Exploration Of New Process For Non-blast Furnace Ironmaking

As one of the basic industries of all industrialized countries in the world,iron and steel industry is an important symbol to measure the comprehensive competitiveness of the country.Ironmaking process is the upstream process of metallurgy,and blast furnace ironmaking is in the dominant position,but it existing some problems such as huge energy consumption,heavily dependent on coke and serious environmental pollution.Although non-blast furnace ironmaking process realizes non-coke smelting to a certain extent,its development is always restricted by small production scale,low energy utilization and poor economic benefits.Therefore,on the basis of existing research,this paper aims to develop a new non-blast furnace ironmaking process,which is suitable for large-scale industrial production,get rid of sintering and coking processes,high and reasonable energy utilization,environment-friendly,high economic efficiency.Based on the theoretical analysis of the development process and technical bottleneck of non-blast furnace ironmaking process,this paper explored the advantages and potential of COREX and FINEX processes in many ironmaking processes.The technical problems to be solved in this paper were clarified,including the matching of reduction temperature caused by the bonding of burden,the adaptability of raw materials and fuels,the connection between two stages and the recycling of top gas.Based on the research of iron oxide reduction and melting process,the chemical reaction and temperature change atlas in the melting gasifier were established,including the main reactions during the melting process and their endothermic and exothermic changes,temperature distribution and state changes.The main bonding mechanism of furnace charge was summarized as the bonding mechanism of iron whisker,high active iron and low melting point eutectic.On the basis of analyzing the composition,morphology and distribution conditions of bonding material,the reasons for bonding of shaft furnace and fluidized bed were determined respectively.By studying the correlation between bonding mechanism and reduction temperature,it was concluded that it was unscientific to restrain bonding by increasing H₂ concentration in reducing gas,and the reason why lump ore was easier to bond than pellet ore was explained in principle.It was caused by pellet shape,strength and the presence of internal flux molecules.Finally,it was conjectured that there was an ideal limit state in smelting reduction ironmaking process.Under the conditions of higher temperature and suitable composition of reducing gas,the burden could smoothly complete the whole reduction process in the shaft furnace or fluidized bed,and the direct reduction iron with metallization rate of 100%could be obtained.The direct reduction iron could only complete the melting process in the smelting gasifier.No final reduction was required.Aiming at the existing technical bottleneck of smelting reduction ironmaking process,the research significance was clarified,the existing process schemes were summarized,and the advantages and disadvantages of each process scheme were compared through calculation,and the best scheme was obtained.On this basis,the new ironmaking process developed in this paper was put forward,and the key technologies,including hot-pressing carbon pellet process and gas upgrading and temperature control process,were explored in depth.The new ironmaking process solves the existing technical bottleneck of smelting reduction ironmaking process in theory.However,in order to realize industrial application,the key technologies need to be studied and demonstrated in depth.