CN114481131A - Improved MnO2Preparation method and application of coated electrode - Google Patents

Improved MnO2Preparation method and application of coated electrode Download PDF

Info

Publication number
CN114481131A
CN114481131A CN202210183037.7A CN202210183037A CN114481131A CN 114481131 A CN114481131 A CN 114481131A CN 202210183037 A CN202210183037 A CN 202210183037A CN 114481131 A CN114481131 A CN 114481131A
Authority
CN
China
Prior art keywords
mno
layer
preparation
electrode
metal substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210183037.7A
Other languages
Chinese (zh)
Inventor
周玉琳
熊卫江
蒋良兴
陈祥嘉
艾涛
余可
陈匡义
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hunan Zhuye Nonferrous Metals Co ltd
Original Assignee
Hunan Zhuye Nonferrous Metals Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hunan Zhuye Nonferrous Metals Co ltd filed Critical Hunan Zhuye Nonferrous Metals Co ltd
Priority to CN202210183037.7A priority Critical patent/CN114481131A/en
Publication of CN114481131A publication Critical patent/CN114481131A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/134—Plasma spraying
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/06—Electrolytic production, recovery or refining of metals by electrolysis of solutions or iron group metals, refractory metals or manganese
    • C25C1/10—Electrolytic production, recovery or refining of metals by electrolysis of solutions or iron group metals, refractory metals or manganese of chromium or manganese
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/02—Electrodes; Connections thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D9/00—Electrolytic coating other than with metals
    • C25D9/04—Electrolytic coating other than with metals with inorganic materials

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Inorganic Chemistry (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)

Abstract

The invention discloses MnO for non-ferrous metallurgy2Improved method of coating electrode and its application, the composite anode structure is metal substrate/non-oxide intermediate layer/thermal decomposition MnO2Protective layer/electrodeposited MnO2A catalytic layer. Wherein the non-oxide intermediate layer prevents the metal substrate from being caused by high temperature during thermal decompositionOxidizing; thermal decomposition of MnO2The layer can avoid substrate passivation caused by higher current density in the electrolytic process; electrodeposition of MnO2The layer can fill the cracks on the surface of the thermal decomposition layer, selectively catalyze and separate oxygen, and inhibit Mn in the electrolytic process2+And (4) depletion. The composite anode prepares MnO by combining two types2Advantages of the layer method, improved over conventional metal-based MnO2Coated electrodes, reduced electrode pairs IrO2、SnO2And the dependence of the intermediate layer is reduced, so that the preparation cost of the electrode is reduced.

