Resource utilization device for high-concentration nitric acid waste liquid

Abstract

The utility model relates to a high-concentration nitric acid waste liquid resource utilization device, and belongs to the field of industrial water treatment. The high-concentration nitric acid waste liquid in the high-concentration nitric acid waste liquid storage tank is pumped into the nitric acid vacuum concentration device by a pump; waste water discharged by the nitric acid vacuum concentration device automatically flows into the middle water tank; the high-concentration nitric acid concentrated by the nitric acid vacuum concentration device automatically flows into a high-concentration nitric acid storage tank; wastewater discharged by the nitric acid vacuum concentration device automatically flows into the middle water tank; wastewater in the middle water tank is pumped out through a pump and flows into the electrically-driven membrane device through a pipeline, fresh water generated by the electrically-driven membrane device flows into the wastewater tank, and concentrated water generated by the electrically-driven membrane device flows into the dilute nitric acid tank. The high-concentration nitric acid waste liquid can be purified, nitric acid with the concentration of 98% or above can be obtained after the high-concentration nitric acid waste liquid is treated by the device, and the nitric acid concentration of discharged wastewater is reduced to 0.1% or below.

Description

Technical Field

[0001] The invention relates to a resource utilization device for high-concentration nitric acid waste liquid, in particular to a treatment device for recycling high-concentration nitric acid waste liquid by a physical and chemical method, and belongs to the field of industrial water treatment. Background Art

[0002] The current treatment method for high-concentration nitric acid waste liquid containing nitric acid mass concentration of 46-52% is as follows:

[0003] 1. Mixing + neutralization + evaporation crystallization. After the waste mother liquor is mixed with the washing water, a large amount of sodium hydroxide is added to make its pH 6-9, and then the evaporation crystallization method is used for treatment. The problem is that the crystallized material in the evaporator is sodium nitrate mixed with organic matter, which not only cannot be sold as a product, but is also defined as hazardous waste, greatly increasing the cost of treatment.

[0004] 2. Vacuum concentration treatment of high-concentration nitric acid waste liquid + sodium hydroxide neutralization. Vacuum concentration treatment of high-concentration nitric acid waste liquid can concentrate 46-52% nitric acid to 98%. The nitric acid waste water produced has an acidity of 0.5-5%. A large amount of sodium hydroxide is added to neutralize the nitric acid waste water and then discharged into the wastewater station for treatment. This method has a low nitric acid recovery rate and high treatment cost. Utility Model Content

[0005] The purpose of the present invention is a device for resource utilization of nitric acid waste liquid; the treated nitric acid can be effectively recovered and reused through the device.

[0006] The object of the present invention is achieved through the following technical problems.

[0007] A high-concentration nitric acid waste liquid resource utilization device comprises: a high-concentration nitric acid waste liquid storage tank, a nitric acid vacuum concentration device, an intermediate water tank, a high-concentration nitric acid storage tank, an electric drive membrane device, a nitric acid storage tank, a wastewater tank and a pump.

[0008] The high-concentration nitric acid waste liquid in the high-concentration nitric acid storage tank is pumped out and flows into the nitric acid vacuum concentration device through a pipeline, and the high-concentration nitric acid waste liquid is concentrated to more than 98% and flows into the high-concentration nitric acid storage tank through a pipeline. The external waste water (acidity 5-0.5%) flows into the middle water tank through a pipeline, and the waste water in the middle water tank is pumped out by a pump and flows into the electric drive membrane device through a pipeline. Under the action of an external direct current electric field, the selective permeability of the ion exchange membrane to the hydrogen ions and nitrate ions in the solution is utilized to cause ion migration of the hydrogen ions and nitrates in the solution, and the purpose of separation is achieved through anion and cation exchange membranes respectively, wherein the fresh water is the waste water (acidity ≤ 0.07%) that loses hydrogen ions and nitrate ions, and the concentrated water is dilute nitric acid (acidity 10-13%). The fresh water (less than 0.1%) produced by the electric drive membrane flows into the wastewater tank through a pipeline.

