An electrolytic cell for electrolyzing manganese metal

Abstract

The present invention discloses an electrolytic cell for electrolyzing manganese metal, characterized in that it comprises an upper cell body (1) and a lower cell body (2), wherein a partition (8) is arranged inside the lower cell body (2), an anode support (15) is connected to the upper part of the partition (8), an anode liquid convergence chamber (16) is arranged below the partition (8), and the anode liquid convergence chamber (16) is connected to an anode liquid guide groove (17); a sealing strip (3) is arranged on the side of the lower cell body (2), and the upper cell body (1) and the lower cell body (2) are sealed and connected via a connecting component (4); during the electrolysis process, the gas pressure on the liquid surface of the lower cell body (2) is kept greater than the gas pressure outside the electrolytic cell. The present invention can suppress the occurrence of hydrogen evolution reaction and concentration polarization, and has a high current efficiency.

Description

Technical Field

[0001] The invention relates to the field of manganese metal metallurgy, and in particular to an electrolytic cell for electrolyzing manganese metal. Background Art

[0002] Metallic manganese is an important industrial raw material, widely used in metallurgy, chemical industry, light industry, electronic materials and other industries. The most important application is the steel metallurgical industry. In the steel industry, the amount of manganese used is second only to iron. In modern society, 90% of manganese is consumed in the steel industry, and 10% of manganese is used in other industries. Manganese is a strategic reserve resource. At the end of 2021, there were 49 enterprises in production in my country's electrolytic manganese industry, with a total industry production capacity of 2 million tons.

[0003] In the traditional electrolytic manganese process, a wooden electrolytic cell is used. The electrolytic cell is handmade, and the specifications and dimensions are difficult to guarantee. There are problems such as poor sealing performance, easy acid regeneration, high energy consumption, and low current efficiency. Energy saving and consumption reduction is one of the main problems that the electrolytic manganese industry currently faces and solves. The DC power consumption of electrolytic manganese manufacturers is mostly 6000-7000kW·h / t, and the DC efficiency is basically around 75%, leaving 25% space for exploration and research. In the production process of electrolytic manganese, more than 95% of the energy consumption is concentrated on the electrolytic cell, and the design of the electrolytic cell directly determines the level of energy consumption. In addition, the electrolytic cell of the traditional electrolytic manganese industry is prone to acid regeneration during the electrolysis process, resulting in unstable pH value in the cathode area. Ammonia water needs to be added during the electrolysis process to adjust the pH value, and the ammonia nitrogen pollution in the workshop environment is relatively serious.

[0004] The applicant has found that the main reasons affecting the electrolysis energy consumption during the use of the electrolytic cell are: ① When the acid reversion phenomenon occurs, the metallic manganese on the cathode plate will dissolve back, which will also cause the hydrogen evolution potential to increase, and the high potential on the cathode will be preferentially precipitated, that is, the hydrogen evolution reaction will occur; ② Due to the Mn in the liquid layer near the cathode surface, the 2+ deposited on the cathode, thus reducing the Mn 2+ The concentration near the cathode. If the Mn in the bulk manganese electrolyte 2+ If it cannot be replenished in time, the Mn near the cathode liquid layer 2+ The concentration of the substance will be lower than that in the bulk solution, so the electrode potential will be lower than its equilibrium value, resulting in concentration polarization. Summary of the invention

[0005] The invention provides an electrolytic cell for electrolyzing metallic manganese, which can inhibit hydrogen evolution reaction, avoid concentration polarization phenomenon and improve current efficiency.

[0006] The technical solution of the present invention is as follows: an electrolytic cell for electrolyzing metallic manganese comprises an upper cell body and a lower cell body, wherein a partition is arranged in the lower cell body, an anode bracket is connected to the upper part of the partition, an anode liquid convergence chamber is arranged at the lower part of the partition, and the anode liquid convergence chamber is connected to the anode liquid guide groove; a sealing strip is arranged on the side of the lower cell body, and the upper cell body and the lower cell body are sealed and connected by a connecting component; during the electrolysis process, the air pressure on the liquid surface of the lower cell body is kept greater than the air pressure outside the electrolytic cell.

[0007] In the electrolytic cell for electrolyzing metallic manganese, the gas pressure above the liquid surface of the lower cell is 0.11-0.2 MPa.

