The classification of the electrolytic bath

Aqueous electrolytic cell

The form of aqueous electrolytic cell, can be divided into two categories, diaphragm electrolyzer and diaphragm electrolyzer.Diaphragm cell and can be divided into both to membrane (asbestos wool), ionic membrane and solid electrolyte membrane (such as beta Al2O3) form;No diaphragm cell is divided into mercury cell and oxide electrolyzer, etc. titaniumcn

Using different electrolyte, the structure of the electrolytic cell is also different.

Aqueous solution with diaphragm and diaphragm electrolyzer points two kinds.General multi-purpose diaphragm electrolyzer.In chlorate production of chlorine and caustic soda production and mercury method, adopting the diaphragm electrolyzer.As far as possible increase of electrode surface area per unit volume, can improve the production of electrolytic tank strength.Therefore, in modern diaphragm cell electrodes are upright.Electrolytic cell because of different internal components, structure, installation and other materials show different performance and features.

Molten salt electrolytic cell

Much used for preparing low melting point metal, its characteristic is running at high temperatures, and should try to prevent moisture to enter, avoid hydrogen ions on the cathode reduction.When preparing sodium metal, for example, due to sodium ions in the cathode reduction potential is very negative, reduction is difficult, must use do not contain anhydrous hydrogen ions in molten salt or molten hydroxide, lest cathode hydrogen.For electrolytic process should be carried out at high temperatures, such as electrolysis of molten sodium hydroxide at 310 ℃, such as mixed electrolytes containing sodium chloride, the electrolytic temperature about 650 ℃.

The high temperature of electrolyzer can by changing the electrode spacing, the ohmic voltage drop of electric energy into heat energy to achieve.Electrolysis of molten sodium hydroxide, tub available iron or nickel, often due to raw material in electrolysis of molten electrolyte containing chloride inevitably into a small amount of water, can make the anode generated, wet chlorine gas corrosion effect of electrolytic cell is very strong, so the electrolysis of molten chlorides, general use or phosphate ceramic materials, and the part of the role is not affected by chlorine gas available iron.Yin, anode products of molten salt electrolytic cell, also requires properly separated, and should be generalized by the slot as soon as possible, so as to avoid product sodium metal cathode long floating on the surface of the electrolyte, further with the anode product or oxygen in the air.

Nonaqueous electrolytic cell

As a result of nonaqueous solution electrolysis cell in preparing organic products or electrolytic organic matter, often accompanied by a variety of complex chemical reaction, make its application is restricted, industrialization.Commonly used organic electrolyte, low conductivity, response speed and small.Therefore, must use low current density, pole spacing to narrow as far as possible.Using fixed bed or fluidized bed electrode structure has a larger surface area, can improve the cell production capacity.

Classified by the electrode connections

The electrolytic cell according to the electrode connections, can be divided into two categories, unipolar and bipolar electrolyzer.Monopolar type electrolytic cell with the polarity of electrodes and the dc power supply in parallel connection, both sides of the same polarity, electrode at the same time as the anode or at the same time as the cathode.Double pole at the ends of the cell electrodes respectively with that of the dc power supply is connected to the cathode, become the anode or cathode.Current flow through a series of electrodes electrolytic cell, the middle side of each electrode as anode, the other side as the cathode, thus has the dual polarity.When the total area of the electrode at the same time, the complex pole electrolytic cell current is small, high voltage, dc power supply for investment than the single pole type province.Double pole type generally adopt pressure filter structure form, more compact.But easy to leakage and short circuit, groove structure more complicated than the single pole type and operation management.Monopolar type cell cross section is rectangular or square, commonly cylindrical covers an area of big, the space utilization rate is low, use less.