[0009] The invention can realize the purification of high-concentration nitric acid waste liquid. After the high-concentration nitric acid waste liquid is treated by the device, more than 98% of nitric acid can be obtained, and the nitric acid concentration of the discharged waste water is reduced to less than 0.1%.

[0010] Working process: The high-concentration nitric acid waste liquid in the high-concentration nitric acid storage tank is pumped into the nitric acid vacuum concentration device to separate and concentrate the nitric acid; the wastewater flows into the intermediate water tank by gravity and is pumped into the electric-driven membrane device. Under the action of the DC electric field, the nitrate ions in the wastewater migrate to the positive electrode. Since the ion exchange membrane has selective permeability, the nitrate ions in the fresh water chamber pass through the anion membrane into the concentrated water chamber, but the nitrate ions in the concentrated water chamber cannot pass through the cation membrane and remain in the concentrated water chamber. The hydrogen ions migrate to the negative electrode and enter the concentrated water chamber through the cation membrane. The hydrogen ions in the concentrated water chamber cannot pass through the anion membrane and remain in the concentrated water chamber. In this way, the concentration of nitrate ions and hydrogen ions in the concentrated water chamber increases continuously due to the continuous entry of these two ions; the concentration of the fresh water chamber decreases due to the continuous outward migration of these two ions. The result of ion migration is that the compartment between the two electrodes of the electric-driven membrane device is transformed into a concentrated chamber and a dilute chamber with different solution concentrations. The concentrated chamber is dilute nitric acid, and the dilute chamber is the wastewater after the dilute nitric acid is removed. It is necessary to ensure that the nitric acid content in the concentrated water is within the range of 9%-13%. If the requirement cannot be met, the number of cycles of dilute nitric acid can be increased; the concentrated water flows into the nitric acid storage tank, and the fresh water flows into the wastewater tank.

[0011] Beneficial Effects

[0012] 1. The high-concentration nitric acid waste liquid resource utilization device of the present invention can obtain 98% nitric acid and 10-13% dilute nitric acid after the waste acid and waste liquid are treated by the device.

[0013] 2. The device for resource utilization of high-concentration nitric acid waste liquid of the present invention can meet the requirements of the nitrate fume absorption device for absorption liquid. A large amount of nitric acid mist is generated during the product production process. The nitric acid mist is treated by the nitrate fume absorption device. During the treatment process, the nitric acid purified by the device can be used as the absorption liquid to increase the nitric acid concentration from 9%-13% to about 40%. The 40% nitric acid can be discharged into the high-concentration nitric acid storage tank, thereby realizing the resource utilization of high-concentration nitric acid waste liquid and reducing the cost of nitric acid waste liquid treatment.

[0014] 3. The high-concentration nitric acid waste liquid resource utilization device of the present invention can achieve that after 46-52% of the high-concentration nitric acid waste liquid is treated by the device, the acidity of the effluent is reduced to 0.07%, thereby reducing the neutralization cost and the difficulty of the subsequent treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the device of Example 1. DETAILED DESCRIPTION

[0016] The present invention will be further explained below in conjunction with the accompanying drawings and embodiments.

[0017] Example 1

[0018] A high-concentration nitric acid waste liquid resource utilization device comprises: a high-concentration nitric acid waste liquid storage tank, a nitric acid vacuum concentration device, an intermediate water tank, a high-concentration nitric acid storage tank, an electric drive membrane device, a nitric acid storage tank, a wastewater tank and a pump.

[0019] The high-concentration nitric acid waste liquid in the high-concentration nitric acid waste liquid storage tank is lifted by a pump and entered into the nitric acid vacuum concentrating device; the waste water discharged from the nitric acid vacuum concentrating device flows by gravity into the intermediate water tank; the high-concentration nitric acid concentrated by the nitric acid vacuum concentrating device flows by gravity into the high-concentration nitric acid storage tank; the waste water discharged from the nitric acid vacuum concentrating device flows by gravity into the intermediate water tank; the waste water in the intermediate water tank is pumped out by a pump and flows into the electric-driven membrane device through a pipeline, the electric-driven membrane device produces fresh water that flows into the wastewater tank, and the electric-driven membrane device produces concentrated water that flows into the dilute nitric acid tank.

