- 百种中国杰出学术期刊
- 中国精品科技期刊
- “中国科技期刊卓越行动计划二期”领军期刊
- 入选“中国精品科技期刊顶尖学术论文(F5000)”
- 入选《科技期刊世界影响力指数(WJCI) 报告》
- EI、CA、JST收录期刊
- 中国金属学会会刊
- 中文核心期刊
- 中国科技核心期刊
- 中国科学引文数据库(CSCD)来源期刊
The rapid development of the aluminum industry has led to a stockpile of red mud exceeding 1.5 billion tons, yet its comprehensive utilization rate remains below 12%. This massive accumulation not only occupies substantial land resources but also causes environmental pollution and resource waste. This review first systematically outlines the sources, distribution, and environmental hazards of red mud, and analyzes its characteristics in terms of chemical and mineral compositions. It then summarizes the current status and developmental trends in red mud treatment and comprehensive utilization, with a focus on reviewing research progress in its applications, such as in building materials, metal recovery, and environmental remediation. Finally, future prospects are discussed. The paper highlights the need to strengthen technological innovation to address the challenges of high alkalinity and heavy metal stability. It proposes achieving efficient resource utilization of red mud through the co-processing of multi-source solid wastes and the tiered utilization of all its components. Emphasis is also placed on demonstrating practical projects, improving the standard system for various application fields, and leveraging market drivers to promote the large-scale and high-value utilization of red mud resources.
Platinum group metals (PGMs) play a vital role in the automotive, petrochemical and electronic devices industries due to their unique physical properties and excellent catalytic activity, rendering them indispensable strategic resources for the country. However, China's PGM mineral resources are scarce with low ore grades and high mining costs. Consequently, recovering PGMs from secondary resources, particularly the large quantities of spent PGM catalysts has become the primary source of these metals. Based on the operating conditions, current PGM enrichment processes can be divided into pyrometallurgical and hydrometallurgical processes. Pyrometallurgical processes feature high processing capacity and short process flows, making them suitable for large-scale operations, but they are energy-intensive and cause considerable environmental pollution. In contrast, hydrometallurgical processes operate under milder reaction conditions and good selectivity for specific materials, though they involve longer process flows and high reagent consumption. After enrichment, PGMs in the solution require purification and refining. The precipitation method is applicable for enriching solutions with high metal ion concentrations but tends to introduce impurities. Solvent extraction yields high-purity products, yet the extractants are often toxic and volatile which increases operational difficulty. Ion exchange achieves high separation efficiency and low pollution, but it is costly and severely restricted by the solution system. This paper summarizes common enrichment processes and conducts detailed analysis of their respective advantages and disadvantages. It also overviews different purification processes and elaborates on their merits and demerits. On this basis, the paper outlines future research directions for PGM recovery from spent catalysts, providing new insights for promoting efficient recycling of secondary PGM resources and developing economical, environmentally friendly, and intelligent recovery processes.
