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The content of zinc in copper smelter slags obtained from pyrometallurgical copper production is comparable to the content of this metal in zinc ores. Therefore, these slags are considered a valuable secondary resource for zinc recovery. At the same time, the features of the mineralogical composition of the slag make the extraction of zinc from it very problematic. Most of the zinc is concentrated in the refractory zinc ferrite (ZnFe2O4). To avoid the formation of a viscous pulp when leaching copper smelter slag with an aqueous solution of sulfuric acid, in this work, the slag was leached with sulfuric acid also in isopropanol and n-pentanol, under the following conditions: 0.5 M H2SO4, pulp density 50 g/L, magnetic stirrer rotation speed 600 rpm. The influence of the duration and temperature of leaching milled (≤100 μm) copper smelter slag of the Balkhash copper smelter on the extraction of zinc into solution was investigated. It was found that the maximum zinc recovery into an aqueous solution was 75 ± 2% at 363 K and 210 min. Replacing water with isopropanol or n-pentanol led to an increase in zinc recovery to 82 ± 2% at 210 min and a lower temperature (353 K) than in an aqueous environment. An increase in temperature to 383 K during leaching in n-pentanol made it possible to extract 92 ± 2% of zinc. A shrinking core model was used to describe the kinetics of the zinc leaching process. It was found that the limiting stage of the process under all investigated conditions is the chemical leaching reaction. Some kinetic characteristics of the leaching process were calculated, in particular, the apparent reaction rate constants, as well as the activation energy. [ABSTRACT FROM AUTHOR]

The Direct Reduction (DR) process has been growing worldwide, and there are strong context suggestions that it will grow even more. One of these factors is the environmental pressure that occurs worldwide, and there are already projects to migrate Blast Furnace route steel plants to the Direct Reduction (DR) route, due to its smaller carbon footprint. Considering the importance of this process and the challenges of carrying out experimental tests on a pilot scale, an adequate way to evaluate the process and its impacts is through numerical simulations. There are different techniques applied to models that describe the counter-current reactor in the DR process, but none of them account for the clustering phenomenon. Clustering occurs because of the sintering of the metallic iron on the surface of the pellets in such a way that they attach to each other, forming clusters that hinder the gas flow through the shaft. The present study attempted to adapt a numerical model of a DR process to account for the effect of the cluster formation. Some clustering index equations from literature and some developed as part of this study were used and tested in the model, as a function of temperature, by varying the solid volume fraction in the control unit. The equation that resulted in the adjusted output closest to the current empirical value was implemented in the model and proved to be successful. [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs) are precious rare metals mined only in a few regions of the world. Recycling PGMs used in automotive catalytic converters is of utmost importance to meet increasing global demand. The Rose process is the main recycling process used in Japan to recover PGMs from spent automotive catalytic converters. The recycling process involves smelting a ceramic structure, in which PGMs are supported, with Cu, Cu2O, reductants, and fluxes such as CaO and SiO2. This study compared the Pd and Pt recovery capability of Cu or Cu2O as extractants. Pd and Pt particles were simultaneously suspended in Al2O3CaOSiO2 molten slag, and the extractant Cu or Cu2O was added. The concentration of Pd and Pt in the slag as a function of processing time was investigated at 1723K of the operating temperature in the Rose process, under carbon saturation. The results show that the suspended Pd and Pt particles were combined by collisions in the slag, and the recovery ratio and recovery speed of Pd and Pt suspended particles were higher when using Cu2O than when using Cu. The Cu2O dissolved in the slag was reduced to metallic Cu in the slag and alloyed with the suspended PGMs particles to form Cu-PGMs alloys. As a result, the particle size of the PGMs increased and sedimentation motion in the slag is promoted. [ABSTRACT FROM AUTHOR]

The fight against climate change has emphasized the importance of understanding the environmental performance of metal production technologies. This is especially true for copper whose consumption will increase significantly due to electrification and, therefore, understanding the associated footprint becomes essential. This study uses simulation-based life cycle assessment (LCA) together with a commercial flowsheet simulation program to compare several copper smelting technologies against each other when producing metallic blister copper from sulfide copper ore. The lowest LCA values for three concentrate compositions and three capacities were obtained for Flash Smelting technology with Peirce-Smith converting (FSF-PSC). The unit CO2 emissions decreased with increasing capacity. The reduction obtained when the capacity was doubled was 1–9%, depending on the technology. The main source of CO2 emissions was electricity generation, including the use for oxygen production. For instance, for FSF-PSC it accounted for 91% of the climate change when global data source was used for electricity, translating into an 80% reduction if non-fossil electricity was introduced. A reduction of up to 85% in climate change can be achieved by changing from the highest emission producing technology, the Side Blowing Furnace – Top Blowing Converter (SBF-TBC), to the lowest (FSF-PSC) and by using non-fossil electricity.