[0020] Collect 46.2% high concentration nitric acid waste liquid.

[0021] Take 10L of high-concentration nitric acid waste liquid and pump it into the nitric acid vacuum concentration device. The concentration of nitric acid after concentration is more than 98%; the concentrated nitric acid flows into the high-concentration nitric acid storage tank by gravity; the discharged wastewater flows into the intermediate water tank by gravity and is pumped into the electric drive membrane device. 10L of pure water is used as the absorption liquid. Under the action of the DC electric field, the nitrate ions in the wastewater migrate to the positive electrode. Since the ion exchange membrane has selective permeability, the nitrate ions in the fresh water chamber pass through the anion membrane into the concentrated water chamber, but the nitrate ions in the concentrated water chamber cannot pass through the cation membrane and remain in the concentrated water chamber. The hydrogen ions migrate to the negative electrode and enter the concentrated water chamber through the cation membrane. The hydrogen ions in the concentrated water chamber cannot pass through the anion membrane and remain in the concentrated water chamber. In this way, the concentration of nitrate ions and hydrogen ions in the concentrated water chamber increases continuously due to the continuous entry of these two ions; the concentration of the fresh water chamber decreases due to the continuous outward migration of these two ions. The result of ion migration is that the compartment between the two electrodes of the electric drive membrane device becomes a concentrated chamber and a dilute chamber with different solution concentrations. The concentrated chamber is dilute nitric acid, and the dilute chamber is the wastewater after the dilute nitric acid is removed. It is necessary to ensure that the nitric acid content in the concentrated water is within the range of 9%-13%. If the requirement cannot be met, the number of cycles of dilute nitric acid can be increased; the concentrated water flows into the dilute nitric acid storage tank, and the fresh water flows into the wastewater tank.

[0022] The specific implementation data are as follows:

[0023]

[0024] Example 2

[0025] The mother liquor in the production process of p-nitrobenzoic acid is collected, and the mother liquor contains 49.5% nitric acid.

[0026] The specific implementation steps are:

[0027] ① Take 10L of p-nitrobenzoic acid mother liquor and pump it into the nitric acid vacuum concentration device;

[0028] ① Use a pump to pump out through the electric drive membrane device, and use 10L of pure water as the absorption liquid;

[0029] The specific implementation data are as follows:

[0030]

[0031] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-concentration nitric acid waste liquid resource utilization device, characterized in that: It includes a high-concentration nitric acid waste liquid storage tank, a nitric acid vacuum concentration device, an intermediate water tank, a high-concentration nitric acid storage tank, an electric-driven membrane device, a dilute nitric acid storage tank, a wastewater tank and a pump; The high-concentration nitric acid waste liquid in the high-concentration nitric acid waste liquid storage tank is pumped out by a pump and flows into the nitric acid vacuum concentration device through a pipeline. The high-concentration nitric acid waste liquid concentrated to more than 98% flows into the high-concentration nitric acid storage tank through a pipeline; the acidity of 0.5%-5% in the nitric acid vacuum concentration device is discharged through a pipeline and flows into the intermediate water tank, the wastewater in the intermediate water tank is pumped out by a pump and flows into the electric-driven membrane device through a pipeline, the generated wastewater with an acidity of ≤0.1% that loses hydrogen ions and nitrate ions flows into the wastewater tank through a pipeline, the wastewater in the wastewater tank is pumped out by a pump and flows into the biochemical treatment system through a pipeline, and is discharged in compliance with the standards after biochemical treatment.

2. A high-concentration nitric acid waste liquid resource utilization device as claimed in claim 1, characterized in that: The dilute nitric acid produced by the electric-driven membrane device flows into the dilute nitric acid storage tank through a pipeline, is pumped out by a pump and flows into the nitrate fume absorption system through a pipeline. The nitrate fume absorption device processes the nitric acid mist. During the processing, the dilute nitric acid purified by this device can be used as an absorption liquid to increase the nitric acid concentration from 10%-13% to 40%. The 40% nitric acid flows into the high-concentration nitric acid storage tank through a pipeline.

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