In response to the issues caused by reduced supply of high sulfur low silicon ore powder on the Shougang pellet production line consisting of a grate-rotary kiln-annular cooler, including insufficient sulfur source for the acid production system, decreased magnesium to aluminum ratio in the blast furnace, and deteriorated slag fluidity, a systematic study was conducted on the feasibility of using highsulfur boron-containing iron powder (HSBC, containing B2O3 5%, MgO 10.18%, S 1.0% by mass) to replace Peruvian fines in the production of acid pellets. The phase composition microstructure and thermal decomposition characteristics of HSBC were characterized using a combination of X ray diffraction reference intensity ratio (XRD-RIR), scanning electron microscope energy dispersive spectroscopy (SEM-EDS), and thermogravimetric analysis differential scanning calorimetry (TG-DSC) method. Five gradient tests with HSBC mass ratios of 0, 2%, 4%, 6%, and 8% were designed and implemented on an industrial 10 kg scale disc pelletizer grate machine rotary kiln and annular cooler line for green pellet preparation, basket roasting and sampling detection. The results show that HSBC particles have a rough surface and a fibrous structure. Their particle size is relatively coarse with 72.6% below 74 μm complementing the extremely fine Macheng powder in particle size distribution. This complementarity increased the drop strength of green pellets from 6.2 times to 8.5 times. TG-DSC analysis revealed an exothermic peak at 379 ℃ corresponding to the conversion of Fe3O4 to Fe2O3 and an endothermic peak between 661.7 and 916 ℃ associated with sulfide oxidation dolomite decomposition and ludwigite lattice reconstruction with a total weight gain of 2.9%. The roasted pellets exhibited a core shell structure characterized by a liquid phase shell and a porous core with porosity increasing from 17.7% to 25.9%. As the HSBC mass ratio increased from 0 to 8%, pellet reducibility decreased from 58.50% to 50.32% while reduction swelling increased from 10.98% to 22.34%. The compressive strength after one hour of reduction improved by 169 N and the softening temperature interval Δt widened from 91 ℃ to 115 ℃. Considering metallurgical performance indicators and blast furnace adaptability, the optimal HSBC addition ratio is determined to be 5%. At this ratio, the compressive strength of the finished pellets reached 3 173 N, the desulfurization rate is 91.5% and the sulfur input is 1 117 mg/m3, which is close to the baseline level. Additionally the pellets demonstrated good reducibility at 55.02% and a controllable reduction swelling rate of 16.36%. The research findings provide a theoretical basis and technical support for the large scale application of high-sulfur boron-containing iron powder in pellet production.
With the advancement of green and low-carbon transformation in the steel industry, the demand for comprehensive utilization of solid wastes in the metallurgical sector continues to grow. Carbide slag, a high-calcium solid waste generated by the chemical industry, not only occupies land resources but also poses environmental risks due to its large-scale accumulation. As a high-calcium solid waste, carbide slag holds significant potential for replacing conventional calcium-based fluxes in iron ore sintering. This study aimed to systematically investigate the feasibility of using carbide slag as a substitute for conventional fluxes in iron ore sintering and its impact mechanism on the sintering and mineralization processes. Mineralogical analyses of carbide slag, limestone, and quicklime were conducted using XRF, XRD, laser particle size analyzer and thermogravimetric analyzer. The results indicate that compared to conventional fluxes, carbide slag exhibits higher CaO content, finer particle size, lower thermal decomposition temperature and higher thermal stability, demonstrating its suitability as a sintering flux. Through fundamental sintering characteristic tests and micro-sintering experiments, combined with the mineralogical properties of carbide slag, the effects of its substitution for conventional fluxes on sintering characteristics and the mineral phase structure of sinter were systematically analyzed. The results show that as the substitution ratio of carbide slag increases from 0 to 60%, the assimilation temperature decreases, while the fluidity of the liquid phase, the strength of the binding phase and the formation capacity of calcium ferrite improve, promoting the development of an interwoven-corroded structure. However, when the substitution ratio exceeds 60%, although the assimilation temperature continues to decrease, the fluidity of the liquid phase and the formation capacity of calcium ferrite decline, accompanied by an increase in silicate minerals and porosity, leading to a deterioration in the mineral phase structure of the sinter. At a substitution ratio of 60%, the sinter exhibits a uniform mineral phase structure, the highest content of calcium ferrite, predominantly in acicular and columnar forms. The findings of this study provide new insights into the resource utilization of carbide slag and the cost reduction and efficiency improvement in sinter production.