Meeting the increasing demand for energy storage based on lithium-ion batteries (LIB) is not only a question of resource availability but also an issue of resource conservation and efficient recycling management. In this respect, sustainable recycling concepts play a central role in mindful interactions with valuable materials. Based on this approach, a process interconnection of hydromechanical preparation, flotation, and pyrometallurgical treatment was investigated. The hydromechanical preparation showed promising results in achieving highly pure mixtures of LIB-active material. It was found that a pre-opening step could achieve an even better separation of impurities for downstream processes such as Cu and Al to avoid excessive particle size reduction. According to an optimized mixing stage during flotation, the C amount was reduced from 33 wt.% to 19.23 wt.%. A Li-free metal alloy was obtained through the subsequent pyrometallurgical treatment, and evidence for Li removal via the gas phase was provided. Furthermore, heating microscope trials confirmed the results of the process interconnection and showed that further optimization steps for the pre-treatment are necessary for favorable product quality. Therefore, a high-stratification plot was created, which allows a quick future statement about the suitability of the input material for use in the process.

As the electrification sector expands rapidly, the demand for metals used in batteries is increasing significantly. New approaches for lithium-ion battery (LIB) recycling have to be investigated and new technologies developed in order to secure the future supply of battery metals (i.e., lithium, cobalt, nickel). In this work, the possibility of integrating LIB recycling with secondary copper smelting was further investigated. The time-dependent behavior of battery metals (Li, Co, Ni, Mn) in simulated secondary copper smelting conditions was investigated for the first time. In the study, copper alloy was used as a medium for collecting valuable metals and the distribution coefficients of these metals between copper alloy and slag were used for evaluating the recycling efficiencies. The determined distribution coefficients follow the order Ni >> Co >> Mn > Li throughout the time range investigated. In our study, the evolution of phases and their chemical composition were investigated in laboratory-scale experiments under reducing conditions of oxygen partial pressure p(O2) = 10−10 atm, at 1300 °C. The results showed that already after 1 h holding time, the major elements were in equilibrium. However, based on the microstructural observations and trace elements distributions, the required full equilibration time for the system was determined to be 16 h.

Flue dust waste coming from a copper (Cu) smelting company has been valorized using a newly developed metallurgical process with the aim of recovering a dust concentrated in valuable metals, such as lead (Pb) and zinc (Zn), and studying the feasibility of replacing anthracite with biochar as reducing agent. Metallurgical trials using different mixtures of reducing agents have been performed in a furnace at 1400 °C. This furnace employs a high-power thermal plasma (HPTP) system as energy source. Using copper as the base metal, pellets containing a mixture of the waste, different reducing agents, and binder were introduced into the furnace for their dissolution. Recovery yields in the range of 45–85 wt.% for Pb and Zn were obtained in the flue dusts. All the trials proved the effectiveness of the developed process to enrich the flue dusts in valuable metals, including those only using biochar as reducing agent. Further trials will be carried out in order to better control the parameters involved in the metallurgical process developed and improve its efficiency.

Zinc leaching residue is an important secondary sources of zinc. To realize recycling utilization of this zinc secondary resource, a novel technology is proposed for the recovery of zinc from the zinc leaching residue by the bottom-blown reduction process in this study. The effects of reduction temperature, reduction time, coal rate, and lime addition on the metal content in the slag and the volatilization rate of lead and zinc during reduction were evaluated. The optimized conditions for the recovery of Pb and Zn in the bottom-blown reduction process were determined as 1473 K with a coal rate of 35% and a lime addition of 4% for a reduction time of 70 min. Under the optimized conditions, the recovery rate of Pb and Zn is over 90% and 94%, respectively. The lead, zinc, and copper content in the reduced slag is 0.15%, 0.7%, and 0.07%, respectively. An industrial test was carried out for the recovery of Pb and Zn from the zinc leaching residue by bottom-blown reduction, resulting in a ZnO content of less than 3% in the reduced slag and a coal rate of 35%, not less than 0.6 for CaO/SiO2 (mass ratio) and 1.0 ~ 1.2 for FeO/SiO2 (mass ratio). [ABSTRACT FROM AUTHOR]

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Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A fundamental theory on pyrometallurgic direct smelting of waste printed circuit boards was investigated in this work. First, the effects of the Fe/SiO2 (mass ratio) and CaO/SiO2 (mass ratio) on the liquidus temperature and viscosity of slag were systematically analyzed at a PO2 value of 10–12 atm. Then, a verification experiment was carried out. Thermodynamic calculation results showed that the liquidus temperature of slag first decreased then increased as Fe/SiO2 and CaO/SiO2 were increased. At 1250°C, the viscosity of slag is lower than 0.5 Pa s in the Fe/SiO2 range of (0.8–1.2):1 and CaO/SiO2 range of (0.25–0.85):1. The verification experiment indicated that an alloy with high content copper can be obtained. Microanalysis of the alloy and slag demonstrated that the distinguishable crystal phase in the alloy mainly contained metallic copper, metallic iron, and a small amount of intermetallic compounds such as (Fe, Ni) and Ni3Sn2. The slag was mainly composed of fayalite (Fe2SiO4), calcium silicate (Ca2SiO4, CaSiO3), and gehlenite (Ca2Al2SiO7). [ABSTRACT FROM AUTHOR]

