Selection and optimization of electrode paste in mine heating furnace
As the key equipment in the smelting process of ferroalloy, calcium carbide, etc., the operating efficiency and electrode life of the ore heating furnace directly affect the production cost and product quality.As an important conductive material in ore heating furnaces, the selection and optimization of electrode paste is of great significance to improve smelting efficiency and extend electrode life.
1. The composition and function of electrode paste
Electrode paste, also known as self-baking electrode, is a conductive material used in electric furnace equipment such as ferroalloy furnaces and calcium carbide furnaces.It is made of raw materials such as anthracite coal, metallurgical coke, graphite crushed, petroleum coke and bituminous coke, and asphalt and coal tar are used as binders to produce it.The electrode paste relies on heat to complete the roasting in the mine heat furnace, and has good electrical conductivity, high temperature resistance and adhesion properties.
The main functions of electrode paste include：
Electrical conductivity: As a conductive material, the electrode paste can effectively conduct current, so that the current is input into the furnace through the electrode to generate an arc for smelting.
High temperature resistance: The electrode paste needs to maintain stable electrical conductivity at continuous high temperatures to withstand arc temperatures up to 3500℃.
Bonding performance: The electrode paste can be firmly bonded to the electrode and is not easy to fall off, ensuring the integrity and stability of the electrode.
2. The selection principle of electrode paste
When choosing electrode paste, the following factors need to be considered comprehensively：
Raw material quality: The raw material quality of the electrode paste directly affects the roasting quality and consumption index of the electrode.Raw materials with high carbon content, low volatile content, low ash content, and low porosity should be selected, such as electric calcined anthracite coal, calcined petroleum coke, etc.
Adhesive selection: The adhesive has a great impact on the performance of the electrode paste.The use of modified asphalt as a binder can improve the quality of the electrode paste, because the toluene insolubles and coking values of the modified asphalt are higher than that of medium-temperature coal asphalt.
Particle size control: The particle size composition of the electrode paste should be reasonable, so that the particles are filled with each other most densely, and the electrodes with high strength and good conductivity can be obtained.At the same time, particles that are too large or too small may cause problems in the use of electrode paste.
Additive use: Adding an appropriate amount of additives to the electrode paste, such as graphite fragments, carbon rods, etc., can improve the compressive strength, bulk density and plasticity of the electrode paste, and reduce the resistivity and ash content.
3. Optimization measures for electrode paste
In order to further improve the use effect of electrode paste, the following optimization measures can be taken：
Improve the quality of electrode paste: improve the quality of electrode paste by improving the formula of raw materials, selecting alternative raw materials, and rationally adding additives.For example, adding residues and carbon rods with a particle size of 8mm-20mm and a proportion of about 20% to the electrode paste can effectively improve the compressive strength and bulk density of the electrode paste.
Strengthen electrode management: strictly implement the electrode management system and pay attention to the adjustment and control of electrode consumption.Under the conditions that the electrode working length is sufficient, the furnace temperature begins to rise, the product quality is relatively stable, and the baking operation is smooth, do not reduce the pressure release time.At the same time, it is necessary to closely track the temperature changes in the electrode paste roasting process, the color state of the flue gas on the electrode cylinder and other parameters to ensure that the roasting speed of the electrode matches the consumption speed.
Optimize the electrode paste injection height: The electrode paste injection height is essential to the operating efficiency and electrode life of the furnace.The ideal electrode paste injection height should be 1.2 to 1.5 times the electrode diameter, but it needs to be flexibly adjusted according to the actual situation.Regularly check and adjust the electrode paste injection height to ensure that the gap between the electrode and the charge is reasonable, and to avoid premature electrode burning or oxidation.
Use advanced equipment: update crushing, screening, grinding, batching, kneading, forming and other equipment to improve the production efficiency and product quality of electrode paste.Especially the use of paste forming machines can increase the plasticity of electrode paste and solve the problem of holes that are easy to form when large pieces of paste are melted in the furnace during use.
The selection and optimization of electrode paste is of great significance to improve the operating efficiency of the mine heating furnace and extend the life of the electrode.Through reasonable selection of raw materials, optimization of particle size composition, use of high-performance adhesives and additives, strengthening electrode management, and optimization of electrode paste injection height and other measures, the use effect of electrode paste can be further improved, production costs can be reduced, and product quality can be improved.Therefore, in the production process of mine heating furnaces, great attention should be paid to the selection and optimization of electrode paste.
