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In this study, industrial lithium-ion battery (LIB) waste was treated by a froth flotation process, which allowed selective separation of electrode particles from metallic-rich fractions containing Cu and Al. In the flotation experiments, recovery rates of ~80 and 98.8% for the cathode active elements (Co, Ni, Mn) and graphite were achieved, respectively. The recovered metals from the flotation fraction were subsequently used in high-temperature Cu-slag reduction. In this manner, the possibility of using metallothermic reduction for Cu-slag reduction using Al-wires from LIB waste as the main reductant was studied. The behavior of valuable (Cu, Ni, Co, Li) and hazardous metals (Zn, As, Sb, Pb), as a function of time as well as the influence of Cu-slag-to-spent battery (SB) ratio, were investigated. The results showcase a suitable process to recover copper from spent batteries and industrial Cu-slag. Cu-concentration decreased to approximately 0.3 wt.% after 60 min reduction time in all samples where Cu/Al-rich LIB waste fraction was added. It was also showed that aluminothermic reduction is effective for removing hazardous metals from the slag. The proposed process is also capable of recovering Cu, Co, and Ni from both Cu-slag and LIB waste, resulting in a secondary Cu slag that can be used in various applications. [ABSTRACT FROM AUTHOR]

Since the current volumes of collected end-of-life lithium ion batteries (LIBs) are low, one option to increase the feasibility of their recycling is to feed them to existing metals production processes. This work presents a novel approach to integrate froth flotation as a mechanical treatment to optimize the recovery of valuable metals from LIB scrap and minimize their loss in the nickel slag cleaning process. Additionally, the conventional reducing agent in slag cleaning, namely coke, is replaced with graphite contained in the LIB waste flotation products. Using proper conditioning procedures, froth flotation was able to recover up to 81.3% Co in active materials from a Cu-Al rich feed stream. A selected froth product was used as feed for nickel slag cleaning process, and the recovery of metals from a slag (80%)–froth fraction (20%) mixture was investigated in an inert atmosphere at 1350 °C and 1400 °C at varying reduction times. The experimental conditions in combination with the graphite allowed for a very rapid reduction. After 5 min reduction time, the valuable metals Co, Ni, and Cu were found to be distributed to the iron rich metal alloy, while the remaining fraction of Mn and Al present in the froth fraction was deported in the slag. [ABSTRACT FROM AUTHOR]

Innovative recycling routes are needed to fulfill the increasing demand for battery raw materials to ensure sufficiency in the future. The integration of battery scrap recycling and nickel slag cleaning by reduction with methane was experimentally researched for the first time in this study. Industrial nickel slag from the direct Outotec nickel flash smelting (DON) process was mixed with both synthetic and industrial battery scrap. The end products of the slag-scrap mixtures after reduction at 1400 °C in a CH4 (5 vol %)-N2 atmosphere were an Ni–Co–Cu–Fe metal alloy and FeOx–SiO2 slag. It was noted that a higher initial amount of cobalt in the feed mixture increased the recovery of cobalt to the metal alloy. Increasing the reduction time decreased the fraction of sulfur in the metal alloy and magnetite in the slag. After reduction, manganese was deported in the slag and most of the zinc volatilized. This study confirmed the possibility of replacing coke with methane as a non-fossil reductant in nickel slag cleaning on a laboratory scale, and the recovery of battery metals cobalt and nickel in the slag cleaning process with good yields. [ABSTRACT FROM AUTHOR]

Computational methods have become reliable tools in many disciplines for research and industrial design. There are, however, an ever-increasing number of details waiting to be included in the models and software, including, e.g., chemical reactions and many physical phenomena, such as particle and droplet behavior and their interactions. The dominant method for copper production, flash smelting, has been extensively investigated, but the settler part of the furnace containing molten high temperature melts termed slag and matte, still lacks a computational modeling tool. In this paper, two commercial modeling software programs have been used for simulating slag–matte interactions in the settler, the target being first to develop a robust computational fluid dynamics (CFD) model and, second, to apply a new approach for molten droplet behavior in a continuum. The latter is based on CFD coupled with the discrete element method (DEM), which was originally developed for modeling solid particle–particle interactions and movement, and is applied here for individual droplets for the first time. The results suggest distinct settling flow phenomena and the significance of droplet coalescence for settling velocity and efficiency. The computing capacity requirement for both approaches is the main limiting factor preventing full-scale geometry modeling with detailed droplet interactions. [ABSTRACT FROM AUTHOR]

