In recent years, the concept of green, low-carbon and clean energy consumption has been deeply rooted in the hearts of the people, and countries have actively advocated the use of new energy. In the face of problems such as resource shortage and environmental pollution, we began to explore the use of new fuels instead of coal for production. Biomass resources have the characteristics of being renewable and carbon neutral and having large output. As an energy utilization, it is helpful to promote the transformation of the energy structure in various countries. Applying it to ironmaking production is not only conducive to energy conservation and emission reduction in the ironmaking process but also can achieve efficient utilization of crop waste. By introducing the source and main preparation methods of biochar, this paper expounds the main links and advantages of biochar in the ironmaking process and puts forward the direction of biochar in ironmaking in the future.

The development of blast furnace smelting technology with a high proportion of pellets is an important means for improving the utilization rate of complex co-associated mineral resources. The effect of basicity on the reduction swelling performance of pellets prepared from Bayan Obo iron ore concentrate is characterized by the aspects of microscopic morphology, element distribution and weight-loss behavior. The results show that with the increase in basicity, the reduction swelling rate and the weight-loss rate of pellets follows the change rule by first increasing and then decreasing. With a basicity of 0.8, the pellets have the largest swelling rate (75.743%) and the largest weight-loss rate (24.77%). The reduction swelling rate is proportional to the porosity and inversely proportional to the amount-of-liquid phase. In the first stage of reduction, pellets with a basicity of 0.8 changed from tabular to granular, and there were a large number of cracks. In the third stage of reduction, pellets with a basicity of 0.8 had coarse iron whiskers. In the same reduction stage, the amount of K and Na elements in the pellets with a basicity of 0.8 entering the iron oxide lattice was much larger than that in the pellets with a different basicity. As the reduction progresses, the ability of alkali metals to enter the iron oxide gradually increases.

Low-ash-melting-point bituminous coal and high-ash-melting-point anthracite coal are mixed and burned in different proportions. The ash melting characteristics of blended coal were determined experimentally. At the same time, the ash samples of bituminous coal, anthracite, and blended coal were analyzed by X-ray diffraction (XRD), and the ash melting characteristic improvement mechanism of blended coal was analyzed by quantum chemical calculations. The results show that when high-ash-melting-point anthracite is added, the ash melting characteristics of blended coal are improved, and the deformation temperature, softening temperature, hemispheric temperature, and flow temperature of the blended coal are significantly increased. The melting point of blended coal ash with a bituminous coal ratio of less than 50% can meet the requirements of blast furnace injection. The reason for the improved melting characteristics of the blended coal ash is that mullite in anthracite ash reacts with gehlenite in bituminous coal ash during the combustion process to produce anorthite.

CaO–MgO–Al₂O₃–SiO₂–Cr₂O₃ diopside glass–ceramics were prepared from blast furnace slag, low-carbon ferrochromium alloy slag, and quartz sand by the melting method. The prepared glass–ceramics were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD),scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). The effect of Cr₂O₃, a nucleating agent, in the crystallization process of diopside glass–ceramics was studied. The results show that chromium is present in glass–ceramics as Cr³⁺ and Cr⁶⁺, and Cr³⁺ accounts for more than 80% of the chromium contents. When the mass percentage of Cr₂O₃ in glass–ceramics is less than 1.60%, a small amount of diopside phase is precipitated during heat treatment, and Cr³⁺ is dispersed in the diopside phase. When the mass percentage of Cr₂O₃ reaches or exceeds 1.60%, Cr³⁺ preferentially forms the magnesia chrome spinel phase, which further induces the in situ growth of diopside. The leaching concentration of chromium meets the Chinese national standard, indicating that diopside glass–ceramics can effectively solidify the heavy metal chromium, and this fact makes the application of glass–ceramics feasible.