Oxidized nickel ores account for the majority of industrial ores suitable for nickel production. The processing of such ores using traditional pyrometallurgical technology is not economically viable due to the low nickel content. One of the most cost-effective methods of processing oxidized nickel ores is sulfuric acid leaching technology followed by sorption extraction. The aim of this work is to establish the kinetic and thermodynamic parameters of the sorption extraction of nickel and cobalt using iminodiacetate chelating ion-exchange sorbents from various manufacturers, to select a desorbing solution and to determine the degree of desorption. The sorption of nickel and cobalt was carried out in a weakly acidic medium from a model solution containing impurities of other metals in static and dynamic modes. The limiting sorption capacity for the studied sorbents is 18-26 mg/g for nickel and 1-2 mg/g for cobalt in the static mode. The sorption capacity in the dynamic mode for nickel is equal to 25.5 g/L for Purolite S 930, 29.2 g/L for Lewatit TP 207, 1.4 g/L, and 1.8 g/L for cobalt, respectively. The best desorption parameters are achieved when using a 2 M sulfuric acid solution. The degree of desorption for sorbents Purolite S 930 and Lewatit TP 207 exceeds 90%. The use of the Lewatit TP 207 sorbent for the extraction of nickel from the leaching solution of nickel ore of the Gornostaevskoye deposit in 5 cycles made it possible to obtain a commercial desorbate with a nickel content of 18 g/L. The use of a part of the commercial desorbate obtained in the previous cycle, further strengthened to the initial concentration of sulfuric acid, for re-extracting nickel from the saturated sorbent during a cyclic process leads to a deterioration in desorption characteristics. It is recommended to remove the commercial desorbate from the process after several cycles of desorption and supply new solution of sulfuric acid for desorption to restore the sorption parameters. [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs) are strategic metals. Auto-exhaust catalysts are their main application fields. The recovery of PGMs from spent auto-exhaust catalysts has remarkable economic value and strategic significance. Aiming at the problems of ferrosilicon generation for Fe capturing and subsequent oxygen blowing to remove iron with high energy consumption and heat release, a technology of Fe–Sn synergistic capturing PGMs was proposed. Taking full the advantage of the lower melting point of Fe–Sn alloy (<1200 °C) and its unique affinity for PGMs, the PGMs were captured at approximate 1400 °C with Fe–Sn as the collector. In experiment, 500 g of spent auto-exhaust catalysts were employed to minimize error and approximate industrial production. The mechanism of Fe–Sn synergistic capturing PGMs was elucidated. The generation of Fe–Sn-PGMs alloy lowered the activity of [PGMs] in the system, accelerated the reduction of the PGMs oxides and promoted the alloying of [PGMs]. Therefore, Fe–Sn synergistic capturing PGMs was realized. The inability of Si to enter the alloy phase was confirmed by theoretical calculations, avoiding the generation of ferrosilicon. The effects of basicity, CaF 2 , m (Fe)/ m (Sn) and the amount of collector on capturing PGMs were optimized. Under the optimized conditions (basicity R = 1.1, spent auto-exhaust catalysts 70 wt%, CaO 30 wt%, B 2 O 3 10 wt%, CaF 2 7 wt%, m (Fe)/ m (Sn) = 1/1 and the collector 15 wt%), the content of PGMs in the slag phase was 2.46 g/t. It is feasible to remove Fe and Sn by oxidation to achieve the purpose of PGMs enrichment. This technology offers guidance on the safe, environmentally sound, and efficient disposal of spent auto-exhaust catalysts, promoting the sustainable development of PGMs. [Display omitted] [ABSTRACT FROM AUTHOR]

Recent concerns have emerged regarding the improper disposal of spent lithium-ion batteries (LIBs), which has garnered widespread societal attention. Graphite materials accounted for 12–21 wt % of LIBs' mass, typically contain heavy metals, binders, and residual electrolytes. Regenerating spent graphite not only alleviated the shortage of plumbago, but also contributed to the supports environmental protection as well as national carbon peak and neutrality ("dual carbon" goals). Despite significant advancements in recycling spent LIBs had been made, a comprehensive overview of the processes for pretreatment, regeneration, and functionalization of spent graphite from retired LIBs, along with the associated technical standards and industry regulations enabling their smooth implementation still needed to be mentioned. Hence, we conducted the following research work. Firstly, the pre-treatment process of spent graphite, including discharging, crushing, and screening was summed up. Next,. Subsequently, graphite recovery methods, such as acid leaching, pyrometallurgy, and combined methods were summarized. Moreover, the modification and doping approach was used to enhance the electrochemical properties of graphite. Afterwards, we reviewed the functionalization of anode graphite from an economically and environmentally friendly view. Meanwhile, the technical standards and industry regulations of spent LIBs in domestic and oversea industries were described. Finally, we provided an overview of the technical challenges and development bottlenecks in graphite recycling, along with future prospects Overall, this study outlined the opportunities and challenges in recovering and functionalizing of anode materials via a efficient and sustainable processes. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, the volume swelling and carbon deposition behavior of pellets under shaft furnace smelting conditions were studied. The research process on swelling reduction utilized an online detection imaging method to determine the volume changes of pellets. The results suggest that an increase in temperature and a higher proportion of carbon monoxide in the reducing gas contribute to an escalation in the swelling rate during pellet reduction. Carbon deposition induced by carbon monoxide primarily occurs at 750 °C, and the powdery carbon deposition products on the surface of the pellets change over time, transitioning from carbon to a mixture of carbon and iron carbide (Fe 3 C) to a mixture of carbon, Fe 3 C, and metallic iron. This study elucidated the behavior of pellets in the low-temperature reduction section during the shaft furnace smelting process, offering a technical foundation for shaft furnace smelting technology. [Display omitted] • The volume change of the pellet during the hydrogen rich reduction process was observed using a real-time camera system. • Investigated the reasons for variations in pellet reduction swelling index under different gas mixtures. • Investigated the mechanism of carbon deposition on the surface of pellets with hydrogen-rich gases. • Investigated the evolution mechanism of carbon deposition products at different stages. [ABSTRACT FROM AUTHOR]

