Future technologies for energy-efficient iron and steel making

Techniques for the reduction of the specific energy consumption for iron and steel making are identified and characterized to assess the potential for future energy-efficiency improvement and research and development priorities. Worldwide average specific energy consumption for steel making is estimated to be 24 GJ/tonne. The most energy-efficient process requires 19 GJ/tonne for primary steel and 7 GJ/tonne for secondary steel. Seven specific smelting reduction processes and four groups of near-net-shape casting techniques are described and evaluated. In the longer term, the specific energy consumption for making steel from iron ore can be reduced to 12.5 GJ of primary steel per tonne. A further reduction of up to 2.5 GJ of crude steel per tonne may be achieved when techniques are developed that can recover and apply heat from the hot steel at a high temperature. The specific energy consumption for secondary steel making can be reduced to 3.5 GJ/tonne by energy-efficient melting and shaping techniques.