Advances in equipment and process technologies of the HIsmelt smelting reduction furnace

In the context of China's ‘double carbon’ goals, the green transformation of the steel industry is urgently required to be supported by breakthrough technologies. The HIsmelt smelting reduction technology is characterized by its unique iron-bath smelting reduction process. This process successfully bypasses the high-pollution steps integral to traditional blast furnace operations, such as coking, sintering, and pelletizing, thereby achieving source reduction of carbon emissions. This review systematically summarizes advances in cooling equipment and refractory materials for the commercialized HIsmelt 2.0 smelting reduction furnace. Three major breakthroughs have been achieved. First, in response to temperatures up to −1600 °C and intense stirring inside the SRV furnace, a double-layer cast iron cooling pipe system was developed, resulting in a significant improvement in cooling capacity and slag-hanging stability. Second, an innovative slag area cooler was designed, which reduces the slag-line refractory erosion rate. Third, with high-melting-point spinel protective layers formed at the erosion interface, Alumina-chrome refractory bricks are enabled to resist chemical erosion from high-FeO slag. These innovations are vital for the long-term stable and safe operation of the SRV furnace, providing theoretical and practical guidance for the commercial application of HIsmelt technology.