With an ever-growing demand for critical raw materials for the production of lithium-ion batteries and a price increase of respective commodities, an ever louder call from the industry for efficient recycling technologies can be noticed. So far, state-of-the-art industry-scaled pyrometallurgical recycling technologies all suffer from the same bottleneck of lithium slagging. At the Chair of Thermal Processing Technology at Montanuniversitaet Leoben, a novel reactor was developed to recover lithium and phosphorus via the gas phase in a pyrometallurgical process. Critical elements such as Li, Ni, Co, and Mn of the commercially used cathode materials LCO (LiCoO2), LFP (LiFePO4), NCA (LiNi0.8Co0.15Al0.05O2), and NMC622 (LiNi0.6Mn0.2Co0.2) were analyzed in a batch version of the so-called InduRed reactor concept. The analyses underline that the reactor concept is highly suitable for an efficient recovery for the metals Ni and Co and that slagging of Li can not only be largely prohibited, but the elements lithium and phosphorous can even be recovered from the gas phase. Plant engineering issues were also considered for further development toward a continuous process. The MgO crucible used shows significant diffusion of various elements from the battery material, which is why the choice of crucible material still requires in-depth research.

The application of cobalt and aluminium powders in unconstrained format, not as metal powder in tubular wire nor as pre-alloyed powder, is used in this work to simplify weld metal alloying. The objective of this study is to demonstrate the application of unconstrained cobalt and aluminium powders in Submerged Arc Welding SAW to alloy the weld metal and to control the weld metal oxygen content. Aluminium powder is used to control the oxygen potential at the weld pool-slag interface in order to prevent oxidation of cobalt. The results presented here show that with the addition of Aluminium powder, 70% yield of Cobalt was achieved from the cobalt powder to the weld metal. The carbon steel base-plate material and weld wire materials combination were alloyed to 5.3% Co and 4.2% Al, whilst controlling the weld metal total oxygen content to 230 ppm. Thermodynamic analysis is applied to investigate the possible chemical interaction reactions between Co and Al compounds, as well as the role of the reactions on Co yield to the weld pool. The application of unconstrained metal powders ensures productivity gains in the overall SAW process because the time consuming and expensive manufacturing of alloyed wire and alloyed powder are eliminated.

The rapid human evolution has improved the quality of our lives through the use of technology. This not only resulted in increased raw materials extraction but also in the production of a worrying amount of electronic wastes. Indeed, in 2019 worldwide production of Electronic and Electric Equipment Waste (WEEE) was worth 50 million tons, causing several disadvantages such as the reduced space in landfills and massive shipping to countries with less restrictive regulations. On the other side, the billionaire electrical devices market is causing a significant increase in Precious Metals (PM) demand. Nowadays, the economic importance of PMs is as high as their supply risk. The answer to this problem consists of finding selective methods to extract and raffinate precious metals from disposed WEEE. On average, WEEEs contain around 30 % of plastics, 30 % ceramics, and 40 % metals; among these only around 0.1 % is characterized by PMs, such as gold, silver, rhodium, platinum, and palladium. The separation of PMs from other non-precious components is generally obtained using pyrometallurgy, which consists of fusing the wastes at temperatures up to 1500 ÷ 1700 °C. However, this method produces toxic gaseous byproducts and implies high energy costs. A possible alternative is given by hydrometallurgical processes, consisting of leaching the WEEE with solutions containing acids and oxidants at temperatures lower than 100°C. One of the main issues of the hydrometallurgical process is to leach copper and other non-precious base-metals selectively while keeping PMs in the solid-state. In this work, we report preliminary results of equilibrium and kinetic leaching tests in a well-stirred batch reactor, aimed at the optimization of the main operating parameters of a hydrometallurgical process for selective leaching of copper and other base-metals from Wasted Printed Circuit Boards (WPCBs). In particular, experiments have been carried out at different HCl and NaCl concentrations of the leaching solutions, exploring also the effect of temperature variation (20, 50, and 70 °C). [ABSTRACT FROM AUTHOR]

A review is made of the growth dynamics of metal radioactive waste on a world scale. The most commonly applied technologies (hydro- and pyrometallurgical) for deactivation of this waste are presented. The implementation of the blocks obtained by remelting for the manufacture of fasteners of nuclear reactors is demonstrated. Based on the conducted experiments and drawn conclusions, the inference is made that the pyrometallurgical methods of processing have greater advantages. The paper exhibits a convincing motivation for the essential necessity of investigation of the metal radioactive waste processing, following the system D&D (deconstruction + deactivation), using effective and environmentally friendly technology. [ABSTRACT FROM AUTHOR]

Spodumene is the main source of lithium among the lithium-containing minerals. A number of studies have been done on the extraction of lithium from naturally occurring α-spodumene as well as pre-treated β-spodumene and the effect of key factors that influence extraction and optimum processing conditions have been discussed. Some of these methods have remained at a laboratory scale because they were not economically and operationally feasible, while some have been developed further. The increasing demand for lithium justifies efforts for the development of new methods as well as improving the existing commercial extraction processes. A comprehensive and detailed study of the available literature on lithium extraction studies is a useful starting point for this research. The present article is a review of the extraction methods of lithium from spodumene concentrate, after beneficiation, which have been studied to date. [ABSTRACT FROM AUTHOR]

