钢铁钒钛

Microwave roasting-assisted separation and enrichment of titanium-enriched phases from titanium-bearing electric furnace smelting slag

CHEN Mao, LI Yehui, CHEN Buxin, HU Meilong

2026, 47(3): 1-9. doi: 10.7513/j.issn.1004-7638.2026.03.001

Abstract(49) HTML (16) PDF(16)

Abstract:
Titanium dioxide (TiO₂) in titanium-bearing electric furnace molten slag is characterized by complex mineral phases, low titanium grade, and high impurity content, which greatly increases the difficulty of titanium separation and enrichment. In this work, a combined process of microwave roasting and separation was proposed to realize titanium enrichment from titanium-bearing electric furnace molten slag. The effects of microwave roasting on the separation and enrichment of titanium-rich phases (mainly anosovite) were systematically investigated, and the process parameters of microwave roasting, alkaline leaching and flotation were optimized. Based on experimental results, grinding efficiency, flotation recovery, and comprehensive analyses of XRD, SEM-EDS, and Zeta potential, the regulatory mechanism of microwave roasting on the phase composition, microstructure, and phase boundary characteristics of titanium-bearing molten slag was clarified. The results show that the optimal microwave roasting parameters are as follows: particle size of 1–5 mm, microwave power of 2400 W, roasting in a corundum crucible, and heat preservation at 900 ℃ for 20 min. Under these conditions, the proportion of ground particles finer than 74 μm increases from 63% for the raw slag to 96%, which significantly improves the mineral dissociation efficiency. Microwave roasting generates thermal stress cracks via selective heating, which weakens the interfacial bonding strength between anosovite, magnesia-alumina spinel and titanaugite, thereby providing favorable conditions for the subsequent efficient separation of titanium-bearing phases. The optimal alkaline leaching condition is a NaOH concentration of 20% for 1 h. The best flotation performance is achieved at a slurry pH of 6 and a sodium oleate collector concentration of 30 mg/L. After treatment by the combined microwave roasting–alkaline leaching–flotation process, the anosovite content and recovery rate of flotation concentrates reach 94.2% and 85.4%, which are 38.2% and 36.1% higher than those of the raw slag treated by the same process, respectively. This study provides an effective and feasible technical route for the efficient enrichment and utilization of titanium resources from titanium-bearing molten slag.

The investigation of efficient preparation process and optimization of vanadium dioxide powder

CHEN Mingdi, HAN Yuxi, WU Binhe

2026, 47(3): 10-19. doi: 10.7513/j.issn.1004-7638.2026.03.002

Abstract(27) HTML (11) PDF(3)

Abstract:
VO₂ powder features high specific surface area, strong adsorption capability, and reversible insulator–metal phase transition. These properties endow it with significant application potential in gas sensing, smart windows, and optoelectronic switches and other fields. To address the limitations of conventional fabrication routes, such as long preparation cycle and unstable process parameters, monoclinic-phase (M-phase) VO₂ powder was synthesized using V₂O₅ as vanadium source via an optimized sol–gel method combined with annealing process. The precursor preparation process was improved, resulting in a significant reduction in synthesis time, from over 24 hours to less than 8 hours. Static air oxidation was employed to prevent product dispersion during synthesis. The latent heat of the phase transition, as measured by differential scanning calorimetry (DSC), was employed as the performance evaluation indicator for material evaluation. Using this parameter, two critical processing variables, annealing temperature and ambient pressure, were systematically investigated and optimized. The optimal annealing conditions were determined to be 450 ℃ and 1.5 × 10⁴ Pa. The results of this study enabled the efficient and stable synthesis of monoclinic-phase (M-phase) VO₂ powder, facilitating further practical application of this phase-transition material in optoelectronic functional devices.

Research on vanadium extraction from vanadium-titanium iron concentrate pellets by gradient calcination roasting and sulfuric acid selective leaching

WANG Qiang, WU Enhui, LI Jun, XU Zhong, ZHANG Yuan, LIU Peng, ZUO Chengyang

2026, 47(3): 20-30. doi: 10.7513/j.issn.1004-7638.2026.03.003

Abstract(29) HTML (13) PDF(2)

