Copper Metallurgy Research Articles (Page 1)

The development of copper metallurgy in ancient Mongolia: The current state of knowledge

Abstract The Ganga‐Yamuna Valley in India has long been a site of archaeological significance, with numerous ancient copper hoards discovered over the years. These copper hoards have been the subject of intense study, as they offer a unique window into the metallurgical practices and trade networks of the region's past civilizations. The study was designed using recent advanced techniques EDXRF, FESEM‐EDAX, and ICP‐MS, including computed tomography scanning, to explore the copper metallurgy, casting technology, alloy composition, and the types of ores used in the creation material of excavated ancient copper hoards. The results of the present study denote that the studied copper hoard of the Ganeshpur assemblage was manufactured with pure copper (up to 98%) with the presence of Pb, Si, Co, Ni, and Fe as trace elements, and Ca, Cr, Al, Sn, and Au were reported as traceable impurities. The higher values of oxygen in SEM results are noticed in the microstructures and the formation of copper (I) oxide (Cuprite, Cu2O), and the higher value of carbon is also identified as malachite as green patina on the corroded portion. Trace elements analysis indicate that cuprite was smelted from raw ores containing copper, iron, and sulphite. The lost wax casting method (Cire Purdue Technology) was used for the casting of the objects in the ancient period, which were supported by the results of noninvasive medical Computed Tomography. As per correlation with archaeological references, previous excavations, and the results of the present study, these copper hoards of the Ganeshpur assemblage of the Ganga‐Yamuna River valley may also be contemporary with the OCP period.

Steel is one of the most manufactured materials (about 2 billion metric tons annually) and accounts for approximately 7% of global CO2 emissions. The general approach to steelmaking requires refinement of mined iron ore to metallic iron (ironmaking) which is then combined with other elements to make steel (steelmaking). As steel is primarily composed of iron, the ironmaking step in conventional steelmaking (via the blast furnace (BF) – basic oxygen furnace (BOF) route) accounts for 90% of CO2 emissions associated with steel production. An alternative to the BF-BOF steelmaking route is electric arc furnace (EAF) steelmaking and is the primary method for steel manufacturing in the US. The EAF utilizes electricity instead of carbon-based fuels, producing new steel by recycling scrap steel and fresh ore-based metallic (OBM) iron. Depending on the source of the OBM, CO2 emissions from EAF steelmaking can be as low as 0.3 tons of CO2 per ton of steel produced (compared to 2.2 tons of CO2 per ton of steel in traditional BF-BOF steelmaking) [1]. However, most OBMs are still produced via carbon intensive processes and can contribute up to an additional 0.8 tons of CO2 per ton of steel [1]. Even for EAF steelmaking, technology that supports low-emission ironmaking is necessary to fully decarbonize the steel industry.To address the high emissions associated with traditional ironmaking, Electra has developed a low temperature (≈ 60 C) electrochemical + hydrometallurgical ironmaking process to refine iron ores into > 99% pure iron metal using renewable energy [2]. This acidic electrolysis process is similar to conventional electrowinning (EW) methods for copper and zinc refining. By dissolving iron ore in acid, conventional and scalable hydrometallurgical processes are employed to remove impurities that are detrimental to iron electrodeposition and produce a Fe2+ electrolyte stream that feeds the EW step in Electra’s 2-step electrochemical process [2, 3]. Like conventional Zn and Cu EW processes, the iron metal electrodeposited on cathodes in the EW cell must be periodically removed and harvested [4-5]. In most EW industries, the cathode material is either a “starter sheet”, which is a thin, high purity cathode of the same material as the electrowon metal or a reusable cathode material that is stable in the electrolyte (such as stainless steel or aluminum). In the former, the entire cathode is harvested for production whereas in the latter the electrowon metal needs to be stripped from the reusable cathode. For reusable cathodes, a careful balance between iron adhesion and removability is critical: the deposit must adhere well enough to the cathode such that it does not delaminate prior to the desired harvest time but also be able to be removed by traditional EW stripping methods [6].To help inform process setpoints and design for iron removal at a ≈ 1m2 EW cell form-factor, Electra is utilizing well-known methods (i.e., bent-strip, ring-shear, etc. [7]) and developing in-house techniques to characterize and study factors affecting adhesion such as (1) interfacial bonding between the substrate and deposit, (2) internal stresses, and (3) fracture mechanisms that result in failure. For substrate-deposit interfacial bonding, Electra has developed a “pull off test” that evaluates the practical adhesion of deposited iron at a range of process conditions. This technique involves bonding a dolly to the plated surface and pulling that dolly in tension until the iron deposit is removed from the substrate. The force needed to remove the deposit is related to the adhesive tensile strength between the deposit and cathode. This presentation will detail method development for the technique and how different process conditions for electrowinning such as electrolyte composition, temperature, current density, cathode material/finish, etc. influence iron adhesive strength and draw correlations from these measurements to iron adhesion and removability in Electra’s electrowinning cells. References “Iron and Steel Technology Roadmap,” IEA, Paris, License: CC BY 4.0 (2020).Pham, et al. (2022) 2-Step Iron Conversion System. US Patent Office No. US11767604B2.Braun, et al., Electrochem. Soc. Interface, 33 38 (2024).K. Biswas, et al., Extractive Metallurgy of Copper, p. 401-412, Elsevier Science Inc, Tarrytown, NY (2020).J. Sinclair, The Extractive Metallurgy of Zinc, p. 113-130, The Australasian Institute of Mining and Metallurgy, Victoria, Australis (2005).Weston, et al., The link between operational practice and maximizing the life of stainless steel electrodes in electrowinning and electrorefining applications, Cobre 2003, the 5th international conference, Santiago Chile, Dec 2003.W. Dini, Electrodeposition – the materials science of coatings and substrates, p. 46, Noyes Publications, Park Ridge, NJ (1993).

