Chapter 1.3 - The Direct Reduction of Iron

Abstract

For hundreds of years, the dominant technology to produce iron from iron ores has been the blast furnace, which utilizes carbothermic reduction at elevated temperatures to make a molten iron product and a liquid slag. However, economic ironmaking in this fashion requires massive facilities for economy of scale and is environmentally problematic with its sinter plants, coke ovens, and large production of carbon dioxide. Direct reduction is an alternate form of ironmaking that is economic at much smaller scales, generally uses natural gas as a reductant instead of coke, and costs considerably less than a blast furnace facility. Shaft furnace direct reduction operations are capable of using a wide variety of feed gases, as long as the gas entering the process is a mixture of CO and H2. Operation of DR plants using pure hydrogen has great potential for drastically reducing CO2 emissions, but there are significant challenges. Numerous initiatives are underway around the world to aid in the decarbonization of the ironmaking process.