To systematically investigate the influence of mass fraction of Y2O3 and w(CaO)/w(Al2O3) on the physicochemical properties of the CaF2-CaO-Al2O3-MgO-Y2O3 slag systems, this study addresses the severe burning loss of the Y element during the electro-slag remelting process of Y-containing rare earth steels. It proposes improving slag system performance by adding Y2O3 and adjusting the w(CaO)/w(Al2O3), thereby increasing the yield of Y. Experiments were conducted to prepare five slag systems with different mass fractions of Y2O3 and four slag systems with different w(CaO)/w(Al2O3) values. Various testing and analytical methods were comprehensively utilized, including an X-ray diffractometer, an X-ray fluorescence spectrometer, hemispherical melting temperature testing, rotating cylinder viscosity measurement, a Fourier transform infrared spectrometer, and a scanning electron microscope, to conduct a systematic study on the phase composition and content, melting characteristics, viscosity changes, structural features, and precipitated phase characteristics of the slag system. The aim is to provide theoretical support for optimizing slag composition, suppressing the burning loss of the Y element, and improving its yield. The results indicate that the addition of Y2O3 promotes the formation of the CaYAlO4 phase. As the mass fraction of Y2O3 increased from 0 to 20%, the melting temperature of the slag first decreased and then increased, while the viscosity first increased and then decreased, with the optimal Y2O3 mass fraction of 15%. With the increase of the w(CaO)/w(Al2O3) from 0.8 to 1.4, the characteristic peaks of the CaYAlO4 phase in the slag systems gradually intensified, the melting temperature and viscosity of the slag systems decreased, and the proportion of needle-like CaYAlO4 in the slag systems increased. The decrease in viscosity might be primarily attributed to the depolymerization of[AlOnF4-n]- tetrahedral complexes and the transformation of[AlO4]5- tetrahedra into[AlO6]9- octahedra induced by the elevated w(CaO)/w(Al2O3). The low viscosity led to the reduction of ionic clusters migration resistance, which in turn reduced the energy potential barrier for nucleation and crystal growth, accounting for the increase in the percentage of CaYAlO4. The needle-like morphology of CaYAlO4 may be affected by the growth mechanism controlled by screw dislocations. Based on the above discussion, the optimal slag composition is determined as follows, Y2O3mass fraction of 15%, w(CaO)/w(Al2O3) is 1.4. The melting temperature of this slag ratio is 1 346 ℃, and its viscosity at 1 600 ℃ is 0.28 Pa·s.
This study investigated the effects of rare earth(RE) and magnesium treatments on non-metallic inclusions in ultra-high purity (UHP) 316L austenitic stainless steel, aiming to enhance steel cleanliness to meet the stringent requirements for semiconductor equipment materials. Traditional aluminum deoxidation processes produce alumina, which is prone to shedding during service and contaminates the entire semiconductor processing system. Although rare earth and magnesium are considered potential alternative deoxidizers, systematic studies on their combined treatment process, particularly the influence of addition sequence on inclusions in UHP 316L stainless steel, remain insufficient. Using a VIM+VAR duplex process, three deoxidation routes were designed, RE (Y) treatment only, Mg-Ce sequential treatment, and Ce-Mg sequential treatment. The effects of each process, under industrial production conditions on the size, distribution, type, and rating of inclusions were systematically examined. Inclusion characteristics and their evolution at various processing stages were evaluated using metallographic microscopy, SEM-EDS, and Thermo-Calc thermodynamic simulations. The results demonstrate that in VIM+VAR smelting of UHP 316L stainless steel, the Ce-Mg sequential deoxidation sequence is the most effective strategy for high-level inclusion control. This approach results in the lowest inclusion distribution density and smallest average equivalent diameter in VIM+VAR samples, with no large inclusions (≥8 μm) observed. The fine Type D inclusion rating is below 0.5, meeting industry standards for UHP 316L stainless steel. In contrast, the Mg-Ce treatment shows poor inclusion control due to severe premature magnesium loss, which limits effective synergy with rare earth. The proper RE-Mg addition sequence fully utilizes the strong deoxidation capability of rare earth elements and the bubble flotation and stirring effects of magnesium vapor, providing a key process route for achieving high cleanliness control in UHP 316L stainless steel.