Description

Improved MnO2Preparation method and application of coated electrode
Technical Field
The invention belongs to the field of wet metallurgy, and particularly relates to improved MnO2A preparation method and application of the coated electrode.
Background
In the process of non-ferrous metallurgy, taking the electrodeposition of manganese as an example, the anode which is most widely applied is a Pb-Sn-1% Ag-Sb quaternary alloy anode, but the anode has the following problems to be solved:
(1) the Pb alloy anode has poor oxygen evolution electrocatalytic activity, and the oxygen evolution overpotential in the electrolytic process taking electrolytic manganese as an example is about 1V, so that the useless power consumption is close to 1500 kWh/t and accounts for about 50 percent of the power consumption of the anode.
(2) The Pb alloy has poor corrosion resistance (large anode loss, short life, contamination of cathode products by corrosion products). PbO generated on the surface of the Pb alloy anode in the polarization process2The protective film is loose and porous and is easy to fall off under the scouring of oxygen and liquid flow. On one hand, the Pb alloy substrate needs to be continuously oxidized for self-repairing to cause corrosion of the anode, and on the other hand, corrosion products can enter the electrolyte and enter the cathode through inclusion or discharge and other modes to pollute the cathode product.
(3) The Pb alloy anode has high density and low strength (creep easily occurs, which causes short circuit between the cathode and the anode to reduce the current efficiency of the cathode, even damages the anode and increases the labor intensity.
(4) The noble metal Ag needs to be added in the preparation process of the Pb alloy anode, so that the cost of the anode is greatly increased.
（5）Mn2+The depletion was severe. Due to the continuous oxidation of manganese ions, so thatThe electrolytic manganese cannot be fully utilized, and the necessity of dividing the electrolytic cell into two parts of the anode chamber and the cathode chamber increases the difficulty of operation, and the highly active powdery MnO generated in the solution during electrolysis2But is mixed with metallic lead and the lead removing process is complicated, so that MnO is caused2The utilization is difficult.
In order to improve the above disadvantages, the preparation and improvement of titanium-based DSA anodes have become of interest. The inventor finds MnO through earlier stage experiments2The DSA anode as the catalyst layer can inhibit Mn2+Greatly reducing the yield of anode mud. At present, MnO is used2The DSA anode is a catalytic layer, and is adhered to titanium substrate directly or with IrO2、RuO2、SnO2Etc., which greatly increases the manufacturing cost of the electrode. And the Ti/MnO used at present2Electrode MnO2Layers all made by a single thermal decomposition or a single electrodeposition process2The layer is relatively compact and has a crystal form of gamma-MnO2Has high catalytic activity, but has weak combination with the matrix, is easy to fall off in the electrolytic process, and MnO prepared by a thermal decomposition method2The layer is strongly bonded to the substrate, but the electrolyte easily reaches the surface of the Ti substrate due to many surface cracks, and the thermal decomposition layer is broken by a strong oxygen evolution reaction.
Therefore, from the viewpoint of reducing the energy consumption in the electrolytic manganese process and the amount of sludge produced from the anode, the metal-based MnO is improved2The coating electrode has important practical significance in prolonging the service life of the electrode and reducing the preparation cost of the electrode.
Disclosure of Invention
The invention mainly aims to provide an improved MnO2Preparation method and application of coating electrode, aiming at solving single thermal decomposition layer MnO2Electrodes, susceptible to oxygen washout and single electrodeposited MnO2The electrodes, the catalytic layer and the substrate are not firmly combined. The service life of the electrode is prolonged, and the preparation cost of the electrode is reduced.
In order to achieve the purpose, the invention adopts the following technical scheme:
improved MnO2The preparation method of the coating electrode comprises a metal substrate, an anti-oxidation intermediate layer and MnO prepared by a thermal decomposition method2Protective layer, MnO made by electrodeposition2And a catalytic layer. The electrode is pretreated according to a Ti substrate → an anti-oxidation intermediate layer → thermal decomposition MnO2→ electrodeposition of MnO2The sequence of (a) and (b).
MnO prepared by electroplating method2MnO as a surface catalyst layer for anodes, produced by thermal decomposition2As an intermediate protective layer for MnO during electrodeposition2The particles are deposited in the gaps of the pyrolytic layer, allowing the two to form an interlocking structure, so that two layers of MnO are2Mutual protection increases MnO2The stability of the layer, and the preparation of a layer of anti-oxidation film with good chemical corrosion resistance and conductivity between the manganese dioxide and the metal matrix reduces the electron transfer resistance between the metal matrix and the manganese dioxide and can prevent the oxidation of the metal matrix caused by overhigh temperature in the thermal decomposition process.