Abstract:
Using vanadium-titanium magnetite concentrate as the raw material and calcium oxide as the additive, the selective extraction of vanadium was carried out by the process of gradient calcination roasting and sulfuric acid leaching. The influence laws of the gradient calcination roasting system and the selective leaching process parameters on the leaching rates of vanadium and iron from the calcined balls and the strength of the balls were systematically studied. The research results of the gradient calcination roasting system indicated that as the primary oxidation temperature increased and the primary oxidation time extended, the leaching rate of vanadium first increased and then decreased. Increasing the secondary oxidation temperature and extending the secondary oxidation time led to an increase in the leaching rate of vanadium first and then tended to be stable. The experimental results of the selective leaching showed that as the leaching time extended and the liquid-solid ratio increased, the leaching rate of vanadium first increased and then tended to be stable. As the sulfuric acid concentration increased, the leaching rate of vanadium first increased and then decreased. With a fixed calcium oxide ratio of 3%, the optimized gradient calcination system was a primary oxidation temperature and time of 850 ℃ and 90 min, a secondary oxidation temperature and time of 1200 ℃ and 45 min. The optimized leaching process parameters were an leaching time of 120 h, a sulfuric acid concentration of 2 mol/L, and a liquid-solid ratio of 7. Under these aforementioned conditions, the leaching rates of vanadium and iron were 79.86% and 0.65%, respectively, and the compressive strengths of the balls before and after leaching were 1920.8 N/Pellet and 143.3 N/Pellet.

Experimental study on the fluidization quality of hot carbonized slag beds under slurry injection

YUE Dong, WANG Jianxin, WEN Liangying, LIU Bo, YANG Yangjun

2026, 47(3): 31-38, 83. doi: 10.7513/j.issn.1004-7638.2026.03.004

Abstract(21) HTML (12) PDF(2)

Abstract:
A thermal simulation test system was established for the purpose of investigating the actual return slurry conditions in a fluidized chlorination furnace for hot carbonized slag containing titanium carbide. The limit of liquid phase entering the fluidized bed layer of carbonized slag, the correlation between the actual amount of liquid phase entering the bed layer after superheated evaporation and the amount of liquid added were studied. In depth analysis was conducted on the aggregation and dispersion behavior of carbonized slag particles in the fluidized bed with liquid phase intervention, as well as the changes in fluidization quality indicators. The results indicate that when liquid phase is introduced into a carbonized slag fluidized bed with relatively stable pressure pulsations, the liquid bridges solid particles, causing them to agglomerate and leading to a sharp increase in bed pressure drop. In instances where the quantity of liquid phase introduced into the carbonized slag fluidized bed is comparatively minor (with a liquid-to-solid ratio of less than 0.005), the agglomerated particles can undergo disaggregation and dispersion as a consequence of the mixing and shearing action of the fluidizing gas and the liquid absorption by the solid phase. This process serves to restore the bed pressure drop to the gas-solid fluidization state, obviating the necessity for liquid phase introduction. Conversely, as the liquid-solid ratio increases to between 0.03 and 0.10, the fluidization quality index remains relatively stable, whilst the standard deviation of bed pressure drop pulsations decreases significantly, indicating enhanced fluidization quality stability in the carbonized slag bed. In conjunction with online thermogravimetric tracking, it was ascertained that under the test conditions of this study, the amount of liquid entering the carbonized slag fluidized bed exhibits a satisfactory linear correlation with the amount of liquid added.

Research progress and prospects of Ti particle-reinforced magnesium matrix composites: A review on microstructure and mechanical properties

LIU Xingyu, YANG Hong, FAN Jichuan, PAN Xiaohuan, TAN Zhen, CHEN Xianhua, PAN Fusheng

2026, 47(3): 39-53. doi: 10.7513/j.issn.1004-7638.2026.03.005

Abstract(45) HTML (15) PDF(11)

Abstract:
Ti particle-reinforced magnesium matrix composites have emerged as ideal materials combining lightweight design and high performance, demonstrating significant application potential in frontier fields such as aerospace and biomedical engineering. In recent years, researchers worldwide have made remarkable progress in the fabrication methods, alloy system development, and understanding of strengthening and toughening mechanisms of these composites. In this regard, this review starts from the perspective of the matrix alloys used for preparing Ti particle-reinforced magnesium matrix composites, discusses the influencing laws of factors including matrix alloy systems, reinforcement characteristics, preparation techniques, and deformation methods on the microstructure and mechanical properties of magnesium matrix composites, comprehensively summarizes the strengthening and toughening mechanisms of Ti particle-reinforced magnesium matrix composites, and finally presents a practically meaningful prospect for future research contents and development directions.