To meet the construction requirements of liquid ammonia transport ships, this study adopted a low-carbon Nb-Ti-Al composite microalloyed composition design combined with controlled rolling and controlled cooling (CRCC)processes to develop the low-temperature steel plate LT-FH32. Through tensile tests, low-temperature impact tests, metallographic observation and scanning electron microscopy analysis, systematic investigations were conducted on the variation of the microstructure and properties of the test steel with rolling process. The results indicate that with decreasing finish rolling temperature, the microstructure of the test steel transitions from a multiphase structure consisting of polygonal ferrite+quasi-polygonal ferrite+acicular ferrite to a dual-phase structure of polygonal ferrite+bainite. The volume fraction of the soft phase, polygonal ferrite increases from 37% to 63% and the hardness difference between soft and hard phases rises from 68HV0.01 to 119HV0.01. With further application of post-rolling relaxation process, the microstructure evolves into a dual-phase structure of polygonal ferrite+large-sized lath or blocky M/A (Martensite/Austenite) constituents. The volume fraction of polygonal ferrite continues to increase to 89% and the hardness difference between soft and hard phases further increases to 379HV0.01. This microstructural evolution leads to a decrease in yield strength, initial increase followed by decrease in tensile strength and a continuous reduction in the yield-to-tensile ratio. The crack initiation energy first increases then decreases while the crack propagation energy declines continuously, and the ductile-brittle transition temperature rises. When the finish rolling temperature is 770 ℃ and direct water cooling is applied after rolling, the test steel exhibits moderate strength margins with yield strength of 406 MPa and tensile strength of 519 MPa ensuring good safety performance. The yield-to-tensile ratio is 0.78, and the low-temperature toughness reserve is sufficient with ductile-brittle transition temperature below -80 ℃, thus achieving the optimal comprehensive performance.
Complex corrosion environments such as strong irradiation, variable climate and high temperature high humidity high salt condition in marine areas impose higher requirements on high-performance weathering bridge steel.A new low C+(Cu-Cr-Ni) alloyed Q550qENH weathering steel was taken as the research object while ordinary Q355B carbon steel served as the reference steel to investigate corrosion behavior in simulated marine atmospheric environment. Cyclic immersion test, scanning electron microscope(SEM), X-ray diffractometer(XRD) and electrochemical test were employed to study corrosion weight loss and rust layer evolution of Q550qENH steel in 3.5% NaCl solution at different corrosion cycles(72, 168, 360, 576 h). The results show that during 72 h to 360 h of corrosion, the surface rust layer of Q550qENH steel transforms from partial coverage to full coverage, and the corrosion weight loss rate increases rapidly with time extension. X-ray diffractometer analysis of corrosion products indicates that corrosion products of the experimental steel at different cycles consist of α-FeOOH, γ-FeOOH and Fe3O4, among which α-FeOOH accounts for the highest proportion, followed by Fe3O4 and γ-FeOOH. When corrosion time extends to 576 h, the corrosion weight loss rate of the experimental steel increased slightly, the corrosion products are mainly α-FeOOH, and the content of γ-FeOOH decreases. Electrochemical test results demonstrate that as corrosion time extends from 72 h to 576 h, the polarization curves of Q550qENH steel all shift to the right, and corrosion current density shows a trend of first increasing and then decreasing. This phenomenon means that, with the progress of corrosion the rust layer on Q550qENH steel surface gradually thickens and its compactness enhances. Compared with ordinary Q355B carbon steel, the weight loss rates of Q550qENH steel at different corrosion cycles are 53.56%, 67.38%, 96.45% and 74.85% of those of Q355B, respectively. In the later stage of corrosion, the content of α-FeOOH in corrosion products of Q550qENH steel is significantly higher than that of Q355B steel, and the rust layer is denser.This effectively inhibits the penetration of corrosive media into the matrix, thus endowing Q550qENH steel with better corrosion resistance than Q355B steel.