The research of the invention discovers that the service life of the electrode prepared by the invention is longer than that of the traditional Ti/MnO2The electrode is extended by at least 2 times, and the oxygen evolution potential of the electrode is reduced by at least 100 mV in the electrolytic manganese solution.
Preferably, the metal in the metal substrate is a pure metal or a hard alloy thereof, and the metal in the metal substrate is selected from at least one of Al, Ti and Fe.
Further preferably, the metal in the metal substrate is Ti.
Preferably, the anti-oxidation interlayer is selected from TiN and TiB2TiC, WC.
Further preferably, the oxidation-resistant intermediate layer is TiN. When metal titanium is selected as a substrate and the anti-oxidation intermediate layer is TiN, the preparation process is simple, and the preparation cost and the preparation time of the intermediate layer are greatly reduced.
Preferably, the TiN preparation method is a gas nitriding method, and the nitrogen source comprises at least one of nitrogen and ammonia, and the temperature is kept for a period of time at a certain temperature.
Further preferably, the nitriding nitrogen source is ammonia gas. When the active ammonia gas is selected as the nitrogen source, the reaction with the titanium substrate is quicker, and the produced TiN film has less impurity phase.
In the preferable scheme, the heat preservation temperature of the ammonia nitriding is 700-1000 ℃, and the heat preservation time is 1-24 h.
Further preferably, the Ti/TiN which meets the requirements of oxidation resistance and electrolyte corrosion can be prepared by keeping the temperature at 850 ℃ for 6 hours. When the temperature is lower than 800 ℃, the nitriding speed is slow, and when the temperature is higher than 900 ℃, the mechanical strength of the titanium substrate is reduced.
In a preferred embodiment, the thermally decomposed MnO2The preparation method of the layer comprises the steps of uniformly brushing a precursor solution containing Mn on the surface of Ti/TiN by a brush, flatly placing the Ti/TiN in a drying oven for drying, then placing in a muffle furnace for thermal decomposition at a certain temperature, repeating the steps for a plurality of times, and finally placing in the muffle furnace for sintering.
Further preference is given to: the Mn-containing precursor solution is 50% Mn (NO)3)2And diluted to a certain concentration by one of absolute ethyl alcohol, isopropanol, n-butanol and distilled water.
Further preference is given to: the drying temperature is 60-100 ℃, the thermal decomposition temperature is 150-250 ℃, the sintering temperature is 200-300 ℃, and the repetition times are 5-20 times, preferably 15 times.
Further preferred is: the drying temperature is 70 ℃, the drying time is 5 min, the thermal decomposition temperature is 200 ℃, the thermal decomposition time is 10 min, the sintering temperature is 250 ℃, and the sintering time is 1 h.
The inventor researches and discovers that the excessive high heat treatment temperature and the excessive long heat treatment time can cause a great deal of uneven and deep mud cracks on the surface of the electrode, and the low heat treatment temperature and the short heat treatment time can cause the preparation of MnO2The layer is loose and can be carried into the precursor solution during brushing.
The preferable scheme is as follows: the electrodeposited MnO2The layer is prepared by using Ti/TiN/thermal decomposition MnO2As anode, metallic copper as cathode, and MnSO4+H2SO4Or Mn (CH)3COO)2The electrolyte is subjected to constant current deposition at a certain temperature and current density, and after the deposition is carried out for 1h, the electrolyte is taken out and is dried in an oven at 100 ℃ for 1 h.
Further preference is given to: when selecting MnSO4+H2SO4MnSO is adopted as electrolyte4Concentration of 0.5 to 1.5 mol/L, preferably 1 mol/L, H2SO4The concentration is 0-1 mol/L, preferably 0.5 mol/L, the electrodeposition temperature is 70-95 ℃, preferably 90 ℃, and the current density is 1-10A/cm2Preferably 2 to 5 mA/cm2。
Further preference is given to: when Mn (CH) is selected3COO)2When used as an electrolyte, Mn (CH) is used3COO)2The concentration is 0.125-0.5 mol/L, preferably 0.3 mol/L, the electrodeposition temperature is 70-95 ℃, preferably 90 ℃, and the current density is 1-5 mA/cm2Preferably 2 to 3 mA/cm2。
More preferably, MnSO is used4 +H2SO4The system is used as an electrolyte. The research of the inventor finds that MnO prepared under a manganese acetate system2The catalyst layer is loose and not compact, and is easy to be washed by gas and dispersed into the solution in the electrolytic process.
In the present invention, MnO is thermally decomposed2The layer has a certain binding force with the Ti/TiN substrate, but because the stress difference of the layer and the Ti/TiN substrate can cause phenomena of insecurity, falling off and the like, the substrate needs to be etched, the roughness of the substrate is increased, and the MnO is further increased2Contact surface with metal substrate, enhanced thermal decomposition of MnO2The bonding strength of the layer to the Ti/TiN substrate can be optimized by controlling the concentration of oxalic acid and the etching time.
In a preferred embodiment, the etching process includes: the method comprises the steps of placing a polished and polished titanium substrate in a trisodium solution for oil removal treatment, then cleaning the surface of the substrate with absolute ethyl alcohol, and then placing the substrate in a boiling oxalic acid solution for etching for 1 hour, wherein the oxalic acid solution is an oxalic acid aqueous solution with the mass fraction of 10%, and the trisodium solution is an aqueous solution of sodium hydroxide, sodium phosphate and sodium carbonate.