The paper presents results of investigations of the chemical composition of iron sulphides contained in dust from the pyrometallurgical production process of zinc and lead. The main mineral components of these dusts are sphalerite, galena, iron sulphide – pyrite, zincite, anglesite and probably kirchsteinite. The tests performed have demonstrated that the chemical composition of iron sulphide grains was not close to stoichiometric, the grains were non-uniform in terms of phase composition and they always included admixtures in the form of inclusions of other sulphides, i.e. zinc sulphide and lead sulphide, and accompanying elements (Ca, Mn, Se, As, Ag, Cu, Cd). [ABSTRACT FROM AUTHOR]

This paper assesses the effect of galena emitted with dust from an electrostatic precipitator at Miasteczko Śląskie Zinc Smelting Plant (Poland) onto a soil and water environment. The Eh–pH diagrams plotted in the temperature range of − 3 to 25 °C serve to determine the conditions of PbS stability and conditions under which its decomposition may occur, resulting in the release of ionic forms of lead into the soil and water environment. Determination of the mobility of galena emitted with metallurgical dust is a current and important issue in view of the geochemistry of mineral components in the environment. [ABSTRACT FROM AUTHOR]

Nickel alloying of carbon steel is used to enhance steel strength and toughness. Nickel alloying of the weld metal via solid weld wire presents several difficulties as highlighted previously, such as work hardening of the solid weld wire in manufacturing and feeding through the SAW wire feeding mechanism, and expensive and time consuming manufacturing of multiple weld wire formulations. The application of nickel and aluminium powders in unconstrained format, meaning not as fluxed cored wire or as metal cored wire, is used to simplify weld metal alloying. Al powder is used to control the oxygen potential at the weld pool-molten flux interface. The results presented here show that the addition of Al powder to the weld metal enhances Ni yield to the weld metal, at 85%, compared to pre-alloyed powder Ni yields of 57–78% as applied in previous work. Carbon steel was alloyed to 6.9% Ni and 3.7% Al. Thermodynamic analysis is applied to elucidate the chemical interaction between Ni and Al, and its effects on Ni yield in the weld pool. Overall process productivity gains stem from weld metal alloying from unconstrained metal powders because the expensive and time consuming step of manufacturing alloyed wire and alloyed powder is eliminated.

The extensive usage of portable electronic products and the acceleration of their replacement have led to the discarding of a growing amount of LiCoO2 batteries. It is necessary to recycle the batteries from the both viewpoints of environment and economic benefits. Current recycling approaches for LiCoO2 are dominantly based on hydrometallurgy and pyrometallurgy, which usually require multiple complicated steps and involve the use of high temperature or harmful chemicals, like acids and alkalis. There remains an urgent need for a green and simple process. In this paper, suspension electrolysis technology is proposed to recycle spent batteries, in order to achieve the leaching, purification and regeneration of LiCoO2 in one step. The most advantageous of the present technology are that reacting in one reactor at atmospheric condition and no use of highly corrosive and harmful reagents. The reaction of LiCoO2 leaching in the anode region and simultaneously re-synthesizing in the cathode region in ammonia electrochemical system is established for the first time. Three chemical reaction systems of NH4HCO3, NH4HCO3-NH3, and NH4HCO3-(NH4)2SO3, are explored. The results of the laboratory scale experiments show that LiCoO2 can be regenerated in NH4HCO3-(NH4)2SO3 reaction system. Under the investigated conditions of this study, 66.3 % of Li and 75.4 % of Co were leached out in the anode region and 53.2 % of LiCoO2 was regenerated in the cathode region under the conditions of 0.5 mol/L (NH4)2SO3 concentration, 2.5 mol/L NH4HCO3 concentration, 1.5 A current, 2 g/L solid to liquid ratio, 50 °C, and 1.5 h. The reaction system for realizing LiCoO2 leaching in the anode region and simultaneously re-synthesizing in the cathode region is established. This work provides a promising method for recovering LiCoO2 efficiently and environmentally friendly, promoting the sustainable utilization of the resources. [ABSTRACT FROM AUTHOR]

The pyrometallurgical production of germanium concentrates from the raw materials (coal, argillite, siltstone) of brown coal fields is accompanied by the formation of molten silicate slags. The mineral component of the raw materials concentrates in slags, reaching 60 wt %. It is obvious that the process indices are mainly determined by the physicochemical properties of the molten slags, such as density ρ and surface tension σ, reflecting the structure of molten silicates. The compositions of the slags after processing of carbonaceous raw materials differ significantly from those of the slags of nonferrous and ferrous metallurgy: they contain higher contents of SiO2 (up to 50–55%), Al2O3 (up to 20–22%), K2O, and Na2O (up to 5–6%). In addition, the slags contain significant contents of sulfide sulfur (up to 3%) and trace amounts of nonferrous metals and rare elements (up to 5%). The differences between the compositions of the molten slags of germanium production and the slags of main metallurgy influence their properties and require special studies. Industrial cyclone melting and electric smelting slag samples are studied. Semi-synthetic samples are analyzed; these samples are produced from industrial ones by the addition of SiO2 and CaO in order to determine the influence of composition on ρ and σ. The measurements are based on the maximum pressure in an inert gas bubble blown in a melt, more specifically, on the differential version to improve the accuracy. The cell consists of the melt to be studied in an alundum crucible with an immersed alundum capillary and a reference capillary immersed into distilled water. The melt temperature is measured in the range 1100–1400°C. ρ and σ of the melts are found to fall in the ranges from 2.20 to 4.3 t/m3 and from 218 to 531 mN/m, respectively. The values of ρ and σ significantly depend on the basicity (ratio of the sum of the CaO and MgO contents to SiO2) and the Al2O3 content. The temperature dependences of ρ and σ are found to be linear with negative temperature coefficients. In the general case, ρ and σ of the melts significantly differ from, for instance, the blast furnace slags at the same basicity. The obtained results are valuable for predicting the structures of melts and their behavior under real conditions. [ABSTRACT FROM AUTHOR]

