Smelting Process Research Articles

Research and Development of a Big Data Application Platform for Intelligent Blast Furnace Intensive Management and Control.

The blast furnaces of Anshan Iron and Steel have completed large-scale modernization, and a large amount of information technology has been popularized and applied to the process of blast furnaces. This paper takes the Anshan Iron and Steel blast furnace group as the research background. Based on big data and industrial Internet technology, combining the smelting process mechanism of blast furnace production and using artificial intelligence, cloud analysis, and other technologies, the data management platform was used to effectively integrate the data of each process of the blast furnace and design the data asset catalogue. The big data application platform for the intensive control of the blast furnace was established. The data were in multidimensional in-depth mining, and the intelligent application model of the blast furnace was established. The visual intelligent monitoring of the safe production and operation of the blast furnace was realized, and the production operation of the blast furnace was guided. The overall information and intelligent level of production operation and management of the blast furnace have been improved.

Research on spatial-temporal synergistic sensor fault diagnosis method for top-blowing furnace

Top-blowing furnace systems, characterized by a large number of sensors and harsh working environments, are prone to sensor failures due to factors like component aging and external interference. These failures can significantly impact the system's safe and reliable operation. However, traditional sensor fault diagnosis methods often neglect the exploration of spatial-temporal characteristics and focus solely on learning temporal relationships between sensors, failing to effectively consider their spatial relationships. In this study, we propose a spatial correlation model based on the maximal information-based graph convolutional network (MI-GCN) by constructing a sensor network knowledge graph using maximal mutual information. The MI-GCN leverages the graph convolution mechanism to extract multi-scale spatial features and capture the spatial relationships between sensors. Additionally, we develop a spatial-temporal graph-level prediction model, known as the spatial-temporal graph transformer (STGT), to extract temporal features. By combining the spatial features extracted by the MI-GCN with the temporal features captured by the STGT, accurate predictions can be achieved. Sensor fault diagnosis is conducted by analysing the normalized residuals between the predicted values and the ground truth. Finally, the feasibility and effectiveness of the proposed method are validated using test data from a top-blowing furnace system in the nickel smelting process.

Decomposition of zinc ferrite-based solid waste by reductive leaching: Leaching kinetics and mechanism

Zinc ferrite-based solid waste is a vital zinc and iron secondary source in view of the numerous zinc ferrite will be ineluctably produced and enters into slags or residues during zinc smelting process. In this study, a reductive leaching process with zinc sulfide powder was employed to decompose zinc ferrite from solid waste. The leaching efficiency of zinc and iron can reach 90.27 % and 81.96 %, respectively, while the process went to the 90th min at 90 ℃ under the conditions: sulfuric acid concentration of 500 g/L, liquid-to-solid ratio of 20 mL g−1, mass ratio of silver flotation tailings to zinc sulfide of 5/1, silver flotation tailings particle size of + 180–250 μm, rotary speed of 400 rpm. Then, this leaching process confirmed to shrinking core model and was conducted by surface chemical reaction after kinetics and thermodynamics investigations. Ultimately, according to various tested data, the corresponding reaction mechanism was speculated as: Fe3+ was reduced to Fe2+ by zinc sulfide and hydrogen sulfide which was the product of zinc sulfide with H+, resulting in potential reduction and H+ activity elevation, accelerating zinc dissolution eventually. Meanwhile, almost all zinc sulfide and hydrogen sulfide were oxidized to monomorphic sulfur by Fe3+ where the utilization ratio of zinc sulfide was 97.28 %.

Numerical Simulation and Improvement of TSL Smelting Process: the Effect of Lance Bending

Numerical Simulation and Improvement of TSL Smelting Process: the Effect of Lance Bending

Effective utilization of Ni-Cr bearing composite burdens for high-Cr ferronickel preparation

In this paper, two types of Ni-Cr bearing composite burdens including SP1 (79% Ni-bearing sinter and 21% Cr-bearing oxide pellets) and SP2 (84% Ni-bearing sinter and 16% Cr-bearing pre-reduced pellets) were used for the more efficient preparation of high-Cr ferronickel. Based on the metallurgical performance characterization, thermodynamic analysis and smelting parameters optimization, the qualified high-Cr ferronickel were prepared by the utilization of the Ni-Cr bearing composite burdens. The recovery rates of iron, chromium and nickel exceed 95%, 90% and 98% whereas their grades are 85.56–85.88%, 7.82–8.02% and 1.59–1.62%, respectively. Compared with SP1, SP2 possesses lower smelting duration, which indicates the appropriate proportioning of Cr-bearing pre-reduced pellets is beneficial for the smelting process. The obtained high-Cr ferronickel consisting of (Fe, Cr)3C and (Fe, Cr)7C3 can be used as a low-cost substitute for the conventional raw materials of 200 or 300 series of stainless steel.