[0008] In the electrolytic cell for electrolyzing metallic manganese, the gas pressure above the liquid surface of the lower cell is 0.11-0.17 MPa.

[0009] In the electrolytic cell for electrolyzing metallic manganese, the gas pressure above the liquid surface of the lower cell is 0.12-0.14 MPa.

[0010] The electrolytic cell for electrolyzing manganese metal is provided with a pressure gauge pipe opening, an exhaust valve pipe opening and an air charging valve pipe opening on the upper cell body, and the air pressure on the liquid surface of the lower cell body is adjusted by the exhaust valve and the air charging valve.

[0011] In the electrolytic cell for electrolyzing manganese metal, the gas introduced by the charging valve is nitrogen, hydrogen or a mixture of the two.

[0012] In the electrolytic cell for electrolyzing metallic manganese, the partition is provided with more than two anode supports, the interval between the anode supports is the cathode area, and the lower cell side wall corresponding to each cathode area is provided with a liquid inlet valve port, and the MnSO4-(NH4)2SO4-H2O solution enters the electrolytic cell in a diversion manner.

[0013] In the electrolytic cell for electrolyzing manganese metal, the anode support comprises two support side plates, the upper part of which is connected to a support top plate, and an anode slot is arranged on the support top plate.

[0014] In the electrolytic cell for electrolyzing metallic manganese, the anode support is provided with a diaphragm cloth and a diaphragm cloth pressing plate.

[0015] The electrolytic cell for electrolyzing manganese metal is provided with cathode plate hanging bars and anode plate hanging bars in the lower cell body. The cathode plate hanging bars are connected to the negative electrode wire, and the anode plate hanging bars are connected to the positive electrode wire.

[0016] Beneficial effects: Compared with the existing equipment, the present invention has the following advantages:

[0017] (1) The electrolytic cell of the present invention is sealed at the top, and the MnSO4-(NH4)2SO4-H2O liquid surface pressure in the electrolytic cell is greater than the atmospheric pressure, that is, greater than the pressure at the anolyte outlet. Due to the pressure difference, the anolyte flows directly from the anolyte convergence chamber through the anolyte conduit, and no anolyte backflow occurs. The pH value is relatively stable during the electrolysis process, the occurrence of hydrogen evolution reaction is suppressed, and the current efficiency is high.

[0018] (2) The MnSO4-(NH4)2SO4-H2O solution used for electrolysis in the electrolytic cell of the present invention enters the electrolytic cell in a split flow manner, that is, each cathode corresponds to a liquid inlet, and the electrolyte flows from the liquid inlet → cathode area → anode area → anode chamber. During the electrolysis process, the Mn in the liquid layer near the cathode surface 2+ deposited on the cathode, thus reducing the Mn 2+ The concentration near the cathode. Mn in the electrolyte 2+ If it can be replenished in time, the Mn near the cathode liquid layer 2+ The concentration is equal to that in the bulk solution, avoiding concentration polarization and resulting in higher current efficiency.

[0019] (3) The liquid surface of the electrolytic cell of the present invention is in a slightly positive pressure state, and the electrolytic manganese metal undergoes the following two competing reactions on the cathode:

[0020] Reaction of metallic manganese precipitation:

[0021] Mn 2+ +2e - =Mn

[0022]

[0023] Hydrogen evolution reaction:

[0024]

[0025]

[0026] When the pressure on the MnSO4-(NH4)2SO4-H2O liquid surface in the cathode region is high, E[H + / H2(g),] value decreases, and the electrode reaction on the cathode is that the electrode with higher potential is precipitated first, that is, the reaction of precipitating metallic manganese occurs.

[0027] (4) During the electrolysis process, due to the slightly positive pressure state and each cathode corresponds to a liquid inlet, the electrolyte MnSO4-(NH4)2SO4-H2O flows faster, mass transfer is enhanced, additives and selenium dioxide are reduced on the cathode, and elemental selenium is generated and adsorbed on the cathode, occupying the cathode surface, inhibiting the discharge of hydrogen ions and reduction at the cathode, increasing the hydrogen precipitation overpotential, and thus improving the current efficiency of the electrolytic manganese metal process.