The main structure of electrolytic bath

electrode
The anode
The effect of anode and cathode, on the material requirements also vary.
Points two categories, soluble and insoluble.In the refined copper electrolytic cell, for soluble anode materials for refining crude copper.It into in the process of electrolytic solution, to replenish from the precipitate in the solution on cathode copper.In electrolytic solution (such as salt aqueous solution) using electrolytic cell, for insoluble anode, basic don't change them in the electrolytic process, but for the electrode on the surface of the anode reaction often has a catalytic role.In the chemical industry, USES mostly insoluble anode.titaniumCN
Anode material should meet the basic requirements of general electrode materials (such as electrical conductivity, catalytic activity intensity, processing, source and price), still need strong in anodic polarization and high temperature of the fluid of the anodic dissolution and passivation, has the very high stability.For a long time, graphite anode materials is the most widely used.But porous graphite, mechanical strength is poor, and easily oxidized to carbon dioxide, are constantly in the process of electrolytic corrosion spalling, electrode spacing increases gradually, slot voltage rise.Used in electrolytic salt aqueous solution, the analysis on the graphite electrode overpotential is higher also.
The cathode
With metal or alloy as the cathode, due to the work under more negative potential, often can play a role of cathodic protection, corrosion resistance is small, so easy to choose cathode materials.In aqueous solution in the electrolytic cell, cathode generally produce hydrogen evolution reaction, higher overpotential.So the cathode material of the main improving direction is to reduce hydrogen evolution overpotential.In addition to lead must be used when using sulfuric acid as electrolyte and graphite as cathode, low carbon steel is a common cathode materials.Methods used to reduce power consumption, the current preparation of high specific surface area, and has the catalytic activity of the cathode, such as porous nickel plating cathode.
The diaphragm
In order to prevent the product mix, Yin and Yang poles to avoid the possibility of harmful reaction, in the electrolytic cell, basically use the diaphragm to Yin and anode chamber is separated.Diaphragm needs to have certain porosity, can make the ions, and not make the molecules or bubbles through, when have a current flows through the diaphragm of the ohmic voltage drop.These performance requirements in use process, and requirements in the Yin, the anode chamber under the action of the electrolyte, good chemical stability and mechanical strength.Electrolysis of water, the Yin and the anode chamber with liquid electrolyte, electrolytic cell membrane to separate Yin and anode chamber, in order to ensure the purity of hydrogen, oxygen, and to prevent hydrogen and oxygen mixture explosion.More complex situation is Yin in electrolytic cell anode chamber, different composition of the electrolyte.At this time also need to prevent Yin, anode diaphragm chamber and electrolyte in electrolytic product diffusion effect, such as chlor-alkali production in the diaphragm electrolyzer diaphragm method, can increase the cathode chamber hydroxyl ion diffusion into the anode chamber and migration resistance.

