evaporation temperature is 35℃ to 39℃, and the volumetric evaporation concentration ratio is 4 to 8 times.

7. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, Step (3) of the low-temperature evaporation and concentration further includes: (3.1) The dosage is 0.5~2kg / m 3 Add an alcohol-based defoamer to the browning waste liquid after hydrogen peroxide decomposition and stir well; (3.2) By using a circulating pump and a vacuum pump, a negative pressure is created inside the evaporator, which automatically sends the browning waste liquid into the low-temperature evaporation equipment; (3.3) Control the vacuum pressure to -0.092MPa to -0.099MPa so that the browning waste liquid is evaporated and concentrated at 35 to 39℃; (3.4) The volumetric evaporation concentration ratio is controlled to be 4 to 8 times. The pollutant indicators in the condensate, including COD and copper, are lower than the comprehensive wastewater indicators, so that the concentrate is close to saturation but does not crystallize out.

8. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, The curing agent mentioned in step (4) is solidified dry sludge produced by adding lime in other wastewater treatment processes in the plant. The mass ratio of the solidified dry sludge to the concentrate is 0.5:1 to 3:1, and the copper content in the solidified dry sludge is 2% to 3%.

9. The method for reducing the volume of browning wastewater according to claim 1, characterized in that, The solidification of the concentrate in step (4) further includes: (4.1) Analyze the copper content in the concentrate produced in step (3). When the copper content is ≤40g / L, use a solidification method for treatment. (4.2) Use solidified dry mud produced by adding lime in other wastewater treatment processes in the plant, with a copper content of 2% to 3%, and grind the dry mud to a particle size of <150μm using a ball mill; (4.3) Add solidified dry mud at a mass ratio of 0.5:1 to 3:1 of solidified dry mud to concentrated liquid. Add the concentrated liquid and the ball-milled solidified dry mud to the concentrated liquid solidifier in sequence. After thorough mixing in the concentrated liquid solidifier, powdered granular dry mud is obtained. (4.4) The solidified sludge is outsourced for treatment at a price.

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