Pig Iron Production (Post Blast Furnace Era)

Abstract

It has become an environmental drive world-wide to reduce the production of Carbon Dioxide (CO2) in the steelmaking process. Alternative reductants other than coal-based materials has been found to be a true replacement with resultant major reduction in CO2, by using “cleaner” reductants like natural gas. Coke consumption in the Blast Furnace requires coke to produce pig iron for which alternative reductant routes are now sought. It has been proven that natural gas is a suitable reductant in the production of Direct Reduced Iron (DRI) in a shaft furnace or a Rotary Hearth Furnace (RHF) process. This DRI can then be used as raw material for pig-iron production in a closed Submerged-Arc Furnace (SAF), (being a circular AC Furnace, DC Furnace, or a large 6-in-line Rectangular Furnace), where a reduced amount of reductant is required for final reduction and introducing additional carbon required for the subsequent steelmaking processes. The SAF also acts as a slag modifier which adds value to this traditional waste product. Instead of producing aggregate, high quality granulated slag is produced which can be used as a clinker replacement material in the classical cement production. This contributes to the reduction of CO2 gasses by reducing traditional cement fabrication. Fossil-based reductant are still required through this process route, but the sum equates to a reduction of fossil-based reductants. The use of renewable energy as a source of electricity further adds to the reduction of emissions adding even more value to the whole production chain. A natural progression from this process step would be the introduction of environmentally friendly Hydrogen (H2) in the future.