High-throughput CALPHAD-guided multi-objective design of TC4 titanium alloy

NING Zhen, ZHU Yanlin, WU Die, LIAO Zhehan, LIU Yihang

2026, 47(3): 54-62. doi: 10.7513/j.issn.1004-7638.2026.03.006

Abstract(23) HTML (10) PDF(4)

Abstract:
To address the pressing need for TC4 (Ti-6Al-4V) titanium alloys that combine high strength and toughness for aerospace, deep-sea, and biomedical applications, we established a high-throughput CALPHAD workflow based on Thermo-Calc/TC-Python. A total of 6,241 candidate compositions were rapidly screened for phase equilibria, solid solubility, and mechanical properties under the constraints of yield strength > 950  MPa, Laves-phase onset temperature <850  K, and Ti₃Al-phase onset temperature < 800  K. The results show that Al content is the primary factor in increasing the α-phase volume fraction and solid-solution strengthening; V and Fe, as β stabilizers, markedly modulate the α/β phase fraction ratio. Although O strongly contributes to solid-solution strengthening, it indirectly reduces α-phase fraction by enhancing the solubility of V in the β phase. A multi-objective analysis identifies an optimal compositional window of Al 5.8–6.3 wt. %, V 3.6–4.2 wt. %, Fe ≤ 0.18 wt. %, and O 0.09–0.15 wt. %, which simultaneously meets the strength requirement and suppresses the formation of brittle phases. Compared with traditional empirical design, this numerical strategy narrows the candidate compositional space to <2 %, significantly lowering experimental trial-and-error costs and providing a solid data foundation for subsequent multi-objective optimization of targeting strength, toughness, and workability.

Ti⁴⁺ doping coupled with zirconium nitrate solution quenching for synergistic modification of lithium-rich layered oxide cathodes

LI Jie, ZENG Hua, LIU Bo, LI Daoyu, NI Wei, YUAN Xinran, XIN Yanan

2026, 47(3): 63-72. doi: 10.7513/j.issn.1004-7638.2026.03.007

Abstract(28) HTML (9) PDF(4)

Abstract:
Lithium-rich layered oxides (LLOs) are the most promising next-generation cathode materials for lithium-ion batteries. However, the performance degradation triggered by their bulk-surface dual deterioration severely hinders commercial application. Herein, a synergistic modification strategy of bulk Ti⁴⁺ doping and zirconium nitrate solution quenching is proposed to construct a dual stabilization system of “bulk strengthening-surface protection.” Ti⁴⁺ substitutes Mn sites in the bulk, significantly inhibiting lattice oxygen release, transition metal (TM) ion migration, and irreversible structural phase transition via strong Ti-O bonds; solution quenching enables rapid ion exchange and in-situ structural reconstruction, forming a Zr-based multifunctional layer with Zr⁴⁺ doping and a disordered rock-salt shell on the particle surface, which functions as interfacial isolation, lattice oxygen stabilization and Li⁺ diffusion channel expansion. The results demonstrate that the structural stability and electrochemical performance of TZ-LNMO are remarkably enhanced. Specifically, it delivers a reversible specific capacity of 271.8 mAh/g with an Initial Coulombic efficiency (ICE) of 85.21% at 0.1C. After 300 cycles at 1C, the capacity retention reaches up to 90.8% with a small voltage fading rate of 0.56 mV per cycle.

Research progress on vanadium nitride preparation technology

ZHANG Lei, WANG Ning, WU Jinshu, ZHU Ningfang, LIANG Guangfen, YU Bin, YE Mingfeng

2026, 47(3): 73-83. doi: 10.7513/j.issn.1004-7638.2026.03.008

Abstract(30) HTML (8) PDF(5)

Abstract:
Vanadium nitride is a kind of microalloying additive with excellent performance, and it also possesses significant practical value in other fields such as supercapacitors, hard coatings, and industrial catalysis. The optimization and innovation of its preparation technology have attracted continuous research attention in the fields of metallurgy and materials science. In this paper, a classified introduction to the existing vanadium nitride preparation methods was provided, including carbothermal reduction-nitridation, ammonia reduction-nitridation, carbonaceous gas reduction-nitridation, precursor method, direct nitridation of metallic vanadium, magnesiothermic reduction-nitridation, and chemical vapor deposition (CVD). Among these, the carbothermal reduction-nitridation method was discussed in terms of the two-step method and one-step method. A comparative analysis of raw material selection, process parameter configuration, and product element content was additionally presented, with a systematic evaluation of the advantages, disadvantages as well as application scale and scenarios of each process. It was proposed that the preparation processes of vanadium nitride were characterized by taking the carbothermal reduction-nitridation method as the core, with the ammonia reduction-nitridation method, carbonaceous gas reduction-nitridation method and precursor method developing steadily, while other research methods were still in the stage of small-scale exploration. In addition, considering factors such as cost, environmental protection and product performance, this paper presented the possible directions for the future development of vanadium nitride preparation technology.

