Chlorine-free high-purity electrolytic manganese production method and device

Abstract

The application relates to the technical field of electrolytic high-purity manganese, and discloses a high-purity electrolytic manganese production method and device without chlorine gas precipitation, which adopts a three-chamber electrolytic cell, and a mixed solution of manganese chloride and ammonium chloride, a manganese sulfate solution and a sulfuric acid solution are respectively injected into a cathode chamber, an intermediate chamber and an anode chamber; direct current is applied, Mn 2+ is reduced and deposited in the cathode, and water is oxidized and oxygen is released in the anode; Cl ⁻ in the cathode is blocked by a cation exchange film, so that chlorine gas is not generated by anode discharge. The purity of the metal manganese deposited in the cathode is stabilized at above 99.995%, and the pollution of sulfur impurities is effectively avoided; chlorine gas hazards can be eliminated, the production environment is friendly, and the process is relatively safe.

Description

Technical Field

[0001] This invention relates to the field of manganese electrolytic preparation technology, specifically to a method and apparatus for producing high-purity electrolytic manganese without chlorine gas evolution. Background Technology

[0002] High-purity sputtering targets are key materials for thin film fabrication in integrated circuits. Ultra-high purity Cu-Mn alloys can effectively suppress electromigration and RC delay caused by reduced linewidth, representing an important development direction in copper interconnect technology. Electrolysis is the main method for producing metallic manganese. Traditional processes use manganese sulfate (MnSO4) solution for electrolysis, but this results in sulfur contamination of the metallic manganese. Using a manganese chloride (MnCl2) system can effectively avoid sulfur contamination, but the core issue lies in: ① During electrolysis, chloride ions (Cl... - ① At the anode, it is easily oxidized to produce highly toxic chlorine gas (Cl2), causing serious environmental hazards, equipment corrosion and safety risks, and requires a complex exhaust gas treatment system, which greatly increases construction and operating costs; ② During the electrolysis process, nitrogen trichloride is easily produced. Nitrogen trichloride is extremely unstable and is prone to explosion when heated or vibrated.

[0003] Therefore, it is necessary to study a new electrolysis process that can effectively avoid pollution from sulfur impurities and the generation of chlorine and nitrogen trichloride. Summary of the Invention

[0004] The purpose of this invention is to address the technical shortcomings of existing manganese sulfate systems (sulfur pollution) and manganese chloride electrolysis systems (inelectrolysis of manganese), which inevitably produce chlorine gas, pollute the environment, and corrode equipment. The invention provides a method and apparatus for producing high-purity electrolytic manganese that can eliminate chlorine gas precipitation.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for producing high-purity electrolytic manganese without chlorine gas evolution, comprising the following steps:

[0007] S1 uses a three-chamber electrolyzer. The electrolyzer is divided into a cathode chamber, an intermediate chamber, and an anode chamber by two parallel cation exchange membranes and an anion exchange membranes. A specified electrolyte is injected into the cathode chamber, the intermediate chamber, and the anode chamber respectively.

[0008] S2 applies a direct current, and Mn is generated at the cathode. 2+ The reduction deposition, OH is carried out at the anode. - The oxidation and oxygen evolution reaction;

[0009] Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻ Blocked by a cation exchange membrane;

[0010] Anion exchange membranes are placed in the intermediate and anode chambers of S4. NH4⁺ in the intermediate chamber and H⁺ in the anode chamber are blocked by the anion exchange membranes and cannot enter each other's regions.

[0011] Furthermore, the cathode chamber is equipped with a cathode plate and contains a mixed electrolyte of manganese chloride and ammonium chloride with a concentration of 0.5-1.5 mol / L and a concentration of 1.5-2 mol / L, and its pH value is maintained at 6.8-7.2.

[0012] Furthermore, the intermediate chamber contains a manganese sulfate solution with a concentration of 0.6-1.0 mol / L, and its pH value is maintained at 6.8-7.2.