Deep eutectic solvents (DESs) have garnered as promising alternatives to conventional solvents for metal extraction due to their facile synthesis, high chloride concentration, non-aqueous nature, and low cost. This work explores a green route for ultrafast extraction of atacamite [Cu2Cl(OH)3] from a deep eutectic solvent at room temperature in a short time using copper (II) sulfate pentahydrate as a precursor. The phase, chemical, morphological, and structural properties of the extracted atacamite were investigated using XRD, Rietveld method, SEM-EDX, and FTIR techniques. As a result of XRD analysis, it was determined that the atacamite with an average diameter of 85.59 µm has an orthorhombic crystal structure. Also, it was determined that the crystal structure parameters obtained from XRD and the theoretical calculations of these values were in good agreement according to the Rietveld refinement. SEM/EDX analysis showed that the extracted atacamite particles exhibited heterogeneity in terms of size and morphology, while elemental composition was found to be homogeneous throughout the particles. UV-Vis analysis and theoretical calculations, the optical band of atacamite particles was found as 2.72 eV. Also, this study demonstrates that the hydrolysis method can serve as an efficient, low-energy pathway for the recovery of metals from DESs, highlighting its potential as a novel approach in copper metallurgy.

Research on energy efficiency and carbon efficiency evaluation for copper metallurgy based on data envelopment analysis

The present paper explores the relevance of ethnographic data on ritual metallurgy for the understanding of the intersection of ritual and technology in prehistoric metallurgy. Focusing on sub-Saharan Africa, the paper details ritual practices surrounding iron smelting, including gendered roles, the use of ?medicines?, and accompanying rituals and taboos. The case study of Chalcolithic copper metallurgy in the Southern Levant is compared to patterns of social articulation of African metallurgy, and it is concluded that the ?Transformer pattern?, where technological and ritual roles of the metalworkers are most intertwined, was found to be the most relevant for extractive metallurgy. The study concludes that while direct analogies between ethnographic and archaeological data should be avoided, ethnographic research provides valuable insights into various ways in which prehistoric metalworking could be socially and ritually articulated.

Abstract This study aims to investigate ancient Indian copper metallurgy based on selected copper artifacts recovered from India. The collected objects belong to the period c. 1200 BCE to 400 CE. The paper discusses the analysis of seven artifacts from two archaeological sites (Agiabir and Raipura) around the Varanasi region in Northern India. The study explores the manufacturing techniques and alloying practices applied to the artifacts by analyzing the excavated objects using optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray fluorescence spectroscopy. The microstructure of the artifacts revealed the practice of annealing, casting, and forging. Elemental analysis of these objects shows that most of the artifacts are copper–tin alloys, having varying amounts of tin. This study indicates that the tin amount has been varied according to the object's functionality.