Research Progress of New Generation of Aluminum–Lithium Alloys Alloying

Aluminum–lithium alloy, being the lightest aluminum‐based alloy, holds significant potential for applications in the aerospace and military sectors. Currently, alloying treatment stands as a crucial method for enhancing the comprehensive performance of aluminum–lithium alloy. This article provides an overview of the production process of aluminum–lithium alloys, encompassing smelting and deformation processing characteristics. Additionally, it outlines the developmental history of the chemical composition for the primary grades of aluminum–lithium alloy, detailing the copper (Cu) and lithium (Li) content of the main alloying elements. And discusses the influence of various microalloying elements on the alloy's properties. Additionally, it summarizes the structure, properties, and precipitation morphology of the three primary strengthening phases formed by the alloying of aluminum–lithium alloys: T1 (), (), and (). The analysis also examines the impact of anisotropy on the mechanical properties of the primary dispersion. Finally, the article addresses the challenges involved in alloying aluminum–lithium alloys and proposes key research directions for element composition design.

Comprehensive recycling of slag from the smelting of spent automotive catalysts

Spent automotive catalyst is a valuable source of platinum group metals (PGMs), making them crucial secondary resources. Currently, the main process for recovering PGMs from these catalysts is metal capture method. The smelting process would produce a significant amount of residual slags containing various components like SiO2, Al2O3, CaO, Fe2O3, Na2O, as well as high levels of heavy metals including Cr, Pb, and Ni. These slags are considered either solid waste or hazardous waste and usually disposed of in landfills, which can have detrimental effects on the environment. Furthermore, the smelting slags also contain approximately 2–5 % rare earth elements and trace amounts of precious metal elements. In this study, vacuum carbothermal reduction is employed to pretreat the smelting slags. This method not only successfully removes the heavy metal element lead, but also efficiently achieves the recovery of rare earths, and the enrichment of platinum group metals by mineral phase transformation of cerium-zirconium solid solution and in-situ iron capture. The lead removal rate exceeded 99 %, and the grade of precious metals in the enrichment process was approximately 12 times higher than the original material, with a recovery rate more than 90 %. The leaching rate of rare earths also increased from less than 50 % to more than 95 % after vacuum carbothermal reduction. The effect of vacuum carbothermal reduction pretreatment on the smelting slag phase was systematically studied, and the mechanism behind the increasing rare earth leaching rate due to this pretreatment was further analyzed.

Determination and correlation of the solubility of magnesium sulfate in ethanol solutions with different concentrations: Application to the removal of magnesium from zinc electrolytic waste solution

In this study, the solubility of anhydrous magnesium sulfate (MgSO4) in ethanol solutions with concentrations ranging from 10 % to 50 % was determined at 15–50 °C. Next, the results were correlated by using the Apelblat model, polynomial empirical equation, ideal solution equation of state model, and Van’t Hoff–Jouyban–Acree model. The results indicated that all four models exhibited correlation coefficients greater than 97 %, and average relative deviations of 3.82 %, 4.24 %, 3.96 %, and 3.96 %, respectively. Notably, the Apelblat model was found to be more accurate and reliable in correlating the solubility of MgSO4 in ethanol solutions with different concentrations. Further, the Van’t Hoff equation was applied to determine the enthalpy and entropy of dissolution. Herein, a certain amount of anhydrous ethanol was added to the zinc (Zn) electrolytic waste solution (ZEWS) to crystallize Zn2+ and Mg2+ through the solvent crystallization method, with the precipitation rates reaching 20.13 % and 39.38 %, respectively. The concentration of Mg2+ reduced to below 15 g⋅L−1, meeting the quality standard of ZEWS. The XRD, TG, and SEM analyses of the output salt mix crystallization confirmed the primary components to be MgSO4·7H2O and ZnSO4·7H2O, with the morphological features primarily consisting of short rods and some crystal agglomerates. This study shows that the removal of Mg2+ from Zn smelting process can be effectively achieved by the proposed solvent crystallization method.