Research on the microstructure and wear-resistance of TiC reinforced high chromium cast iron composites

XU Chi, WANG Shuai, LI Jinwei, WANG Juan, CHEN Rongqin, ZHENG Kaihong

2026, 47(3): 84-91. doi: 10.7513/j.issn.1004-7638.2026.03.009

Abstract(21) HTML (12) PDF(3)

Abstract:
TiC reinforced high-chromium cast iron matrix composites with different TiC mass fractions (30%, 40%, 50%) were prepared by powder metallurgy method, and the relationship between their microstructure and properties was systematically studied. The results show that the composite material is mainly composed of Fe-Cr phase, (Cr,Fe)₇C₃ phase, and TiC particles, with significant differences in microstructure under different TiC contents. At a TiC mass fraction of 30%, it exhibits a dispersed distribution structure, where black TiC particles are uniformly dispersed in the matrix without obvious agglomeration, the porosity is only 3.5%, and the structure is dense. At 40%, the reinforcing phase aggregates compactly, the spacing of TiC particles further decreases, and they bond closely with the matrix interface, significantly enhancing the dispersion strengthening effect. When the TiC content increases to 50%, it presents an agglomeration-porosity structure, the agglomeration phenomenon intensifies sharply, the porosity jumps to 11.4%, local connected micropores are formed, and the density decreases significantly. Correspondingly, the hardness and wear resistance first increased and then decreased. The 40% composite material had the best comprehensive performance, with a hardness （HV）of 1619.1 and an impact wear weight loss rate as low as 0.0732 g/h. Due to the synergistic effect of agglomeration-pore defects, the hardness of 50% of the samples fluctuated significantly, and the wear rate rebounded to 0.168 g/h, with a marked deterioration in performance.

Study on notch sensitivity of Ti-46Al-5Nb-0.1C alloy: high-temperature tensile and fatigue testing

JI Xiankun, ZHAO Chunling, LI Kui, HE Jian, CHEN Dewan, DING Xianfei, LIANG Yongfeng

2026, 47(3): 92-100. doi: 10.7513/j.issn.1004-7638.2026.03.010

Abstract(17) HTML (9) PDF(4)

Abstract:
Investigating notch mechanics behavior of TiAl alloys is a fundamental approach for ensuring safe and low-risk operation of TiAl alloy low-pressure blades. In this study, notch specimens with different stress concentration factors were prepared and subjected to tensile and fatigue tests at two different temperatures to investigate the notch sensitivity of Ti-46Al-5Nb-0.1C alloy under high-temperature tensile and fatigue conditions. The results from investigation of high-temperature tensile performance notch sensitivity indicate that, under the same temperature conditions, average tensile strength of Ti-46Al-5Nb-0.1C alloy firstly increases and then decreases with the increase of the stress concentration factor Kt. Under the same stress concentration factor Kt, average tensile strength slightly decreases with the increase of temperature, but the change is not significant. The results from investigation of high-temperature fatigue performance notch sensitivity indicate that fatigue strength of Ti-46Al-5Nb-0.1C alloy decreases with increasing stress concentration factor Kt. The fatigue strength of Ti-46Al-5Nb-0.1C alloy at 700 ℃ is higher than that at 550 ℃, indicating that the alloy exhibits good high-temperature fatigue performance. Scanning electron microscopy (SEM) was used to observe the fracture surface morphology and crack propagation and widening of the Ti-46Al-5Nb-0.1C alloy under tensile and fatigue loading. It was found that high stress concentration increased the surface roughness of the fracture surface but did not alter the crack propagation path. Transmission electron microscopy was used to observe the dislocation distribution in the tensile and fatigue deformation microstructures of the Ti-46Al-5Nb-0.1C alloy. The results indicated that dislocations glide were the primary deformation mechanism, with a small amount of deformation twinning observed in the deformation microstructure.