[0028] (5) There is no acid return during the electrolysis process. The pH value of the cathode area is basically between 7-7.5. There is no need to add ammonia water. There is no ammonia nitrogen pollution in the workshop environment. The manganese ions in the electrolyte rarely discharge at the anode and react with the hydroxide ions ionized by ammonia water. Therefore, the amount of anode mud produced is relatively small.

[0029] (6) During electrolysis, the electrolytic cell can be inflated to make the gas pressure on the liquid surface of the lower tank positive. The applicant has found that hydrogen will be precipitated during the electrolysis process. When the pressure on the liquid surface increases or the hydrogen concentration in the gas on the liquid surface increases, E[H + / H2(g),] value decreases, inhibiting the occurrence of hydrogen evolution reaction.

[0030] To prove the technical effect of the present invention, the applicant conducted the following experiment: MnSO4-(NH4)2SO4-H2O related electrolyte solution (containing Mn 2+ 34g / L, ammonium sulfate concentration 100g / L,) into the electrolytic cell, set the pressure on the electrolytic cell liquid surface according to the table below, turn on the power, connect the cathode and anode, the electrolytic cell is sealed, the cell voltage is 4.3V, and the cathode current density is 320A / m 2 After 24 hours of electrolysis, the cathode plate was taken out and the metal manganese was obtained after peeling. The Mn content in the anode liquid was determined. 2+ The concentration value, calculated energy consumption of electrolytic manganese, and the corresponding pressure value on the liquid surface of the electrolytic cell are shown in the following table.

[0031]

[0032] According to the above experimental data, the relationship between liquid surface pressure and power consumption is as follows: Figure 7 The experimental results show that when the pressure on the liquid surface of the electrolytic cell is greater than the external air pressure of the electrolytic cell, the power consumption of manganese electrolysis can be reduced. Controlling the pressure on the liquid surface of the electrolytic cell at 0.11-0.2Mpa can achieve a better energy-saving effect. Controlling the pressure on the liquid surface of the electrolytic cell at 0.12-0.14MPa has the best energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1 It is a schematic diagram of the structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of the separator and the anode support of the present invention;

[0036] Figure 3 is a top view of the lower tank body of the present invention;

[0037] Figure 4 This is the AA section view of the lower tank body;

[0038] Figure 5 It is a schematic diagram of the placement of the anode plate and the cathode plate on the anode support;

[0039] Figure 6 It is a structural schematic diagram of the diaphragm cloth pressing plate;

[0040] Figure 7 This is a graph showing the relationship between liquid surface pressure and power consumption.

[0041] Marked as follows in the accompanying drawings: 1-upper tank body, 2-lower tank body, 3-sealing strip, 4-connecting component, 5-pressure gauge pipe mouth, 6-exhaust valve pipe mouth, 7-inflating valve pipe mouth, 8-partition, 9-cathode plate hanging bar, 10-anode plate hanging bar, 11-negative electrode line, 12-positive electrode line, 13-liquid inlet valve mouth, 14-anode liquid outlet, 15-anode bracket, 16-anode liquid convergence chamber, 17-anode liquid guide groove, 18-diaphragm cloth pressure plate, 19-anode plate, 20-cathode plate, 151-bracket side plate, 152-bracket top plate, 153-anode slot. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0043] Embodiment. An electrolytic cell for electrolyzing manganese metal comprises an upper cell body 1 and a lower cell body 2, wherein a partition 8 is arranged inside the lower cell body 2, an anode support 15 is connected to the upper part of the partition 8, an anode liquid convergence chamber 16 is arranged below the partition 8, the anode liquid convergence chamber 16 is connected to an anode liquid guide groove 17, and the anode liquid guide groove 17 is connected to an anode liquid outlet 14 on its side; a sealing strip 3 is arranged on the side of the lower cell body 2, and the upper cell body 1 and the lower cell body 2 are sealed and connected via a connecting component 4; during the electrolysis process, the gas pressure on the liquid surface of the lower cell body 2 is kept greater than the gas pressure outside the electrolytic cell. Figure 1 As shown, the connecting component 4 is connected by a buckle and a fixing bolt. The connecting component 4 can also be other existing connecting components such as a screw nut assembly, and the sealing strip 3 is a rubber sealing strip.

[0044] The air pressure on the liquid surface of the lower tank 2 is 0.11-0.2 MPa.

