Experiments on iron ore direct reduction by char were carried out using thermogravimetric analysis (TGA) and laboratory test equipment. The properties of the reduced products at different reduction temperatures and atmospheres were compared. TGA shows that the reduction process of 1∶1 char-ore mixture can be divided into three stages from room temperature to 1 100 ℃. The activation energy of three stages increases with temperature in N 2 atmosphere, but increases first and then decreases in H 2 and CO atmosphere. According to analysis results of the products from fixed-bed direct reduction, the reaction temperature and atmosphere have certain influences on the reaction process and degrees of reduction reactions. Under the three atmospheres, the metallic is the main types of iron in the product after 900 ℃, however, the introduction of reducing gases such as H 2 and CO will benefit to the reduction at lower temperature. Iron ore can be reduced by char after 900 ℃ in N 2 atmosphere, but the metallization rate of direct reduction iron is <90%(mass fraction), unsatisfying the requirements of direct steelmaking. Active atmosphere such as H 2 and CO can help to improve the quality of reduction products.
direct reduction iron