Vanadium titanium magnetite is a featured strategic metal resource in China. The existing mainstream of vanadium extraction at home and abroad is the blast furnace ironmaking-converter process, which has high carbon emissions and low recovery rate of vanadium and titanium. A large amount of titanium element enters blast furnace slag and accumulates over 100 million tons, which not only wastes resources, but also significantly increases the pressure of environmental protection. The existing non-blast furnace smelting processes to make up for the shortcomings of the blast furnace process are introduced, including direct reduction process and smelting reduction process, and the process flow and application status are summarized. The principles, application status, advantages and disadvantages of titanium extraction methods of titanium-containing slag at home and abroad, such as modified enrichment, carbonization-chlorination and hydrometallurgical extraction, are summarized. In addition, the future development for comprehensive utilization of vanadium titanium magnetite is prospected. It is considered that the full-process technology of hydrogen-based shaft furnace reduction-electric furnace melting separation-comprehensive utilization of titanium slag for vanadium titanium magnetite holds tremendous development prospects. This technology can strongly support China's vanadium titanium steel industry in achieving the "dual carbon" goals.

Gallium is an important rare metal resource. Gallium and its compounds have been found extensive applications in diverse fields, e.g. solar energy, semiconductors, biology, chemical engineering, and alloys. Gallium resources have evolved into a crucial strategic asset owing to the continually increased demand. Gallium is sparsely distributed within minerals like bauxite, apatite, nepheline, and alunite in an extremely scarce quantity. More than 90% of the world's primary gallium is derived from the by-products of alumina production. Currently, methods for recovering gallium from Bayer liquor can be included as precipitation, electrochemistry, extraction, and resin adsorption. However, improving the recovery efficiency of gallium and reducing its recovery cost are remained key concerns in the relevant industry. Recent research findings on the occurrence forms of gallium in bauxite, the migration behavior of gallium during the Bayer process cycle, and methodologies for gallium separation, extraction, and recovery are presented. The current status of gallium resource recovery from bauxite is mainly introduced, the advantages and disadvantages of the employed technologies are summarized, and some future research directions for gallium extraction from bauxite are outlined.

The changes of China's annual crude steel output, average daily crude steel production on a monthly basis over the past two years, end-of-month rebar prices, direct steel exports, indirect exports of steel products, and CO₂ emissions were reviewed and analyzed. It is concluded that China's crude steel production is generally in a situation of oversupply, and the steel industry has entered a downward phase of reduction fluctuations. Under the premise of no significant increase in crude steel output, China's steel industry can be considered to have entered a CO₂ emission stabilization period. The study explores targets and measures for total crude steel output control from perspectives including future production forecasts, supply-side structural reforms, and adjustments to import/export policies. By integrating projections of future crude steel output and scrap resources, it is proposed that under the goals of "Carbon peak and Carbon neutrality", China's steel industry will gradually develop three typical manufacturing processes: BF-BOF long process, full scrap EAF process, and hydrogen reduction-EAF process. The evolutionary alternation of these three processes is discussed, emphasizing that China's steel industry should leverage the "Carbon peak and Carbon neutrality" context to guide scrap resources toward EAF process, thereby gradually optimizing the sector's ferrous resource structure, product structure, and process structure. Pathways for enhancing manufacturing continuity are explored through interface technology optimization, dynamic precision design, and full-process intelligentization. Finally, through the construction and analysis of a "dual carbon" analytical model for the steel industry, the study identifies controlling and reducing crude steel output as the most effective decarbonization measure, with process structure optimization in steel plants being equally critical.

The sintering process constitutes a crucial stage in the blast furnace ironmaking technology, but it also generates significant amounts of pollutants. In the context of ultra-low emissions, steel enterprises urgently need to upgrade and transform their existing desulfurization and denitrification processes to address the problems that exist in their practical applications. Based on the current status of flue gas desulfurization and denitrification technologies in sintering processes of steel enterprises, mainstream desulfurization and denitrification technologies applied in China′s sintering flue gas treatment field are systematically introduced. Meanwhile, an outlook is provided for the removal technologies of sulfur dioxide and nitrogen oxides in sintering flue gas that are widely applied in steel enterprises currently. Selecting mature desulfurization and denitrification processes based on flue gas characteristics will become the main path for the steel industry to complete ultra-low emission transformation. The semi-dry desulfurization technology needs to actively develop technologies for the harmlessness and resource utilization of desulfurization ash, and at the same time apply automation and intelligentization technologies to address the problem of desulfurization efficiency under changing operating conditions.The research focus of SCR denitrification is low-temperature SCR technology, especially the development of low-temperature catalysts with anti-water and anti-sulfur poisoning ability.The simultaneous desulfurization and denitrification process of active coke should be studied more in the aspects of preventing crystallization plugging, system corrosion and standardized operation.