Potential of Aluminum as a Metal Fuel for Supporting EU Long‐Term Energy Storage Needs

AbstractThe EU's energy transition necessitates availability of green energy carriers with high volumetric energy densities for long‐term energy storage (ES) needs. A fully decarbonized scenario considering renewable energy availability is analyzed underpinning the need for such carriers. Considering the shortcomings of Power‐to‐X technologies in terms of efficiency and low volumetric density, Aluminum (Al) is identified as a potential alternative showing significantly high volumetric energy densities (23.5 kWh L−1). In this paper, an Al‐based long‐term ES concept is investigated, taking advantage of the inherent recycling of the active species (i.e., Al2O3 to Al) coupling decarbonized Hall–Héroult process with an Al‐steam oxidation for simultaneous hydrogen (H2) and heat generation. This work demonstrates an innovative lab‐scale fine Al powder‐steam oxidation process at ≈900 °C without use of catalysts or additives, exploiting alumina as inert material. Conducted SEM‐EDX analysis on oxidized Al provides supporting evidence in favor of employed oxidation pathway, hindering tendency of aluminum oxide (Al2O3) clumping and enabling direct use of oxides in the smelting process for fully recyclability. Moreover, outcomes of XRD analyses are presented to validate the measured total H2 yields.

Production of complex Fe-Si-Mn-Cr ferroalloy using high-ash coal: a sustainable metallurgical approach

The article presents the results of comprehensive thermodynamic modeling and laboratory tests conducted for smelting a complex ferroalloy of silicon, manganese, and chromium (Fe-Si-Mn-Cr) from chromium, medium-grade manganese ores, and high-ash coals from Kazakhstan. Thermodynamic analysis was performed using HSC Chemistry software to model the Fe-Si-Mn-Cr smelting process over a temperature range of 900 °C–1800 °C. This analysis involved six actual charge compositions with solid reductant (Csolid) consumption ranging from 5 to 20 kg per 100 kg of Cr and Mn ore mixture. The mechanism of the combined carbothermic reduction of Cr, Mn, Si, and Fe was investigated using the Cr-Si-Al-Ca-Mn-Mg-O-C system. According to thermodynamic data, the optimal consumption of Csolid per 100 kg of ore mixture is 17 kg, and the optimal temperature range for smelting ferroalloys is between 1600 and 1700 °C. Laboratory tests were conducted in a high-temperature Tamman furnace at 1700 °C, resulting in experimental samples of the new complex ferroalloy with an average composition of 14.85% Fe, 14.05% Si, 7.55% Mn, 57.54% Cr, and 6.01% C, with P < 0.03% and S < 0.02%. The phase composition included (Cr, Fe, Mn)3Si and carbides Cr23C6 and (Fe, Mn)3C. The resulting alloy is suitable for alloying high-carbon and tool steels.

Smelting characteristics of nickel‑chromium‑manganese bearing prereduced pellets for the preparation of nickel saving austenite stainless steel master alloys

Nickel saving austenite crude stainless steel master alloys were innovatively produced by smelting of nickel‑chromium‑manganese bearing prereduced pellets in an effective and economical way. The thermodynamics analysis and systematic process mineralogy were also conducted to further reveal the smelting characteristics of prereduced pellets and the related enhanced mechanism. The results showed that the preferable stainless steel master alloys with 66.29% Fe, 4.21% Ni, 17.28% Cr, 6.53% Mn and 4.76% C can be prepared from the nickel‑chromium‑manganese bearing prereduced pellets with a corresponding recovery of valuable metals more than 95%. Furthermore, during the enhanced smelting process, the optimization of slag types can further realize the phases transformation from high-melting-point enstatite and forsterite to low-melting-point diopside and monticellite to obtain a decreased smelting temperature and viscosity of slag. The smelting duration and the alloy grain included in the smelting slag were both obviously decreased, resulting in an improved smelting performance.

Digital twin-driven smelting process management method for converter steelmaking

AbstractThe converter is an indispensable key equipment in the steel manufacturing industry. With the increasing demand for high-quality steel, there is an increasing demand for monitoring and controlling the status of the converter during the smelting process. Compared to other manufacturing industries, such as food processing and textile, converter steelmaking requires a larger keep-out zone due to its ultra-high temperatures and harsh smelting environment. This makes it difficult for personnel to fully understand, analyze, and manage the smelting process, resulting in low production efficiency and the inability to achieve consistently high-quality results. Aiming at the low virtual visualization level and insufficient monitoring ability of the converter steelmaking process, a process management method based on digital twin technology is proposed. Firstly, a digital twin system framework for full-process monitoring of converter steelmaking is proposed based on the analysis of the process characteristics of converter steelmaking. The proposed framework provides critical enabling technologies such as point cloud-based digital twin model construction, visual display, and steel endpoint analysis and prediction, to support full-process, high-fidelity intelligent monitoring. After conducting experiments, a digital twin-driven smelting process management system was developed to manage the entire smelting process. The system has proven to be effective as it increased the monthly production capacity by 77.7%. The waste of smelting materials has also been greatly reduced from 34% without the system to 7.8% with the system. Based on these results, it is evident that this system significantly enhances smelting efficiency and reduces both the costs and waste associated with the process.

