uhp 700 graphite electrode factory
What are the manufacturing processes of Datong graphite electrode
Due to its low natural content, graphite electrodes are mostly manufactured by uhp 700 graphite electrode factory. The common method is to mix quartz sand and coke, use the silica and petroleum coke, add salt and wood chips, put it in an electric furnace, heat it to a high temperature of about 2000°C, and obtain graphite electrode powder after various chemical processes. . Graphite electrode (SiC) has become an important abrasive due to its great hardness, but its application range exceeds that of general abrasives.
For example, its high temperature resistance and thermal conductivity make it one of the first-choice kiln furniture materials for tunnel kilns or shuttle kilns, and its electrical conductivity makes it an important electric heating element. To prepare SiC products, firstly, SiC smelting block [or: SiC pellets] must be prepared. Because it contains C and is super hard, SiC pellets were once called: emery.
But be careful: it has a different composition from natural emery (also known as garnet). In industrial production, SiC smelting block usually uses quartz, petroleum coke, etc. as raw materials, auxiliary recovery materials, spent materials, and after grinding and other processes, they are blended into a charge with a reasonable ratio and suitable particle size (in order to adjust the gas permeability of the charge, an appropriate amount needs to be added. When preparing the green graphite electrode, add appropriate amount of salt) to prepare it at high temperature.
The thermal equipment for preparing SiC smelting block at high temperature is a special graphite electrode electric furnace. Its structure is composed of furnace bottom, end wall with graphite electrode on the inner surface, detachable side wall, furnace core body (full name: electric heating element in the center of the electric furnace, Generally, graphite powder or petroleum coke is installed in the center of the charge according to a certain shape and size, generally circular or rectangular. Its two ends are connected with graphite electrode). The firing method used in the electric furnace is commonly known as: buried powder firing. It starts heating as soon as it is energized. The temperature of the furnace core is about 2500°C, or even higher (2600-2700°C). When the furnace charge reaches 1450°C, SiC is synthesized (but SiC is mainly formed at ≥1800°C) and releases co.
However, SiC will decompose when ≥2600℃, but the decomposed si will form SiC with C in the charge. Each electric furnace is equipped with a set of transformers, but only a single electric furnace is powered during production, so as to adjust the voltage according to the electrical load characteristics to basically maintain a constant power. The high-power electric furnace needs to be heated for about 24 hours. After a power failure, the reaction of generating SiC is basically over. After a period of cooling, the side wall can be removed, and then the charge can be taken out gradually. The furnace charge after high temperature calcination is: unreacted material (for heat preservation in the furnace), oxygen graphite electrode (semi-reactive material, the main components are C and SiO.), adhesive layer (for bonding Very tight material layer, the main component is C, SiO2, 40%～60% SiC and Fe, Al, Ca, Mg carbonate), amorphous material layer (the main component is 70%～90% SiC, and it is Cubic SiC is β-sic, and the rest are C, SiO2 and carbonates of Fe, Al, Ca, Mg), second grade SiC layer (the main component is 90% to 95% SiC, the layer has formed hexagonal SiC, which is the mouth One SiC, but the crystal is small and fragile, and cannot be used as an abrasive), the first-class SiC layer (SiC content <96%, and it is hexagonal SiC, which is a coarse crystal of SiC), and furnace core graphite.
Among the above-mentioned layers, the unreacted material and a part of the oxygen graphite electrode layer material are usually collected as spent material, and the other part of the oxygen graphite electrode layer material is collected together with amorphous material, secondary product, and part of the bonded material as recycled material. Charges, and some bonds with tight bonding, large lumps, and many impurities are discarded. The first grade product is classified, coarsely crushed, finely crushed, chemically treated, dried and sieved, and magnetically separated into black or green SiC particles of various sizes. To make graphite electrode fine powder, it needs to go through a water selection process; to make a graphite electrode product, it needs to go through a process of forming and sintering. When uhp 700 graphite electrode factory was founded, it established the development strategy of “science and technology, innovation, and leadership”, adhering to the business philosophy of “quality first, service first”, after process improvement, quality improvement, and market development.