This article examines the copper smelting complex as a control object, and provides a technological diagram of the relationship between the tasks of managing the complex. Substantial formulations of control problems for individual stages of the metallurgical complex have been formulated. As an example of a specific control problem, the mathematical formulation of the problem of optimal charge preparation and the method for solving it are considered. In recent years, the development of copper metallurgy is characterized by an increase in the use of raw materials, the use of oxygen, and automated controlled processes for charging and smelting copper concentrates. The creation of automated process control systems is one of the important areas of development of non-ferrous metallurgy. Non-ferrous metallurgy is one of the major sectors of the national economy. Management in general and management of metallurgical production in particular is an informational process in nature that ensures the implementation of the material process, subject to the achievement of the pre-formulated goal of the functioning of the production management system.

The Cu-Fe-Ni-S system is unique in terms of the number of crystalline phases with a variety of combinations of properties, which makes it relevant for prospective material studies. The phases of this system compose typical associations of massive zonal sulfide Cu-Ni ores, and their copper-rich zones are characterized by a high content of noble metals. Therefore, this system is among the most important of those used for the geochemistry of sulfides and for the metallurgy of copper and nickel. There is insufficient quantitative information on the equilibrium distribution coefficients of macrocomponents and the behavior of impurities upon crystallization of solid solutions in the region of the solid-melting diagram corresponding to natural ores or intermediate products of metallurgical production. Therefore, the goal of the work was to obtain new data on the phase diagram of the Cu-Fe-Ni-S system and corresponding phases of noble metals (Rh, Ru, Ir, Pt, Pd, Ag, Au) during the process of fractional crystallization of the melt simulating zonal copper-rich ores of platinum-copper-nickel sulfide deposits. We conducted quasi-equilibrium directional crystallization of the melt with a composition of (at. %): Fe 29.20, Ni 5.85, Cu 17.60, S 47 with addition of 0.05% of Rh, Ru, Ir, Pt, Pd, Ag, and Au. The obtained sample was studied using optical and scanning electron microscopy, energy-dispersive spectrometry (SEM/EDS), and X-ray phase analysis. Differential thermal analysis (DTA) was used to determine the liquidus temperatures along the crystallization path. The distribution of macrocomponents along the cylindrical ingot showed that it consisted of five primary zones. Primary phases and phase associations crystallized from the melt in the following sequence: mss / mss + iss / iss / iss + bnss / bnss + pnss, where mss is monosulfide solid solution (FexNi1-x)S1±y, iss is intermediate solid solution (Cu,Fe)S1-x, bnss is bornite solid solution Cu5±xFe1±xS4±y, and pnss is pentlandite solid solution (FexNi1–x)9±yS8. This indicated a complex structure of the solid-melting diagram in the studied region. We determined the crystallization temperatures of mss and iss. A new type of secondary (phase) zoning was identified, formed as a result of subsolidus transformations of primary phases, which can be present in Cu-Ni sulfide ores. It was found that impurities can dissolve in the main sulfide phases, form individual microphases in the sulfide matrix, or be present in these microphases in the form of solid solutions. The main concentrators of Pd were pn and sug. Ir, Rh, and Ru were distributed between mss and pn, and Ag preferred bnss. Most impurities of noble metals formed inclusions as independent microphases: RuS2, Pt3Fe, Au* gold-based alloy, Pt-Fe-Au alloy, CuIr2S4, and native Ag. The results of the work showed that the behavior of macrocomponents could be described using distribution coefficients, and the behavior of microcomponents did not strictly correspond to the classical theory of fractional crystallization of multicomponent melts with impurities

High-value terminal treatment: Utilizing copper slag heat in the manufacture of copper-containing weathering steel

More resource efficient recycling of copper and copper alloys by using X-ray fluorescence sorting systems: An investigation on the metallic fraction of mixed foundry residues.

An environmentally benign process for effective recovery and solidification of Cr from stainless-steel slag

Abstract Relative to the centuries preceding and following it, the tenth century a.d. in Mesoamerica is poorly understood by scholars. Although there is some regional variation in the timing of these events, archaeologists commonly ascribe a pattern of political decline, dynastic collapse, or social reorganization to this period. Paradoxically, increasing interregional interactions and emergent market exchange networks are also characteristics of macroregional patterns during the tenth century. These contradictory phenomena contribute to confusion surrounding interpretations of this transitional time. This article contributes a comparative dataset from systematic archaeological investigations of El Coyote, a monumental center in the lower Cacaulapa valley, Department of Santa Barbara, Honduras. The late occupational phase contains evidence for Early Postclassic chronological markers, including Tohil Plumbate pottery; obsidian from Pachuca, Hidalgo; and copper metallurgy. Calibrated radiocarbon assays with a 2σ error place these contexts between a.d. 710 and 1040, with a clustering of intercepts circa a.d. 900. These results are consistent with a pattern described throughout Mesoamerica and demonstrate that despite variation in the use of cultural terminology—Epiclassic, Terminal Classic, or Early Postclassic—there is uniformity in the timing of this macroregional interaction.