COMPLEX MATHEMATICAL MODEL OF THE PROCESS OF LOADING A MULTICOMPONENT CHARGE INTO A BLAST FURNACE

The rational mode of loading the blast furnace is the most important condition for its highly efficient operation. The selection of rational values of the control parameters of the load mode is carried out on the basis of information obtained with the help of instrumental tools and mathematical models. Mathematical models of the process of blast furnace loading are necessary components of expert (intelligent) control systems for blast furnace melting. The presented complex mathematical model of the process of loading a multicomponent charge into a blast furnace differs from known developments taking into account the redistribution of components into the volume of loaded portions during movement along the path "charge feed - blast furnace", which provides the possibility of obtaining calculated characteristics of the distribution of each component of the charge and determining the composition of the formed mixtures of charge materials in any given zone of the furnace. The existence of such a model opens up new opportunities in the management of the blast furnace smelting process, as well as in conducting analytical studies of the conditions of slag formation and the distribution of properties of melts across the section of the blast furnace.

A thermodynamic model for predicting activity of CaO–SiO2–Al2O3–MgO–TiO2–V2O3–FeO slags during electric furnace smelting process

A thermodynamic model for predicting activity of CaO–SiO2–Al2O3–MgO–TiO2–V2O3–FeO slags during electric furnace smelting process

Abrams’ Law Formulation for Blended Cement Paste Incorporated with Ground Ferronickel Slag

Ground ferronickel slag (GFS) is a form of an industrial waste by-product generated during the smelting process of nickel ore that has been crushed and ground into fine powder. GFS is a pozzolanic substance that may be employed as an environmentally beneficial binding agent when blended with Portland cement. This research aims to apply the Abrams Law formulation to blended cement combined with GFS. GFS was utilized as a Portland cement composite (PCC) replacement at varying percentages of 0, 10, 20, 30, 40, and 50 wt.%. The blended cement paste incorporated with GFS was tested at three water to cementitious material ratio (w/cm) levels of 0.4, 0.5, and 0.6. After samples have been made, a compressive strength test is carried out. The research results showed that at 28 days, the optimum amount of GFS was found in the percentage of 20 wt.% induced the compressive strength by 40.41 MPa with a w/cm of 0.4. The equations based on Abrams’ Law have been proposed for estimating the correlation of 28-day compressive strength with w/cm in the range from 0.4 to 0.6. In addition, the hardened densities of binary blended cement paste were investigated. It was found that the density decreased with an increase of w/cm. The proposed equations provide the beneficial interpretation for estimating the compressive strength of blended cement paste based on the w/cm..

Research progress of hydrogen production and CO2 fixation in molten slag cooling process

AbstractSteel slag is a waste discharged from the iron and steel smelting process, which has the characteristics of large output, high temperature, complex chemical composition and poor stability. The application of steel slag in hydrogen production and CO2 fixation is of great significance for reducing energy consumption, obtaining renewable energy and fixing CO2 in the air. In this paper, the research progress of high‐temperature sensible heat of steel slag used for hydrogen production and CO2 fixation at medium and low temperature is introduced, the reaction mechanism of different hydrogen production methods and the treatment path and direction of high‐efficiency hydrogen production in the future are deeply analyzed, and the steel slag used for CO2 fixation is discussed and summarized from the theory, effect and treatment mode of CO2 fixation. In the future, the research on the economic benefits of hydrogen production and CO2 fixation from steel slag is a major focus, which can achieve economic benefits while utilizing steel slag resources.

From source to sink via a ferronickel smelting process: Chromium, nickel, and mercury in sediments of the Evoikos Gulf, Greece

Ferronickel smelters are highly waste intensive industrial processes. In the Larymna Bay (LB) of the Evoikos Gulf (Greece), the slag produced after the processing of lateritic ores for nickel extraction used to be discharged to an authorized marine area (slag disposal area; SDA). This study assessed the distribution of Cr, Ni, Fe and Mn, largely related to ultramafic parent rocks, laterites, and the slag, as well as Hg as a tracer of combustion processes in the sediments of Evoikos Gulf. A very severe (Cr) and moderate (Ni) enrichment was found both in LB and SDA in relation to local background levels. Mercury was severely enriched in LB. LB becomes enriched with magnetic particles and metals through washout and deposition of dust. Magnetic susceptibility was found to be a good proxy for Cr and Ni distributions, as well as the dispersal of slag because both parent rocks and slag contain magnetite-like magnetic minerals. The strong tidal currents of the area do not cause the dispersal of slag particles southwards, beyond SDA, yet they are responsible for the accumulation and focusing of Hg in the South Evoikos Gulf, close to the Chalkida city. Metals mobilization potential from the slag was higher compared to laterites, but lower compared to SDA's sediments, due to reduction processes in the plant and oxidation after its disposal, respectively. Oxidation processes result in the genesis of Cr(VI) in SDA and LB, through oxidative reactions with Mn oxides. This is the first time (to the best of our knowledge) that the formation of Cr(VI) from slags is reported. This finding is important for settings rich in Mn oxides, receiving Cr-rich wastes from Fe–Ni smelter plants.