The use of rare earth elements (REEs) is increasing, mainly due to the growing demand for electric vehicles and new applications in green technology. This results in annual growth of the in-use REE stocks and the amount of End-of-Life (EoL) products containing REEs. REEs are considered critical elements by the EU, mainly because the rest of the world is dependent on China's supply. Recycling of REEs can help alleviate the criticality of REEs, however, no REEs are currently functionally recycled. In this study, the time-dependent behavior of REEs in copper matte-slag system in primary copper smelting conditions was investigated experimentally at a laboratory scale. Lanthanum and neodymium were chosen to represent all REEs, as they are generally found in the highest concentrations in EoL products, and because REEs all have similar chemical behavior. The experiments were conducted as a function of time in air and argon atmospheres. SEM-EDS, EPMA and LA-ICP-MS methods were used for sample characterization. The results of this work indicate that the REEs strongly favor the slag and the deportment to the slag begins almost instantly when the system reaches high temperatures. With increasing contact times, the REEs distribute even more strongly into the slag phase, where they may be recovered and recycled, if their concentrations are sufficiently high and a suitable hydrometallurgical process can be found. [ABSTRACT FROM AUTHOR]

The skulling behavior in the blast furnace (BF) hearth has yet to be investigated as few (if any) industrial/experimental studies with particular focus on hot metal are reported in the open literature. As a necessary first step toward a better understanding of the sophisticated behavior, an experimental technique is introduced in the present paper. The experimental apparatus, which mainly consists of a vertical tube furnace, a rotating and moveable pedestal, and a moveable water‐cooled probe covered with a multi‐layer structured refractory sleeve can utilize industrial coke, pig iron, and BF hearth carbon brick as raw materials. The technique is shown to be capable of producing chemical, thermal, and mechanical conditions similar to those in the real process. The feasibility and potential of the technique are demonstrated by a set of experimental runs. The results indicate that the air gap between the cooling device and the refractory lining plays a decisive role in both skull formation and lining erosion. Furthermore, the microstructure of graphite precipitated during solidification is influenced by the cooling rate, which in practice is affected by the BF hearth operating parameters. It is hoped that the current contribution will stimulate the growing research interest in this subject. An experimental technique that can be adopted to investigate the skulling behavior in the blast furnace hearth is introduced in the present paper, where the feasibility and potential of the technique are demonstrated by a set of experimental runs. The technique is shown to be capable of producing chemical, thermal, and mechanical conditions similar to those in the real process. [ABSTRACT FROM AUTHOR]

Phase equilibria in the CaO–SiO2–CrOx system were experimentally investigated at 1600°C and pO2 of 10−10 to 10−11 atm using the high‐temperature isothermal equilibration/drop quenching/electron probe X‐ray microanalysis technique. The constrained isothermal sections of the CaO–SiO2–CrOx system were constructed at 1600°C and pO2 of 10−10 to 10−11 atm based on the experimental results. The primary phase fields including cristobalite (SiO2), larnite (Ca2SiO4), (Ca,Cr)Cr2O4, and corundum (Cr2O3) were determined. Simulations by thermodynamic software MTDATA, FactSage, and Thermo‐Calc were compared with the present experimental results. [ABSTRACT FROM AUTHOR]

The equilibrium phase relations of the Al 2 O 3 -SiO 2 -CrO x system were experimentally studied at 1600 °C and p O 2 of 10-10-10-11 atm. The high-temperature isothermal equilibration experiments were conducted in a vertical tube furnace, followed by drop quenching and direct phase composition analysis using an Electron Probe X-ray Microanalyzer. The single liquid equilibria, liquid-solid phase equilibria including liquid-corundum, liquid-mullite, and liquid-cristobalite, as well as the three-phase equilibria of liquid-cristobalite-corundum and liquid-corundum-mullite, were observed. The 1600 °C isothermal sections of the quasi-ternary Al 2 O 3 -SiO 2 -CrO x phase diagram at p O 2 of 10-10 and 10-11 atm were constructed. The present experimental results display significant discrepancies with the simulations by MTDATA, FactSage, and Thermo-Calc. [ABSTRACT FROM AUTHOR]