Foamed slag technology is the core process of ultra-high-power electric furnace steelmaking, which is crucial for enhancing thermal efficiency, protecting furnace lining and optimizing molten steel quality. It takes biomass charcoal as the research object, systematically analyzed its performance and influencing factors as a blowing agent, and compares it with traditional fossil-based blowing agents (coke, graphite, anthracite). Waste wood block charcoal, corn stover charcoal, waste bamboo charcoal and industrial wood charcoal were used in the experiment, combined with chemically formulated electric furnace slag, and their foaming ability was evaluated by high-temperature foaming experiments with comprehensive foaming index (K). The results showed that the waste wood charcoal showed the best overall performance due to its high fixed carbon and low ash. The corn stover charcoal significantly reduced the viscosity of the slag due to its high ash content and high alkali metal content, resulting in the worst foaming area and duration. The waste bamboo charcoal, although with the highest fixed carbon, had a high potassium content in the ash content that exacerbated the deterioration of the foam stability, and had a second best overall performance than that of the waste wood charcoal. Compared with fossil blowing agents, graphite showed the highest maximum foaming area and comprehensive foaming index, but industrial wood charcoal showed substitution potential by virtue of its longer foaming time and low-carbon environmental protection characteristics. The synergistic effects of slag alkalinity, viscosity and surface tension on foaming performance were further revealed. It was pointed out that alkali metals (e.g., K, Na) in the ash fraction of biomass char reduced the viscosity by disrupting the silica-oxygen network, but an excessive amount shortened the foam life. This study meets the development needs of green metallurgy under the "double carbon" strategy, and provides a theoretical basis for the large-scale application of biomass carbon in electric furnace steelmaking.

With the increasing demand for domestic copper resources, there is a large gap between the production and consumption of refined copper, and the recycling of scrap copper has become a necessary way to solve the shortage of copper resources. Scrap copper can be divided into three categories according to copper grade, namely high, medium and low grade, in which the high-grade scrap copper can be recycled by direct utilization or one-stage process, while the medium and low grade scrap coppers are mainly recycled by two-stage process, flotation and hydrometallurgical process. The recycling process of different types of scrap copper was discussed in detail, and the principles, advantages and disadvantages of various processes were summarized by analyzing the implementation cases of pyrometallurgy, hydrometallurgy and flotation methods for scrap copper. Based on the current situation of copper scrap recycling in China, improving the classification standards and recycling system of copper scrap can effectively enhance the comprehensive utilization of scrap copper resources.

Hot-rolled ribbed steel bars constitute the largest proportion of steel consumption in China, with low cost, high strength, multi-functionality, and long life being the trends in their development. Microalloying technology, serving as a primary means of enhancing steel bar properties, is employed by domestic steel enterprises in the production of hot-rolled ribbed steel bars. Numerous studies have shown that the strengthening mechanisms of microalloying elements primarily involve solid solution strengthening and precipitation strengthening of carbonitrides. V, Nb, and Ti are commonly used microalloying elements for strengthening. With the in-depth research on strengthening mechanisms and the upgrading of production equipment, the roles of rare earths in enhancing mechanical properties, corrosion resistance, weldability, and cost reduction have emerged as new directions in the development of seismic steel bars. The current research status of microalloying in seismic steel bars is introduced and reviewed, aiming to provide a reference for the preparation of microalloyed seismic steel bars with superior performance.

Hydrogen energy, as a critical component of future energy systems, necessitates efficient transportation methods to facilitate global energy transition. Pipeline transportation has emerged as the preferred solution for long-distance hydrogen delivery due to its safety and economic advantages. However, hydrogen embrittlement in pipeline steels remains a primary safety concern, involving multi-scale mechanisms spanning hydrogen atom behavior and dislocation movement that challenge comprehensive characterization. This review summarizes predominant hydrogen embrittlement mechanisms in hydrogen pipelines, including hydrogen-enhanced decohesion, hydrogen-enhanced localized plasticity, and hydrogen adsorption-induced dislocation emission, with emphasis on their synergistic interactions. Key influencing factors of hydrogen embrittlement are discussed in terms of chemical composition, microstructure, precipitated phases, inclusions and segregation. Meanwhile, a multi-dimensional characterization method, ranging from macroscopic mechanical testing to microstructure characterization, is summarized for the cross-scale behavior of hydrogen in the steel of hydrogen transmission pipelines. Addressing energy transition imperatives, enhancing hydrogen embrittlement resistance has become pivotal for scaled hydrogen transportation. Innovative approaches integrating machine learning and cross-scale modeling are introduced for anti-hydrogen embrittlement material design, demonstrating how inverse design strategies accelerate development of high-strength hydrogen embrittlement-resistant pipeline steels. Finally, combined with the current research status of hydrogen pipeline steels, the key points and prospects for future research on hydrogen pipeline steels are summarized.

GH4738 alloy is a high-performance nickel-based superalloy. It plays a key role in aviation, aerospace and petrochemical industries due to its excellent high temperature strength and excellent creep and fatigue properties. The basic research progress of GH4738 alloy in the past half century is reviewed (from 1973 to present), including its composition, smelting process, homogenization treatment, hot deformation behavior, heat treatment and development trend. The innovative achievements of a series of engineering preparation technologies, such as the synergistic increase of Al and Ti content, the substitution of W for Mo to improve the comprehensive performance, the development of a triple smelting process and the control technology of inclusions and harmful elements, the establishment of a thermal deformation constitutive equation and recrystallization grain structure evolution model, and the application of finite element numerical simulation in the microstructure prediction of large-size complex forgings, are described, and the future development is prospected based on the current research situation. The aim is to meet the urgent needs of high performance, high reliability and long life of the new generation of aero-engine materials and to promote the further promotion of GH4738 alloy.