A purification apparatus for spent sulfuric acid regeneration and method of use thereof

Abstract

The present application relates to waste sulfuric acid regeneration technical field, disclose a kind of for waste sulfuric acid regeneration purification device and its use method, purification device includes osmotic cylinder and electrolytic cylinder;Osmotic cylinder is equipped with cation membrane, cation membrane separates osmotic cylinder into sulfuric acid chamber and hydrochloric acid chamber;Electrolytic cylinder is equipped with anion membrane, anion membrane separates electrolytic cylinder into positive chamber and negative chamber, positive chamber inserts and is connected with the positive pole of direct current power supply positive pole electric stick, negative chamber inserts and is connected with the negative pole of direct current power supply negative pole electric stick;Sulfuric acid chamber and negative chamber are used for adding the waste sulfuric acid solution to be purified containing ammonia nitrogen respectively, sulfuric acid chamber and negative chamber are connected by first circulation pipeline;Hydrochloric acid chamber and positive chamber are used for adding the hydrochloric acid solution providing chlorine source respectively, hydrochloric acid chamber and positive chamber are connected by second circulation pipeline.The ammonia nitrogen in waste sulfuric acid solution to be purified is NH4 + Ion is purified and regenerated, and can be recycled, to prevent the phenomenon of pipe blockage.

Description

Technical Field

[0001] This invention relates to the field of chemical waste treatment technology, and in particular to a purification device for the regeneration of waste sulfuric acid and its usage method. Background Technology

[0002] In the PCB manufacturing process, etching solution is used to etch the PCB board to obtain the required circuit pattern, and the copper metal in the etching solution is recovered by electrolytic etching waste liquid.

[0003] The steps for recovering copper from alkaline etching waste liquid include: 1) selectively extracting copper ions from alkaline etching waste liquid using an organic phase extractant; 2) obtaining a high-concentration copper sulfate solution through sulfuric acid back-extraction; and 3) generating electrolytic copper and regenerating the sulfuric acid solution by electrolyzing the copper sulfate solution.

[0004] To improve environmental benefits and reduce the discharge of sulfuric acid solution, the sulfuric acid used in the above steps needs to be recycled.

[0005] Ammonia nitrogen in the recycled sulfuric acid solution will continuously accumulate. When the ammonia nitrogen in the sulfuric acid solution reaches a certain concentration, it will crystallize, causing blockage in the pipes of the alkaline etching solution copper recovery system.

[0006] Cleaning clogged pipes not only affects the efficiency of copper recovery from alkaline etching solutions, but also incurs high cleaning costs. Summary of the Invention

[0007] To address the aforementioned shortcomings, the primary objective of this invention is to provide a purification device to solve the problems of ammonia nitrogen accumulation in waste sulfuric acid and ammonia nitrogen crystallization in waste sulfuric acid clogging pipes.

[0008] The second objective of this invention is to obtain a method for regenerating waste sulfuric acid using the above-mentioned purification device, so as to simplify the process of waste sulfuric acid regeneration.

[0009] To achieve this objective, the present invention adopts the following technical solution: A purification device for regenerating waste sulfuric acid includes a permeation tank and an electrolysis tank; The permeation tank is equipped with a cation exchange membrane, which divides the permeation tank into a sulfuric acid chamber and a hydrochloric acid chamber. The electrolysis cylinder is equipped with an anion exchange membrane, which divides the electrolysis cylinder into a positive electrode chamber and a negative electrode chamber. The positive electrode chamber is fitted with a positive electrode rod connected to the positive terminal of a DC power supply, and the negative electrode chamber is fitted with a negative electrode rod connected to the negative terminal of a DC power supply. The sulfuric acid chamber and the negative electrode chamber are respectively used to add waste sulfuric acid solution containing ammonia nitrogen to be purified, and the sulfuric acid chamber and the negative electrode chamber are connected through a first circulation pipeline; The hydrochloric acid chamber and the positive electrode chamber are respectively used to add hydrochloric acid solution that provides a chlorine source, and the hydrochloric acid chamber and the positive electrode chamber are connected by a second circulation pipeline.

