Detailed explanation of the physical and chemical properties of electrode paste
Electrode paste is a kind of conductive material used in electric furnace equipment such as ferroalloy furnaces and calcium carbide furnaces. It plays a vital role in the smelting process of electric furnaces.Electrode paste not only requires high temperature resistance and oxidation resistance, but also good electrical conductivity and mechanical strength.The following is a detailed analysis of the physical and chemical properties of the electrode paste.
High temperature resistance and coefficient of thermal expansion
The electrode paste can withstand high temperatures and has a small coefficient of thermal expansion.In the smelting process of electric furnace, the electrode needs to withstand an arc temperature of up to 3500℃, and the electrode paste made of carbon material can be slowly oxidized at such a high temperature due to its unique physical and chemical properties, maintaining the stability of the electrode structure.The high temperature resistance characteristics of the electrode paste enable it to work in an electric furnace for a long time without failure.
Conductivity
The electrode paste has a small resistivity, which helps to reduce the loss of electrical energy.During the sintering process of the electrode paste, the resistivity gradually decreases as the temperature increases.The electrode paste has a higher resistivity within 200℃, but when the temperature reaches 300-500℃, the resistivity decreases significantly; when the temperature continues to rise to 500-800℃, the resistivity steadily decreases to below 10µΩ·m; when the temperature reaches above 800℃, the resistivity basically tends to stabilize.At this time, most of the current is input into the furnace through the sintered electrodes, ensuring the smooth progress of the smelting process.
Mechanical strength
The electrode paste has high mechanical strength, can resist the influence of mechanical and electrical loads, and prevent the electrode from breaking.During the sintering process of the electrode paste, the mechanical strength of the electrode paste gradually increases as the volatile components of coal asphalt are discharged and carbonized to form a network-like structure.When the sintering temperature of the electrode paste reaches 300-800℃, the compressive strength reaches 17-33MPa, the flexural strength is 7-17MPa, and the tensile strength is 4-8Mpa.This high strength ensures the stability and durability of the electrode in the smelting process.
Porosity and oxidation
The electrode paste has a smaller porosity, which helps to slow down the oxidation rate of the electrode under heating.The porosity is related to the fluidity of the electrode paste, the type and quantity of adhesive, and the particle size composition of the fixed carbonaceous part.By optimizing the formula and controlling the production process, the porosity of the electrode paste can be reduced and its oxidation resistance can be improved.
Sintering process and physical and chemical changes
The sintering process of electrode paste is a complex process of physical and chemical changes.During the sintering process, a continuous bridge structure is formed between the various materials and particles in the electrode paste through the weak Van der Waals force and the various binding forces generated by the asphalt “film” of the binder.As the temperature rises, the binder coal bitumen condenses and concentrates, bonding the solid material in the electrode paste into a dense body.At the same time, the volatile components in the electrode paste are gradually discharged, and the volume of the electrode shrinks, forming a dense electrode structure.
Particle size and fluidity of electrode paste
The particle size distribution of the electrode paste has an important influence on its performance.If the particle size is too large, it is easy to cause the electrode paste suspension to fail; if the particle size is too small, it is easy to cause the phenomenon of spraying paste.Therefore, in the production and use process of electrode paste, the particle size distribution needs to be strictly controlled to ensure its good fluidity and use effect.
Precautions in practical applications
In the process of using the electrode paste, it is necessary to pay attention to the height control of the electrode paste column.The electrode paste column is too high or too low, which will affect the roasting quality and consumption speed of the electrode.The height of the suitable electrode paste column is conducive to improving the quality of electrode roasting and reducing consumption.In addition, it is necessary to pay attention to the insulation measures of the electrode and the load control during restart to avoid the electrode breaking due to temperature changes.
