There are two main steelmaking processes commonly used around the world: blast furnace-oxygen top-blown converter and electric arc furnace steelmaking. There are also steelmaking methods that use a combination of the two steelmaking processes or other different processes.
The main difference in the process lies in the raw materials used. The main raw materials of the blast furnace-oxygen top-blown converter are iron ore, coke, and scrap steel. The electric arc furnace mainly relies on scrap steel and electricity to make steel. Depending on the plant setup and scrap supply, other metallic iron raw materials such as direct reduced iron and molten iron can also be used for electric arc furnace steelmaking.
Blast furnace-oxygen top-blown converter steelmaking output accounts for 70.7%. First, iron ore is reduced to obtain iron, also known as molten iron or pig iron. Then the molten iron is smelted into steel in an oxygen top-blown converter. After casting and rolling, the molten steel is processed into steel coils, steel plates, profiles or bars, etc. Deliverable finished product.
Electric arc furnace steelmaking uses an electric arc to melt scrap steel. Alloys are used as additives to adjust to the desired chemical composition, and electrical energy can be supplemented by oxygen injected into the arc furnace. Downstream processing techniques, such as casting, reheating, and rolling, are similar to those of blast furnace-oxygen top-blown converter. Approximately 28.9% of steel is produced in electric arc furnaces.
Another steelmaking technology, the open-hearth steelmaking method, accounts for 0.4% of global steel production. This process consumes a lot of energy and is rarely used now due to environmental and economic disadvantages.
Most steel has a useful life of several decades before recycling. However, the scrap steel currently available is not enough to meet the demand for electric arc furnace steelmaking, so most steelmaking methods using a combination of electric furnace-oxygen top-blown converter and electric arc furnace are used.
Therefore, these production processes can use scrap steel as raw material. Most newly manufactured steel contains scrap steel.