[0010] Furthermore, this invention proposes a method for regenerating waste sulfuric acid, using the purification device described above, comprising the following steps: S1) Inject appropriate amounts of hydrochloric acid solution into the hydrochloric acid chamber of the permeation tank and the positive electrode chamber of the electrolysis tank of the purification device, respectively; S2) Inject appropriate amounts of waste sulfuric acid solution to be purified into the sulfuric acid chamber of the permeation tank and the negative electrode chamber of the electrolysis tank of the purification device, respectively. S3) Turn on the DC power supply to put the electrolysis cylinder into a powered working state; S4) Start the circulation pumps in the first and second circulation pipelines respectively; S5) Detection of NH4 in the sulfuric acid solution in the sulfuric acid chamber or negative electrode chamber. + Ion concentration, when NH4 + When the ion concentration drops to the preset value, the DC power supply is turned off, and the circulation pumps in the first and second circulation pipelines are also turned off. The purification of the waste sulfuric acid solution in the sulfuric acid chamber and the negative electrode chamber is completed, and a regenerated sulfuric acid solution is obtained.

[0011] Preferably, in step S1), the H+ of the hydrochloric acid solution... + ions or Cl - The concentration of ions is 4.5-5.0 mol / L.

[0012] Preferably, in step S2), the H of the waste sulfuric acid solution to be purified + The ion concentration is 3.0-3.5 mol / L, NH4+ + The ion concentration is 1.5-2.0 mol / L.

[0013] Preferably, in step S3), the current density of the electrolysis cylinder is 60-100 mA / cm². 2 .

[0014] Preferably, in step S5), NH4 + The preset value for ion concentration is 0.8 mol / L.

[0015] The beneficial effects of the technical solution of the present invention are as follows: The purification device of the present invention can convert the waste sulfuric acid solution to be purified into NH4. + The ammonia nitrogen in the ions is purified, and a regenerated sulfuric acid solution is obtained for recycling in the production of copper recovery from the etching solution. This prevents the ammonia nitrogen in the recycled sulfuric acid from crystallizing due to excessive concentration and clogging the pipes.

[0016] Furthermore, the present invention proposes a method for regenerating waste sulfuric acid, which, using the purification device described above, through the cooperation of a permeation tank and an electrolysis tank, can separate and remove NH4 contained in the waste sulfuric acid solution under acidic conditions. + Ions purify and regenerate waste sulfuric acid solution without the need for alkalization treatment. The process is simple, easy to implement, and reduces the cost of waste sulfuric acid regeneration. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a purification device for regenerating waste sulfuric acid according to an embodiment of the present invention; The components include: permeation tank 1; electrolysis tank 2; first circulation pipeline 3; second circulation pipeline 4; cation exchange membrane 10; sulfuric acid chamber 11; hydrochloric acid chamber 12; anion exchange membrane 20; positive electrode chamber 21; negative electrode chamber 22; positive electrode rod 210; and negative electrode rod 220. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1 The technical solution of the present invention will be further illustrated through specific embodiments.

[0019] In the description of this specification, references to the terms "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention.

[0020] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0022] A purification device for regenerating waste sulfuric acid includes a permeation tank 1 and an electrolysis tank 2; The permeation tank 1 is equipped with a cation membrane 10, which divides the permeation tank 1 into a sulfuric acid chamber 11 and a hydrochloric acid chamber 12. The electrolysis cylinder 2 is equipped with an anion exchange membrane 20, which divides the electrolysis cylinder 2 into a positive electrode chamber 21 and a negative electrode chamber 22. The positive electrode chamber 21 is fitted with a positive electrode rod 210 connected to the positive terminal of a DC power supply, and the negative electrode chamber 22 is fitted with a negative electrode rod 220 connected to the negative terminal of a DC power supply. The sulfuric acid chamber 11 and the negative electrode chamber 22 are respectively used to add waste sulfuric acid solution containing ammonia nitrogen to be purified. The sulfuric acid chamber 11 and the negative electrode chamber 22 are connected through the first circulation pipeline 3. The hydrochloric acid chamber 12 and the positive electrode chamber 21 are respectively used to add hydrochloric acid solution that provides chlorine source, and the hydrochloric acid chamber 12 and the positive electrode chamber 21 are connected through the second circulation pipeline 4.