The equilibrium phase relations of the MgO–SiO2–CrOx system were investigated at 1600°C in air and at pO2 of 10–10 to 10–11 atm using a high‐temperature isothermal equilibration technique followed by rapid quenching and direct phase composition analyses with electron probe X‐ray microanalysis. Two‐phase equilibria (liquid–cristobalite, liquid–spinel, liquid–corundum, and liquid–olivine) and three‐phase equilibria (liquid–cristobalite–spinel, liquid–olivine–spinel, liquid–spinel–corundum, and cristobalite–spinel–corundum) were observed. The 1600°C isothermal sections at various oxygen partial pressures were constructed for the MgO–SiO2–CrOx system based on the experimentally determined liquid and solid compositions. Data from the literature and the predictions by FactSage and MTDATA software were compared with the present experimental results. [ABSTRACT FROM AUTHOR]

Brown corundum dust is a solid waste produced during the preparation of brown corundum with bauxite as the raw material. The dust has a relatively high gallium content; therefore, it is of great value to recover the gallium from this kind of dust. In this paper, a range of analysis and characterization methods, including XRD, XRF, SEM-EDS, and EPMA, were used to determine the occurrence of gallium. It was found that gallium was mainly present in the potassium-rich phase, wrapped by amorphous silicate and the corundum phase. Roasting activation followed by an acid leaching process was proposed to extract gallium from brown corundum dust. An investigation was carried out on the effects of roasting temperature, roasting time, and additive dosage on the recovery of gallium and the evolution of the phase composition of the dust. The results show that the roasting activation of sodium carbonate was better than that of calcium oxide. After roasting at 1073 K for 40 min with a sodium carbonate dosage of 0.5 (mass ratio of sodium carbonate to dust), the phase composition changed completely to mainly consist of sodium silicate, sodium aluminosilicate, and potassium aluminosilicate. In that case, around 93% of Ga could be recovered from the roasted dust through H2SO4 (4.6 mol/L) leaching for 90 min. The leaching process was described well by the kinetic equation of k3t = 1/(1 − α)1/3 − 1, with an apparent activation energy of 16.81 kJ/mol, suggesting that the leaching rate was limited by the transfer of leaching agent across the contacting interface of the dust particles. [ABSTRACT FROM AUTHOR]

The equilibrium-phase relations between copper mattes and spinel-saturated iron silicate slags were investigated at 1250°C and pSO2 of 0.25 atm. The experiments were conducted in synthesized spinel crucibles (Fe3O4) in controlled CO-CO2-SO2-Ar gas mixtures using a high-temperature isothermal equilibration/quenching technique. The equilibrium-phase compositions were characterized using an electron probe X-ray microanalyzer. The compositions of matte and slag were displayed as a function of matte grade or oxygen partial pressure. The present results obtained at spinel saturation in the matte-slag equilibrium system were compared with observations in the literature. This study improves the experimental thermodynamic data on the matte-slag-spinel-gas equilibria systems. [ABSTRACT FROM AUTHOR]

• The ignition and combustion of nickel concentrates were investigated using a laminar flow furnace. • The effects of temperature and oxygen enrichment in the process gas were determined. • The ignition of the nickel concentrates started at a temperature below 800 °C. • The highest sulfur removal from nickel concentrates was achieved under the most oxidizing conditions. • Fe and S were preferentially oxidized forming SO 2 and a porous FeO x -rich rim. The suspension oxidation of nickel sulfide concentrates in flash smelting conditions was studied using a laboratory-scale laminar flow furnace. The effects of temperature (800–1100 °C) and oxygen concentration (40–85 vol%) in the process gas were investigated. The surface morphology and mineralogical compositions of samples were examined using scanning electron microscopy equipped with energy-dispersive X-ray spectrometry. The sulfur removal from concentrates was determined using chemical analysis assuming iron as a non-volatile component. It was found that ignition of the nickel concentrates started at a temperature below 800 °C. The sulfur removal from the sieved concentrates increased with increasing temperature. The oxidation was initiated with preferential oxidation of iron in sulfides forming an iron oxide-rich scale on sulfidic core. [ABSTRACT FROM AUTHOR]

The equilibrium phase relations of the MgO–CaO–TiO 2 system were investigated at 1500–1600 °C in air using the high-temperature isothermal equilibration of samples in platinum crucibles followed by the rapid quenching technique. The phase compositions were analyzed using an electron probe X-ray microanalyzer (EPMA). The isothermal sections at 1500 °C and 1600 °C were constructed based on the experimentally determined liquid phase compositions. The present results deviate significantly from previous observations as well as the predictions by MTDATA and FactSage using their oxide databases, in particular in the perovskite primary phase field. [ABSTRACT FROM AUTHOR]