The inventor finds that the metal substrate can achieve a good effect after being etched in the boiling oxalic acid solution for 1 hour, and the bonding strength of the composite anode can be improved to a certain extent.
Further preferably, the mass ratio of each part in the trisodium solution is NaOH: na (Na)3PO4：Na2CO3：H2O = 2: 2: 1: and when the oil is soaked for 40 min, the good oil removing effect can be achieved.
The invention has the advantages and positive effects that:
1) using conventional Ti/MnO2When the electrode is used for the electro-deposition of nonferrous metallurgy, if the thermal decomposition method is adopted to prepare MnO2The catalyst layer has many surface cracks, and the gas generated in the electrolytic process can wash the catalyst layer off, so the service life of the electrode is short, and Mn is not inhibited2+The effect of depletion; if the electrodeposition method is adopted to prepare MnO2The catalytic layer can prepare smooth and compact MnO2The layer, however, has low bonding strength with the metal substrate, is very easily exfoliated, and the lower current density does not allow the catalytic layer to grow to such an extent that the substrate can be protected from passivation. The electrode life can be prolonged by more than 2 times by improving the electrode by adopting the method of the invention.
2) Firstly put forward the method of thermal decomposition to prepare MnO2Preparation of MnO by post-layer electrodeposition2The catalytic layer technology prepares MnO by two methods2The anode can further reduce the anode potential and prolong the service life of the anode under the condition of ensuring that the anode can inhibit the generation of anode slime in the manganese electrolysis process.
3) Preparation of MnO by thermal decomposition2Protective layer, e.g. IrO2、RuO2The noble metal oxide has lower price and larger industrial application prospect.
4) Preparation of MnO by thermal decomposition2Protective layer, less SnO2、Sb2O3The preparation conditions of the oxide intermediate layer are milder, the heat treatment temperature is reduced by nearly 200 ℃, and the non-oxide ceramic is added as the anti-oxidation intermediate layer, so that the oxygen of the metal titanium caused by high temperature in the thermal decomposition process is greatly reducedAnd the internal electron transfer resistance of the electrode is reduced.
5) MnO prepared by thermal decomposition2Preparing MnO on the crystal nucleus by electrodeposition2Catalytic layer of so that MnO2The catalyst layer can grow in the surface cracks of the thermal decomposition layer to make the two layers combined more tightly, and the thermal decomposition layer is MnO in the process of electrodeposition2The grown crystal nuclei are provided so as to be more easily brought to a desired thickness.
Drawings
FIG. 1 shows the use of Ti/TiN/thermal decomposition MnO2Electrodeposition of MnO2Electrode and Ti/electrodeposited MnO2Constant current polarization curve of 24h during manganese electrolysis of the electrode.
Detailed Description
The following are exemplary embodiments of the invention, but it should be understood that the invention is not limited to these embodiments.
Example 1:
the method used in the invention is adopted to prepare Ti/TiN/thermal decomposition MnO2Electrodeposition of MnO2And the electrode is used as an anode in the electrolytic manganese process.
The metal titanium substrate is plate-shaped, after being polished smooth, the surface of the metal titanium substrate is degreased by trisodium solution, then the metal titanium substrate is etched in 10 percent oxalic acid solution for 1 hour, then the TiN layer is prepared by taking ammonia as a nitrogen source and preserving the heat for 6 hours at 850 ℃, the thickness of the TiN layer is about 3 mu m, and MnO is thermally decomposed2Layer selection isopropanol: the volume ratio of the manganese nitrate is 10: 6 is precursor solution, the drying temperature is 70 ℃, the drying time is 5 min, the thermal decomposition temperature is 200 ℃, the thermal decomposition time is 10 min, the coating is repeatedly brushed for 15 times, and then the coating is placed in 200 ℃ for sintering for 1 h. Electrodeposition of MnO2The layer is MnSO4+H2SO4The system is electrolyte, MnSO4Concentration of 1 mol/L, H2SO4The concentration is 0.5 mol/L, the temperature of the electrolyte is 90 ℃, and the current density is 2 mA/cm2The deposition time was 30 min.
The prepared composite anode is applied to a simulated electrolytic manganese experiment, and the cathode is made of flat stainless steel.
The electrolyte component is MnSO4 (Mn2+ 15g/L)、(NH4)2SO4 (1 mol/L)、SeO2 (0.3 g/L) at 42 ℃ at 700A/m2Anode current density of 320A/m2The cathodic current density of (a) was subjected to electrodeposition for 6 h. Compared with the current Pb-Ag-Sn-Sb alloy anode, the anode potential is reduced by 330 mV, and no anode mud is generated at the bottom of the anode chamber.
The prepared anode is subjected to accelerated life test in simulated electrolytic manganese anolyte, and the cathode is stainless steel with the same area and size.