Effect of processing technology on the properties of pure titanium coil for high-quality anode sheets

FAN Xiaojie, YANG Jiajing, LU Jinwu, WANG Ningbo, SHI Mingjie, ZHANG Hongfei

2026, 47(3): 101-106. doi: 10.7513/j.issn.1004-7638.2026.03.011

Abstract(22) HTML (9) PDF(3)

Abstract:
This study utilized low-oxygen, low-hydrogen OA-grade sponge titanium as the raw material. The ingot was prepared via the EB + VAR dual melting process, and pure titanium coils for anode sheets were obtained through different processing routes. The surface quality, microstructure, and mechanical properties of the coils were systematically characterized using a surface inspection system, optical microscope, and universal mechanical testing machine. The results indicate that adjusting the processing route can effectively control the surface condition and mechanical properties of the coils. When employing a two rolling procedure combined with bell annealing at 560 °C × (10+8) h, the resulting titanium coils exhibited good surface quality and excellent mechanical properties, with a grain size rating reaching Grade 9 or higher, meeting the technical requirements for titanium anode coils.

Experimental study on the degradation law of f-CaO and optimization of expansion performance in steel slag treatment under different carbonation conditions

JIA Yao, LIU Fei, LI Dongdong, WANG Yifei, LIU Zunqing

2026, 47(3): 107-115. doi: 10.7513/j.issn.1004-7638.2026.03.012

Abstract(40) HTML (14) PDF(9)

Abstract:
To address the issues of expansion risks caused by the hydration of free calcium oxide (f-CaO) in steel slag and its low utilization rate of resources in road engineering applications, a carbonation treatment technology was employed. Single-factor and orthogonal experiments were conducted to investigate the effects of temperature, humidity, CO₂ concentration, and carbonation time on the f-CaO content in steel slag. The improvement effect of carbonation treatment on the volume stability of steel slag is verified by expansion rate tests. The results show that carbonation treatment can significantly reduce the f-CaO content in steel slag, and the f-CaO content decreases with the increase of temperature, humidity, CO₂ concentration, and carbonation time. The optimal carbonation process condition, derived from orthogonal experiments, were temperature of 25 ℃, humidity of 70%, CO₂ concentration of 20%, and carbonation time of 90 minutes. Under these conditions, the f-CaO content is minimized and carbonation efficiency was optimal, with the influence factors in descending order being temperature > CO₂ concentration > carbonation time > humidity. Expansion rate tests revealed that the optimal carbonation group exhibited a water immersion expansion rate of only 0.86% after 10 days, significantly lower than 1.8% of the uncarbonated group, demonstrating a significant improvement in the volume stability of steel slag. Additionally, incorporating carbonated steel into asphalt mixtures also significantly reduced the expansion rate while maintaining intact surface structure, confirming the effectiveness of carbonation treatment in improving the volume stability of steel slag. This study demonstrates that steel slag carbonation treatment not only effectively suppresses expansion and improves aggregate performance but also achieves CO₂ sequestration, providing a feasible pathway for the resource utilization of steel slag and the implementation of the "dual carbon" strategy.

Investigation into the heterogeneous photo-Fenton processing of coking wastewater utilizing titanium carbide-enhanced NiFeLDHs

AN Ning, CHEN Peng, WANG Fei, LIU Fang, WANG Yong

2026, 47(3): 116-123. doi: 10.7513/j.issn.1004-7638.2026.03.013

Abstract(15) HTML (11) PDF(4)

Abstract:
Low-cost, easy-to-manage, practical, and consistently compliant advanced wastewater treatment technology is the key to ensuring stable compliant discharge of coking wastewater. The heterogeneous photo-Fenton technology, characterized by low operating cost, no iron sludge burden, and low operational requirements, meets the criteria for an alternative technology. The practical application of this technology, however, hinges on the development of catalysts. In recent years, layered double hydroxides (LDHs), with large specific surface area, regular layered structure, abundant active sites, and rich hydrophilic groups, have emerged as ideal candidates for photo-Fenton catalysts. Nevertheless, the rapid recombination of photogenerated electron-hole pairs in LDHs limits their application in water treatment; while Ti₃C₂, with its excellent electrical conductivity, helps to address this drawback. In this study, the introduction of Ti₃C₂ not only increased the specific surface area of NiFeLDHs by 1.4 times but also improved the separation efficiency of photogenerated carriers. Consequently, TiC@NiFeLDH2 exhibited excellent performance in the advanced treatment of coking wastewater via photo-Fenton process, achieving a COD removal rate of 76.75% in coking wastewater within 120 min, which was 1.8 times higher than that of NiFeLDHs.