[0013] Furthermore, the anode chamber is equipped with an anode plate and contains a sulfuric acid solution with a concentration of 0.4-0.6 mol / L, the pH of which is maintained as acidic.

[0014] Furthermore, the cathode current density is 250-450 A / m², and the anode current density is 550-850 A / m².

[0015] Furthermore, the electrolytic cell operates at a temperature of 35-55℃ and a voltage of 3.0-4.5 V.

[0016] Furthermore, the anode plate is a titanium-based coated anode, and its active coating is iridium tantalum oxide, wherein the molar ratio of IrO2 to Ta2O5 is 6-8:2-4, and the coating thickness is 8-15 μm.

[0017] Furthermore, the present invention provides a high-purity electrolytic manganese production apparatus without chlorine gas evolution. The electrolytic cell body is divided into a cathode chamber, an intermediate chamber and an anode chamber by two parallel cation exchange membranes and an anion exchange membranes, respectively. The cathode chamber is equipped with a circulation pump.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. Environmentally Friendly and Process Safe: The electrolytic cell is divided into sections using cation exchange membranes and anion exchange membranes. The cathode chamber contains a mixed solution of manganese chloride and ammonium chloride, while the intermediate chamber contains a manganese sulfate solution. The cation exchange membrane blocks anion migration, thus isolating chloride ions in the cathode chamber. The anode chamber contains a sulfuric acid solution, and the anion exchange membrane blocks cation migration, thus isolating ammonium ions and H+ ions. + The barrier effectively prevents the generation of chlorine and nitrogen trichloride in the electrolytic cell.

[0020] 2. High product purity: The cathode electrolysis system adopts a mixed electrolysis system of manganese chloride and ammonium chloride, which effectively avoids contamination by sulfur impurities. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the electrolytic cell of the present invention.

[0023] Reference numerals: 1-Cathode chamber, 2-Intermediate chamber, 3-Anode chamber, 4-Cathode plate, 5-Anode plate, 6-Cation exchange membrane, 7-Anion exchange membrane, 8-DC power supply, 10-Metallic manganese deposition layer, 11-Oxygen bubble. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] like Figure 1 As shown, a high-purity electrolytic manganese production device without chlorine gas evolution has an electrolytic cell body that is separated into a cathode chamber 1, an intermediate chamber 2, and an anode chamber 3 by two parallel cation exchange membranes 6 and anion exchange membranes 7. The cathode chamber 1 is equipped with a circulation pump 9. A cathode plate 4 is inserted into the cathode chamber 1, and an anode plate 5 is inserted into the anode chamber 3. The cathode plate 4 and the anode plate 5 are connected to a DC power supply 8. During electrolysis, a metallic manganese deposit layer 10 is generated on the cathode plate 4, oxygen bubbles 11 are generated on the anode plate 5, and very little chlorine gas is generated on the cathode plate 4.

[0026] A method for producing high-purity electrolytic manganese without chlorine gas evolution includes the following steps:

[0027] S1 uses a three-chamber electrolyzer. The electrolyzer is divided into a cathode chamber, an intermediate chamber, and an anode chamber by two parallel cation exchange membranes and an anion exchange membranes. A specified electrolyte is injected into the cathode chamber, the intermediate chamber, and the anode chamber respectively.

[0028] S2 applies a direct current, and Mn is generated at the cathode. 2+ The reduction deposition, OH is carried out at the anode. - The oxidation and oxygen evolution reaction;

[0029] Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻Blocked by a cation exchange membrane;

[0030] Anion exchange membranes are placed in the intermediate and anode chambers of S4. NH4⁺ in the intermediate chamber and H⁺ in the anode chamber are blocked by the anion exchange membranes and cannot enter each other's regions.

[0031] Furthermore, the cathode chamber is equipped with a cathode plate and contains a mixed electrolyte of manganese chloride and ammonium chloride with a concentration of 0.5-1.5 mol / L and a concentration of 1.5-2 mol / L, and its pH value is maintained at 6.8-7.2.