[0023] The waste sulfuric acid solution to be purified contains H₂SO₄ and (NH₄)₂SO₄. For example... Figure 1 As shown, the waste sulfuric acid solution containing ammonia nitrogen flows between the sulfuric acid chamber 11 and the negative electrode chamber 22 through the first circulation pipeline 3, and the hydrochloric acid solution flows between the hydrochloric acid chamber 12 and the positive electrode chamber 21 through the second circulation pipeline 4.

[0024] In permeation tank 1, under the action of concentration polarization, NH4 in the waste sulfuric acid to be purified in sulfuric acid chamber 11... + Ions permeate through the cation exchange membrane into hydrochloric acid chamber 12, where H+ ions... + Ions permeate through the cation membrane into the sulfuric acid chamber 11.

[0025] In the energized electrolytic cylinder 2, the Cl in the hydrochloric acid in the positive electrode chamber 21 - Ions are electrolytically decomposed into chlorine gas (Cl2), while H+ in the waste sulfuric acid to be purified in the negative electrode chamber 22 is also decomposed. + Ions are electrolytically decomposed into hydrogen gas (H2); under the influence of an electric field, SO4 in the negative electrode chamber 22... 2- Ions migrate through the anion exchange membrane to the positive electrode chamber 21; chlorine gas (Cl2) in the positive electrode chamber 21 dissolves in water in the hydrochloric acid solution and hydrolyzes to produce hypochlorous acid (HOCl) and H+. + Ions and Cl - The ions and their corresponding chemical reaction formulas are: Cl₂ + H₂O → HOCl + H₂ + +Cl - .

[0026] Subsequently, NH4 + The ions then enter the positive electrode chamber 21 from the hydrochloric acid chamber 12 through the second circulation pipe 4. The NH4+ in the positive electrode chamber 21... + The ions react stepwise with hypochlorous acid to successively produce monochloramine (NH₂Cl), dichloramine (NHCl₂), and trichloramine (NCl₃). The corresponding chemical reaction equations are as follows: NH4 + +HOCl→NH2Cl+H2O+H + , NH₂Cl + HOCl → NH₂ + H₂O NHCl2 + HOCl → NCl3 + H2O; NCl3 is unstable and will decompose into N2 and Cl2.

[0027] Therefore, the corresponding overall chemical reaction formula is: 2NH4 + +6HOCl→N2↑+6H2O+2H + +3Cl2↑.

[0028] Therefore, under acidic conditions, the waste sulfuric acid solution to be purified contains NH4. + The ammonia nitrogen in the ions is continuously purified, and a regenerated sulfuric acid solution is obtained for use in the production of copper recovery from the etching solution. This prevents the ammonia nitrogen in the recycled sulfuric acid from crystallizing due to excessive concentration and clogging the pipes.