A high titania slag that is used as a feedstock for TiO2 manufacturing is obtained by ilmenite smelting (FeO.TiO2). The composition of the slag obtained by smelting is dependent on the composition of the mineral used for slag preparation, i.e., ilmenite in our study. At the laboratory scale, ilmenite slags are mostly obtained by using ilmenite as the raw material. An easy and simple way would be to prepare the synthetic slag using the individual components and heating them to high temperature in a furnace. The titania slag has a high oxidizing nature and requires an inert atmosphere to prevent oxidation of the slag as well as the molybdenum crucible. This paper describes the preparation of synthetic ilmenite slag using an induction furnace and the study of the composition and the phases formed in the slag. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES) were used as analytical techniques for studying the slag. A comparison between obtained synthetic slag and industrial ilmenite slag was performed to test the possibility of preparing slags in the laboratory as per the required composition. The slags show similar phase formation as obtained in industrial ilmenite slags, which means that the synthetic slags are identical to the industrial slags. [ABSTRACT FROM AUTHOR]

Copper pyrometallurgy has been holding a special place in the copper smelting industry. However, it is hard to explore the effect of parameters on production effectively due to the inoperable practice in the factory. The physical and chemical changes during the metallurgical process of copper smelting are also too complex to be observed. Therefore, we designed and built a virtual factory for copper pyrometallurgy, copper pyrometallurgy virtual simulation system (CPVSS), to simulate the copper smelting plant. The entire technical routes, system function, the main productive principle, technological process, and conditional tests were fully simulated in the CPVSS. It also provided a solution for the observation of internal phenomena in this paper. Moreover, sample computations were provided in this paper to illustrate the parameter simulation of the smelting process. A novel interactive experimental model was also constructed with virtual simulation technology and network multimedia technology, which provides powerful support for copper pyrometallurgy learning. [ABSTRACT FROM AUTHOR]

Sb distribution in the phases of SiO2 saturated Sb-Fe-O-SiO2-CaO system was determined for the first time through heightemperature experiment and quenching techniques, followed by Electron probe X-ray microanalysis (EPMA) in air (Ptot = 1 atm, PO2 = 0.21 atm). The phases were quantified in the temperature range of 900 °C-1200 °C and the effects of Fe/SiO2 (mass fraction) and CaO/SiO2 (mass fraction) on Sb2O3 content in the Sb-Fe-O-SiO2-CaO system were investigated at 1200 °C. The results indicated that the Sb-containing phase primarily existed in the solid solution phase at 1200 °C. With the increase of temperature from 1100 °C to 1200 °C, the Sb2O3 content in the solid solution phase increased drastically from 7.52 wt% to 17.36 wt%. Lowering the values of CaO/SiO2 and Fe/SiO2 in the smelting process effectively reduced Sb2O3 content in the slag. The verification of the experiment results suggested that the antimony content in slag was 0.57 wt%, the crude antimony yield rate was lower than 4%, and the crude antimony grade was beyond 94 wt%, which meant that the reduction of antimony content in the slag could be achieved. [ABSTRACT FROM AUTHOR]

Recycling cathode materials from lithium-ion battery scraps can play a significant role in reducing environmental contamination and resource depletion. In this study, we employed pyrometallurgical techniques to regenerate LiMn 2 O 4 cathode materials from recovered cathode scraps. First, the binder was removed under optimal conditions by a heating and stirring method to maximize the dissolution rate of the cathode scrap materials. Next, inductively coupled plasma spectroscopy was used to define the Li and Mn contents, and finally, the LiMn 2 O 4 cathode material was regenerated by a pyrometallurgical method. After calcination under the optimum conditions of 500 °C for 12 h, electrochemical performance testing revealed obvious charge and discharge platforms in the charge/discharge curves; further, a high first-cycle discharge capacity was observed at 136.6 mAh·g-1 (3.0–4.3 V and 0.1 C), which decreased to 93 mAh·g-1 after 50 cycles. This process is low-cost and environmentally friendly, with the potential for recovering other cathode scrap materials. [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs) are widely applied in the field of catalysts due to their excellent catalyst activity and high-temperature stability. The rapid generation of the waste catalyst has become the significant characteristic of PGMs with the accelerating consumption of limited PGMs nature resources. It is necessary to recover/recycle PGMs from a waste catalyst for both economic and environmental benefits. This paper reviews the PGMs recovery from waste catalysts using a metals smelting-collection process, which belongs to the main pyrometallurgical process, in the presence of various metal collectors, such as lead, copper, iron, matte, print circuit board (PCB) or reactive metals of calcium and magnesium. The current status of recovery of PGMs from waste catalysts through the addition of various metals as the collector is discussed and existing advantages and challenges are highlighted in this paper. Meanwhile, in the view of the promising processes of PGMs recovery, the influencing factors such as the economic, environmentally friendly, sustainable recycling, commercial scale, and low-grade materials are considered. [ABSTRACT FROM AUTHOR]