Shahdad is located on the western side of the great “Lut” desert in the south-central Iranian Plateau. Shahdad has been a major focus of archaeological research in the region due to extensive metallurgical activities, which were documented at the site and supposedly have the most abundant remains of copper metallurgy in southeastern Iran during the Bronze Age (3rd millennium BC). Due to the archaeological studies of the vast peripheral area, the settlement was a permanently occupied city during the 3rd millennium BC. New excavations at Shahdad offer a unique opportunity to reconsider the pyro-technological remains which were probably related to metallurgical practices during this era. This research will focus on the characterization of typical Shahdad pottery styles and remains of metallurgical slags scattered across the area in association with amounts of other metallurgical remains such as copper ores, moulds, crucibles, furnaces and metallic residues. The typical characteristic style of pottery are their dense structure heavy with rough fabrication. The objects have been studied through optical microscopy, ICP-MS, and XRF to determine their chemistry, micro-chemistry, and mineralogy. The evident complexity of pottery production at Shahdad may eventually allow a better understanding of the timing of innovations and/or the adaptation of technological features observed in the overburden of Shahdad that as yet have not been scientifically documented. The scientific examination of slags and pottery sherds presented here recognizes new information regarding the microchemistry and production techniques of pottery and their possible potential application for metallurgical purposes.

The aim of the article is to formulate a hypothesis explaining the chronology and genesis of the Lublin-Volhynian Culture, with particular emphasis on such important elements of this culture as the white painting of pottery, the use of trough retouch, and the deposition of flint daggers retouched in this way in the graves of some men. At the same time, two different Eneolithisation processes are reconstructed: from the east (with flint daggers) and from the south-west (with copper metallurgy). It has been pointed out that adaptation of the cultural elements mentioned above must have taken place no later than 4100 BC. The most likely place where this happened was the basin of the upper Styr and Horyn in Volhynia. From about 4400 BC, the area was inhabited by representatives of the late phase of the Malice Culture. This community exploited local deposits of excellent-quality Volhynian flint and supplied it to the population of the Tiszapolgár Culture on the upper Tisza and Bodrog rivers. Processes fuelling cultural heterogeneity were taking place in Volhynia. In some grave complexes, there are elements of the Malice, Trypillia, and Polgar cultures. Heterogenisation and cultural hybridisation fostered the emergence of new cultural units. The emergence of the Lublin-Volhynian Culture was impacted decisively by the Skelya Culture, which instilled among the late-Malice people the ideas of hierarchisation of local communities and the rise of the elites (a group of male warriors, distinguished by the possession of blade-daggers).

Abstract Unalloyed copper objects were produced in the Chalcolithic Southern Levant in a two‐step process. Copper ore was smelted in pit furnaces, and the mechanically extracted copper prills melt in crucibles and cast into objects. However, the air supply remained unknown, and practical considerations shed doubt on the validity of some of the reconstructed practices. To refine the reconstruction, the metallurgical material from Abu Matar was reassessed. Most importantly, several previously unreported fragments suggest the use of bellows and covering the furnace with large pottery fragments. Our results provide probably the earliest evidence for the use of bellows.

Abstract The spread of innovations is an important driver for transformation processes in human societies. It is carried by two crucial conditions – the flow of information and the adoption/appropriation of the innovation. While the latter is a social and cultural process, the first is among others carried by mobility. Mobility in this context can take on different forms and range from migration events up to small-scale everyday mobility between neighbours. In this article, the transmission of ideas and technology without major migration events will be treated. This is based on two case studies – the spread of agriculture from Central Europe to South Scandinavia and the spread of copper metallurgy from Southeast to Central Europe. For both, the spatio-temporal spread of the innovation will be described and factors influencing the information flow and the process of adoption will be taken into account. This will help to develop a more detailed understanding concerning the transmission of ideas and technology without major migration events and allows us to follow the question of what roles did mobility and other factors play in it.