[0029] Furthermore, this invention proposes a method for regenerating waste sulfuric acid, using the purification device described above, comprising the following steps: S1) Inject appropriate amounts of hydrochloric acid solution into the hydrochloric acid chamber 12 of the permeation tank 1 and the positive electrode chamber 21 of the electrolysis tank 2 of the purification device, respectively; S2) Inject appropriate amounts of waste sulfuric acid solution to be purified into the sulfuric acid chamber 11 of the permeation tank 1 and the negative electrode chamber 22 of the electrolysis tank 2 of the purification device, respectively. S3) Turn on the DC power supply to put the electrolysis cylinder 2 into a powered working state; S4) Start the circulation pumps in the first circulation pipeline 3 and the second circulation pipeline 4 respectively; S5) Detecting NH4 in the sulfuric acid solution in sulfuric acid chamber 11 or negative electrode chamber 22. + Ion concentration, when NH4 + When the ion concentration drops to the preset value, the DC power supply is turned off, and the circulation pumps in the first circulation pipeline 3 and the second circulation pipeline 4 are turned off. The purification of the waste sulfuric acid solution in the sulfuric acid chamber 11 and the negative electrode chamber 22 is completed, and a regenerated sulfuric acid solution is obtained.

[0030] Existing technologies use stripping, chemical precipitation, or membrane treatment to purify ammonia nitrogen in waste sulfuric acid solutions. Stripping, chemical precipitation, and membrane treatment all require alkalization of the waste sulfuric acid solution to bring its pH value into an alkaline range before implementation, which increases the cost of waste sulfuric acid regeneration.

[0031] The present invention discloses a method for regenerating waste sulfuric acid, which utilizes the purification device described above. Through the combined use of a permeation tank 1 and an electrolysis tank 2, NH4 in the waste sulfuric acid solution can be separated and removed under acidic conditions. + Ions purify and regenerate waste sulfuric acid solution without the need for alkalization treatment. The process is simple, easy to implement, and reduces the cost of waste sulfuric acid regeneration.

[0032] Preferably, in step S1), the H+ of the hydrochloric acid solution... + ions or Cl - The concentration of ions is 4.5-5.0 mol / L.

[0033] Preferably, in step S2), the H of the waste sulfuric acid solution to be purified + The ion concentration is 3.0-3.5 mol / L, NH4+ + The ion concentration is 1.5-2.0 mol / L.

[0034] H+ in hydrochloric acid solution + The ion concentration is higher than that of the H+ in the waste sulfuric acid solution to be purified. + The ion concentration can be replenished by hydrochloric acid solution to address the H+ ion concentration loss caused by hydrogen evolution in the negative electrode chamber 21. + Ion loss, maintaining the H+ of hydrochloric acid solution + An ion concentration of not less than 4.5 mol / L is also beneficial for improving the removal of NH4 from waste sulfuric acid solutions. + Improve the current efficiency of ions and reduce energy consumption.

[0035] Preferably, in step S3), the current density of the electrolysis cylinder 2 is 60-100 mA / cm². 2 .

[0036] Current density is 60-100 mA / cm 2 At that time, the higher the current density, the better the removal of NH4 from the waste sulfuric acid solution. + The higher the current efficiency of ions.

[0037] Preferably, in step S5), NH4 + The preset value for ion concentration is 0.8 mol / L.

[0038] When NH4 + When the ion concentration drops to 0.8 mol / L, if electrolysis tank 2 continues to be powered on, NH4+... + The concentration of ions will not continue to change significantly, and electrical energy will be wasted.

[0039] Examples 1-3 and Comparative Examples 1-3 1. Referring to the parameters listed in Table 1, purify the NH4 from the waste sulfuric acid in any of Examples 1-3 or Comparative Examples 1-3 according to the following steps. + ion: S1) Inject appropriate amounts of hydrochloric acid solution into the hydrochloric acid chamber 12 of the permeation tank 1 and the positive electrode chamber 21 of the electrolysis tank 2 of the purification device, respectively; S2) Inject appropriate amounts of waste sulfuric acid solution to be purified into the sulfuric acid chamber 11 of the permeation tank 1 and the negative electrode chamber 22 of the electrolysis tank 2 of the purification device, respectively. S3) Turn on the DC power supply to put the electrolysis cylinder 2 into a powered working state, and adjust the current density according to the corresponding parameters, and detect and record the corresponding working voltage. S4) Start the circulation pumps in the first circulation pipeline 3 and the second circulation pipeline 4 respectively; S5) Detect and record the NH4+ in the sulfuric acid solution in sulfuric acid chamber 11 or negative electrode chamber 22. + Ion concentration, when NH4 + When the ion concentration does not continue to decrease for three consecutive hours, turn off the DC power supply and shut down the circulation pumps in the first circulation pipeline 3 and the second circulation pipeline 4. The purification of the waste sulfuric acid solution in the sulfuric acid chamber 11 and the negative electrode chamber 22 is completed, and a regenerated sulfuric acid solution is obtained. In step S2), the H of the waste sulfuric acid solution to be purified + The ion concentration is 3 mol / L, NH4+ + The ion concentration is 2.0 mol / L.

