Search

• The distribution characteristics of CaS in the radial direction of the hearth were analyzed. • The formation mechanism and migration process of CaS in the hearth were analyzed. • The interface reaction between slag and coke is the main source of CaS formation in the furnace hearth. As the main occurrence form of sulfur element in blast furnace hearth, high content of CaS within the blast furnace hearth have a certain impact on low-carbon smelting of blast furnace. In this paper, the micro-morphology and distribution of CaS in the hearth area are studied by scanning electron microscopy and industrial CT, and the formation process of CaS in the deadman is clarified by drilling core samples of residual iron in the hearth of 3200 m3 blast furnace in China. The research results indicate that CaS in the hearth is mainly formed by slag-coke interface reaction and slag-iron interface reaction. Based on an analysis of the relative difficulty of these two pathways, it was observed that CaS is more readily generated through the slag-coke interface reaction. Based on the analysis of the difficulty of the two generation paths, it is found that CaS in the blast furnace hearth is more easily generated through slag coke interface reaction. The CaS particles generated in the hearth take the slag as the growth matrix, and with the flow of slag and iron and the renewal of the deadman coke, they are finally enriched and precipitated in the edge area of the deadman in the form of agglomerates. Based on the formation mechanism of CaS in the hearth, it is analyzed that the formation of CaS aggregates in the hearth is mainly affected by three factors: sulfur load, slag basicity and hearth temperature. This study provides a certain theoretical reference and guidance for steel enterprises aiming to reduce fuel consumption and achieve green production practices. [ABSTRACT FROM AUTHOR]

• 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]

• Occurrence state of cinder multiphase components in the bird's nest area is reviewed. • Formation mechanism of tuyere cinder is proposed. • Modification methods of tuyere cinder are reviewed. • Future research directions of tuyere cinder are proposed. The presence of cinder in the tuyere bird's nest region poses a significant obstacle to the energy-saving production of blast furnaces by impeding the penetration of high-temperature gas into the charge column. This paper provides a comprehensive review of the multiphase occurrence state, formation mechanism, and modification methods of cinder. Firstly, the phase composition and high-temperature performance of cinder are investigated from various perspectives, including tuyere coke, tuyere slag, coal ash slag, and the interaction between residual carbon and coal ash slag. These aspects shed light on the characterization of cinder and its behavior at elevated temperatures. Secondly, the formation mechanism of cinder is explored, aiming to unravel the factors contributing to its generation. Understanding the underlying mechanisms is crucial for devising effective strategies to mitigate or modify its formation. Thirdly, the paper examines the modification methods of cinder from three aspects: tuyere flux injection technology, tuyere hydrogen-rich injection technology, and tuyere sequence impulse injection technology. These approaches offer potential means to alter the characteristics and behavior of cinder. Finally, future research on cinder can focus on the characterization and performance analysis, depth analysis of formation mechanisms, and exploration of the modification mechanisms. [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]