Red mud is a polymetallic waste generated during Bayer's process of alumina production. High alkalinity (pH > 11), multiple elements, and micron-sized particles make red mud recycling energy-intensive and challenging. The following work presents a hydrometallurgical flowsheet for separation of different red mud elements and recovery of high purity Fe (II) product using cost-effective reagents, energy-efficient

In the current study, the transition of the flow pattern in a 1000 mm × 237 mm continuous casting mold with the injected argon gas was measured using nail boards and the effect of flow pattern on the distribution of non-metallic inclusions along slab thickness was analyzed using an automatic SEM. The flow pattern in the mold transformed from double roll to complex flow and single roll as the argon

In order to understand the pre-reduction behaviour of fine hematite particles in the HIsarna process, change of morphology, phase and crystallography during the reduction were investigated in the high temperature drop tube furnace. Polycrystalline magnetite shell formed within 200 ms during the reduction. The grain size of the magnetite is in the order of magnitude of 10 µm. Lath magnetite was observed

In this work, a 6061-SiC composite was prepared using the compound casting method and then processed using a vacuum-assisted high-pressure die-casting technology under fast shot speeds of 1, 2 and 3 m/s, respectively. The effect of fast shot speed and wall thickness on the skin layer, porosities and mechanical properties were studied. The results showed that, with the increase of the fast shot speed

In this work, the kinetics of decarburization and demanganization of Fe–15Mn–1C alloy by bubbling mixtures of Ar–O2 into the melt at 1823 K was studied. Experiments were conducted at total gas flow rates of 200 and 300 Nml/min and gas mixtures of Ar containing 6.7 to 20 pct O2. Increasing the gas flow rate and oxygen in the gas mixture resulted in higher overall rates of decarburization and demanganization

Chromium is normally added to liquid alloy in the form of different grades of ferrochromium (FeCr) alloys for the requirement of different alloy grades, such as stainless steels, high Cr cast iron, etc.. In this work, inclusions in two commercially produced alloys, i.e., high-carbon ferrochromium (HCFeCr) and low-carbon ferrochromium (LCFeCr) alloys, were investigated. The FeCr alloy/liquid iron interactions

The precise solubility data of a component in high-temperature melts are essential for the design and optimization of various processes including pyrometallurgical and solution growth processes. In this study, we developed an in situ method for measuring the solubility of a component in molten metals and alloys and investigated C solubility in molten Si using a system comprising Si and SiC substrate

In this study, three machine learning (ML) models were developed to predict the secondary dendrite arm spacing (SDAS) and then predictions were validated experimentally. First, a three-layer artificial neural network (ANN) was built to predict the SDAS. Then, a linear regression model (LR) with backward selection method is applied to study the relationship of different elemental properties, processing

A comprehensive numerical model is proposed to study the influence of an axial magnetic field (AMF) on the solidification behavior of a Titanium-based (Ti–6Al–4V) vacuum arc remelting (VAR) ingot. Both static and time-varying AMF are examined. The proposed 2D axisymmetric swirl model includes calculating electromagnetic and thermal fields in the entire system composed of the electrode, vacuum plasma

The effects of different Ca and S contents of steel on the modification of endogenous Al2O3 inclusions were studied in the laboratory. Three Ca levels (35, 20, 10 ppm) and two S levels (30, 20 ppm) were studied. An automated SEM-EDS system was used for the characterization of inclusions. It was found that the quantity of inclusions in steel increases with the amount of Ca and S contents in the melt

To reduce the environmental impact during purification of molten aluminum, an environmentally friendly flux is being considered as a potential replacement for the highly toxic chlorine-containing gas currently used. However, the reactivity of the flux is much lower relative to the gases, resulting in low-efficiency purification. Here, a new approach using water modeling was implemented to investigate

The dissolution of Al2O3 particles in CaO-Al2O3-SiO2 slags was investigated by confocal scanning laser microscope at the temperature range from 1723 K to 1853 K. It was found that the rate-limiting step was the diffusion in the liquid slag. The dissolution of Al2O3 particles in CaO-Al2O3-SiO2 slags with various temperatures, CaO/Al2O3, and CaO/SiO2 in slag was in situ observed. Increasing the C/A and

A numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type

Proeutectoid ferrite is harmful to the toughness of slab or billet during continuous casting since it can provide crack propagation path at low temperature preferentially. Single variable controlling method is used in this paper and the results show that the proeutectoid ferrite of medium-carbon sulfur-containing bloom is more developed than that of sulfur-free bloom, especially on the surface. Thermodynamic

The effects of halophilic bacteria (Halobacillus sp. and Marinobacter sp.) on pyrite and chalcopyrite surface oxidation in artificial seawater are studied by electrochemical impedance spectroscopy (EIS) in conjunction with X-ray diffraction (XRD) and cyclic voltammetry analysis (CV), in order to explain the influence of these microorganisms on the minerals floatability. EIS analyses on pyrite electrodes

Molten slag is a critical material generated during blast furnace (BF) ironmaking. Slag flow behavior in the lower part of BF is closely related to the selection of charge materials, coke packed bed permeability, process stability, productivity, and hot metal quality. To better understand slag flow behavior, a numerical approach was applied to characterize the slag flow through a coke funnel analog

The desulfurization mechanism is of great significance to quality improvement in metallurgical process. In this work, the structural features, chemical and dynamical properties of the liquid FeO·SiO2 were calculated under 2000 K through ab initio molecular dynamics simulations. Further calculation of desulfurization was conducted based on the structural evolution information. The results showed that

Slag holdups in a fixed bed of carbonaceous particles were investigated using three-dimensional (3D) computational fluid dynamics (CFD) and discrete element method (DEM) simulations. In particular, the effect of improved wettability on the slag holdup, as a result of the formation of a SiC coating on the carbonaceous particle surface, was investigated. Wettability with four different contact angles

A single-phase zirconium oxycarbide was successfully synthesized by carbothermal reduction route at 1600 °C for 8 hours under argon atmosphere using ZrO2 and graphite powder as raw materials (the molar ratio of ZrO2 to graphite is 1:2.6). Effects of temperature, reaction time and molar ratio of ZrO2 to graphite on zirconium oxycarbide preparation were also investigated. The microstructure and composition

Impurity levels of titanium (Ti) and vanadium (V) depreciate the electrical conductivity of aluminum (Al) when present in solution. Industrially, a boron (B) based alloy is introduced to remove these impurities from the Al melt as borides. Subsequently, these boride particles are separated from the Al melt by gravity settling or filtration, rendering much improved electrical conductivity to the solidified

Sulfur dissolves in molten oxide slag as a sulfide (S\(^{2-}\)) under many high-temperature metallurgical processing environments. O\(^{2-}\) and S\(^{2-}\) exchange reaction in the molten oxide has been well known. Traditionally, a sulfide capacity (\(C_{\text{S}}\)) was used to characterize the S-holding ability of molten slags under given sulfurizing potential (\(p_{{\text{S}}_2}/p_{{\text{O}}_2}\))—dilute

Analytical liquidus equations were evaluated using differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Results of 180 measurements in the Fe-C-Si-Mn-Al-P subsystems were considered, where the experimental methodology was demonstrated for four alloys in the Fe-Si-Mn-Al system. Excellent agreement between the DSC/DTA dataset and the most recently published equation was found

A review of studies by Safarian et al. and Kim show that the smelting reaction at equilibrium for ferromanganese and silicomanganese alloys is defined by the coupled reaction in the carbon-saturated condition \( 2\underline{\text{Mn}} + \, \left( {{\text{SiO}}_{ 2} } \right) \, = { 2 }\left( {\text{MnO}} \right) \, + \underline{\text{Si}} \). The behavior of slag at equilibrium is described by MnO

The formation of entrainment defects, (also known as double oxide film defects or bifilms), caused by the entrapment of a doubled-over surface oxide film containing a small amount of local atmosphere, has been investigated by combining practical experiments using a commercial-purity Mg-alloy under protective gases, with theoretical thermodynamic calculations. Evolution of the entrainment defects was

This study describes an original approach to determine the structure of molten fluorinated salts at high temperatures. This approach focused on model mixtures of the type MF-AlF3 (M=Na, K), MF-AlF3-Al2O3 (M = Na, K) compositions industrial interest such as NaF-AlF3- Al2O3-CaF2 used as electrolytes in the production of aluminum by electrolysis. Thus, it is necessary to know the electroactive species

A water model experiment and a transient 3D numerical model were designed and implemented to quantitatively evaluate the flow-induced erosion behavior of the refractory lining in a continuous casting tundish. A relationship between the erosion rate and flow characteristic parameters was proposed and experimentally verified. Boric acid tablets were used in the water model experiment to determine the

The blank of thermodynamic properties in the CaO-Al2O3-Ce2O3 basic slag system limits the application of rare earth element in relevant materials. In the current work, H, Cp (298 K), and Cp (T) of ternary oxide minerals were estimated using the split-combination method, Neumann–Kopp rule, and Kubaschewski method, respectively. Then, a thermodynamic model for calculating the activity of oxides in the

A correction to this paper has been published: https://doi.org/10.1007/s11663-021-02234-2

To elucidate the reoxidation mechanism of Al-killed ultra-low C steel by FetO-containing slag, the kinetics of a reaction 2Al + 3(FetO) = (Al2O3) + 3Fe between the steel and CaO–Al2O3–FetO–MgOsat. slag was investigated mostly at 1823 K. Al contents (total and soluble), and total O content in steel samples were measured during the reactions under various initial compositions of slag ((pct CaO)\(_0\)/(pct

Laser powder bed fusion has the potential of redefining state-of-the-art processing and production methods, but defect formation and inconsistent build quality have limited the implementation of this process. Numerical models are widely used to study this process and predict the formation of these defects. Presently, the uncertainties of model input parameters and thermophysical properties used by

In the current study, three-dimensional models were established to simulate the transient formation and dripping of droplets during Electroslag Remelting (ESR) of steel, combining the κ-ε two-equation turbulence model, Volume of Fraction (VOF) multiphase model, and Magnetohydrodynamics (MHD) model. The influence of the interfacial tension on the varied size distribution and the transient dripping velocity

Boron (B) and phosphorus (P) are the most problematic impurities to be removed in the production of solar-grade silicon by the metallurgical process. In this work, the distribution of B and P between CaO-(La2O3)-SiO2 slags and Si-10 mass pct Sn melt was experimentally studied. B distribution coefficient increased from 2.93 in binary CaO-SiO2 slag to 3.33 and 3.65 with 2 and 10 mass pct La2O3 additions

Nickel sulfide concentrates are critical materials for the production of metallic nickel. The disadvantages associated with the conventional nickel extraction process are the considerable amounts of sulfur dioxide emissions in the smelting process and the complex Ni refining steps to produce a marketable product. The authors proposed a novel thermal treatment method for nickel sulfide concentrates

Hydrogen is a carbon-free clean energy and a potential fuel to mitigate CO2 emission in ironmaking blast furnaces (BFs) where the co-injection of hydrogen/coal is one of the most promising and feasible technologies. In this article, a 3D steady-state industrial-scale CFD model is improved and used for investigating the co-injection of hydrogen/coal in BFs. The model involves gas–particle-solid flow

A four-phase solidification model is introduced to comprehensively investigate the formation of macrosegregation, especially the A-segregation during the solidification of a 55-ton ingot (Fe-3.3 wt pct C). The model considers the simulations of melt convection, shrinkage, dendritic equiaxed grains nucleation and sedimentation, and competitive growth of solid phases, etc. The final patterns of macrosegregation

High-temperature molten steel slag is a large amount of industrial solid waste containing available heat energy and resources. This paper introduces an efficient and comprehensive utilization process of high-temperature molten steel slag. The waste heat energy in the high-temperature molten steel slag can be fully recovered through the three-stage heat exchange. Through mass balance and energy balance

Recycling of spent lithium-ion batteries (LIBs) for metal recovery is inevitable because of environmental and resource conservation considerations. Evaluation of the kinetics parameters is crucial for understanding the thermal response of mixed electrode material for the development of the thermal recycling process. In this study, thermal treatment of mixed electrode (anode and cathode) material resulted

To understand the effect of CaCl2 addition on the dephosphorization ability of steelmaking slags, laboratory experiments were carried out to study the phosphorus distribution between CaO–SiO2–FeOx–P2O5–CaCl2 slags and carbon-saturated iron at steelmaking temperature. The phosphorus distribution ratio between slag and pure iron foil (\( L_{\text{P}}^{{{\text{Fe-}}\gamma }} \)) was measured by equilibrium

To increase the utilization of V-Ti-Magnetite ore in the burden of a blast furnace, we investigated replacing CaO with MgO. The high fraction of TiO2-bearing raw materials leads to a super-high TiO2 content in the blast furnace slag, typically above 30 wt pct, which affects normal blast furnace operation. The present study focuses on the sulfide capacity of slag containing a super-high TiO2 content

The goal of the current work is to develop a methodology to study the wetting behaviour of two immiscible liquids at high temperatures, and to investigate the parameters which influence the wetting properties. The wetting behaviour between synthetic FeMn alloy and synthetic slag has been investigated using the sessile drop technique. Two experimental procedures were implemented under both Ar and CO

Continuous casting of steel in an industrial billet caster is modeled numerically including multiphase turbulent flow, mold electromagnetic stirring (M-EMS), heat transfer, and solidification. Two different steel grades (case-hardening and micro-alloyed steel) and casting powders are considered in the study to evaluate the castability and powder performance. Existing models to estimate thermophysical

In the current study, a three-dimensional semi-coupling macrosegregation model was established for a curved bloom continuous casting strand. The fluid flow, heat transfer, and solidification were calculated firstly with the effect of the mold electromagnetic stirring (M-EMS) and final electromagnetic stirring (F-EMS). Then, the transport of the solute was solved after the fluid flow reached a steady

During the refining of Si deoxidized spring steel by low-basicity slag, with the addition of BaCO3 to refining slag, many BaO-containing CaO-SiO2-Al2O3 inclusions existed in steel, which were with approximate chemical compositions to other CaO-SiO2-Al2O3 inclusions. Thermodynamic calculation revealed that (BaO) in slag can be hardly reduced by [Si] in steel, which meant that CaO-SiO2-Al2O3-BaO inclusions

In this study, porosities in thick slabs were successfully decreased by soft reduction technology coupled with an optimal secondary cooling process. Heat transfer calculation showed that asynchronous solidification occurred in the slab when unreasonable secondary cooling was used. As a result, a W-shaped solidification frontier was formed with two liquid craters near the edges of the solidifying slab

In practical continuous casting, consecutive longitudinal depressions often occur in the off-corner areas of slab wide faces, which may cause surface cracks in the depression areas and subsurface cracks beneath the depressions. To investigate the formation mechanism of the longitudinal depression, a 3D transient thermomechanical-coupled model was developed in the present work with consideration of

Physical modelling experiments, together with numerical modelling calculations, are essential for scientific investigations of real flow phenomena. As for the physical model experiments, it has been common to combine reduced scale ratios with one or two dimensionless number(s) similitude(s). Simultaneous similitude of multiple dimensionless numbers concerned with the objective flow phenomena is ideal

Photovoltaic cutting waste (PCW) is a promising pre-reductant for the enrichment of vanadium and the removal of iron from vanadium slag. However, the dissolution of SiO2 contained in PCW affects the kinetic conditions and composition of vanadium slag during silicothermic reduction. In the present work, the dissolution behavior of SiO2 was investigated from 1823 K to 1873 K under FeO concentrations

Submerged arc welding has been performed by employing fused CaO-SiO2-MnO fluxes of varying MnO and CaO contents on EH36 shipbuilding steel grade. Transfer levels of O, Si, and Mn between fluxes and weld metals have been quantified and evaluated from thermodynamic perspectives. The results show that both slag-metal and gas-slag-metal equilibrium considerations are capable of placing limits on the direction

Two hypotheses exist to explain the viscosity decrease mechanism of calcium ferrite (CF) melts during isothermal melting in air: variations in either the short-range structure near Fe3+ or the Fe redox state. Here, the synchrotron X-ray total scattering pattern of an aerodynamically levitated CF droplet was monitored during isothermal melting. No variations were observed in the short-range structure

Slag entrainments in a continuous casting mold result in serious defects in steel products. This slag entrainment is directly connected with the meniscus vortex accompanying a large meniscus deformation. To exactly evaluate the air or slag entrainments, it is critical that numerical studies can reproduce the meniscus vortex deformation. In our study, we found that Reynolds-averaged Navier–Stokes (RANS)

Desulfurization ability and hydration resistance of CaO-MgO mixture were studied by comparing CaO-MgO, CaO and MgO rods. In desulfurization experiment, Ni-base superalloy and NiS powder were melted together, and each rod was held in the melt for a prescribed time under 1600 °C. S content in the alloy was lower in CaO-MgO desulfurization than that in CaO desulfurization in every holding time up to 300

Laboratory experiments were performed to study the transient evolution of inclusions in Si–Mn-killed stainless steels with additions of 60 and 360 ppm yttrium using low- and high-oxygen yttrium-containing ferroalloys. With the increase of the yttrium content in the steel, the evolution path of inclusions was CaO–Al2O3–SiO2–MnO → Y2O3–Al2O3–SiO2(–CaO–MnO) → Y2O3 and YS → Y2O3. The YS inclusion was generated

Nitrogen oxide (NO) gas is one of the major environmental pollutants being generated from the steel industry. Since there are no techniques that can predict how much of NO will be formed from coal, it is extremely required to derive some indices based on the understanding of how coal properties are related with the formation of NO. The current research investigated how coal properties such as nitrogen

Air gap formation during solidification greatly affects interfacial heat transfer and both must be understood quantitatively for accurate numerical simulation of casting processes, which are needed for fundamental understanding to enable quality improvements. Displacement and temperature in a 23 kg steel ingot and mold were measured simultaneously during solidification using a new experimental system

The existence of angular and hard AlN inclusions would seriously deteriorate the service life of high-nitrogen stainless bearing steels (HNSBSs). In this work, the formation mechanism of AlN inclusion in HNSBSs under as-cast, annealing and austenitizing states was systematically investigated by microstructure observation and thermodynamic, kinetic analyses. The results showed that the concentration

The deformation mechanism and constitutive equation of Ti-Mo steel in the mushy zone were investigated through high-temperature compression deformation. Nonlinear fitting and polynomial fitting were used to build a precise constitutive model. The law of microstructure evolution was also researched. During the deformation of Ti-Mo steel in the mushy zone, the liquid phase was squeezed to the edge, and

This paper presents the effects of Li2O addition on the non-isothermal melt crystallization of Cuspidine in CaO–SiO2–CaF2 glass. The addition of Li2O retarded crystallization at all cooling rates and converted the mode of nucleation from instantaneous to progressive. Two types of kinetic analysis indicated anti-Arrhenius behavior in the samples, which means that overall crystallization was governed

The environmental and economic recovery of rare-earth (RE) from NdFeB magnet waste is becoming increasingly important. In this study, the sulfurization possibility of two main RE-bearing phases of Nd2O3 and NdFeO3 in the fully oxidized NdFeB waste by ferric sulfate was evaluated. TG-DTA curves of the Nd2O3 and NdFeO3 sulfurization with 1.5 times of the theoretical Fe2(SO4)3·5H2O dosage showed that

A combined experimental and thermodynamic study has been carried out to determine the CaO effect on the equilibria between slag/matte/metal (Fe or Cu)/tridymite phases in the Cu-Fe-O-S-Si-Ca system at 1473 K (1200 °C). The experimental methodology included equilibration of the mixtures at high temperatures on substrates made from the primary phase, followed by rapid quenching of the samples and direct

This work presents post-mortem microstructural analysis on the inner surfaces of single-use ladle shrouds of a ten-heat casting series of Ti-alloyed, Al-killed IF steel, in continuation of earlier work on the origin of alumina clogging formation in the casting system. It is found that ladle shrouds can be used as a representative sampler of materials exiting the ladle during the casting, which can