[0040] 2. Calculate and record the energy consumption and current efficiency of each embodiment or comparative example. The results are shown in Table 1.

[0041] 3. The acidity of sulfuric acid in the sulfuric acid chambers of Comparative Examples 1-3 was simultaneously detected, and the results are shown in Table 2.

[0042] Table 1. Process parameters, experimental results, and analytical data for Examples 1-3 and Comparative Examples 1-3

[0043] Table 2. Acidity changes in the sulfuric acid chambers of Comparative Examples 1-3

[0044] As can be seen from the data listed in Table 1 above, in Examples 1-3, when the electrolysis time was 12 hours, 10 hours, and 8 hours respectively, NH4 + The ion concentration decreased to 0.8 mol / L, and NH4+ + The ion concentration did not continue to decrease; the NH4 in Example 1 of Examples 1-3... + The energy consumption is lowest when the ion concentration decreases from 2.0 mol / L to 0.8 mol / L, and the corresponding current efficiency is the highest.

[0045] The current density of Comparative Example 1 is 40 mA / cm². 2 This differs from Example 1; although Comparative Example 1 purified NH4 + The energy consumption of the ions is lower than that of Example 1, and the corresponding current efficiency is also higher than that of Example 1, but the NH4 in Comparative Example 1 +It takes 16 hours of electrolysis to reduce the ion concentration from 2.0 mol / L to 0.8 mol / L, which is too time-consuming and not conducive to industrial production, resulting in low production efficiency.

[0046] Comparative Example 2: Hydrochloric acid added H + With an ion concentration of 3.0 mol / L, the H+ of hydrochloric acid in Comparative Example 2... + Ion concentration and H+ of waste sulfuric acid solution + With the same ion concentration, NH4+ in Comparative Example 2 + It takes 10 hours of electrolysis to reduce the ion concentration from 2.0 mol / L to 1.4 mol / L, and NH4+... + The ion concentration no longer decreased, therefore Comparative Example 2 purified NH4. + The effect of ions is not good.

[0047] Comparative Example 3: Hydrochloric acid added H + The ion concentration was 6.0 mol / L, and the NH4+ in Comparative Example 3 was... + The rate of decrease in ion concentration was almost identical to that in Example 1, but the purification of NH4 + The effect of ions was not as good as in Examples 2 and 3, indicating that the H+ in hydrochloric acid... + An ion concentration of 4.5 mol / L maintains optimal current efficiency and lower energy consumption; further increasing the H+ concentration of hydrochloric acid... + The effect of ion concentration is not obvious.

[0048] H in the hydrochloric acid located in hydrochloric acid chamber 12 + Ions can permeate through the cation exchange membrane into sulfuric acid chamber 11. Analysis of the data recorded in Table 2 shows that the acidity in sulfuric acid chamber 11 of Comparative Example 1 remains above 3.0. + The ion concentration in Comparative Example 2 did not increase significantly over time, nor was there any loss; however, the acidity in sulfuric acid chamber 11 continuously decreased over time, indicating a loss; and the acidity in sulfuric acid chamber 11 of Comparative Example 3 continuously increased over time, but the purified NH4 in Comparative Example 3... + The effect of ions was not due to H + Further improvement is achieved by increasing the ion concentration; therefore, hydrochloric acid with H+ was chosen. + An ion concentration of 4.5-5.0 mol / L is more suitable.