[0032] Furthermore, the intermediate chamber contains a manganese sulfate solution with a concentration of 0.6-1.0 mol / L, and its pH value is maintained at 6.8-7.2.

[0033] Furthermore, the anode chamber is equipped with an anode plate and contains a sulfuric acid solution with a concentration of 0.4-0.6 mol / L, the pH of which is maintained as acidic.

[0034] Furthermore, the cathode current density is 250-450 A / m², and the anode current density is 550-850 A / m².

[0035] Furthermore, the electrolytic cell operates at a temperature of 35-55℃ and a voltage of 3.0-4.5 V.

[0036] Furthermore, the anode plate is a titanium-based coated anode, and its active coating is iridium tantalum oxide, wherein the molar ratio of IrO2 to Ta2O5 is 6-8:2-4, and the coating thickness is 8-15 μm.

[0037] The present invention will be further illustrated below with examples:

[0038] Example 1

[0039] A method for producing high-purity electrolytic manganese without chlorine gas evolution includes the following steps:

[0040] In S1, cation exchange membranes and anion exchange membranes are installed in the electrolytic cell, and the anode and cathode plates are fixed with a distance of 30 mm between them. A mixed solution of 0.5 mol / L manganese chloride and 1.5 mol / L ammonium chloride, prepared using purified manganese chloride and ammonium chloride, is injected into the cathode chamber as the catholyte. A 0.5 mol / L manganese sulfate solution, prepared using purified high-purity manganese sulfate, is injected into the intermediate chamber. A 0.4 mol / L sulfuric acid solution, prepared using purified sulfuric acid, is injected into the anode chamber as the anolyte. A circulation pump, which is a peristaltic pump, is connected to the pipes inside the cathode chamber to precisely control the liquid flow rate.

[0041] S2 uses a titanium plate as the cathode and a titanium-plated iridium-tantalum mesh as the anode, with a cathode current density of 300 A / m² and an anode current density of 600 A / m². The electrolytic cell operates at a temperature of 40℃ and a cell voltage of 3.0 V. A peristaltic pump is used to control the flow rate in the cathode chamber at 250 mL / h, and the electrolysis time is 24 h, yielding high-purity manganese metal plates with a purity of over 99.995%.

[0042] Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻ Blocked by a cation exchange membrane;

[0043] Anion exchange membranes are placed in the intermediate and anode chambers of S4. NH4⁺ in the intermediate chamber and H⁺ in the anode chamber are blocked by the anion exchange membranes and cannot enter each other's regions.

[0044] Example 2

[0045] A method for producing high-purity electrolytic manganese without chlorine gas evolution includes the following steps:

[0046] In S1, cation exchange membranes and anion exchange membranes are installed in the electrolytic cell, and the anode and cathode plates are fixed with an electrode distance of 40 mm. A mixed solution of 1 mol / L manganese chloride and 1.8 mol / L ammonium chloride, prepared with purified manganese chloride and ammonium chloride, is used as the cathode solution. A 0.8 mol / L manganese sulfate solution, prepared with purified high-purity manganese sulfate, is injected into the intermediate chamber. A 0.5 mol / L sulfuric acid solution, prepared with purified manganese chloride, is used as the anolyte.

[0047] S2 uses a titanium plate as the cathode and a titanium-plated iridium-tantalum mesh as the anode, with a cathode current density of 350 A / m² and an anode current density of 700 A / m². The electrolytic cell operates at a temperature of 45℃ and a cell voltage of 4.0 V. A peristaltic pump is used to control the flow rate in the cathode chamber at 200 mL / h, and the electrolysis time is 24 h, yielding a high-purity manganese plate with a purity of over 99.995%. The active coating of the titanium-plated iridium-tantalum mesh is iridium-tantalum oxide, with a molar ratio of IrO₂ to Ta₂O₅ of 7:3, and a coating thickness of 12 μm.

