The titanium anode is called a titanium-based metal oxide coated anode (MMO). Also known as DSA anode, dimensionally stable anode. It uses titanium as the substrate (filament, rod, tube, plate, mesh), and coats the precious metal coating on the titanium substrate to make it have good electrocatalytic activity, electrical conductivity and oxidation resistance. Compared to the original graphite anode and lead anode, the titanium electrode has the following advantages:
1. The electrode size is relatively stable, and the distance between the electrodes does not change during the electrolysis process, ensuring that the electrolysis operation is performed under the condition that the cell voltage is stable;
2. High catalytic activity and low working voltage;
3, the working voltage is low, so the power consumption is small, the DC power consumption can be reduced by 10% – 20%;
4. The working life of titanium anode is long. The metal anode of the chlor-alkali industry is resistant to chlorine and alkali corrosion. The life of the anode has reached 5~7 years, while the graphite anode is only 8 months.
5. It can overcome the dissolution problem of graphite anode and lead anode, avoiding the pollution of electrolyte and cathode products, thus greatly improving the purity of metal products;
6, can increase the density of current, increase the efficiency of electrolysis;
7. The oxides of noble metals lanthanum and cerium have oxidation resistance, so the corrosion resistance of titanium electrodes is strong;
8. It can avoid the short circuit problem after the lead anode is deformed, so that the work efficiency can be improved;
9. Titanium electrode is light in weight, which can reduce labor intensity compared with graphite anode and lead anode;
10, titanium matrix shape and production is easier, high precision;
11. The substrate can be used repeatedly without damage.
Titanium anode classification:
1. According to the anodic precipitation gas in the electrochemical reaction, the chlorine anode is separated, such as the lanthanide coated titanium electrode: the oxygen evolution is called the oxygen evolution anode, such as the lanthanide coated titanium electrode and the platinum titanium mesh. /board.
Chlorine anode (tantalum coating titanium electrode): The electrolyte has a high chloride ion content, generally in a hydrochloric acid environment and electrolyzed seawater, and an electrolytic salt water environment. Corresponding to our company’s products are 钌铱Titanium anode, bismuth tin titanium anode.
2. Oxygen evolution anode (lanthanide coating titanium electrode): The electrolyte is generally in a sulfuric acid environment. Corresponding to our products are 铱钽 anode, bismuth tin titanium anode, sorghum titanium anode.
3. Platinum anode: Titanium is the substrate. The surface is plated with precious metal platinum, the thickness of the coating is generally 1-5um, and the mesh size of the platinum titanium mesh is generally 12.5×4.5mm or 6×3.5mm.
Third, the production process flow
1. Purchase the GR1 model titanium substrate to ensure that the surface of the plate is smooth and flat, without deep scratches and defects.
2. Machining the purchased titanium substrate and processing it to the size required by the customer.
3. Annealing and leveling the titanium substrate at a temperature of >500 °C. (To eliminate stress and ensure flatness.)
4. When the annealing leveling treatment, a dense titanium oxide layer is formed on the surface of the titanium substrate, and it is polished by mechanical or artificial means, and the surface thereof is made of titanium metallic luster.
5. The titanium substrate is subjected to pickling etching with 10% strength oxalic acid, and is subjected to a micro-boiling state for several hours to etch the surface oxide layer into a titanium hydride surface.
6. Qualitative and quantitative configuration of the precious metal solution according to the anode environment applied by the customer.
7. Detecting that the pickled titanium substrate is qualified, that is, the surface layer is gray uniform matte structure, and then manually coating and arranging, sintering at a set temperature, sintering naturally, cooling, and cooling to normal temperature for a second coating Resume, and so on, until the configuration solution is finished after 17~20 times.
8. After the sintering of the above processed parts is completed, the life test will be carried out with the test piece of the furnace, and the qualified package will be shipped.
Fourth, the main application areas
1. Electrolytic production of chlor-alkali industrial chlorate industrial sodium hypochlorite
The chemical industry for producing chlorine gas, hydrogen gas and caustic soda by electrolyzing salt solution is called chlor-alkali industry. It is widely used in the modern electrochemical industry and plays an important role in the national economy.
In addition to the above, it is also possible to prepare a downstream product of hydrogen chloride (aqueous solution is hydrochloric acid), sodium hypochlorite, chlorinated guanidine, polyvinyl chloride (referred to as PVC Polyvinyl chloride polymer = PVC molecular structure), hydrogen peroxide and the like.
In the production of chlor-alkali, the pure saturated brine is used as the electrolytic solution, the titanium electrode is used as the anode, the iron mesh asbestos is used as the cathode, the anode chamber generates chlorine gas, the cathode chamber generates hydrogen and sodium hydroxide, and after purification, it is widely used in various industries. in production.
The application of titanium anode greatly promotes the development of chlor-alkali industry, and it is an epoch-making contribution to the field of electrochemistry. The electrode has high catalytic activity for chlorine evolution and has good electrocatalytic activity, mechanical stability and chemical stability for chlorine evolution. It is an irreplaceable electrode material in the chlor-alkali industry today, with a service life of more than five years.