The classification of the titanium anode

Soluble and insoluble anode TitaniumCN
The soluble anode in the electrolysis process of added metal ions and the conductive role, insoluble anode conductive role only.Is the earliest insoluble anode graphite and lead anode of titanium anode in the 1970 s as a new technology used in electrolysis and electroplating industry.The insoluble anode can be divided into two broad categories: chlorine evolution anodes and oxygen evolution anode.Chlorine evolution anodes is mainly used for chloride electrolysis system, in the process of electroplating anode with free chlorine, so called chlorine evolution anodes;Oxygen evolution anode is mainly used for sulfate, nitrate, hydrocyanic acid salt electrolytic fluid system, such as electroplating anode in the process of oxygen is released, so called the oxygen evolution anode.Lead alloy anode oxygen evolution anode, titanium anode respectively according to their different surface catalytic coating effect with functions of oxygen, chlorine, or both.
Chlor-alkali industrial titanium anode
Compared with graphite electrode, the method of diaphragm caustic soda production, the working voltage of graphite anode for 8 a/DM2 coating anode can be multiplied, up to 17 a/DM2.This product can be doubled in the same electrolysis environment, and the raw products of high quality, high purity chlorine.
Plating titanium anode
Plating on titanium substrate with insoluble anode is (mesh, plate, strip, tube, etc.) on the coating with high electrochemical catalytic properties of noble metal oxide coating, coating of valve metal oxide containing high stability.New insoluble titanium anode with high electrochemical catalytic ability, oxygen evolution overpotential is lower than insoluble lead alloy anode is about 0.5 V, significant energy saving, high stability, polluting the plating solution, light weight, easy to replace.New type of titanium insoluble anode of the oxygen evolution potential and less than platinum plating insoluble anode, but life is more than double.Is widely used in various kinds of plating used as anode or auxiliary anode, can replace conventional lead alloy anode, in the same conditions, can lower the cell voltage, save power consumption;Insoluble titanium anode in the electroplating process has a good stability (chemical, electrochemical), long service life.This gold-plated anode is widely used in nickel plating, chrome plating, galvanized, electroplating non-ferrous metals such as copper plating industry.
Lead and lead alloy anode
Belongs to the oxygen evolution anode lead alloy anode, oxygen evolution reaction of the electrolyte for sulfuric acid and sulfate, is mainly used for metallurgical electrolysis.Such anode electrolysis in the process of the defects of geometry size will change.First of all, in the process of electrolysis, lead anode matrix into lead sulfate, and then into the lead.Lead sulfate is a middle tier, it is an insulator, to play the role of a chemical barrier layer, can protect the inner lead substrate in sulfate environment.Lead oxide in the outer layer is the practical significance of electrode, the oxygen evolution reaction, oxygen evolution potential of lead oxide is very high, and with the increase of current density increases rapidly, the feature of lead alloy anode is lead oxide by its outer layers of the inherent characteristics of lead oxide - is a poor conductor of electricity.In addition, in the process of electrolysis, electrochemical properties of lead oxide anode structure constantly attenuation, falls off to produce oxide layers of its internal stress, in addition, the formation of lead oxide and lead to oxide dissolution, as an intermediary lead sulfate is converted to once again lead oxide, become the new outer oxide electric catalytic active substance, the inner layer of lead substrate by oxidation, form a new lead sulfate layer in the middle.As a result, in the process of electrolysis, lead and its alloys are dissolved into electrolyte and precipitation in the solution pollution (chemical precipitation in the solution) and cathode product contamination (contaminants on the surface of the cathode electrodeposition, electrolysis to the purity of copper not good guaranteed).
Coating titanium anode
Coating titanium Anode, called DSA (Dimensionally Stable Anode dimension Stable Anode), also called DSE arithmetic (Dimensionally Stable Electrode), is developed in the late 1960 s, a new type of insoluble Anode material.DSA coating titanium anode is mainly used in the electrochemical and power metallurgy sector.
DSA coating titanium anode application areas are: chlor-alkali industry, chlorate production, production of hypochlorite, perchlorate, persulfate electrolysis, electrochemical organic synthesis, production of electrolytic extraction of non-ferrous metal, electrolytic silver catalyst, manufacturing electrolysis copper foil, electrolytic oxidation recycling mercury, electrolysis, chlorine dioxide production, hospital wastewater treatment, electroplating factory cyanide wastewater treatment, water and food utensils disinfection, power plant cooling circulating water treatment, woolen mill dyeing wastewater treatment, industrial water treatment, electrolysis legal system in acid and alkaline ionized water, copper zinc plated, rhodium, palladium plating, plating, plating lead, electrodialysis desalination, electrodialysis method take tetramethyl ammonium hydroxide, molten salt electrolysis, battery production, cathodic protection, in the production of the cathode foil, aluminum foil anodic oxidation, etc.Applications involving chemical, metallurgical, water treatment, environmental protection, electroplating, electrolysis and other fields in organic synthesis.

