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• The temperature field in the bird's nest area of blast furnace tuyere is characterized. • The phase composition of coal-coke-slag is quantitatively characterized. • The radial physicochemical properties of coal-coke-slag are analyzed. • Modification suggestions of coal-coke-slag are proposed. Understanding the occurrence of phases and the evolution of physicochemical properties in coal-coke-slag powder within the blast furnace tuyere's bird's nest area is crucial for reducing carbon emissions and energy consumption in the blast furnace. By dissecting a 2200 m3 blast furnace in China, the temperature field and high-temperature physicochemical properties of coal-coke-slag powder in the tuyere bird's nest area along the radial direction were determined. Firstly, the temperature range in the tuyere bird's nest area spanned from 1523 °C to 1709 °C, with the maximum temperature near the end of the bird's nest area. Secondly, the mass proportions of coal, coke and slag in coal-coke-slag powder were 42.16 %, 25.90 % and 31.94 %, respectively. Along the radial direction of the blast furnace, the degree of graphitization of carbon components of coal-coke-slag increased gradually, and the melting temperature and viscosity of the slag phase also exhibited a gradual increase. Finally, the modification suggestions of the physicochemical properties of coal-coke-slag were put forward, with a focus on three factors: fuel, slag, and temperature. By employing tuyere injection operations with Ca-Fe flux, and using fuel with low ash content, larger particle size, fewer harmful elements, and excellent combustion performance, more heat input was provided to the front of the bird's nest area, which contributed to improved furnace efficiency and performance. [ABSTRACT FROM AUTHOR]

• The physicochemical properties of cinder slag in the birdnest region are characterized. • The modification effects of Ca2+, Mg2+ and Fe2+ on the cinder slag are analyzed. • The interaction modification of Ca2+ and Fe2+ is more strongly. • The injection content of alkaline flux from the tuyere is clarified. An important factor in increasing gas utilization and lowering carbon emissions is the removal of cinder from the tuyere birdnest region of the blast furnace. Based on a 2200 m3 blast furnace in China, the physicochemical characteristics of cinder are investigated in this paper. Alkaline flux's chemical modification and flux injection content are examined to alter the fluidity of cinder slag. Firstly, the basicity and aluminum content of cinder slag are 0.80 and 40.33%, respectively. The melting characteristic of cinder slag is high and the liquid phase fluidity is poor. Secondly, as the content of CaO, MgO, and FeO grow while the viscosity keeps declining, the melting temperature of the cinder first decreases and then rises, rises, and decreases. Compared to Mg2+, Ca2+ and Fe2+ have higher diffusion rates and a stronger interaction modification impact. The potential of flux modification is CaO + FeO > CaO + MgO > CaO > FeO > MgO. Finally, the optimum chemical modification occurs when the basicity of cinder slag is 1.05 and the FeO content is 0.40%. During regular blast furnace operation, 1.62 kg/tHM of limestone and 5.92 kg/tHM of basic oxygen furnace (BOF) slag are injected into the tuyere. [ABSTRACT FROM AUTHOR]

• Systematic classification of concepts in the oxygen blast furnace. • Reported the recent advancements in industrial oxygen blast furnaces. • Explored future development directions for oxygen blast furnace based on practices. • Analyzed the smelting of vanadium-titanium magnetite in the oxygen blast furnace. Climate change poses a shared global challenge. Given its substantial contribution to CO 2 emissions, the steel industry must shoulder a significant responsibility for the carbon neutrality goal. Achieving carbon neutrality in the iron and steel industry is a complex and gradual endeavor, requiring sustained efforts rather than offering a swift resolution in practical terms. Despite the ambitious development of numerous non-blast furnace processes, the traditional blast furnace (TBF) is poised to persist as the dominant ironmaking process in the upcoming decades. Conversely, the oxygen blast furnace (OBF) process, distinguished by its exceptional emission reduction potential and low retrofit costs, emerges as one of the most promising ironmaking technologies for the future. Therefore, this review comprehensively explores the origin and evolution of the OBF process, elucidating technological advancements across various historical periods. Furthermore, the review puts forth a comprehensive analysis of the feasibility of employing the OBF process for smelting vanadium-titanium magnetite (VTM), considering the benefits of the OBF and the challenges it encounters. Looking ahead, the advancement of the OBF should concentrate on pivotal domains like enhancing furnace condition control technology, exploring and innovating coke substitutes, and developing new materials with high-temperature and oxidation resistance. Concurrently, the Carbon Capture, Utilization, and Storage (CCUS) technologies are vigorously developed to further enhance the carbon reduction potential of OBF. This review aims to ignite readers' research curiosity regarding the OBF process and its application in smelting VTM. It also endeavors to propel the industrialization process and foster the sustainable development of the OBF. [ABSTRACT FROM AUTHOR]