The electrolyte component is 0.15 mol/L H2SO4、1 mol/L (NH4)2SO4Solution at a current density of 1A/cm2The electrode distance was 5 cm. When the anode potential exceeds 10V in the electrolytic process, the electrode is determined to be failed, and then the experiment is stopped. The experimental lifetime of the electrode was found to be 62 min.
Comparative example 1:
the metallic titanium substrate was treated in the same manner as in example 1. The Ti/MnO is prepared by directly adopting an electrodeposition mode after the substrate is treated2Electrode, electrodeposited MnO2The preparation conditions of (2) were the same as in example 1, except that the deposition time was extended to 2 hours. The conditions used during the manganese electrolysis and accelerated life tests of the electrode were exactly the same as in example 1. Experiments show that the anode potential of the anode is reduced by 210 mV compared with a lead anode in the manganese electrolysis process, no anode mud is generated at the bottom of the anode chamber, and the anode mud performs only 10 min in the accelerated life experiment.
Comparative example 2:
the metallic titanium substrate was treated in the same manner as in example 1. Preparing Ti/MnO by directly adopting thermal decomposition mode after substrate is treated2Electrode, thermal decomposition MnO2The preparation conditions of (1) were the same as in example 1 except that the number of thermal decompositions was increased to 20. The conditions used during the manganese electrolysis and accelerated life tests of the electrode were exactly the same as in example 1. Experiments show that the anode potential of the electrolytic manganese process is reduced by 150 mV compared with a lead anode, a little anode mud is generated at the bottom of an anode chamber, and the performance of the electrolytic manganese process in an accelerated life experiment is prolonged to be more than that of the electrolytic manganese process in comparative example 16 min。
Comparative example 3:
the Ti/TiN electrode is processed in the same way as the example 1, and then Ti/TiN/MnO is prepared on the Ti/TiN surface directly by adopting an electrodeposition mode2Electrode, electrodeposited MnO2Exactly the same conditions as in comparative example 1 were used. The conditions used during the manganese electrolysis and accelerated life tests of the electrode were exactly the same as in example 1. Experiments show that the anode potential of the anode is reduced by 300 mV compared with a lead anode in the manganese electrolysis process, no anode mud is generated at the bottom of the anode chamber, and the performance of the anode chamber in the accelerated life experiment is still poor and is only 2 min.
Comparative example 4:
the Ti/TiN electrode was processed in the same manner as in example 1, and then Ti/TiN/MnO was prepared on the surface of Ti/TiN only by thermal decomposition2Electrode, thermal decomposition MnO2Exactly the same conditions as in comparative example 2 were used. The conditions used during the manganese electrolysis and accelerated life tests of the electrode were exactly the same as in example 1. Experiments show that the anode potential of the electrolytic manganese process is reduced by 200 mV compared with that of a lead anode, a little anode mud is generated at the bottom of an anode chamber, a thermal decomposition layer is flushed by gas and falls to the bottom of the electrolytic tank in the electrolytic process, and the service life of the thermal decomposition layer is 8 min in an accelerated life experiment.
Example 2:
cutting an Al plate into samples of 10mm multiplied by 2 mm by a linear cutting method, polishing the surface of the sample by using 1200-mesh metallographic abrasive paper, placing the sample in 10% acetone solution for ultrasonic oscillation to remove oil stains and impurities on the surface of an Al substrate, taking out the Al substrate, and cleaning the Al substrate by using distilled water and ethanol for later use.
And preparing the TiN coating on the surface of the Al substrate by adopting a plasma spraying mode. The spraying parameters are as follows: the spraying operating voltage is 10V, the spraying distance is 10 cm, the spraying current is 450A, and the main gas flow is 1650L/h.
Preparation of thermolytic MnO on Al/TiN surface Using the preparation method as in example 12Layer and electrodeposited MnO2And (3) a layer. And the conditions used during the electrolytic manganese experiments were exactly the same as in example 1. Through experiments, the anode electricity of the electrode in the manganese electrolysis process is foundThe position is similar to that of a Ti-based electrode, but the preparation method is more complex and the preparation cost is higher.
Comparative example 5
Other conditions were the same as in example 2, and the intermediate layer of the composite anode was SnO2，SnO2The preparation method comprises the following steps: the precursor solution is coated on the titanium substrate by a brush by using citric acid, ethylene glycol and stannous chloride with the molar ratio of 1: 4.5: 0.33 as the precursor solution, and then the titanium substrate is dried for 10 minutes at 130 ℃ and is thermally treated for 20 minutes at 400 ℃. This process was repeated 10 times and finally annealed at 400 ℃ for 1 hour. It was found that the surface of the metal substrate had been slightly oxidized after the heat treatment. And the anode potential is similar to that of the traditional lead anode in the manganese electrolysis process, which is caused by the fact that the resistance of the electrode is integrally improved due to the oxidation of the metal aluminum.