This study systematically investigates the influence of the sequence between rolling and precipitation processes on the microstructural evolution and high-temperature mechanical properties of heat-treatable Al-Mg-Si-Mn alloy, aiming to provide a theoretical basis for optimizing the manufacturing process and enhancing the overall performance of such alloys. Al-Mg-Si-Mn alloy slabs with excellent surface quality were successfully produced using an independently developed twin-roll casting (TRC) technique. Microstructural analysis shows that under the precipitation-rolling (P-R) process with prolonged precipitation treatment, the average size of precipitates is approximately 70 nm, with a number density of 15 μm-2. In contrast, the rolling-precipitation (R-P) process combined with short-duration precipitation treatment increases the average precipitate size to 90 nm and raises the number density to 17 μm-2. Under identical precipitation durations, the R-P process leads to a pronounced spheroidization trend of the dispersion phases, accompanied by the formation of extensive recrystallized microstructures. High-temperature mechanical tests indicate that at 350 ℃, the R-P processed alloy achieves a tensile strength of 83 MPa with an elongation of 5%, while the P-R processed alloy exhibits a tensile strength of 65 MPa and an elongation of 6%. The study demonstrates that the R-P process promotes the precipitation of a greater number of strengthening phases within a shorter time, thereby significantly improving the mechanical properties of the alloy under high-temperature conditions. This provides new insights for optimizing short-process routes for heat-treatable strengthened alloys.
High-strength automotive beam steel serves as a critical component for supporting vehicle mass and external loads, requiring high strength, high toughness, and excellent cold formability. However, hard inclusions such as Al2O3, magnesium-aluminum spinel, and calcium aluminate present in the steel do not readily deform during rolling. Improper control will damage product performance. Cerium (Ce) plays a role in modifying inclusions and refining grain structure in steel. It can transform Al2O3, Mg-Al-O and Ca-Al-O inclusions into rare-earth inclusions such as CeAlO3 and Ce2O2S. These cerium-containing inclusions can act as nucleation sites, refining the solidification structure of the steel. Through melting and casting experiments using a high-temperature tube furnace, combined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermodynamic calculations, the effects of different Ce content on inclusion modification and as-cast structure refinement in high-strength beam steel were systematically studied. The results show that as the Ce content in the steel increases, the inclusion modification sequence follows CeAl11O18→CeAlO3→Ce2O3→Ce2O2S→CeS, with the final modified product depending on the Ce content. When the mass fraction of Ce is 0.005 5%, the modified inclusions are Ce-Al-O types, exhibiting polygonal or (near-)spherical morphologies due to genetic effects and modification-induced spheroidization. When the mass fraction of Ce reaches 0.018 0%, the inclusions are further modified into Ce-O-S types with spherical morphologies, showing characteristics of aggregation and growth, while the originally angular Mg-Al(-Ti)-O inclusions disappear. Ce effectively reduces the average size of inclusions and decreases the number of large-sized inclusions. As the Ce content increases, the number of inclusions first decreases and then increases, with the smallest average size and lowest quantity observed at a Ce mass fraction of 0.005 5%. Additionally, Ce exhibits a grain-refining effect in steel. Both Ce-Al-O and Ce-O-S inclusions promote solidification nucleation, with the most significant refinement of the as-cast microstructure achieved at a Ce mass fraction of 0.018 0%. Thermodynamic calculations further elucidate the formation mechanisms of the relevant inclusions.