With the rapid development of the electric vehicle industry in recent years, the use of lithium batteries is growing rapidly. From 2015 to 2040, the production of lithium-ion batteries for electric vehicles could reach 0.33 to 4 million tons. It is predicted that a total of 21 million end-of-life lithium battery packs will be generated between 2015 and 2040. Spent lithium batteries can cause pollution to the soil and seriously threaten the safety and property of people. They contain valuable metals, such as cobalt and lithium, which are nonrenewable resources, and their recycling and treatment have important economic, strategic, and environmental benefits. Estimations show that the weight of spent electric vehicle lithium-ion batteries will reach 500,000 tons in 2020. Methods for safely and effectively recycling lithium batteries to ensure they provide a boost to economic development have been widely investigated. This paper summarizes the recycling technologies for lithium batteries discussed in recent years, such as pyrometallurgy, acid leaching, solvent extraction, electrochemical methods, chlorination technology, ammoniation technology, and combined recycling, and presents some views on the future research direction of lithium batteries.

Primary world nickel production in 2020 was 2430.7 kt Ni; 69% (1677.7 kt) of them came from oxidized nickel ores (laterites) and 31% from sulfides. Production-wise, 87.7% of the 1677.7 kt came from pyrometallurgical and 12.3% from hydrometallurgical processes. For a long time, Fe-Ni had a 20–40% Ni analysis, but in 2006 a new Fe-Ni quality came into the scene. This is the nickel pig iron (NPI) with 2.5–5.5% Ni that comes from laterite smelting in the blast furnace (B/F). Eventually, the advantages of the R/K-E/F process led to its dispersion in China and Indonesia and resulted in an NPI production with 3–12% Ni. The NPI production in these two countries climbed from zero in 2000, to 1060 kt Ni in 2020 and also stainless-steel production from 5.5% to 67.2%, respectively, of the world’s SS production. The integration of Ni industry with SS production, the economy of scale, the low labor cost, the high Ni content of Indonesian laterite, and the loose environmental laws, reduced significantly the NPI production cost. The addition of SS and/or electric energy production units for cost reduction has been adapted from other Fe-Ni producers, as well. Hellenic Minerals in Cyprus after two years of successful industrial tests is in the commissioning state of a Heap Leaching-Solvent Extraction-Crystallizer (HL-SX-CR) unit for NiSO4.6H2O production. The high demand for Ni and NiSO4.6H2O in the last few years has changed the prospects of Ni laterite hydrometallurgical processing. Regarding the R/K-E/F process used in Greek Fe-Ni, it is characterized by its worldwide acceptance and reliability (more than 77% of world Fe-Ni production comes from this process). Other advantages are the use of all types of laterites and fuels, it has a high metallurgical recovery, and the plant has its own port. However, it is a high energy-consuming process, and it does not recover Co. The Greek laterite, in particular, has the lowest Ni% among global Fe-Ni producers and because of this, electric energy (MWh/t Ni) and wages (wages/t Ni) per ton of Ni are high, making Larco’s viability difficult. The only way to overcome the issue with specific electricity consumption is to enrich the local ores by blending them with imported high grade Ni ores. Other negatives were the excessive electric energy price it had to pay to a dominant energy supplier and the very frequent changes of its administration.

In this paper, research on the effects of agitation rate for desilvering tin silver alloy residue by using pyrometallurgy was carried out. SnAg alloy residue with 92 wt.% tin and 3.56 wt.% silver was used in this study, and 99.999 wt.% zinc was added as metal solvent. Residues were melted to a temperature of 400 °C for enriching tin silver alloy. The obtained tin silver alloy was melted in a temperature range of 450 °C to 500 °C by adding zinc to evaluate zinc dissolution. The obtained tin silver zinc was agitated at different agitation rates for 20 min at a temperature of 480 °C, then cooled down while stirring to an eutectic point of tin zinc alloy (198.9 °C) to remove silver zinc dross. X-ray Fluorescent-1800 (XRF-1800) and Field Emission Scanning Electron Microscopy Energy Dispersive Spectroscopy (FE-SEM-EDS) analyses were performed in this research. Different factors including holding time, zinc dissolution, agitation time and agitation rate were evaluated. The results revealed that an agitation rate of 600 RPM, 25% Zn and 60 min at a temperature of 198.9 °C were efficient. Zinc silver was removed as dross every 20 min to get 92% silver separation efficiency, and the use of supergravity centrifuge is highly recommended to get best separation efficiency.