2, electrolytic function water
Functional water is defined as water that has been subjected to artificial treatment to obtain various useful functions. Electrolyzed water is welcomed as a sterilization treatment technology with good sterilization effect, high practicability and no secondary pollution. The functional water is produced by electrolyzing drinking water or a trace amount of light brine through a titanium electrode, and is widely used in an electrolysis machine.
1) The use of electrolysis to produce hypochlorite, new ecological oxygen, hydroxyl radicals and other strong oxidizing substances to kill microorganisms.
2) The electrolysis electrode is directly applied to the microorganism to cause it to die.
3) Alkaline ionized water can directly treat a variety of diseases, effectively improve the body’s metabolic function, eliminate harmful acidic metabolites, and enhance the body’s ability to prevent and improve disease resistance.
4) Acidic ionized water has the effect of inhibiting the growth of bacteria, and the effect is the same as that of cosmetic astringent water, and is sterilized by applying strong oxidizing property.
3. Manufacture of sodium hypochlorite generator and chlorine dioxide generator electrode. (84 disinfectant)
Appearance: plate, mesh, tubular, etc. Our company supplies long-term supply to a Hunan company. Its electrode size is mesh 370*350*1, current density is 30~60A, voltage is 24V.
4, cathodic protection
In the environment of steel, such as ocean, hull, bridge, etc., due to the corrosion of impurities and micro-batteries in steel, combined with the complex natural environment, although corrosion-resistant alloy steel is selected and the thickness of the material is increased, excellent corrosion-resistant paint is applied. Corrosion of structures is still very serious, which greatly threatens safe production, and cathodic protection is an important and convenient measure for effective protection of permanent steel structures in the ocean.
1) Using the applied current, the entire surface of the protected metal structure becomes a cathode, called impressed current cathodic protection.
2) Connect a metal or alloy with a more negative potential to the metal device to be protected, called sacrificial anode protection.
Applied to the following areas:
1) Prevent corrosion of ships, docks, platforms, gates and cooling equipment in fresh water and sea water.
2) In the alkali and salt solutions, corrosion of the storage tank, the evaporation can, the caustic soda pot, and the like is prevented.
3) Prevent corrosion of pipelines and cables in soil and sea mud.
5, gold plated, steel plate galvanized tin
Titanium electrode has excellent electrical conductivity and corrosion resistance, and its service life is much higher than that of lead anode. It can work stably for more than 4,000 hours and has low cost. It will be an inevitable trend in the development of electroplating zinc and tin production at home and abroad.
Titanium electrodes are currently used in Japan, the United States, Germany, and China, which not only greatly saves plating energy, but also creates conditions for the production of thick galvanized and tin steel sheets because of the increased plating current density.
6, non-ferrous metal extraction
Electrolytic metallurgy occupies a large proportion in the hydrometallurgical industry. Non-ferrous metals produced by electrolytic metallurgy include Zn, Cd, Cu, Mn, Co, Ni, Cr, and the like.
The advantages of electrolytic metallurgy are high selectivity, high purity metals, and the recovery of useful metals. Therefore, it can handle low-grade minerals and complex polymetallic ore components, which is beneficial to the comprehensive utilization of resources. In addition, the pollution to the environment is small, and production is easier to continue and automate.
In recent years, coated titanium electrodes have been widely used in the field of electrolytic extraction of metals, and have become the second industrial field in which titanium electrodes are used on a large scale.
7, electrolytic copper foil
With the development of science and technology, the degree of automation is increasing, which has promoted the rapid development of the electronics industry. The application of large integrated circuits has increased the demand for copper foil in the electronics and instrument industry, and the quality requirements for copper foil are also increasing.
According to the thickness, it can be divided into several types such as 105 μm, 70 μm, 35 μm, 18 μm, 12 μm, 9 μm, and 5 μm, and the copper foil of 12 μm or less is generally referred to as an ultra-thin copper foil.
The electrolytic copper foil is a cathode which is partially immersed in a copper sulfate solution and continuously rotated, and is continuously electrolyzed to produce a foil. The international production of copper foil is mainly controlled by Japan, with about 15 domestic production enterprises and a production capacity of around 35,000 tons.
8, sewage treatment
With the rapid development of industry and agriculture and population growth, the amount of sewage discharged by humans has increased dramatically, causing many waters to suffer from different degrees of pollution. Electrochemical treatment of sewage is divided into direct electrolysis and indirect electrolysis.
1) Direct electrolysis means that contaminants are directly oxidized or reduced on the electrode to be removed from the wastewater. Direct electrolysis can be divided into a cathode process and an anode process. The anode process refers to the oxidation of pollutants on the surface of the anode to be converted into less toxic substances or biodegradable substances, and even inorganic substances to reduce the pollution. The cathode process refers to the reduction of pollutants on the surface of the cathode to be removed. It is mainly used for the recovery and dehalogenation of halogenated hydrocarbons and the recovery of heavy metals.
2) Indirect electrolysis refers to the use of electrochemically generated redox species as reactants or catalysts to convert pollutants into less toxic substances. Indirect electrolysis can be divided into reversible processes and irreversible processes. The reversible process refers to the electrochemical regeneration and recycling of redox species during electrolysis; the irreversible process refers to the oxidation of organic matter by substances produced by irreversible electrochemical reactions.