Artificial Slags with Modulated Properties for Controlled Nickel Dissolution in Smelting Process

In pyrometallurgy process involving drying, calcination and reductive smelting steps, Saprolite ore is subjected in an electric arc furnace to produce Fe–Ni alloy and Ni matte. To optimize the nickel smelting step, the slag consisted of MgO–SiO2–FeO and having a lower viscosity and high fluidity is required. In this study, a number of new slag samples with varied degree of compositions are manufactured and used to examine the effect of their viscosity on nickel dissolution. Further correlation between the slag basicity and FeO addition on the smelting was also tested and simulated using Fe–Ni alloy from saprolite ore. As per the observations, the nickel dissolution increases with the increased content of FeO at a certain degree of activity which in turn can cause oxidation of nickel during the process. The slags with the ratio of MgO/SiO2 = 0.4–0.6, 30% fraction of FeO, and a viscosity of 1.8–1.06 poise in the olivine zone are found effective for the lowest dissolution rate of nickel with 0.021, 0.022, and 0.018 wt.%. The lowest dissolution rate is recorded for the slag with MgO/SiO2 ratio about 0.6. These slags with controlled amount of constituents could be used to recover precious metal from nickel smelter at a lower dissolution rate and thereby allowing to reduce the waste of the metal during smelting process.

Optimization of High-Alumina Blast Furnace Slag Based on Exergy Analysis

Raw material with a high Al2O3 content has led to an increase in the Al2O3 content in blast furnace slag, which has affected the normal operation of a blast furnace. The exergy analysis method is an important method for studying the energy utilization of high-alumina blast furnace smelting. In this paper, to investigate the impact of slag composition on exergy efficiency and optimize exergy efficiency during the smelting process of high Al2O3 iron ore, a gray box exergy analysis model of blast furnace smelting and an objective function for minimizing the total exergy loss were developed. The results indicated that the blast furnace smelting process had an exergy efficiency (η) of 28.29% for hot metal and slag; the exergy efficiency of the blast furnace did not significantly increase with the increasing w(MgO)/w(Al2O3) and R (w(CaO)/w(SiO2)), but the exergy efficiency of the blast furnace declined with increasing w(Al2O3). The regional optimal solution for the objective function method was 7129.42 MJ with slag compositions of R = 1.295, w(MgO)/w(Al2O3) = 0.545, and w(Al2O3) = 15%.

Recovery of Vanadium from Carbonated Solution by Extraction with Transformed Aliquat 336 and Stripping-Precipitation

ABSTRACT The leaching solution from the direct reduction-sodium smelting process of ultra-poor vanadium-bearing titanomagnetite contained sodium, vanadium, and impurities. It was carbonated to ensure sodium recovery, and the recovery of vanadium proved challenging. This study proposed and optimized a novel process of extracting vanadium from this alkaline carbonated solution using the transformed organic phase of 20 vol% (0.44 mol/L) Aliquat 336, 8 vol% 2-octanol, and 72 vol% sulfonated kerosene. To achieve superior vanadium extraction, Aliquat 336 in the organic phase was transformed into carbonate type by successively washing with NaHCO3 and NaOH solutions. The single-stage extraction efficiency of vanadium exceeded 85% at a pH of 8.0‒9.0 and an organic-to-aqueous phase ratio of 1:1. The thermodynamics of the vanadium extraction process was examined, confirming that the extraction process is an exothermic reaction (ΔH 0 = −9.56 kJ/mol). Furthermore, using a solution of 4 mol/L NH4Cl and 1 mol/L NH4OH with a pH of 8.8 as the effective stripping reagent to realize one-step stripping and precipitation of vanadium, the single-stage stripping efficiency of vanadium was 99.8%, and the precipitation efficiency was about 95%. Through this stripping-precipitation process, solid ammonium metavanadate with a purity of 98.14% was obtained in one step. The mechanisms of transformation, extraction, and stripping were studied via infrared spectra of the organic phases.