Claims (10)

1. Improved MnO2The preparation method of the coating electrode is characterized by comprising the following steps: comprising a metal substrate, an antioxidation layer, MnO prepared by a thermal decomposition method2Protective layer and MnO prepared by electrodeposition method2A catalytic layer; the electrode is pretreated according to a metal substrate → prepared with an anti-oxidation layer → thermally decomposed MnO2→ electrodeposition of MnO2The sequential preparation of (a); the metal substrate is selected from at least one of Al, Ti and Fe, and the anti-oxidation intermediate layer is selected from TiN and TiB2TiC, WC.
2. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: the metal in the metal substrate is pure metal or hard alloy thereof, the metal in the metal substrate is selected from at least one of Al, Ti and Fe, and the shape of the metal substrate is one of flat plate shape, porous shape and plate grid shape.
3. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: the preparation method of the oxidation resistant layer is a method which can not oxidize the metal substrate, and the preparation method of the oxidation resistant layerThe method is one of an in-situ synthesis method, a plasma spraying method and a magnetron sputtering method.
4. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: the thickness of the anti-oxidation layer is 5-100 mu m.
5. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: thermal decomposition of MnO2The preparation method of the layer comprises the steps of uniformly brushing a precursor solution containing Mn on the surface of an electrode by a brush, flatly placing the electrode in a drying oven for drying, then placing the electrode in a muffle furnace for thermal decomposition at a certain temperature, repeating the steps for a plurality of times, and finally placing the electrode in the muffle furnace for sintering.
6. A modified MnO according to claim 52The preparation method of the coating electrode is characterized by comprising the following steps: the Mn-containing precursor solution is 50% Mn (NO)3)2And diluted to a certain concentration by one of absolute ethyl alcohol, isopropanol, n-butanol and distilled water.
7. A modified MnO according to claim 52The preparation method of the coating electrode is characterized by comprising the following steps: the drying temperature is 60-100 ℃, the thermal decomposition temperature is 150-250 ℃, the sintering temperature is 200-300 ℃, and the repetition frequency is 5-20.
8. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: the electrodeposited MnO2The preparation method of the layer is characterized in that the MnO is decomposed by the metal substrate/the anti-oxidation intermediate layer/heat2As anode, metallic copper as cathode, and MnSO4+H2SO4Or Mn (CH)3COO)2The electrolyte is subjected to constant current deposition at a certain temperature and current density, and after the deposition is carried out for 1h, the electrolyte is taken out and is dried in an oven at 100 ℃ for 1 h.
9. The modified MnO of claim 82The preparation method of the coating electrode is characterized by comprising the following steps: when selecting MnSO4+H2SO4MnSO is adopted as electrolyte4The concentration is 0.5-1.5 mol/L, H2SO4The concentration is 0-1 mol/L, the electrodeposition temperature is 70-95 ℃, and the current density is 1-10 mA/cm2；
When Mn (CH) is selected3COO)2When used as an electrolyte, Mn (CH) is used3COO)2The concentration is 0.125-0.5 mol/L, the electrodeposition temperature is 70-95 ℃, and the current density is 1-5 mA/cm2。
10. The modified MnO of claim 12The preparation method of the coating electrode is characterized by comprising the following steps: firstly, grinding a substrate, then placing the polished and ground metal substrate in a trisodium solution for soaking, then rubbing the metal substrate with sand paper, then placing the metal substrate in an oxalic acid solution, and etching for 1h under boiling; the trisodium solution is a mixed solution of sodium carbonate, sodium phosphate and sodium hydroxide, and the mass fraction of oxalic acid in the oxalic acid solution is 10%.
CN202210183037.7A 2022-02-27 2022-02-27 Improved MnO2Preparation method and application of coated electrode Pending CN114481131A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210183037.7A CN114481131A (en) 2022-02-27 2022-02-27 Improved MnO2Preparation method and application of coated electrode