[0048] Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻ Blocked by a cation exchange membrane;

[0049] Anion exchange membranes are placed in the intermediate and anode chambers of S4. NH4⁺ in the intermediate chamber and H⁺ in the anode chamber are blocked by the anion exchange membranes and cannot enter each other's regions.

[0050] Example 3

[0051] In S1, cation exchange membranes and anion exchange membranes are installed in the electrolytic cell, and the anode and cathode plates are fixed with an electrode distance of 50 mm. A mixed solution of 1.5 mol / L manganese chloride and 2 mol / L ammonium chloride, prepared with purified manganese chloride and ammonium chloride, is used as the cathode solution. A 0.6 mol / L manganese sulfate solution, prepared with purified high-purity manganese sulfate, is injected into the intermediate chamber. A 0.5 mol / L sulfuric acid solution, prepared with purified manganese chloride, is used as the anolyte.

[0052] S2 uses a titanium plate as the cathode and a titanium-plated iridium-tantalum mesh as the anode. The cathode current density is set at 450 A / m², and the anode current density at 800 A / m². The electrolytic cell operates at a temperature of 50℃ and a voltage of 5.0 V. A peristaltic pump is used to control the flow rate in the cathode chamber at 150 mL / h, and the electrolysis time is 24 h, yielding high-purity manganese metal plates with a purity of over 99.995%.

[0053] Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻ Blocked by a cation exchange membrane;

[0054] Anion exchange membranes are placed in the intermediate and anode chambers of S4. NH4⁺ in the intermediate chamber and H⁺ in the anode chamber are blocked by the anion exchange membranes and cannot enter each other's regions.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for producing high-purity electrolytic manganese without chlorine gas evolution, characterized in that, Includes the following steps: S1 uses a three-chamber electrolyzer. The electrolyzer is divided into a cathode chamber, an intermediate chamber, and an anode chamber by two parallel cation exchange membranes and an anion exchange membranes. A specified electrolyte is injected into the cathode chamber, the intermediate chamber, and the anode chamber respectively. S2 applies a direct current, and Mn is generated at the cathode. 2+ The reduction deposition, OH is carried out at the anode. - The oxidation and oxygen evolution reaction; Cation exchange membranes are placed in the S3 cathode chamber and the intermediate chamber. Cl in the cathode chamber... ⁻ Blocked by a cation exchange membrane; Anion exchange membranes are placed in the intermediate and anode chambers of S4. The NH4⁺ in the intermediate chamber and the H⁺ in the anode chamber are blocked by the anion exchange membranes.

2. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The cathode chamber is equipped with a cathode plate and contains a mixed electrolyte of manganese chloride and ammonium chloride with a concentration of 0.5-1.5 mol / L and a concentration of 1.5-2 mol / L, with the pH value maintained at 6.8-7.

2.

3. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The intermediate chamber contains a manganese sulfate solution with a concentration of 0.6-1.0 mol / L, and its pH value is maintained at 6.8-7.

2.

4. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The anode chamber is equipped with an anode plate and contains a sulfuric acid solution with a concentration of 0.4-0.6 mol / L, whose pH value is maintained as acidic.

5. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The cathode current density is 250-450 A / m², and the anode current density is 550-850 A / m².

6. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The electrolytic cell operates at a temperature of 35-55℃ and a voltage of 3.0-4.5 V.

7. The method for producing high-purity electrolytic manganese without chlorine evolution according to claim 1, characterized in that: The anode plate is a titanium-based coated anode, and its active coating is iridium tantalum oxide, wherein the molar ratio of IrO2 to Ta2O5 is 6-8:2-4, and the coating thickness is 8-15μm.

8. The apparatus used in the method for producing high-purity electrolytic manganese without chlorine evolution according to any one of claims 1-7, characterized in that: The electrolytic cell body is divided into a cathode chamber, an intermediate chamber, and an anode chamber by two parallel cation exchange membranes and anion exchange membranes, respectively. The cathode chamber is equipped with a circulation pump.

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