In Part II of this series of review papers, the reaction mechanisms, thermodynamics, slag chemistry and process flowsheets are analyzed concerning cases where the TSL bath smelter has found its application. These include the primary and secondary production routes of five non-ferrous metals (tin, copper, lead, nickel, zinc), ironmaking and two waste-processing applications (spent pot lining and municipal solid waste/related ash treatment). Thereby, chemistry and processing aspects of these processes are concisely reviewed here, allowing for clear and in-depth overview of related aspects. In contrast to Part I, the focus lies on a holistic analysis of the metallurgical processes themselves, especially the particularities induced by carrying them out in a TSL reactor rather than on the respective equipment and auxiliaries. The methodology employed per metal/application is presented briefly. Firstly, the feed type and associated statistical information are introduced, along with relevant process goals, e.g., the secondary metallurgy of copper involves the recovery of platinum group metals (PGMs) from waste from electrical and electronic equipment (WEEE). Subsequently, associated chemistry is discussed, including respective chemical equations, analysis of the reaction mechanisms and phase diagrams (especially of associated slag systems); these are redrawn using FactSage 8.1 (databases used: FactPS, FToxid, FTmisc, FTsalt and FTOxCN) and validated by comparing them with the literature. Then, based on the above understanding of chemistry and thermodynamics, the flowsheets of several industrial TSL plants are introduced and discussed while providing key figures associated with process conditions and input/output streams. Finally, this article culminates by providing a concise overview of the simulation and digitization efforts on TSL technology. In light of the foregoing discourse, this paper encapsulates basic principles and operational details, specifically those pertaining to TSL bath smelting operations within the non-ferrous industry, thereby offering valuable insights intended to benefit both scholarly researchers and industry professionals.

Seawater has become a viable alternative for different uses in copper hydrometallurgy. In this paper we review the main physical and chemical characteristics of seawater and how these influence copper production. Reliable data on the use of continental water are reported, and the current use and consumption of seawater in the Chilean mining industry is analysed, indicating the main areas of use and the main problems encountered. Additionally, the influence of the elements in seawaterthat have the most influence on the extractive metallurgy of copper are considered. The Chilean copper mining industry currently consumes approximately 4.1 m3/s of seawater, which corresponds to 25% of the total water used. The use of seawater for the leaching of copper sulphide minerals, such as chalcopyrite, is beneficial because it provides 20 g/L of chloride, thereby improving copper dissolution kinetics.

The problem of the beginning of iron production in the Late Bronze Age of the Ural-Kazakhstan region is dis-cussed. For this, 13 iron-bearing artefacts from nine settlements that functioned in the 2nd mil. BC were studied using the SEM-EDS and LA-ICP-MS methods: metal objects, metallurgical slags, and a bimetallic droplet. Most of the studied artefacts are not related to the iron metallurgy. High ferric impurities in copper metal products of the Late Bronze Age on the territory of the Southern Trans-Urals are caused by the use of iron-rich ore concentrates. The raw materials for these products were represented by mixed oxidized-sulphide ores from the cementation subzone of the volcanogenic massive sulphide and skarn copper deposits. Iron droplets, frequently found in the Late Bronze Age copper slag in the Ural-Kazakhstan region, are not directly related to iron metallurgy. They are by-products of the copper metallurgy formed in the process of copper extraction from the iron-rich components of the furnace charge or fluxes (brown iron ore, iron sulphides). The only artefacts that indicate direct smelting of metal from iron ore are the slag fragments from the Kent settlement. Presumably, oxidized martitized ore of the Kentobe skarn deposit or its nearby analogues was used to extract iron at the Kent settlement. Rare finds of iron slags from the Late Bronze Age, known only in the territory of Central Kazakhstan, confirm an extremely small scale of iron production. Iron ore had been already deliberately used for these experiments. However, iron metal-lurgy in the Ural-Kazakhstan region developed into a mature industry much later. The discovery of iron metallurgy based on the smelting of copper-sulphide ores in the Ural-Kazakhstan steppes is doubtful. The use of sulphide ores here is known from the 20th c. BC, and it was widespread. In the meantime, the first iron slags and products appear much later, and their finds are sporadic. The development of iron metallurgy on the basis of experiments with iron ores seems more likely.