To investigate the effect of tempering temperature on the drop-weight tear test (DWTT) properties of X70Q pipeline steel, the influence of different tempering temperatures (300-600 ℃) on the microstructure and mechanical properties, especially the DWTT performance, of X70Q thick-walled pipeline steel and its underlying mechanisms were studied using metallography, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), JMatPro simulation, transmission electron microscopy (TEM), and other methods. The results show that in the low-to medium-temperature tempering range of 300-400 ℃, dislocation recovery and sub-grain coalescence occur in the tested steel, leading to a significant increase in the proportion of high-angle grain boundaries (reaching 68.3% at 400 ℃). Meanwhile, the precipitation of fine M3C carbides contributes to strengthening, resulting in an optimal combination of strength and toughness. During high-temperature tempering at 500-600 ℃, grain coarsening, brittle-phase precipitation, and decomposition of martensite/austenite (M/A) islands cause a remarkable deterioration in DWTT performance. The deterioration of DWTT performance during high-temperature tempering is mainly attributed to three key factors: grain coarsening and equiaxed, brittle phase precipitation along grain boundaries, and decomposition of small M/A islands. Grain coarsening and equiaxed refers to the transformation of needle shaped ferrite with small fracture units and large orientation differences into equiaxed polygonal ferrite after high-temperature tempering, resulting in an increase in effective grain size, especially the abnormal growth of {001} cleavage plane grains, which reduces crack propagation resistance. Brittle phase precipitation along grain boundaries refers to the precipitation of coarse M23C6 along grain boundaries after high-temperature tempering, resulting in chromium depletion near the grain boundaries and weakening the bonding strength of the grain boundaries. The decomposition of small M/A islands refers to the important structure that hinders crack propagation. After high-temperature tempering, the small M/A islands are basically completely decomposed, losing their beneficial effects. The research results provide reference for the production of X70Q heat treatment.
To address the issue that the excessive strength of hot-rolled ultra-low carbon steel sheets is detrimental to subsequent cold rolling and forming, deformation in the austenite-ferrite two-phase zone can be applied to reduce strength, but this significantly increases deformation resistance during hot rolling. Therefore, compression deformation of low-carbon steel in the austenite-ferrite two-phase region (773-845 ℃) was conducted using a Gleeble-1500 thermomechanical simulator. Optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) were employed to investigate the effects of different deformation temperatures and strains on peak stress and microstructure, aiming to obtain process parameters that reduce deformation resistance in the two-phase zone and to analyze the corresponding softening mechanisms. The results show that the microstructure of the steel after two-phase zone deformation consists of ferrite and pearlite. Under a constant strain rate of 1 s-1, strains of 30% or 60%, and deformation temperatures ranging from 775 ℃ to 825 ℃, dynamic recrystallization is difficult to occur when the specimen is deformed at a low temperature of 775 ℃ with a small strain of 30%. During deformation, the microstructure is dominated by coarse grains that have only undergone recovery and growth. Under these conditions, the ferrite grain size reaches a maximum of 55.4 μm, and the deformation resistance is minimized at 103 MPa. The primary mechanism for the reduction in deformation resistance in the two-phase zone under these process parameters is grain coarsening. Investigating the influence of deformation process parameters in the two-phase zone on the deformation resistance of low-carbon steel is of significant importance for achieving precise control of deformation resistance in industrial production and effectively reducing the strength of hot-rolled plates.
As a key area of global carbon emissions, the steel industry's low-carbon transformation is of vital importance, and increasing the proportion of scrap steel usage is a crucial measure for steel enterprises to achieve carbon reduction. However, at present, there are two core problems in the carbon accounting of scrap steel, inconsistent standards and difficulty in coordinating technology and economy, which urgently need to be solved. This article aims to explore the optimized path for scrap steel utilization through multi-standard comparison and modeling, helping enterprises balance carbon reduction and benefits. The research systematically compared four major standards, the LCI methodology of the World Steel Association, the "Evaluation Method for Low-Carbon Emission Steel" of the China Iron and Steel Association, the Responsible Steel (RS) standard, and the German LESS, and analyzed the differences in the definition, classification, and accounting boundaries of scrap steel. In light of the production characteristics dominated by converters in China, a collaborative optimization model for thermal balance, material balance, and carbon emission-cost was constructed. The effects of carbon-based/silicon-based heat supplements and preheating of scrap steel on the scrap steel ratio were quantified, and the roles of scrap steel yield and the price difference between molten iron and scrap steel were explored. The results show that the "Evaluation Method for Low-Carbon Emission Steel" is more in line with the national conditions of China's steel production due to the introduction of localized parameters and is suitable to be used as a unified benchmark for domestic carbon accounting. Among the supplementary heating measures, preheating scrap steel is the optimal carbon reduction technical path, which can increase the scrap steel ratio by approximately 9% and has the least impact on the quality of molten steel. Coke supplementary heating can increase the scrap steel ratio by approximately 7%, while ferrosilicon supplementary heating only raises it by about 1%. In terms of the coordinated optimization of the economy and the environment, when the price difference between molten iron and scrap steel exceeds 300 RMB/t (LCI methodology) or 100 RMB/t (evaluation method for low-carbon emission steel), increasing the scrap steel ratio can achieve a win-win situation of carbon reduction and cost. In addition, the scrap steel harvest rate has a significant impact on the stability of material balance and economic and environmental benefits. Improving the quality of scrap steel is the core guarantee for high-proportion scrap steel smelting.
