Rotary hearth furnace technology (RHF) was developed and built in the United States in 1978 by the International Metal Company affiliated to INCO Group of Canada in order to treat and utilize metallurgical wastes. It can not only be used to treat dust produced by metallurgical plants and other wastes containing iron, chromium， and zinc, but also be used to reduce iron ore.

In order to make the large and medium-sized reduction electric furnaces of ferroalloy run better, it is required that the burden has proper fragmentation and ensures good air permeability. At present, the supply of high-quality lump burden which can be directly fed into the furnace is becoming increasingly tight. In order to adapt to this situation, some manufacturers at home and abroad have adopted various lump technologies to effectively utilize fine ore and concentrate and obtained better smelting indexes.

Gas-based direct reduction iron (DRI), which has been commercialized, is made from natural gas or coal. In recent years, with the global attention to carbon dioxide emissions, active research has been carried out on the low carbonization of DRI processes, mainly carbon dioxide removal in existing commercial DRI processes or the use of renewable energy to produce reducing gas.