Study on the synergistic effect of granulated blast furnace slag and basalt fiber on concrete performance

PAN Xifei, GAO Song, SONG Haipeng, GAO Huaguo, MA Fanglei, JIANG Ziheng

2026, 47(3): 124-133. doi: 10.7513/j.issn.1004-7638.2026.03.014

Abstract(16) HTML (9) PDF(4)

Abstract:
The large accumulation of granulated blast furnace slag (GBFS) has caused potential environmental risks. In this study, GBFS was used to replace part or all of the manufactured sand (MS), and Basalt fiber (BF) was added to prepare concrete. The working performance and mechanical properties of concrete were tested, and the influence mechanism of the two on the above properties of concrete was analyzed by microscopic image. The results show that the GBFS sand replacement meets the requirements of the specification. The compressive strength of the concrete cube is used as the assessment index, the optimal sand replacement rate is 60%, which is 12.4% higher than the strength of the 28d benchmark concrete. The optimum content of BF is 0.3%. The optimal mix ratio of synergistic effect is water-binder ratio 0.35, GBFS replacement rate 60%, BF length 9 mm-0.3%, and water reducing agent 1.5%. GBFS sand replacement can promote secondary hydration, generate more C-S-H gel and refine pores. Meanwhile, BF plays an effective role in bridging and reducing cracks in the matrix, and makes up for the reduction of early strength of concrete caused by GBFS sand replacement.

Study on improving lead poisoning resistance of SCR catalysts for iron-steel sintering machines

LIU Yanbin, KONG Zhenhua, QI Yongsheng, ZHANG Zhidi, YANG Yong, ZHOU Mei, LI Han

2026, 47(3): 134-140, 148. doi: 10.7513/j.issn.1004-7638.2026.03.015

Abstract(19) HTML (10) PDF(3)

Abstract:
Powder catalysts were synthesized via the impregnation method to investigate the effect of Mo and Ce doping on improving the lead poisoning resistance of V-W/Ti catalysts. The physicochemical properties of the catalysts were characterized using BET, XPS, H₂-TPR, and NH₃-TPD. The results showed that doping with Mo and Ce enhanced the low-temperature reducibility of the catalysts, provide additional acid sites, and alleviated the detrimental effects of lead poisoning on the pore structure and oxygen vacancies. After exposure to high concentrations of lead, the V-W-MoCe/Ti-Pb catalyst still maintained excellent low-temperature denitration activity and a broad operating temperature window between 150–400 °C. Specifically, the NOₓ conversion exceeded 90% in the range of 250–400 °C. When the decay of activity reached 20%, the lead poisoning tolerance of the molded V-W-MoCe/Ti catalyst was 5.7 times higher than that of the V-W/Ti catalyst. These findings provide valuable insights for the application and promotion of such catalysts in denitrating flue gases containing lead and other heavy metals.

Study on the pelletization and agglomeration mechanisms of low-iron, high-titanium, high-vanadium iron concentrate in Chaoyang, Liaoning

GUO Yufeng, XIE Yanqin, CHEN Mao, WANG Shuai, ZHANG Yixi, XIA Xinyao, CHEN Feng

2026, 47(3): 141-148. doi: 10.7513/j.issn.1004-7638.2026.03.016

Abstract(33) HTML (24) PDF(10)

Abstract:
The vanadium–titanium magnetite resources in the Chaoyang area of Liaoning Province (also known as Liaoxi) exceed 20 billion tonnes. The iron concentrate obtained from beneficiation is characterized by high Si, Ti, and V contents, complex mineral composition, and the absence of a mature pelletizing process. Therefore, investigating the balling behavior and pellet consolidation mechanism of this concentrate is of great significance for the efficient and comprehensive utilization of these distinctive vanadium–titanium resources. In this study, orthogonal and single-factor experiments were conducted to examine the effects of mixture moisture, balling time, wet grinding, and high-pressure grinding rolls on green pellet properties. The results show that the factors affecting green pellet compressive strength followed the order of high-pressure grinding rolls, wet grinding, balling time, and mixture moisture, whereas those affecting drop strength followed the order of high-pressure grinding rolls, balling time, mixture moisture, and wet grinding. The suitable process parameters were determined as 1.2% bentonite, 8% mixture moisture, and 12 min balling time. After preheating at 900 °C for 8 min and roasting at 1100 °C for 10 min, oxide pellets with a compressive strength of 2641 N per pellet and favorable metallurgical properties were obtained.