Copper, as a foundational material for the global transition to new energy industries, is facing increasing demand. The rapid development of the copper industry is accompanied by substantial consumption of minerals, energy, and water resources, while also generating significant volumes of wastewater and other pollutants, imposing severe environmental pressure. Water serves as both a critical resource and an essential medium in metallurgical processes, with its consumption directly linked to wastewater generation. Therefore, this study takes a typical pyrometallurgical copper smelting enterprise as a case to systematically analyze the characteristics of water metabolism throughout the entire process, identify key water-saving stages, propose water network optimization strategies, and promote the green transformation and sustainable development of the copper industry. Using material flow analysis, the study quantifies the relationships among water consumption, wastewater discharge, and recycling from a holistic process perspective. It integrates all water-use processes into a water balance system, establishes an optimization model and evaluation index system for the water network of the copper smelting enterprise, and proposes a hierarchical water-use strategy based on a "graded treatment-cascading utilization-closed-loop reuse" framework. The results show that after optimization, the enterprise's fresh water consumption decreased from 15.74 m3/t to 12.51 m3/t, a reduction of 20.52%. The recycled water usage increased from 949.67 m3/t to 1 274.54 m3/t, a rise of 34.21%. Water resource efficiency improved by 68.04%, the water recycling rate increased from 98.2% to 98.7%, system reclaimed water usage rose from 1.30 m3/t to 4.05 m3/t, and wastewater discharge decreased from 5.05 m3/t to 4.43 m3/t. This study reveals the characteristics of water flow in copper smelting processes, proposes hierarchical water-use strategies and water network optimization methods, providing a feasible technical pathway for efficient water resource management and near-zero discharge. Future work could further integrate intelligent monitoring and control technologies to achieve dynamic optimization and refined management of water systems.
By adopting an appropriate alloy preparation method and element doping to regulate the composition and microstructure of alloy ingots, metal materials can be modified, which is an important means to address the problems of Sm element volatilization, poor preparation stability, and difficult microstructure control in SmFe12-based rare earth alloys. Based on experimental phenomena, it was determined that induction melting method was more suitable for the preparation of SmFe12-based rare earth alloy ingots than arc melting method. Zr, Co, Cu and Ti were doped into SmFe12 alloy ingots, and the doped ingots were subjected to homogenization heat treatment at 1 100 ℃ for 36 h. The phase composition and microstructure were characterized and analyzed using XRD and SEM. The mechanism of the effect of element doping on the alloy phase composition was studied. The effect of element doping was analyzed from the perspective of thermodynamic parameters such as mixing enthalpy, mixing entropy, Gibbs free energy and atomic size difference. Combined with the experimental results and thermodynamic analysis, the problems of poor stability and difficult preparation of SmFe12 alloy ingots have been addressed by element doping. Under the action of interatomic forces, Sm0.8 Zr0.2 Fe8.5 Co2 Cu0.5 Ti alloy is composed of SmFe11 Ti phase, SmCu5 phase and α-Fe phase. Zr and Ti atoms exist in the form of solid solution in the SmFe11 Ti phase, and the solid solubility of Zr and Ti is higher in the SmFe11 Ti phase around the α-Fe phase. Under the attractive force of Cu atoms on Sm atoms and the repulsive force of Cu atoms on Fe atoms and Co atoms, Cu atoms are precipitated to form SmCu5 phase, which promotes the decomposition of SmFe11 Ti phase and leads to the decrease in SmFe11 Ti phase content and the increase in α-Fe phase content. The results show that, the doping of Zr, Co, Cu and Ti elements improves the stability of the SmFe12-based alloy's main phase while precipitating the SmCu5 phase, which is expected to further optimize the magnetic properties of the SmFe12-based alloys. High-quality raw materials are provided for future powder preparation, and control of the grain size and distribution of SmCu5 phase becomes a new research direction.
