graphite electrode ultra high power
Selection of raw materials for producing different carbon and graphite electrode ultra high power products
For different types of carbon and graphite electrode ultra high power products, there are special requirements and quality indicators according to their different uses. When considering what raw materials should be used to produce a certain product, we should first study how to meet these special use requirements and quality indicators.
(1) Selection of raw materials for conductive graphite electrode ultra high power used in electric metallurgical processes such as electric furnace steelmaking. The conductive graphite electrode ultra high power used in electric furnace steelmaking and other electrometallurgical processes must have good electrical conductivity, appropriate mechanical strength, good resistance to rapid cooling and heating at high temperatures, corrosion resistance, and relatively low impurity content.
① All low-ash raw materials such as petroleum coke and pitch coke are used to produce high-quality graphite electrode ultra high power. However, the production of graphite electrode ultra high power requires more equipment, long process flow, and technically more complicated. The production of 1t graphite electrode ultra high power consumes 6000~·h.
②Use high-quality anthracite or metallurgical coke as raw materials to produce carbon electrodes. The production of carbon electrodes does not require graphitization equipment, and the other production processes are the same as the production of graphite electrode ultra high power. The conductivity of carbon electrodes is much worse than that of graphite electrode ultra high power. The resistivity is generally 2 to 3 times larger than that of graphite electrode ultra high power. The ash content varies depending on the quality of the raw material, generally about 10%. But after special selection, the ash content of anthracite can be reduced to less than 5%. Using this selected anthracite to make products, such as further graphitization, can reduce the ash content of the product to about 1.0%. Carbon electrodes can be used to smelt products such as ordinary electric furnace steel and ferroalloys.
③Using natural graphite as raw material to produce natural graphite electrode ultra high power. Natural graphite must be carefully selected to reduce its ash content before it can be used. The resistivity of the natural graphite electrode ultra high power is about twice that of the graphitized electrode. However, the mechanical strength is relatively low, and it is easy to break during use. In areas with abundant natural graphite production, natural graphite electrode ultra high power can be produced to supply small electric furnaces in the region to smelt ordinary electric furnace steel. When using natural graphite to produce conductive electrodes, the equipment and processes used are easier to solve and master.
④Using graphite electrode ultra high power cutting chips or waste products to be crushed and pulverized to produce regenerated electrodes (or graphitized broken electrodes). This product has a low ash content (about 1%), and its conductivity is worse than that of graphitized electrodes. The resistivity is about 1.5 times that of graphitized electrodes, but the use effect is better than the use of natural graphite electrode ultra high power. The effect is good. Although the production of regenerative electrodes is technically easy to master and the equipment is relatively easy to solve, the source of raw materials for graphitization is limited, so this approach is not the direction of development.
(2) The choice of the original family for the electrolytic salt industry conductive anode. The conductive anode used in the electrolytic salt industry must have good conductivity, compact structure and high mechanical strength, and it is not easy to be corroded and oxidized by the electrolyte. Therefore, petroleum coke and pitch coke are currently used to produce graphitized anodes. After selection, anthracite with very low ash content can also be used to produce graphitized cathodes, but its resistivity is relatively large, and the ash content is also larger. Such anodes have a relatively short service life in the electrolytic cell.
(3) Selection of raw materials for carbon refractory materials for various metallurgical furnaces. Carbon refractory materials used in various metallurgical furnaces, such as carbon blocks for ironmaking blast furnaces, bottom carbon blocks and side carbon blocks for aluminum electrolytic cells, require high mechanical strength and corrosion resistance, and low thermal expansion Coefficient, the bottom carbon block used in the aluminum electrolysis cell also requires good conductivity, but the ash content is generally not strict, so high-quality anthracite and metallurgical coke can be used as raw materials. In order to improve the conductive parts and thermal conductivity of the carbon block, some graphitized crushed or graphitized metallurgical coke can be appropriately added to the batch.
(4) Electrode paste. Electrode paste is a conductive material (continuous self-baking electrode) used in submerged electric furnaces for smelting ferroalloys or producing chemical products such as calcium carbide and yellow phosphorus. It has a relatively low current density and a slightly higher ash content, which has little effect on product quality, and has a wide range of raw materials. Therefore, in the production of electrode pastes, high-quality anthracite and metallurgical coke are generally used, and at the same time, raw crushing of various products and other production return materials are often added. Metallurgical coke or metallurgical coke plus natural graphite can also be used to produce electrode paste, but this kind of electrode paste consumes a lot in use. Many large-scale calcium carbide furnaces and ferroalloy furnaces have enclosed electric furnaces in order to improve operating conditions and recover combustible gas. The electrode paste used in this enclosed electric furnace requires a faster sintering speed, better conductivity and lower ash content. Therefore, when manufacturing the electrode paste used in this enclosed electric furnace, a certain amount of raw materials such as petroleum coke, graphitized crushed or graphitized metallurgical coke should be added, and a binder with a slightly lower softening point (about 50°C) should be used.