Comparative study on the microstructure and properties of arc additive composite plates with different welding materials

WANG Hailin, WANG Jinfeng, ZHANG Yuanhao, YANG Siwei, ZHAN Hongshun, JIANG Mengru, CHEN Haiyang

2026, 47(3): 149-155. doi: 10.7513/j.issn.1004-7638.2026.03.017

Abstract(19) HTML (12) PDF(7)

Abstract:
To optimize the welding process and performance of H13 steel-based composite plates, different welding materials were selected and two high-strength composite plates were fabricated using arc additive manufacturing. The microstructure morphology, micro-Vickers hardness, impact toughness, and fracture characteristics of these plates were compared and analyzed. The results indicate that the bottom and middle parts of the high-strength layer are mainly composed of ferrite, tempered martensite, quenched martensite and a small amount of residual austenite, while the top layers are mainly composed of ferrite, quenched martensite and a small amount of residual austenite, with a significantly reduced proportion of tempered martensite. The average vickers hardness of the high-strength layer in Scheme A is 684. While in Scheme B it drops to 606.7, the vickers hardness curve changes more gradually. The impact toughness of the composite plate in Scheme A is 7.37 J/cm², and the fracture surface of the overlay shows cleavage fracture. In scheme B, the introduction of the 316 L transition layer plays a plastic buffering role, increasing the impact toughness to 8.41 J/cm², with an increase of 14%. The fracture surface of the overlay presents quasi-cleavage fracture.

Precipitation behavior of the second phase in austenite in Ti-Nb microalloyed steel

LIU Kun, GAN Xiaolong, WANG Wenjun, XIONG Ziliu, LIU Bin, YANG Yang

2026, 47(3): 156-163. doi: 10.7513/j.issn.1004-7638.2026.03.018

Abstract(17) HTML (9) PDF(2)

Abstract:
Based on the solid solution precipitation and nucleation growth theory of the second phase of microalloyed composite, a thermodynamic and kinetic model for the precipitation of the (Ti, Nb)C composite second phase in austenite in 0.06%C-0.17%Ti-0.03%Nb microalloyed steel was constructed, and the nucleation rate-temperature(NRT) curve and precipitation-time-temperature(PTT) curve of the second phase precipitates in austenite were drawn. The NrT curve of the test steel showed an anti "C" type feature, while the PTT curve showed a typical "C" type feature. The peak nucleation rate was observed at approximately 900 ℃, a temperature which also corresponds to the optimum point for precipitation kinetics. The theoretical results were verified by stress relaxation test. TEM were used to characterize the second phase precipitates in the typical samples of stress relaxation test. The results showed that the second phase precipitates and the matrix met the N-W orientation relationship, mainly composed of (Ti, Nb)C composite carbides precipitated in austenite.

Microstructure and mechanical properties of post-weld heat-treated joints in vanadium microalloyed Q390FRW steel

BAI Qincheng, CUI Yongfeng, YU Haibao, XIE Tingting, HAN Rudong, LIU Jianying, ZHOU Shuhao

2026, 47(3): 164-171. doi: 10.7513/j.issn.1004-7638.2026.03.019

Abstract(14) HTML (9) PDF(2)

Abstract:
To enhance the comprehensive performance of steel for bridge expansion joints, a fire-resistant and weathering-resistant vanadium-microalloyed Q390FRW steel was prepared in this study. The effects of flux-cored arc welding (FCAW), submerged arc welding (SAW), and subsequent post-weld heat treatment (PWHT-525℃ × 60 min) on the microstructure and mechanical properties of the joints were investigated. Thermodynamic calculations indicated that vanadium carbides (VC) can precipitate at 799 ℃, contributing to grain refinement. Experimental results showed that the FCAW weld joint consisted mainly of ferrite and a small amount of martensite-austenite (M-A) islands, while the SAW weld joint was primarily composed of bainite and ferrite. After heat treatment, the M-A islands in both weld joints decomposed, grain size significantly refined, and the dispersion precipitation of vanadium carbides was promoted. The tensile strength and elongation of the FCAW joint after heat treatment reached 679 MPa and 33.64%, respectively. The remarkable improvement in plasticity was primarily attributed to the precipitation strengthening and microstructural stabilization effects induced by vanadium. Fracture analysis revealed that the heat treatment shifted the fracture mechanism of the joints from a ductile-brittle mixed mode to a ductile fracture mode.