In the blast furnace smelting process, the uniformity of pellet size has a significant impact on the smooth operation of the blast furnace. However, in the industrial pelletizing process, traditional manual screening methods are still used on-site. These methods are inconvenient for direct and continuous measurement of pellet size and have large measurement errors, making it difficult to meet the requirements of real-time measurement. Therefore, this paper proposes a non-contact online method for measuring pellet size. Based on the YOLOv11 model, a multi-scale enhanced upsampling module (MEUM) is introduced to replace the original upsampling structure. Multi-scale feature fusion and edge enhancement design improve the representation ability for different particle sizes and fuzzy boundaries. A local importance attention (LIA) mechanism is embedded in the backbone network to adaptively enhance the response of key regions, improving the robustness of target features in complex backgrounds while maintaining the network's lightweight nature. Furthermore, on this basis, an edge contour-Hough circle joint detection method is proposed to calculate the pellet size. The minimum circumscribed circle is obtained by extracting the edge contour of the processed mask, and then matched and screened through multi-scale Hough circle detection to obtain a stable and reliable fitted circle and calculate the particle size. The results show that the mAP50-95(The average of the average accuracies calculated under multiple thresholds ranging from 0.50 to 0.95 for IoU) of box detection of the improved model increases from 0.885 to 0.906. The recall rate of mask detection increases from 0.993 0 to 0.999 7, and its mAP50-95 increases from 0.833 to 0.847. Compared with the other four comparative models, this model achieves the optimal performance. Meanwhile, the maximum error between the proposed pellet size measurement method and the ImageJ measurement method remains within ±1.7 mm, with an average relative error of 3.98%. The proposed pellet size detection method can efficiently handle pellet particle size identification tasks in complex industrial environments and has broad application prospects in the field of intelligent metallurgical industry, providing new ideas and methods for non-contact pellet size detection.
To address the challenges in predicting the mechanical properties of cold-rolled strip steel posed by multi-process parameter coupling, system nonlinearity, and time-varying characteristics, this paper proposes an intelligent prediction model that integrates bio-inspired regulation mechanisms and operational decision-making theory. First, based on the dynamic feedback mechanism of the biological endocrine system, the model constructs an information feedback structure with self-adaptive regulation capability. Then, by incorporating the multi-objective priority factor theory from operations research, a dynamic allocation strategy for feedback signal weights is designed to optimize the model's response performance under complex working conditions. Furthermore, the hormone-inspired regulation mechanism of the biological endocrine system is introduced to realize real-time self-correction of model parameters during training, effectively mitigating prediction deviations caused by system dynamics. Experimental validation based on actual production line data shows that, compared to long short-term memory and least squares prediction models, the proposed model delivers the best overall performance in predicting tensile strength, yield strength, and elongation after fracture. It achieves the smallest root mean square error, mean absolute error, and mean absolute percentage error, with all coefficients of determination exceeding 0.99. Ablation experiments confirm the necessity of the biological feedback mechanism and parameter dynamic updating modules. This model can perform high-precision intelligent prediction of the key mechanical properties of cold-rolled strip steel, and holds significant technical support value for improving the precision of production quality control, optimizing the presetting of process parameters, and ensuring the stability of product performance.
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