The advantages of titanium anode

1, titanium anode TitaniumCN working life is long, the diaphragm method in the production of chlor-alkali industry, metal anode resistance to chlorine and alkali corrosion, anode has six years of life, and the graphite anode is only 8 months.
2, can overcome the graphite anode and lead anodic dissolution, avoid the pollution to the electrolyte and cathode, and thus can improve the purity of metal products.
3, can improve the current density.Diaphragm method in chlor-alkali production, work of graphite anode current density is 8 a/dm2, titanium anode can multiply, up to 17 a/dm2, so in the electrolysis workshop, under the same conditions, yield can increase 1 times, improve the ability of single tank production, effectively improve the labor productivity.In electrolysis under high working current density, the use of titanium anode is good.
4, with metal anode, chlorate cell operation of high temperature, high current density is possible.Metal anode used to improve cell structure, reduces the power consumption, accelerate the hypochlorite angry chlorate in the chemical reaction, so as to improve the production performance.
5, adopt DSA, mercury method and membrane method the design concept of salt electrolytic cell and operating conditions to improve, to reduce energy consumption.DSA low overpotential properties, electrode and electrode surface bubbles easily between, is the important reason for the metal anode electrolyzer cell voltage is lower.
Because the titanium anode has many advantages, it development of chlor-alkali industry made great economic benefits, so soon used widely all over the world.Chlor-alkali production capacity, the world is about 41 million tons/year, adopts the titanium anode is not less than 70%, titanium anode was regarded as a major technological revolution in the chlor-alkali industry.After that, the titanium anode in a lot of electrolytic industry also has been widely applied.
6, anode size stability, CLP interelectrode distance does not change, electrolytic process ensures electrolytic operating under the condition of cell voltage stability.
7, can avoid lead anode after deformation problem of short circuit and current efficiency can be improved.
8, titanium anode light weight, can reduce labor intensity.
9, switch to make easy, but high precision.
10, low work voltage, so the power consumption is small, can save power consumption, dc power consumption can be reduced by 10% ~ 20%.The main reason for the low titanium anode working voltage: 1) active coating titanium anode overpotential of chlorine and oxygen are relatively low.Electrolytic brine in chlor-alkali production, titanium anode for low chlorine overpotential, in 1 a/cm2 is lower than graphite anode 140 mv;2) can decrease the shielding effect "bubbles", metal anode surface generated by the bubble is small, and out quickly, so greatly reduced degree of aeration between electrodes, ohmic drop between the poles of about 700 mv, air bubble diameter is about 3 mm;3) to reduce the resistance of the anode structure;4) shortens the interelectrode distance.[1]
In the 1960 s, the world salt electrolysis industry consume about 150 billion degrees, use metal anode, each year about 300 million degrees can save electric energy.
After 11, in chlor-alkali production, the use of titanium anode, products with high quality and high purity chlorine, including CO2, alkali concentration is high, can save heating steam, saves the energy.
12, corrosion resistance is strong, can be in many highly corrosive, electrolytic medium with special requirement.
13, titanium substrate metal can be used repeatedly.
14, the presence of the metal anode, the use of chlor-alkali industry in the recent emergence of ionic membrane electrolysis with the latest technology to design and realize industrialization.