It is applied to printing and dyeing wastewater treatment, landfill leachate treatment, manure sewage treatment, cyanide-containing wastewater treatment, pharmaceutical wastewater treatment, hospital sewage treatment, and organic wastewater treatment.
9, PCB electronic circuit board factory etching waste liquid recycling
Etching is an important process in the production of printed circuit boards. With etching, the waste etching solution contains a large amount of copper ions or other metal ions, which can be recycled by electrolysis. Through this recycling process, enterprises not only increase the economic benefits by recycling metals such as copper, but more importantly, they meet emission standards and resource recycling, and have long-term social benefits.
The waste liquid includes: acid etching waste liquid, alkaline etching waste liquid, low copper containing waste liquid, waste fixing liquid, waste frame material, nickel-containing waste liquid, waste liquid containing gold and palladium, and waste tin-removed water.
Five, electrode use precautions
1. The titanium electrode is black after being oxidized and sintered, and the uncoated surface is blue without electrode performance, and the black side is used for the cathode.
2. Once the titanium electrode substrate is acid-washed, all the subsequent production and processing steps and procedures must be carried out with strict care. When transporting, wear clean gloves to catch the ends or edges of the anode, preferably in the uncoated portion. Any foreign matter is strictly prohibited from being scratched on the surface of the coating.
Note: The titanium matrix itself is not electrically conductive, and its outer layer coated with noble metal oxide coating has electrocatalytic activity, electrical conductivity and oxidation resistance, but its thickness is only about 20 microns. If it is scratched or damaged, it is electrolyzed. During the process, the electrode first corrodes from the damage, which in turn affects the quality and effectiveness of the entire electrode.
3, the electrolyte maintains stability, especially can not contain cyanide ions and fluoride ions, these impurities will seriously corrode the titanium matrix;
4. The electrolyte should be added to the electrolysis tank before adding the filter device. It should not contain metal particles with a diameter greater than 0.1mm to prevent the accumulation of too much cathode and anode short circuit.
5. When electrolytically recovering metals such as copper, nickel, gold, silver, cobalt, etc., the cathode deposits shall not be too thick to prevent the pole pitch from being too small or the metal thorn formation to cause a breakdown of the cathode and cathode.
6, the anode and cathode spacing can be set according to the actual production, generally 5-25mm. Generally speaking, the pole distance assembly increases the voltage drop, but it should not be too small, otherwise the cathode scale generated on the cathode surface is liable to cause short circuit of the pole plate;
7. Avoid using the pole. Once the noble metal oxide coating is used as a cathode, the surface undergoes a reduction reaction, which is easily converted into a simple metal element, and cannot be effectively combined with the titanium base, causing the coating to fall off.
8. It is not advisable to immerse in the solution in the power-off mode for a long time when stopping. It is best to load a small current of about 5A to protect the plates.
9. When shutting down or other maintenance conditions, add diluted acid or clean the surface of the electrode with water, but do not wash with nylon or mechanical substances.
10, the temperature of the electrolyte should not be too high, the ideal temperature of 25-40 ° C, there are conditions to add heat exchangers to maintain the electrode environment.
11. The normal working current density is less than 2000A/m2. If the current is too large, the reaction is too intense and the anode life is shortened.
12. When starting up, add current to the electrolyzer in a step-by-step manner. Do not raise it in one position at a time, as well as when it stops.
13. Keep the anode clean during production and use, and do not contaminate oil or other deposits, so as not to affect the electrolysis effect and electrode life.
14, the anode has life, to ensure the stability of production is more beneficial to extend the life cycle.
Titanium anode for industrial wastewater treatment
Electrolytic oxidation or electrochemistry, in the process of treating water, including industrial water and factory wastewater, the electrode not only plays a role in transmitting current, but also catalyzes the oxidative degradation of organic matter. In this process, since it does not cause pollution, Known as green water treatment. With the development of industry, the discharge of organic wastewater is increasing, especially the high-concentration wastewater discharged from the chemical, food, pesticide and pharmaceutical industries. The color is highly toxic and contains a large amount of bio-degradable components, which seriously pollutes the rivers and lakes. sea. The new technology of electrolytic treatment of water has no need to add chemical agents, the equipment is small in size, covers a small area, does not produce secondary pollution, and has been used to treat wastewater containing organic pollution such as hydrocarbons, alcohols, aldehydes, ethers and phenols. The removal of COD mainly depends on the oxidation reaction on the surface of the anode, and directly oxidizes and degrades the organic matter on the surface of the anode, so that the organic matter in the sewage is directly or indirectly converted into CO2 and water through electrochemical conversion. The anode potential must be higher than the decomposition potential of the organic matter, so the two catalytic reactions of organic oxidation and oxygen evolution are carried out on the anode.
The noble metal oxide coated titanium anode has a high oxygen evolution overpotential, and the anode potential is higher than the decomposition potential of the organic matter. Suitable for sewage treatment. The shape of the anode is available in various forms such as plate type, tube type, and mesh type, and the quality is reliable. The titanium matrix can be reused.