In the direct reduction (DR) process, iron ore pellets or lumps are treated with a reducing gas to produce direct reduced iron (DRI), which is also called sponge iron, or to produce hot iron briquettes (HBI). ) are revived.
Based on the production method of regenerating gas, there are two different direct regeneration processes in commercial form. Process based on gas or based on oil or coal.
In the gas-based direct regeneration process, the regenerator gas is created from the chemical regeneration of a combination of natural gas and the exhaust gas from the regenerator. The resulting mixture is a gas rich in hydrogen and carbon monoxide (CO). Common examples of gas-based direct regeneration processes are MIDREX and HYL, which are the dominant technology in countries where natural gas is found in abundance. But in the direct regeneration process based on oil or coal, the regeneration gas is produced from hydrocarbons such as coal, and sometimes oil and natural gas in the furnace regeneration area. This furnace is usually of rotary type. Common processes in the coal-based method are SL/RN and ACCAR. Coal-based direct regeneration is mostly used in India and China. In this method, different types of reactors such as cylindrical furnace, fluidized bed, fluidized furnace and rotating core furnace are used in different processes to reach the required metal.