[0045] More preferably, the air pressure above the liquid surface of the lower tank 2 is 0.11-0.17 MPa.

[0046] More preferably, the air pressure above the liquid surface of the lower tank 2 is 0.12-0.14 MPa.

[0047] The upper tank body 1 is provided with a pressure gauge pipe port 5, an exhaust valve pipe port 6 and an air charging valve pipe port 7, and the air pressure on the liquid surface of the lower tank body 2 is adjusted by the exhaust valve and the air charging valve. The gas fed into the air charging valve is nitrogen, hydrogen or a mixture of the two. The addition of nitrogen can not only provide positive pressure, but also serve as a protective gas. The addition of hydrogen can further inhibit the occurrence of hydrogen evolution reaction, but it should be noted that the amount added should not be too large to avoid the risk of explosion.

[0048] The partition 8 is provided with more than two anode supports 15, the interval between the anode supports 15 is the cathode area, the cathode plate 20 is placed in the cathode area, and the side wall of the lower tank body 2 corresponding to each cathode area is provided with a liquid inlet valve port 13. The MnSO4-(NH4)2SO4-H2O solution enters the electrolytic cell in a diversion manner to avoid concentration polarization.

[0049] The anode support 15 includes two support side plates 151 . The support side plates 151 are connected to a support top plate 152 . The support top plate 152 is provided with an anode slot 153 . The anode plate 19 is inserted into the anode slot 153 .

[0050] The anode support 15 is provided with a diaphragm cloth pressing plate 18, and the diaphragm cloth pressing plate 18 presses the diaphragm cloth.

[0051] The lower tank body 2 is provided with a cathode plate hanging bar 9 and an anode plate hanging bar 10, wherein the cathode plate hanging bar 9 is connected to the negative electrode line 11, and the anode plate hanging bar 10 is connected to the positive electrode line 12. The cathode plate hanging bar 9 is connected to the cathode plate 20, and the anode plate hanging bar 10 is connected to the anode plate 19.

[0052] Working process: install the anode plate 19 and the cathode plate 20, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell by the connecting component 4, open the liquid inlet valve port 13, introduce the MnSO4-(NH4)2SO4-H2O related electrolyte solution into the electrolytic cell, open the charging valve port 7, adjust the exhaust valve port 6 and observe the barometer 5, keep the electrolytic cell in a slightly positive pressure state, turn on the power, connect the cathode and the anode, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, and the electrolyte solution flows from the anode liquid convergence chamber 16 under the lower tank body 2 into the anode liquid guide groove 17, and then flows out from the anode liquid outlet 14. After 24 hours of electrolysis, the cathode plate 20 is taken out and stripped to obtain metallic manganese.

[0053] The technology of the present invention is further described below in conjunction with examples:

[0054] Example 1

[0055] Install the stainless steel cathode plate 20 and the lead alloy anode plate 19, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, open the liquid inlet valve 13, and add the MnSO4-(NH4)2SO4-H2O related electrolyte solution (containing Mn 2+ 34g / L, ammonium sulfate concentration 100g / L,) into the electrolytic cell, open the charging valve port 7, adjust the exhaust valve port 6 and observe the barometer 5, keep the pressure on the liquid surface of the electrolytic cell at 0.12MPa, turn on the power, connect the cathode and anode, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, the cell voltage is 4.3V, and the cathode current density is 320A / m 2 After 24 hours of electrolysis, the cathode plate 20 was taken out and stripped to obtain metallic manganese. The Mn content in the anode liquid was determined. 2+ The concentration is 13g / L, and the energy consumption of electrolytic manganese is calculated to be 5432KWh / t·Mn.

[0056] Example 2

[0057] Install the stainless steel cathode plate 20 and the lead alloy anode plate 19, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, open the liquid inlet valve 13, and add the MnSO4-(NH4)2SO4-H2O related electrolyte solution (containing Mn 2+ 34g / L, ammonium sulfate concentration 100g / L,) into the electrolytic cell, open the charging valve port 7, adjust the exhaust valve port 6 and observe the barometer 5, keep the pressure on the liquid surface of the electrolytic cell at 0.16MPa, turn on the power, connect the cathode and anode, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, the cell voltage is 4.3V, and the cathode current density is 320A / m 2 After 24 hours of electrolysis, the cathode plate 20 was taken out and stripped to obtain metallic manganese. The Mn content in the anode liquid was determined. 2+ The concentration is 13g / L, and the energy consumption of electrolytic manganese is calculated to be 5364KWh / t·Mn.