[0049] In summary, as described in the above embodiments of the present invention, the purification device can purify NH4 from waste sulfuric acid solution. + The ions are removed, and a regenerated sulfuric acid solution is obtained for recycling, which can prevent the ammonia nitrogen in the recycled sulfuric acid from crystallizing and clogging the pipeline due to excessive concentration.

[0050] Furthermore, the waste sulfuric acid regeneration method proposed in this invention, using the above-mentioned purification device, through the cooperation of the permeation tank 1 and the electrolysis tank 2, can separate and remove NH4 contained in the waste sulfuric acid solution under acidic conditions. + Ions purify and regenerate waste sulfuric acid solution without the need for alkalization treatment. The process is simple, easy to implement, and reduces the cost of waste sulfuric acid regeneration.

[0051] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A purification device for regenerating waste sulfuric acid, characterized in that, Including permeation tanks and electrolysis tanks; The permeation tank is equipped with a cation exchange membrane, which divides the permeation tank into a sulfuric acid chamber and a hydrochloric acid chamber. The electrolysis cylinder is equipped with an anion exchange membrane, which divides the electrolysis cylinder into a positive electrode chamber and a negative electrode chamber. The positive electrode chamber is fitted with a positive electrode rod connected to the positive terminal of a DC power supply, and the negative electrode chamber is fitted with a negative electrode rod connected to the negative terminal of a DC power supply. The sulfuric acid chamber and the negative electrode chamber are respectively used to add waste sulfuric acid solution containing ammonia nitrogen to be purified, and the sulfuric acid chamber and the negative electrode chamber are connected through a first circulation pipeline; The hydrochloric acid chamber and the positive electrode chamber are respectively used to add hydrochloric acid solution that provides a chlorine source, and the hydrochloric acid chamber and the positive electrode chamber are connected by a second circulation pipeline.

2. A method for regenerating waste sulfuric acid, characterized in that, Using the purification device according to claim 1 includes the following steps: S1) Inject appropriate amounts of hydrochloric acid solution into the hydrochloric acid chamber of the permeation tank and the positive electrode chamber of the electrolysis tank of the purification device, respectively; S2) Inject appropriate amounts of waste sulfuric acid solution to be purified into the sulfuric acid chamber of the permeation tank and the negative electrode chamber of the electrolysis tank of the purification device, respectively. S3) Turn on the DC power supply to put the electrolysis cylinder into a powered working state; S4) Start the circulation pumps in the first and second circulation pipelines respectively; S5) Detection of NH4 in the sulfuric acid solution in the sulfuric acid chamber or negative electrode chamber. + Ion concentration, when NH4 + When the ion concentration drops to the preset value, the DC power supply is turned off, and the circulation pumps in the first and second circulation pipelines are also turned off. The purification of the waste sulfuric acid solution in the sulfuric acid chamber and the negative electrode chamber is completed, and a regenerated sulfuric acid solution is obtained.

3. The method for regenerating waste sulfuric acid according to claim 2, characterized in that, In step S1), the H+ of the hydrochloric acid solution... + ions or Cl - The concentration of ions is 4.5-5.0 mol / L.

4. The method for regenerating waste sulfuric acid according to claim 2, characterized in that, In step S2), the H of the waste sulfuric acid solution to be purified + The ion concentration is 3.0-3.5 mol / L, NH4+ + The ion concentration is 1.5-2.0 mol / L.

5. The method for regenerating waste sulfuric acid according to claim 2, characterized in that, In step S3), the current density in the electrolysis cylinder is 60-100 mA / cm². 2 .

6. The method for regenerating waste sulfuric acid according to claim 2, characterized in that, In step S5), NH4 + The preset value for ion concentration is 0.8 mol / L.

Images