The combined processing of industrial wastes of titania-bearing slags with coal fly ash is an important part of the circular economy. In the present work, the effect of Al 2 O 3 on the 1400 °C liquidus isotherms of the perovskite, rutile and tridymite primary phase fields in the CaO–SiO 2 –TiO 2 –Al 2 O 3 system has been determined by employing a high-temperature equilibration-quenching technique, followed by X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy-Energy Dispersive X-ray Spectrometry. Titanium was confirmed to be stable as TiO 2 in the present equilibria. The equilibrium solid phases of perovskite CaO·TiO 2 , rutile TiO 2 and tridymite SiO 2 were confirmed to be coexisting with the liquid oxide phase. The comparison of the addition of 0–15 wt% Al 2 O 3 was beneficial for expanding the primary phase field of perovskite to lower TiO 2 concentrations. Comparisons of the experimental 1400 °C isotherm with the predictions using FactSage and MTDATA databases confirmed some differences to the present experimental data, thus demonstrating the direction for updating the present thermodynamic titania-bearing oxide databases. [ABSTRACT FROM AUTHOR]

In the Selective Crystallization and Phase Separation (SCPS) process, manganese oxide is used as an additive to promote the precipitation of perovskite. However, the influence of manganese oxide on the liquid domain of the perovskite primary phase field is still unclear. In the present work, the liquid-perovskite equilibrium with the addition of 0–15 wt% Mn 3 O 4 was experimentally determined using a high-temperature isothermal equilibration-quenching technique, combined with X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). It was confirmed that manganese was mainly existed as Mn2+ and Mn3+ in the molten phase, whereas titanium existed as Ti4+. Within the composition range of the present study, the 1400 °C liquid compositions varying from 0 wt% to 15 wt% Mn 3 O 4 overlapped significantly, mainly located at w (CaO)/ w (SiO 2) ratios between 0.9 and 1.1. The isotherms simulated by FactSage, as well as the data from the literature, generally agreed well with the present experimental results. The calculated 1400 °C isotherms at different Mn 3 O 4 levels indicated that perovskite precipitation by manganese oxide was mainly promoted by increasing the Mn 3 O 4 concentration to expand the primary phase field of perovskite toward both higher and lower TiO 2 content areas. [ABSTRACT FROM AUTHOR]

Alumina is a common substance deporting in copper smelting slags when various secondary copper fractions, e.g. e-scrap or WEEE, are used as feedstock as such or along with primary sulphide concentrates. Properties of iron-silicate slags at high alumina concentrations, in the iron-alumina spinel saturation, have been studied at 1300 °C by a high temperature equilibration-quenching method combined with EPMA (electron probe microanalysis) phase composition data from the polished sections. The equilibrations were performed in fixed oxygen activity with platinum or palladium powder, which dissolved iron from the slag and generated a heterogeneous equilibrium system, characterised by the general equilibrium criterium in isothermal and isobaric conditions, as. μ alloy (Fe) = μ slag (Fe) = μ spinel (Fe). This criterium was used for measuring experimentally iron activities of molten silicate slags. The locations of the spinel-liquid slag tie-lines were also determined in the oxygen partial pressure range of 10−6–10−10 atm. A comparison with the recent critical thermodynamic assessments of the Fe–O–Al 2 O 3 system indicates that the iron-alumina spinel-corundum phase boundary in silica-containing systems as a function of oxygen partial pressure is too steep and thus the assessed databases do not match with the experimental data of this study. The liquid slag domain from silica to iron oxide saturation is also smaller than expected earlier, as the spinel primary phase boundary locates at higher silica concentrations than e.g. obtained in the assessments of the Mtox database. • New, experimentally measured data regarding iron activity in Fe–Pt and Fe–Pd alloys was obtained. • The obtained iron activity values are in reasonable agreement with the assessed values in Mtox database. • Clear differences were observed between the measured spinel-alumina saturation boundary composition and the Mtox database. [ABSTRACT FROM AUTHOR]

The equilibrium phase relations of the CaO–SiO 2 –TiO 2 –Al 2 O 3 –MgO system were investigated experimentally in air at 1250–1400 °C using a high-temperature equilibration/quenching technique, followed by direct phase analysis by scanning electron microscopy equipped with X-ray energy dispersive spectroscopy. The equilibrium solid phases of silica, rutile, and pseudobrookite solid solution were found to coexist with the liquid phase. The 1300–1400 °C isothermal sections were constructed based on the experimentally measured liquid compositions. The experimental results were compared with simulations using MTDATA and FactSage thermodynamic software and their databases. This study provides guidelines for the selective crystallization of pseudobrookite from titania-bearing slag. [ABSTRACT FROM AUTHOR]