The advantage of copper nickel alloy condenser pipe used in ship industry

Heat exchanger and condenser in power plants, chemical plants, petrochemical equipment, and plays a significant role in many fields such as pharmaceutical, food machinery, one of the important equipment which is the important component of heat exchange tube and condensation tube, it directly affects the service life of the unit, Ann, efficiency, heat exchanger and the number of condenser tube is very much, the cost of heat exchanger and the condenser of the cost of 60% 80%, therefore, selects the high ratio of performance and condensation tube heat exchange tube of metal materials, is the crucial one annulus.TitaniumCn
The material, and heat exchange tube condenser pipe shall have excellent heat transfer performance, more want to have good resistance to corrosion, erosion and abrasion resistance, also should have good strength and rigidity and good plasticity, easy processing and manufacturing.
Nickel copper alloy condenser pipe, it is a kind of tubing used in cooling equipment, water cooling system is mainly used in ships.First is to use tin brass, then add the arsenic, so as to improve the quality of the condenser pipe and life.If add Mn, Ni, and trace rare earth elements, can further improve on the strength and corrosion resistance.At present, the main is to use and BF10 BFe30-1-1-1-1.
That compared with titanium, stainless steel material, what is the difference between the three?
(1) titanium
In the future, may use titanium instead of copper and nickel alloys, as the material of ships to the condenser.Because big place in sea water flow, if you use the monel alloy, because its price is too high, so the use value is not high.The use of copper and nickel alloy material, although it is commonly used materials, but cannot be used for a long time, life is limited, so need to be replaced on a regular basis.And titanium, it will not be in all concentrations of sulfide corrosion, so the seawater containing sulfide has good corrosion resistance, service life is longer.
In addition, the heat conduction performance of the titanium is poorer, but by the method of using thin-wall titanium tube can be improved.But overall, titanium condenser pipe compared with nickel copper alloy condenser pipe, there are still some problems.The production and processing of titanium is difficult, production is not high also, and expensive, so the price is not dominant.
(2) stainless steel
It is hard to become the condenser pipe material, because its thermal conductivity for only 38% of copper and nickel alloy, while the corrosion rate and corrosion rate is better than that of copper and nickel alloy, but to solve a problem, that is the problem of biofouling prevention, if you can't solve this problem well, so will affect the use effect.

Titanium mesh can be applied to high temperature resistant filter, shipbuilding, war industry manufacturing, etc.

Titanium mesh is mainly used in acid, alkali environment conditions screening and filter or separation of gas and liquid filtration, and other medium.Plain weave, twilled weave, dense weave the three methods.As a result of the titanium wire drawing is difficult, the current domestic drawing comparison is incredible titanium wire of the finest can do 0.1 mm, titanium wire of low elongation, strength, elasticity, flexibility, low.Great limits the high orders, the production of titanium mesh.The specifications of the titanium mesh 1-100 mesh.Anpingxian have years of experience in screen production, the production of titanium net has the characteristics of filtering performance is stable, fine.
Is the most common method of weaving, the main characteristic is the density of warp and weft wire diameter is the same. TitaniumCN
Twill titanium mesh is suitable for the petroleum, chemical, chemical fiber, aerospace and other industries, has a good acid and alkali resistance, resistance to high temperature, strong tensile resistance and wear resistance properties.
Pure titanium dense mesh plain weave, twill weave a pure titanium lp network performance: has the characteristics of filtering performance is stable, fine.Usage: used for aerospace, petroleum, chemical industry, etc.
Material: GR1, GR2, GR3, R50250, titanium alloy, etc
Material surface: 1. The black surface (containing graphite coating) 2. The light (no graphite coating)
The corrosive resistance characteristics of titanium mesh
High purity titanium mesh in corrosion medium environment, generated on the surface of a dense layer of oxide film, strong adhesion, large inertia, the passivation phenomena, protect the titanium mesh substrate from corrosion, so as to achieve strong corrosion resistance;Especially in the use of the following environment more excellent corrosion resistance, such as: water, wet chlorine, chlorite and hypochlorite solution, nitric acid, chromium acid metal chloride and organic salt (such as nitric acid of 60%, pure titanium mesh in nitric acid solution in the corrosion speed of only 0.001 mm. A - 1);The "twelfth five-year" plan for energy conservation and emissions reduction requirements of the state council, promote the traditional industry upgrade, speed up the use of high technology and advanced applicable technology to upgrade traditional industries.Titanium mesh with excellent corrosion resistant performance to replace traditional material, such as no nickel metal material such as stainless steel net, aluminum net, pure titanium mesh long service life, safe and reliable operation.
Titanium mesh can be applied to high temperature resistant filter, shipbuilding, war industry manufacturing, chemical filter, mechanical filter, electromagnetic shielding wire mesh, mesh, high temperature furnace heat treatment desalination network, oil filter, food processing, medicine, filtering, etc.