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210183037.7A CN114481131A (en) 2022-02-27 2022-02-27 Improved MnO2Preparation method and application of coated electrode

Publications (1)

Publication Number Publication Date
CN114481131A true CN114481131A (en) 2022-05-13

Family

ID=81484801

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210183037.7A Pending CN114481131A (en) 2022-02-27 2022-02-27 Improved MnO2Preparation method and application of coated electrode

Country Status (1)

Country Link
CN (1) CN114481131A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114908378A (en) * 2022-05-18 2022-08-16 中南大学 Method for electrolyzing manganese metal without diaphragm

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114908378A (en) * 2022-05-18 2022-08-16 中南大学 Method for electrolyzing manganese metal without diaphragm
CN114908378B (en) * 2022-05-18 2024-01-26 中南大学 Method for electrolyzing manganese metal without diaphragm

Similar Documents

Publication Publication Date Title
US5435896A (en) Cell having electrodes of improved service life
JP4394159B2 (en) Method for producing electrode for electrolysis
CN111926349B (en) Composite anode for hydrometallurgy and preparation method and application thereof
CN109778100B (en) Long-life energy-saving dimensionally stable PbO2Arc thermal spraying preparation method of anode intermediate layer
US4354915A (en) Low overvoltage hydrogen cathodes
JP2006193768A (en) Cathode for hydrogen generation
JP2761751B2 (en) Electrode for durable electrolysis and method for producing the same
CN114481131A (en) Improved MnO2Preparation method and application of coated electrode
US6368489B1 (en) Copper electrowinning
EP0493326B1 (en) Substrate of improved melt sprayed surface morphology
JP5035731B2 (en) Method for reactivating electrode for electrolysis
JP4335302B1 (en) Method for producing electrode for electrolysis
US5324407A (en) Substrate of improved plasma sprayed surface morphology and its use as an electrode in an electrolytic cell
JPH0726240B2 (en) Electrolytic pickling or electrolytic degreasing method for steel sheet
JP4284387B2 (en) Electrode for electrolysis and method for producing the same
CN102560561A (en) DSA (Dimensionally Stable Anode) electrode and manufacturing method thereof
CN104846399A (en) Titanium-base TiNx/TiO2-RuO2 nano coating anode
JPH0790665A (en) Oxygen generating electrode
JPH0762585A (en) Electrolytic electrode substrate and its production
JPH07229000A (en) Oxygen generating anode
CN114164419A (en) Method for preparing platinum active layer on anode plate by thermal decomposition method
CN114561642A (en) Preparation method and application of manganese oxide composite coating electrode
CN114540824A (en) Method for regenerating titanium anode plate by using waste acid solution
CN111926345A (en) IrO2-Ta2O5 anode with TiN nanotube intermediate layer
CN113562819B (en) DSA electrode and manufacturing method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination