Abstract In this work, the thermal studies of ultrafine and nanocrystalline core–shell structures of Ti(Mo)C and Ti(Mo)C-Co formed in the process of plasma chemical synthesis according to the plasma condensation scheme in a low-temperature nitrogen plasma were performed. The oxidation processes of all phase components in the core–shell structures, determined during the high-resolution transmission

Abstract A particle-free surface coupled (PFC) model was developed using the Eulerian–Eulerian approach to predict fluid flow behavior in a gas-stirred ladle. The relative parameters of the model have been optimized, and the model was validated against measured values. The present model can simultaneously predict the bubble trajectories, free surface fluctuations, and the formation of slag open-eye

Abstract The specific focus of this study is on the boehmite–water interaction during attrition milling of a boehmite prepared by thermal dehydroxylation of gibbsite. Various characterization studies confirm the formation of a new phase, bayerite (an Al-trihydroxide polymorph) during milling of boehmite with water as the dispersant. Bayerite is a more stable (thermodynamically) phase than boehmite

Abstract This paper examines the consistency between experiments and thermodynamic predictions of the modification of non-metallic inclusions by dissolved Ca in liquid Fe-Al alloys. Current thermodynamic predictions made with FactSage (version 7.2) were found to overestimate the amount of dissolved Ca and the Ca in non-metallic inclusions. This was demonstrated in two ways. First, Al-deoxidized Fe

Abstract A new synergistic treatment of stainless steel slag and low zinc content electric arc furnace (EAF) dusts is proposed to immobilize harmful chromium in stainless steel slag. The effects of ZnFe2O4 addition on the mineralogic phase and chromium leachability of CaO-SiO2-MgO-Al2O3-Cr2O3 synthetic slag were investigated to explore the feasibility of this method. The mineralogic phases in stainless

Abstract Fluid–solid reactions often occur under the mixed rate control of chemical and mass transfer processes. The results of this work demonstrate that Sohn’s Law of additive reaction times can be used in combination with the non-basic shape-factor method to obtain closed-form conversion–time relationships for initially porous or non-porous solids of any shape under the mixed control of reaction

Abstract EAF slag constitutes a major waste in the steel industry, which necessitates the development of processes to recover its valuable compounds and thermal energy values. A promising method involves the modification of the composition of EAF slag melts to utilize its waste heat and recover more valuable elements by controlled crystallization of spinel under a cooling process. In this study, crystallization

Abstract Coal-based direct reduction of nickel slag and magnetic separation of iron are effective methods of secondary resource utilization. The growth characteristics of metallic iron particles in this process are of great significance for subsequent grinding and magnetic separation process. The nickel slag is mixed with coal powder and other additives in a certain proportion, and then subjected to

Abstract Development of an energy-efficient method for aluminum manufacturing is the current research trend in the aluminum electrolysis industry. A low-temperature electrolysis process is an appropriate choice for aluminum electrolysis. The NaF-KF-LiF-AlF3 system with its low cryolite ratio may be a suitable candidate electrolyte system because of its reduced liquidus temperature. In this paper, the

Abstract The influence of small amounts of cerium on the solidification phenomena of S31254 high-Mo austenitic stainless steel was investigated by in situ observations and theoretical calculations. In situ observations indicate that cerium addition in molten steel can accelerate austenitic nucleation but inhibit primary austenite grain growth. The initial nucleation temperature occur 32.3 °C in advance

Abstract Field structures including electromagnetic, concentration of ions, and flow fields in an ESR-like process composed of a graphite crucible containing a molten slag, air, and an iron electrode are computed. Both CaF2—(mass pct 2) CaO and CaF2—(mass pct 2) Al2O3 slags are examined. Tertiary current distribution is calculated. Therefore, polarization overpotential and Faradic reactions at metal–slag

Abstract A thorough review and critical evaluation of all experimental sulfur potential and phase diagram data available from the literature has been made for optimizing the Gibbs energy of the copper-sulfur liquid phase at 1 bar total pressure. The extended modified quasichemical model serves as a basis for the mathematical expression of the Gibbs energy of binary Cu-S solutions over the complete

Abstract Direct reduction of iron ore pellets using hydrogen gas has the potential to significantly reduce CO2 emissions from the ironmaking process. In this work, green pellets of titanomagnetite ironsand from New Zealand were oxidatively sintered to form titanohematite. These sintered pellets were then reduced by H2 gas at temperatures ≥ 1043 K, and a maximum reduction degree of ~ 97 pct was achieved

Abstract To control heat transfer between the solidifying shell and the water-cooled mold during continuous casting, the transition metal oxides, ZrO2, Y2O3, and Sc2O3, were separately added into the developed low-reactive CaO-Al2O3-based mold slags to investigate the effect on radiation heat transfer. Two kinds of master mold slags were taken into account, one included 18 pct Al2O3 and 18 pct SiO2

Abstract The phase equilibria of iron silicate slags in liquid/spinel/white metal/gas system for the copper converting process were studied, for the first time, under controlled P(SO2) 0.4 atm and P(O2) 10−6 atm in the spinel primary phase field. The liquidus temperatures of slags in the “FeO”-SiO2-“Cu2O” system were determined, and the solubilities of “Cu2O” in the spinel phase were also quantified

Abstract In the present study, the fundamental model for interfacial heat transfer coefficient (IHTC) in high-pressure die-casting (HPDC) developed by Hamasaiid et al. is re-examined using numerical simulations and established literature. The role of impact pressure on the peak IHTC is re-evaluated for the Aluminum alloy Al-9Si-3Cu and the magnesium alloy AZ91D. Currently, ANSYS FLUENT does not have

Abstract We study the oxidative desulfurization of copper slag at temperatures ranging from 1250 °C to 1450 °C using experimental copper slag as raw material. This is significantly different from the oxidative desulfurization process of low sulfur slag (wS < 0.2 pct) at temperatures > 1500 °C compared with the literature. Based on thermodynamic equilibrium calculation and an experimental study of oxidative

Abstract Titration is often used to determine the iron grade in sulfide ores. In this method, HCl is used as the main solvent. If the ore contains iron sulfide minerals, such as pyrite, it cannot be completely dissolved in HCl, and the measurements error will be high. Therefore, roasting is used to determine the iron grade in such cases. But roasting requires special equipment and it is usually time

Abstract Phosphorus partition between liquid iron and CaO-SiO2-MgO-FeOx slags have been investigated experimentally. Fe doped with Fe3P was equilibrated, at 1873 K, in a closed system, with a fully liquid, MgO saturated slag in a dense-sintered MgO crucible. Synthetic slags with low CaO/SiO2 ratio (1 to 1.32) and varying FeOx concentrations (10 to 30 wt pct) constituted the slag phase. P2O5 concentrations

Abstract This work discusses 3D models of current distribution in a three-phase submerged arc furnace that contains several components, such as electrodes, central arcs, craters, crater walls, and side arcs that connect electrodes and crater walls. A complete modeling approach requires time-dependent modeling of the AC electromagnetic fields and current distribution, while an approximation using a

Abstract Polynomial representation of partial excess Gibbs energy (i.e., activity coefficient) in multicomponent dilute solution has been widely used after Wagner. Although Wagner’s Interaction Parameter Formalism has been known to be only strictly valid at infinite dilute concentration, it has been used often, even at finite concentration, due to its mathematical simplicity. Nevertheless, several

Abstract In recent years, special attention has been paid to continuous methods of severe plastic deformation, such as the ECAP-Conform process. In this research, a new analytical method has been presented to calculate the required torque in ECAP-Conform of grade 2 commercially pure titanium (CP-Ti Gr. 2). In this regard, the process was divided into two regions, mainly the primary roll bending and

Abstract The effect of cerium on inclusions in an ultra-low-carbon Al-killed steel was studied at 1873 K (1600 °C) using laboratory experiments. The content of cerium in the steel varied from 0 to 0.028 wt pct. The contents of the total oxygen (T.O), total nitrogen (T.N), total sulfur (T.S), total cerium (T.Ce) and dissolved aluminum ([Al]) in the steel samples 1, 5, 10 and 30 minutes after adding

Abstract The coupling effect of prior austenite grain size and inclusion characteristics on acicular ferrite (AF) formation was investigated in Ti-Zr deoxidized low carbon steel by utilizing the high temperature confocal laser scanning microscope (HT-CLSM), optical microscope (OM), and scanning electron microscope (SEM) equipped with energy-dispersive spectrometer (EDS). The results indicated that

Abstract The interfacial reactions between liquid Ti-48Al-2Cr-2Nb and various shell mold materials were investigated, and a cost-effective shell mold, containing a reacted component, was developed. Centrifugal investment casting was employed to supplement the low fluidity of the titanium aluminide alloy. The thickest part of the turbocharger was selected for analysis. The reaction-layer depth and the

Abstract In the hot-dip galvanization of steel products, surface oxidation–reduction treatment has been proposed recently to improve the wettability of liquid Zn-Al alloy on Si, Mn-containing high-strength steel. During surface oxidation–reduction treatment, an iron-oxide layer with a nanoscale thickness is formed on the steel surface, which is reduced to a metallic iron layer. Although elemental Si

Abstract Al2O3 greatly influences the formation of complex calcium ferrite, which is the main binder and iron-bearing phase in sinter. Experiments were carried out in air at 1200 °C with different amounts of Al2O3 mixed with CaO·Fe2O3 (calcium ferrite). The samples contained two phases: CaFe2O4 and Ca3.18Fe15.38Al1.34O28 (CFA). The results showed that the morphology of the complex calcium ferrite was

Abstract A phenomenological model for the reduction of iron ore/carbon composite pellets in a multi-layer bed rotary hearth furnace has been developed. A single pellet model has been scaled up to a multi-pellet layer version in a computationally efficient way. The multi-layer pellet bed has been conceived as single column of identical pellets in a rectangular enclosure, assuming symmetry of the pellet

Abstract A combined method of mathematical and physical modeling was used to investigate the circulation flow and slag-metal behavior in industrial SSRF and RH. The circulation flow of molten steel was simulated by using the coupled mathematical model. The results indicate that two different circulation modes are presented separately in SSRF and RH. The incomplete exchange of molten steel was found

Abstract In order to achieve decarburization and manganese retention simultaneously, CO2 was introduced in the smelting process of high-Mn twinning-induced plasticity (TWIP) steel. The effect of CO2 and O2 mixed injection on the decarburization and manganese retention was carried out based on the thermodynamics calculation and experimental research. The calculation results showed that the evaporation

Abstract Inclusions in non-oriented electrical steels were automatically measured using Explorer 4 and extracted with a non-aqueous solution electrolytic method to observe their three-dimension morphology. Extracted inclusions were collected and prepared for micro-XRD test, which is performed to identify the crystal structure of inclusions. Inclusions mainly consist of AlN with P63mc structure, MnS

Abstract Effects of slag composition and alloy content as well as temperature on the deoxidation and desulfurization of Inconel 718 superalloy by CaF2-CaO-Al2O3-MgO-TiO2 ESR-type slag without the addition of a deoxidizer were systematically investigated by laboratory-scale experiments and the developed mass transfer model. The model predictions were verified through comparison with experimental results

Abstract Acids such as aqua regia, a 3:1 mixture of hydrochloric acid (HCl) and nitric acid, that contain strong oxidizing agents are used in the dissolution-based recovery of platinum group metals (PGMs). However, nitrate-nitrogen emission has become subject to increasingly strict environmental regulations in recent years. Accordingly, we herein propose a dissolution process for PGMs via the formation

In aluminium reduction cells, an electrochemical reaction occurs between the molten electrolyte film below the aluminium pad and the carbon cathode blocks, leading to the formation of an Al4C3 layer on the cathode blocks. The properties and role of this Al4C3 layer are therefore important for the aluminium production industry, as they could help increase the life expectancy of electrolysis cells and

The behavior of dual-phase (MnO-SiO2-Al2O3) + (SiO2) inclusions in saw wire steels during hot rolling and cold drawing was investigated in detail. It was found that the inclusion matrix (glassy MnO-SiO2-Al2O3 (silicate)) manifested rheological properties and the precipitated SiO2 experienced poor deformation in hot rolling. After multi-pass hot rolling, these two phases gradually became separated from

The effects of hydrogen gas on the reduction rate of ore and reactivity of coke were estimated by using the Boris type movable reaction furnace shaft inner reaction simulator (SIS). The temperature profile was controlled to reproduce the shaft region in the actual blast furnace, and the gas composition was self-controlled inside the reaction tube. The apparent gas utilization ratio was also affected

Monitoring the meniscus velocities of molten steel in continuous casting molds is critical for revealing the velocity field in the whole mold and consequently for process control and final product quality, however, the realization of contactless online measurement in an actual metallurgy environment is a highly challenging task. In this paper, we develop a special Lorentz force velocimetry (LFV) device

The compositions and crystal orientations of complex nuclei in an industrial Ti and Nb stabilized ferritic stainless steel (FSS) with a high equiaxed zone ratio were investigated to evaluate the nucleation efficiency of (Ti,Nb)(CN) on the surface of oxides. Although the thermodynamic analysis showed that the equilibrium oxide is Ti2O3, two other types of oxides mainly composed of MgAl2O4 were found

High-speed continuous casting of steel billets entails considerable turbulence in the liquid core, which results in significant slag entrapment unless high viscosity slags are used. It has been suggested that such slags remain glassy or crystallize slightly under the prevailing mold cooling, temperature and residence time conditions. Slags whose composition lead to formation of melilite minerals (i

An innovative electroslag remelting furnace with a water-cooled electrode was introduced to recycle the rejected electrolytic manganese metal (EMM) scrap. To clarify the desulfurization process in the rejected EMM scrap, a transient three-dimensional comprehensive numerical model was elaborated. Using the magnetic potential vector approach, the respective electromagnetic fields were calculated via

To predict the behavior of an alumina inclusion in front of the solid–liquid interface during solidification, the interfacial tension between SPFH590 micro-alloyed steel and alumina was experimentally determined. The surface tension of the micro-alloyed steel was measured by the constrained drop method, and the contact angle between the micro-alloyed steel and alumina was investigated by the sessile

Abstract To increase the utilization fraction of vanadium titano-magnetite in the blast furnace burden to > 80 pct, a new slag zone with high MgO was found. The effect of the TiO2 content and MgO/CaO mass ratio on the viscosity and liquidus temperature of the high TiO2-bearing blast furnace slag was investigated in the present work. The results indicated that at a fixed CaO/SiO2 ratio of 1.1, the viscosity

Abstract Deoxidation methods of titanium (Ti) scrap and Ti powder have become increasingly important in recent years. Some rare earth (RE) metals with strong deoxidizing capabilities, including Y, La, Ce, and Ho, are candidate agents for the development of a new deoxidation technology. In this study, a new method was developed to directly remove oxygen (O) from Ti using the Y/YOCl/YCl3 equilibrium

The major challenge while using sintering models for simulation of densification in multi-component alloys is finding the correct transport parameters, which are affected by not only temperature but also chemical composition and phase dispersion. A novel approach for determining the effective self-diffusivity and hence modeling the densification of engineering alloys during sintering is proposed. The

Industrial trials were performed to study the effect of calcium treatment on inclusions in non-oriented electrical steels. The evolution and characterization of inclusions in both molten steel and rolled steel were investigated, including a thermodynamic analysis using FactSage 7.1. In the Ca-treated steel, alumina inclusions were transformed into Al2O3-CaO-CaS, with a mass fraction of CaO that increased

In situ studies of two separate events of the peritectic phase transition during continuous casting, the peritectic reaction and the peritectic transformation, were performed using high-temperature confocal scanning laser microscopy (HTCSLM). The interface migration velocities during the peritectic transformation at different cooling rates were analyzed in situ by measuring the migration distance of

A series of fused CaF2-SiO2 binary fluxes have been developed to investigate element transfer behaviors under high heat input submerged arc welding. Transfer of elements is quantified by Δ quantities, which demonstrate respective contributions from the flux to the weld metal. Effects of SiO2 contents on the transfer of Si, Mn, and O have been thoroughly evaluated. Thermodynamic considerations have

The effect of iron oxide concentration on the conductive behavior of a molten oxide electrolyte has been investigated at 1823 K using stepped linear scan voltammetry. To maximize the current flow through the electrolyte the ohmic drop in the cell was minimized by shortening the electrode distance. The acquired current was then interpreted by means of an ohmic drop correction, taking into account the

The ironmaking processes that directly use iron ore fines as raw material are under development and receiving more and more attention. In a flash reduction process, both the thermal decomposition reaction and the reduction reaction of ore fines are extremely fast and cause loss of oxygen from iron oxides. However, it is difficult to distinguish between the thermal decomposition and reduction during

A three-dimensional (3D) parallel process model simulating ironmaking blast furnaces (BFs) has been developed using computational fluid dynamics (CFD). It explicitly describes the layered burden and cohesive zone (CZ), gas and liquid re-distribution near raceways, trickling liquid flow in the CZ and dripping zone, and stockline variation. The applicability of the model is confirmed by the reasonable

A typical high-sulfur microalloyed steel was investigated by a sub-rapid solidification process for grain refinement of the as-cast microstructure. The size and distribution characteristics of the MnS precipitates were analyzed. The variations in the dendrite morphology and secondary dendrite arm spacing (SDAS) under different cooling rates have been studied, which strongly influence the precipitation

The effects of high undercooling and a large cooling rate can be achieved by the use of a containerless drop tube technique, which is conducive to rapid solidification and formation of a metastable phase. Here, the rapid solidification of Fe78Si13B9 (S1) and Fe78Si9B13 (S2) alloys was completed under microgravity condition. Based on theoretical calculations, a maximum undercooling of 433 K (0.29 TL)

The static and dynamic holdups of liquid slag flow in a packed coke bed were investigated at a temperature of 1723 K by using the three-dimensional combined discrete element method and a computational fluid dynamics model. Coke particles with three different diameters (8, 14, and 22 mm) were considered. The simulation results for the static holdup agreed well with previously reported experimental results

The oxidation kinetics of silicon hexaboride (SiB6) was studied at different partial pressures of oxygen. The specific weight gain was measured at 1173 K, 1223 K, and 1273 K for \( P_{{{\text{O}}_{2} }} \) = 0.1, 0.23, and 0.33 atm using thermogravimetric analysis. The conventional empirical expressions for oxidation were observed at all selected oxygen partial pressures and temperatures. The structural

The distribution of surface macro-inclusions is an important parameter that can directly influence the surface quality of IF steel sheets. In the present work, macro-inclusions > 100 μm within a 20-mm zone from the slab surface across the whole slab width were characterized by step machining methods, and the total analyzed area was 3,300,000 mm2. Three kinds of macro-inclusions were detected: bubbles

Direct to blister (DTB) accounts for a significant process for copper making due to its simplified process chain and the production of a single stable SO2-concentrated off-gas. In this study, the phase equilibria of iron silicate slags in the Cu-Fe-Si-S-O system at controlled atmosphere were, for the first time, experimentally investigated in the spinel primary phase field. The liquidus temperatures

An in situ observation technique of the TiO2 interfacial behavior in molten LiCl-KCl electrolysis was developed. The variation of the thin TiO2 electrode surface were tracked through the high-speed digital microscopy synchronized with the electrochemical measurement. Two characteristic interfacial behaviors were discovered: physical breakage of the titanium oxide and Li(l) spreading on electrode surface

Interfacial properties play a key role in determining the solubility of solids in liquids for both low- and high-temperature processes. In this study, the interfacial interactions between inclusions comprising TiO2 or TiN and the mold flux were investigated. The results of sessile drop tests show that the wettability of the mold flux on the TiO2 substrate was better than that on the TiN substrate when

Multi-hole ceramic filter is regarded as an effective and cheap method of additional flow control device in tundish. In order to evaluate the performance of the ceramic filter, a transient three-dimensional (3D) comprehensive numerical model has been developed to study the flow pattern, temperature distribution and residence time of the molten steel, as well as the elimination of inclusion in a full

As part of ongoing work to develop a low fuel consumption smelting process for comprehensive utilization of Hongge vanadium titanomagnetite (HVTM), the influence mechanism of SiO2 on the oxidation behavior and induration process of HVTM pellets (HVTMP) was investigated in this study. Results showed that as the amount of added SiO2 increased, the oxidation degree and compressive strength of HVTMP decreased