The special properties of nickel and titanium alloy

1, the characteristics of shape memory (shape memory) shape memory is when the mother of a certain shape by Af temperature cooled to Mf temperature above the following after the formation of martensite, the martensite temperature deformation under Mf, and through heat below Af temperature, along with the inverse transformation, material will automatically restore its shape in the parent phase.Actually shape memory effect is one of the nickel titanium alloy by thermal induced phase transformation process. titaniumcn
2, super elasticity (superelastic) of hyperelastic refers to the sample production under external force is greater than the elastic limit stress strain variable, the phenomena of strain can be automatically restored when unload.Namely in the parent phase state, as a result of the action of applied stress, cause stress induced martensite phase transformation, thus alloy showed different from ordinary material mechanics behavior, its elastic limit is far greater than ordinary materials, and no longer comply with hooke's law.Compared with shape memory properties, hyperelastic without heat.To sum up, super elasticity refers to the internal stress within a certain deformation range increase along with the increase of strain, super elasticity can be divided into two categories, linear superelasticity and nonlinear hyperelastic.The stress-strain curve of stress and strain of the nearly linear relationship.Nonlinear hyperelastic refers to the Af above a certain temperature range, respectively, in the process of loading and unloading stress induced martensitic transformation and its inverse transformation results, so the nonlinear hyperelastic also called phase change pseudo elastic.Phase change of the nickel titanium alloy pseudo elastic can reach about 8%.Nickel titanium alloy of hyperelastic can change with the change of the heat treatment conditions, when the arch wire is heated to 400 & ordm;C above hyperelastic began to decline.
3, in the mouth temperature sensitivity: stainless steel wire and treatments of the CoCr alloy wire tooth orthopaedic basic is not affected by the influence of the temperature of the mouth.Treatments of the superelastic Nitinol wire tooth orthopaedic force along with the change of oral temperature changes.When the deformation must be.And correcting force increases as the temperature increases.On the one hand, it can accelerate the movement of the teeth, this is because the change of temperature in the oral cavity can cause capillary stimulation caused by rectification device stagnation of blood flow, blood flow to the sluggish rate so as to make the repair cells in the process of moving teeth get adequate nutrition, to maintain its vitality and normal function.Orthodontic doctors can't accurate control, on the other hand, or force measurement of oral environment correction.
4, corrosion resistance, studies have shown that the corrosion resistant properties of nickel and titanium wire and stainless steel wire
5, poison resistance: niti shape memory alloy special chemical composition, that is, this is a nickel titanium alloy atom, containing about 50% of the nickel, nickel and known have carcinogenic effect and promote cancer.General cases, the surface layer of titanium oxide ACTS as a barrier, the Ni Ti alloy has good biocompatibility.Surface layer TiXOy and TixNiOy can inhibit the release of the Ni.
6, treatments of the soft power: the teeth of commercial application of wire including austenitic stainless steel wire, cobalt - chrome - nickel alloy wire, nickel chromium alloy wire, alloy silk, gold wire and Australia to decide the titanium alloy wire.About the orthodontic correction of wire in the tensile test and three point bending test conditions of load - displacement curve.Nickel titanium alloy curve of unloading platform the lowest and most flat, it can provide most persistent treatments of the soft power.
7, good damping characteristics: caused by chewing and night molars for arch wire vibration, the greater the damage of tooth root and periodontal tissue.Through different attenuation experiment results, the study found the arch wire stainless steel wire vibration amplitude is larger than hyperelastic nickel titanium silk, super elastic nickel-titanium arch wire the initial vibration amplitude is only half of stainless steel wire, good vibration and shock absorption characteristics of the arch wire is important for the health of the teeth, and traditional arch wire such as stainless steel wire, tend to increase the root absorption.