1. Artificial graphite
Among the recarburizers, the best quality is artificial graphite.
Artificial graphite is calcined petroleum coke, adding asphalt as a binder, and then adding other auxiliary materials. After high temperature graphitization at 2500-3000℃, the ash, sulfur, and gas content are greatly reduced. Artificial graphite is expensive to manufacture, so the general recarburizer is made from cutting particles when manufacturing electrodes or pulverized from waste electrodes. In addition, the tailings of the negative electrode material are also a good source of recarburizers. The most important indicator of artificial graphite is that the sulfur content is very low, between 0.01-0.07.
2. Petroleum coke
Calcined petroleum coke is currently a widely used recarburizer.
After being calcined at 1200-1350°C, raw petroleum coke becomes calcined petroleum coke that can be used as a recarburizer. The sulfur content of calcined petroleum coke is between 0.02-3%, and the calcined petroleum coke that can be used as a recarburizer is between 0.02-0.5%.
3. Natural graphite
Natural graphite flake graphite and microcrystalline graphite.
Microcrystalline graphite has high ash content and is generally not used as a recarburizer for cast iron; flake graphite is generally used as a recarburizer for medium carbon flake graphite.
4. Coke and anthracite
When making iron in a cupola, coke is used to increase carbon at the bottom, so the cupola uses a recarburizer rarely. In the process of electric furnace steelmaking, coke or anthracite is added as a recarburizer, and anthracite is more commonly used as a recarburizer. Due to the relatively high ash and volatile content of the two, they are rarely used as recarburizers for smelting cast iron in induction furnaces.