Indications from the steel industry and local and global government institutions are that the breakthrough technologies for decarbonization will be based on hydrogen reduction. The employment of hydrogen in the ironmaking and steelmaking industries will push forward the global transformation of hard-to-abate industries.

Under the background of the rapid development of the world's iron and steel technology, the pace of innovative technology methods is also accelerating, as a kind of efficient blast furnace steelmaking technology, direct reduction iron technology effectively improves the quality of iron and steel products. The article proposes four direct reduction iron production technologies.

Based on the conditions in these aggregates, a test series to experimentally simulate the first few seconds after charging DRI was defined. DRI samples with different carbon contents and hot briquetted iron (HBI) were immersed in high- and low-carbon melts as well as high- and low-iron oxide slags. The reacted samples were quenched in liquid nitrogen. The specimens were qualitatively evaluated by investigating their surfaces and cross sections.

Since the European Union defined ambitious CO2 emission targets, low-carbon-emission alternatives to the widespread integrated blast furnace (BF)—basic oxygen furnace (BOF) steelmaking strategy—are demanded. Direct reduction (DR) with natural gas as the reducing agent, already an industrially applied technology, is such an alternative. Consequently, the melting behavior of its intermediate product, i.e., direct reduced iron (DRI), in either an electric arc furnace (EAF) or a submerged arc furnace (SAF), is of great interest. Based on the conditions in these aggregates, a test series to experimentally simulate the first few seconds after charging DRI was defined.

To further enhance DRI for steelmaking, it can be converted to pig iron or hot metal via melting. There are existing processes in the industry that use electric energy in furnaces such as submerged arc furnaces to convert DRI into hot metal. Air Products’ novel DRI melting process uses oxy-fuel combustion in place of electric power to accomplish this melting. Figure 4 provides a process diagram (patent pending) .

Advantages of charging DRI hot coming out of the shaft reactor have been well documented, namely productivity increase and decrease in power use. Few DRI plants in the world have the ideal setup with an EAF downstream of the DRI plant, where the DRI coming out of the shaft furnace can be charged hot into the EAF.

Direct Reduced Iron (DRI) is the second most viable source of virgin iron used in steelmaking after pig iron or hot metal produced in blast furnaces. DRI is produced by direct reduction of iron ore using carbon monoxide and hydrogen. Natural gas-based shaft reactors are commonly used in North and South America for DRI production while coal-based DRI is common in Asian markets. Inexpensive supply of natural gas in the United States makes DRI an attractive source of iron for steelmakers.