What are the advantages and disadvantages of oxide-coated titanium anodes in applications
Advantages of titanium anodes over traditional graphite electrodes:
(1) It can overcome the dissolution problem of graphite anode and lead anode, avoid the pollution of electrolyte and cathode products, and thus improve the purity of metal products.
(2) Titanium anode has a long working life. In the chlor-alkali industry produced by the diaphragm method, the metal anode is resistant to chlorine and alkali corrosion. The anode life has reached more than 6 years, while the graphite anode is only 8 months.
(3) The short circuit problem after the deformation of the lead anode can be avoided, so the current efficiency can be improved.
(4) The current density can be increased. In the production of chlor-alkali by the diaphragm method, the working current density of the graphite anode is 8A/dm2, and the titanium anode can be doubled to 17A/dm2. In this way, under the same conditions of the electrolysis plant and the electrolytic cell, the output can be doubled, which improves the The single-slot production capacity effectively improves labor productivity. When electrolysis is performed at high operating current densities, it is more appropriate to use titanium anodes.
(5) High temperature, high current density operation of chlorate electrolytic cells is possible due to the use of metal anodes. The use of metal anodes improves the electrolytic cell structure, reduces power consumption, and accelerates the chemical reaction of hypochlorite to generate chlorate, thereby improving production performance.
(6) Using DSA, the design concept and operating conditions of the mercury-method and diaphragm-method salt electrolyzers are improved, and the energy consumption is reduced. The low overpotential characteristics of DSA and the easy removal of air bubbles on the surface between electrodes and electrodes are the important reasons for the reduction of the voltage of the metal anode electrolytic cell.
Due to the many advantages of titanium anode, its development has made the chlor-alkali industry obtain great economic benefits, so it will soon be popularized and used all over the world. The production capacity of chlor-alkali is about 41 million tons per year in the world, and the titanium anode is not less than 70%. Titanium anode is known as a major technological revolution in the chlor-alkali industry. Subsequently, titanium anodes have also been widely used in many electrolysis industries.
(7) The anode size is stable, and the distance between electrodes does not change during the electrolysis process, which can ensure that the electrolysis operation is carried out under the condition of stable cell voltage.
(8) The switch is easy to make and can be made with high precision.
(9) Titanium anode is light in weight, which can reduce labor intensity.
(10) The base metal titanium can be used repeatedly.
(11) It has strong corrosion resistance and can work in many electrolytic media with strong corrosiveness and special requirements.
(12) The working voltage is low, so the power consumption is small, which can save the power consumption, and the DC power consumption can be reduced by 10% to 20%.
(13) With the emergence of metal anodes, the latest ionic membrane electrolysis technology that has recently emerged in the chlor-alkali industry has been designed and industrialized.
(14) In the production of chlor-alkali, after the titanium anode is used, the product quality is high, the chlorine gas is high in purity, does not contain CO2, and the alkali concentration is high, which can save heating steam and energy consumption.
The main reasons for the low working voltage of titanium anode:
1) The overpotentials of active-coated titanium anodes to chlorine and oxygen are relatively low. When salt water electrolysis produces chlor-alkali, the titanium anode has a low chlorine overpotential, which is 140mV lower than that of the graphite anode at 1A/cm2;
2) It can reduce the "bubble shielding effect", the bubbles generated on the surface of the metal anode are relatively small, and the detachment is rapid, so the aeration between the electrodes is greatly reduced, the ohmic drop between the two electrodes is about 700mV, and the diameter of the bubbles is about 3mm;
3) The resistance of the anode structure is reduced; 4) The distance between electrodes is shortened.
In the 1960s, the annual electricity consumption of the salt electrolysis industry in the world was about 150 billion kWh. After using metal anodes, about 300 million kWh of electricity can be saved every year.