[0058] Example 3

[0059] Install the stainless steel cathode plate 20 and the lead alloy anode plate 19, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, open the liquid inlet valve 13, and add the MnSO4-(NH4)2SO4-H2O related electrolyte solution (containing Mn 2+ 34g / L, ammonium sulfate concentration 100g / L,) into the electrolytic cell, open the charging valve port 7, adjust the exhaust valve port 6 and observe the barometer 5, keep the pressure on the liquid surface of the electrolytic cell at 0.21MPa, turn on the power, connect the cathode and anode, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, the cell voltage is 4.3V, and the cathode current density is 320A / m 2 After 24 hours of electrolysis, the cathode plate 20 was taken out and stripped to obtain metallic manganese. The Mn content in the anode liquid was determined. 2+The concentration is 13g / L, and the energy consumption of electrolytic manganese is calculated to be 5692KWh / t·Mn.

[0060] Comparative Example 1

[0061] The stainless steel cathode and lead alloy anode are installed in the traditional electrolytic cell, and the MnSO4-(NH4)2SO4-H2O electrolyte solution (containing Mn 2+ 34g / L, ammonium sulfate concentration 100g / L,) into the electrolytic cell, turn on the power, connect the cathode and anode, fix the upper tank body 1 and the lower tank body 2 of the electrolytic cell, the cell voltage is 4.3V, and the cathode current density is 320A / m 2 After 24 hours of electrolysis, the cathode plate was taken out and the metal manganese was obtained after peeling. The Mn content in the anode liquid was determined. 2+ The concentration is 13g / L, and the energy consumption of electrolytic manganese is calculated to be 6247KWh / t·Mn.

Claims

1. An electrolytic cell for electrolyzing manganese metal, characterized in that: The invention comprises an upper tank body (1) and a lower tank body (2), wherein a partition (8) is provided in the lower tank body (2), an anode support (15) is connected to the upper part of the partition (8), an anode liquid convergence chamber (16) is provided at the lower part of the partition (8), and the anode liquid convergence chamber (16) is connected to an anode liquid guide groove (17); a sealing strip (3) is provided on the side of the lower tank body (2), and the upper tank body (1) and the lower tank body (2) are sealed and connected via a connecting component (4); during the electrolysis process, the gas pressure on the liquid surface of the lower tank body (2) is kept greater than the gas pressure outside the electrolytic cell; the gas pressure on the liquid surface of the lower tank body (2) is 0.11-0.2MPa.

2. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The air pressure above the liquid surface of the lower tank (2) is 0.11-0.17 MPa.

3. The electrolytic cell for electrolyzing metallic manganese according to claim 2, characterized in that: The air pressure above the liquid surface of the lower tank (2) is 0.12-0.14 MPa.

4. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The upper tank body (1) is provided with a pressure gauge pipe opening (5), an exhaust valve pipe opening (6) and an air charging valve pipe opening (7), and the air pressure on the liquid surface of the lower tank body (2) is adjusted by the exhaust valve and the air charging valve.

5. The electrolytic cell for electrolyzing manganese metal according to claim 4, characterized in that: The gas introduced by the inflation valve is nitrogen, hydrogen or a mixture of the two.

6. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The partition (8) is provided with more than two anode supports (15), the interval between the anode supports (15) is a cathode area, and the side wall of the lower tank body (2) corresponding to each cathode area is provided with a liquid inlet valve port (13), and the MnSO4-(NH4)2SO4-H2O solution enters the electrolytic cell in a split flow manner.

7. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The anode support (15) comprises two support side plates (151), the support side plates (151) are connected to a support top plate (152) above, and an anode slot (153) is provided on the support top plate (152).

8. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The anode support (15) is provided with a diaphragm cloth (19) and a diaphragm cloth pressing plate (18).

9. The electrolytic cell for electrolyzing manganese metal according to claim 1, characterized in that: The lower tank body (2) is provided with a cathode plate hanging bar (9) and an anode plate hanging bar (10), the cathode plate hanging bar (9) is connected to a negative electrode line (11), and the anode plate hanging bar (10) is connected to a positive electrode line (12).

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