At present DRI is mainly used at high quality steel grade such as oil industry casing, drill pipe; spring steel, bearing steel, rotor of steam turbine generator, gun barrel and steel for aerospace and atomic energy industry. The output of DRI increased year by year, the 12 countries counted by the World Steel Association produced 86.591 million tons in 2020.
Because DRI does not contain residual elements, it can directly produce steel without residual elements, and the number of inclusions in steel is significantly reduced, which improves the hot rolling and cold rolling properties of steel, especially the tensile properties. With DRI, the content of S in steel can be significantly reduced, and the morphology of sulfur inclusions can be controlled, that will affect the expansion and torsion resistance of steel and improve quality of steel.
The practice proves that adding DRI may affect the productivity and yield of EAF greatly. Especially at poor scrap case, many EAF needs to charge scrap 3~4 times, adding DRI can reduce the charging times and improve productivity. The recovery rate of molten steel is related to the metallization rate of DRI, gangue content and carbon content, etc. In order to achieve higher recovery rate, DRI with higher metallization rate must be added to the EAF or adding carburizer to promote iron reduction.