Ti/N control of precipitates and toughness in welded Mg-treated shipbuilding steel plate

ZHANG Yuqi, YANG Jian, ZHANG Yinhui

2026, 47(3): 172-180. doi: 10.7513/j.issn.1004-7638.2026.03.020

Abstract(16) HTML (12) PDF(2)

Abstract:
In this study, the effect of the Ti/N ratio on the impact toughness at -20 ℃ of Mg-treated shipbuilding steel plates after high heat input welding of 400 kJ/cm had been investigated. When the Ti/N ratio is increased from 3.00 (TN30) to 5.67 (TN57), the main precipitated particles are TiN particles. The average size of nano secondary phase particles increases from approximately 150 nm to 205 nm, with the particle number density in TN57 being approximately 2.5 times than that in TN30. In TN30 steel, Mg-Ti-O-MnS composite inclusions with a size about 3 μm can effectively induce IAF nucleation. The ferrite laths and dislocation pile-ups significantly enhance its toughness. TN57 steel contains Ti(C, N) composite inclusions which are regular in shape, sharply angular and approximately 5 μm in size. These coarse carbonitrides are detrimental to the toughness of the steel. As the Ti/N ratio is increased from 3.00 to 5.67, the low-temperature impact toughness at -20 ℃ decreases from 183 J to 49 J.

Experimental study and application of pre-demagnetization for desulfurization and quality improvement of high-sulfur magnetite ore

HUANG Yuzhi, XIE Xian, LAN Xixiong, LIU Daicai, ZHANG Zijiang, GAN Yunxiao

2026, 47(3): 181-188. doi: 10.7513/j.issn.1004-7638.2026.03.021

Abstract(41) HTML (19) PDF(5)

Abstract:
In this paper component analysis was conducted on the high-sulfur magnetite ore from the Dulong mining area, by means of MLA. Analysis results indicate that the valuable elements in the high-sulfur magnetite ore are mainly iron, sulfur, and tin. Iron mainly exists in the form of magnetite, while sulfides are primarily present in pyrite and pyrrhotite, and tin exists in the form of cassiterite. The gangue minerals mainly consist of talc, iron talc, and biotite. Based on the analysis on the ore components, a separation process of 'pre-demagnetization, flotation desulfurization, and weak magnetic separation had been proposed. Closed circuit separation test results indicated that under the conditions of pre-demagnetization treatment, grinding fineness of -0.074 mm at 89%, activator AS-106 at 3500 g/t, collector B30-2 at 150 g/t, and weak magnetic separation field strength of 0.1 T, a high iron sulfur concentrate with a sulfur grade of 23.94%, iron grade of 60.16%, and sulfur recovery rate of 97.70% could be obtained. Besides, a high-quality iron concentrate with sulfur content of 0.43%, iron grade of 66.79%, and recovery rate of 57.08% was also achieved.

Study on the selective separation of magnetite and hornblende using soluble starch

LI Wanxing, ZHU Siyu, LU Zetong, LIU Shuang'an, ZHANG Qi, ZHANG Pengyu, LI Hongqiang

2026, 47(3): 189-196. doi: 10.7513/j.issn.1004-7638.2026.03.022

Abstract(16) HTML (8) PDF(4)

Abstract:
Hornblende is a ferrous silicate mineral with similar floatability to magnetite, making the two minerals difficult to separate. The feasibility of Soluble Causticized Starch (TF) as depressant of magnetite was assessed in the single-mineral, artificial-mixed-ore and natural ore flotation test. Meanwhile, the adsorption mechanisms of TF on magnetite surface were investigated through contact angle measurement, Zeta potential measurement, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The flotation test results showed that under the condition of pH=7, 7.5 mg/L collector 609 and 10 mg/L TF could effectively depress magnetite, but the depression effect on hornblende was not obvious. Flotation tests on raw ore further confirmed that TF not only could be used as an depressant for the separation of magnetite and hornblende, but also alleviate excessive foam formation. TF adsorbs on the surface of magnetite, thereby significantly increasing its hydrophilicity. Oxygen-containing functional groups -COOH, -OH forming coordination bonds with surface Fe of magnetite via chemical adsorption hinders the adsorption of collector 609 on magnetite surface effectively.

Current Articles 2026, Volume 47, Issue 3

Current Articles
2026, Volume 47, Issue 3