It is used to adjust the carbon content of the steel while it is still liquid before casting.
After analyzing the properties of the molten steel, coal is typically added manually in paper bags, shoveled in bulk, or injected into the ladle.
There may be wide variation in the characteristics of recarburizers, depending on the grade of steel that is being prepared, and the other components being added.
Coal used / Benefits:
Synthetic Graphite / very high fixed carbon content, low ash, low sulfur
Calcined petroleum coke / very high fixed carbon content, low ash, moderate sulfur
Anthracite / Competitive price, low sulfur
Natural Graphite / rapid integration into the molten steel