The aim of this review paper is to critically analyze the existing studies on waste electric and electronic equipment (WEEE), which is one of the most increasing solid waste streams. This complex solid waste stream has pushed many scientific communities to develop novel technologies with minimum ecological disturbance. Noteworthy amount of valuable metals makes e-waste to a core of "urban mining"; therefore, it warrants special attention. Present study is focused on all the basic conceptual knowledge of WEEE ranging from compositional analysis, global statistics of e-waste generation, and metallurgical processes applied for metals extraction from e-waste. This review critically analyses the existing studies to emphasize on the heterogeneity nature of e-waste, which has not been focused much in any of the existing review articles. Comprehensive analysis of conventional approaches such as pyrometallurgy and hydrometallurgy reveals that high costs and secondary pollution possibilities limit the industrial feasibilities of these processes. Therefore biohydrometallurgy, a green technology, has been attracting researchers to focus on this novel technique to implement it for metal extraction from WEEE. [ABSTRACT FROM AUTHOR]

This article discusses the main application fields of the Industry 4.0 concept at the Magnitogorsk Iron and Steel Company (MMK); this concept enables creating a unified information foundation for implementing a set of measures to optimize and improve the efficiency of individual units, workshops, industries, and the overall enterprise. For the blast furnace iron-making process, this concept involves the intellectualization of the process personnel's tasks, provision of solutions to modeling problems, process flow optimization, and implementation of decision-making support systems in production processes automation and control. Using the methodology of system research, the Ural Federal University (UrFU) and Magnitogorsk Iron and Steel Works (MMK) improved the model of the blast furnace process and significantly expanded its practical capabilities; they accomplished such an improvement by considering the thermal mode, gas-dynamic mode, blasting mode, slag mode, available information on the blast furnace operation, and the uneven distribution of materials and gases. Software development using contemporary digital technologies has resulted in the creation of an automated system for analyzing and forecasting blast furnace production situations in the MMK, and this enables solving a set of technological problems for the management of blast furnace smelting. [ABSTRACT FROM AUTHOR]

The pyrometallurgical technology of producing germanium concentrates from the raw materials taken from brown coal deposits (coal, mudstones, siltstones) is accompanied by the formation of silicate slag melts, which concentrate the mineral component of the raw materials (reaching 60% wt %). Obviously, the energy indicators of technology are substantially determined by the physicochemical properties of slag melts. These include electrical conductivity λ, which reflects the structure of silicate melts. The compositions of the slags from processing carbonaceous raw materials differ significantly from nonferrous and ferrous metallurgy slags: they contain high contents of SiO2 (up to 50–55%), Al2O3 (up to 20–22%), and K2O and Na2O (up to 5–6%). In addition, noticeable amounts of sulfide sulfur (up to 3%) and microimpurities of nonferrous metals and rare elements (up to 5%) are present in the slags. The differences between the compositions of the slag melts of germanium production and the slags of the general metallurgy affect their properties and require special-purpose studies. Industrial samples of cyclone melting and electric melting slags are studied. Semisynthetic samples prepared from industrial samples by adding SiO2 and CaO are used to determine the influence of the slag composition on λ. A standard compensation method is used to measure the resistance of the melt with an ac bridge at a frequency of 3.5 kHz. The cell consists of a melt in an alundum crucible with immersed molybdenum electrodes. The melt temperature range is 1100–1550°C. The values ​​of λ of the melts are found to be in the range from 0.01 to 0.30 S/cm and to depend substantially on the basicity (i.e., the ratio of the sum of the CaO and MgO contents to SiO2) and the Al2O3 content. The temperature dependences of λ are shown to be exponential. In the general case, λ of the melts under study is much higher than that characteristic of, e.g., blast-furnace melting at the same basicity. The results obtained are useful for predicting the structure of melts. [ABSTRACT FROM AUTHOR]

Considering that the low recovery efficiency and the massive loss of valuable metals by the traditional pyrometallurgical process smelting low‒nickel matte. Therefore, this paper focuses on studying the optimal process parameters and the mechanism of sulphation roasting followed by water leaching achieving efficient synchronous extraction of nickel (Ni), copper (Cu), and cobalt (Co) from low‒nickel matte with sodium sulfate as the sulfating addictive. Under optimal conditions, the recovery efficiency of Ni, Cu, and Co metals can achieve 95%, 99%, and 94%, respectively, whereas the recovery efficiency of Fe metal is less than 1%. The results revealed that the mechanism of the sulfating roasting pretreatment could form a liquidus eutectic compound sulfates [Na2Me(SO4)2] (Me = Ni, Cu, Co) at the solid–solid interface, which plays a significant role in promoting the leaching efficiency of valuable metals. Not only enhance the reaction kinetics of sulfation, but improve the utilization efficiency of SO2/SO3. Thus, the sulfation roasting‒water leaching process developing an efficient and eco-friendly pathway to simultaneous extraction of Ni, Cu, and Co valuable metals from low grade sulfide ores. [ABSTRACT FROM AUTHOR]

Copper slag is a by-product waste during copper pyrometallurgy. The piling-stack of copper slag not only occupies a large quantity of plowland, but causes potential danger for local residents. In order to reduce the storage of copper slag, this study prepared concretes by replacing ordinary cement by copper slag. The mechanical properties, phase composition, micrographs, pozzolanic activity and volume stability of the compound cementitious materials were evaluated with fly ash as control. It was found that when the content of copper slag was 5% - 10%, the best mechanical properties of concretes were obtained. The phase composition of hydration products of copper slag and fly ash based cementitious materials was similar. The micrographs and pozzolanic activity showed that copper slag had stronger reactivity than fly ash. Copper slag based pastes had good volume stability. Copper slag presented a potential application in mortars and concretes. [ABSTRACT FROM AUTHOR]