Copper Ingots Research Articles

Digital foundry production: modeling systems, personnel training, digitization stages.

The article describes modern digital solutions for production automation, simulation of production processes in order to optimize technology, eliminate defects, improve manufacturability of products, reduce production costs, as well as the company's services in the implementation of calculation projects and training, including reverse engineering of products, opportunities for advanced training. As an example of the implemented calculation is presented the work on optimization of the design of mold used for casting copper ingots in order to improve the durability of equipment; simulation of cyclic thermal heating of mold taking into account stress-strain state and fatigue criterion was performed in the software ProCAST. An example of automatic optimization of the design of feeding system for cast iron casting “pump body” using ProCAST and pSeven packages is also presented. The optimization package performed the rebuilding of 3D model in CAD-system with the change of height and diameter of feeder, calculated the case of filling the mold and solidification of the casting taking into account the changed geometry in the calculation CAE package and evaluated the obtained values of porosity in the casting and yield to find the optimal size of feeder

Constellations of practice in copper ingots from Zambia and northern Zimbabwe, cal. AD 500–1700

ABSTRACT Rectangular, fishtail and croisette copper ingots have been found in many locations in Central and southern Africa where excavated samples date to between the fifth and eighteenth centuries cal. AD. For more than fifty years, scholars have debated whether these ingots were all made in the Central African Copperbelt, where there are many finds of matching moulds, or if moulds found in Zimbabwe show that copies were produced locally. Lead isotopic and chemical analyses have recently confirmed that the Copperbelt supplied copper ingots to both southern Congo-Kinshasa and the Zimbabwe Plateau between the ninth and eighteenth centuries, but that one HXR ingot can tentatively be sourced to the Magondi Belt copper deposits in northern Zimbabwe. We expand this discussion here by linking ingot chemistry and isotopic provenance with distribution patterns and ingot morphologies. The combined evidence suggests that groups making Luangwa Tradition pottery were responsible for transporting HIH and HXR ingots, and the technological styles for making them, far to the south of the Copperbelt. These croisette ingots link constellations of practice in the Copperbelt and Zimbabwe, possibly through the movement of specialised traders and metalworkers. We identify some of the individuals buried at Ingombe Ilede and Chumnungwa as possible examples of these specialists.

Reconstructing the geological provenance and long-distance movement of rectangular, fishtail, and croisette copper ingots in Iron Age Zambia and Zimbabwe.

The southern third of Africa is unusually rich in copper ore deposits. These were exploited by precolonial populations to manufacture wound-wire bangles, other forms of jewelry, and large copper ingots that were used as stores of copper or as forms of prestige. Rectangular, fishtail, and croisette ingots dating between the 5th and 20th centuries CE have been found in many locations in the Democratic Republic of the Congo (DRC), Zambia, and Zimbabwe, with isolated finds in Malawi and Mozambique. Molds for casting these ingots have been found mostly in the Central African Copperbelt, but also around the Magondi Belt copper deposits in northern Zimbabwe. For years, scholars have debated whether these ingots were exclusively made in the Copperbelt or if the molds found in Zimbabwe indicate that local copies were produced from Magondi Belt copper ore (Garlake 1970; Bisson 1976). Before the recent application of lead isotopic and chemical methods to provenance copper in central and southern Africa, there was no way to discern between these hypotheses. Rademakers et al. (2019) and Stephens et al. (2020) showed that copper artifacts from southern DRC (mostly from Upemba) and from northwestern Botswana (Tsodilo Hills) match the lead isotope ratios of ores from the Copperbelt. Building upon these previous studies, we present here the first results from a copper provenance project across the southern third of Africa, from the Copperbelt to northern South Africa. We apply lead isotopic analysis (LIA) and chemical analyses to establish the provenance of 29 croisette ingots recovered in Zimbabwe, 2 fishtail and 1 rectangular ingot recovered from sites in Zambia, and an "X" shaped ingot smelted in an experiment in Zambia in the 1970's. Our chemistry and lead isotopic results indicate that 16 of these objects were smelted with copper from the Copperbelt, 16 objects source more specifically to the Kipushi deposit within this geological district, and only one HXR ingot sources to the Magondi Belt in Zimbabwe. Taken together, we clearly illustrate that croisette ingots were traveling significant distances to reach their eventual sites of deposition, and that there was also local production of these objects in Zimbabwe.

A Metal Production Center on the Southwest Frontier of the Han Empire: An Archaeometallurgical Study of the Heimajing Cemetery Site in Gejiu, Yunnan Province, China

The Gejiu region in southeast Yunnan Province was an important metal and ore production area in China as early as the Han Dynasty (202 b.c.–a.d. 220). Past archaeological investigations in this region discovered an ancient smelting site. Large numbers of smelting-related relics including lead discs, copper ingots, and smelting wastes were also excavated from the Heimajing cemetery site nearby. These discoveries suggest that the burial occupants were probably involved in ancient mining, metal smelting, and the metal production industry. An archaeometallurgical analysis of smelting-related relics was conducted. The results demonstrated that lead, copper, and different copper-base alloys were produced in the region. The chemical compositional analysis and lead isotope studies of the samples collected from the Heimajing cemetery site suggest that there was probably a production and supply system and a demand for copper-base products in the Dian Kingdom (now central Yunnan) and Jiaozhi Commandery (now northern Vietnam) through cross-regional resource allocation. The Gejiu region therefore might have had a complete industry chain on the southwest frontier of the Han Empire.

Deposition of Base Ore and Alloy Elements in the Bronze Age Metal in the Trans-Urals

The paper studies the problems of the geochemical specialization of the Bronze Age metal items from the eastern flank of the Ural mining and metallurgical province produced at the end of the third millennium BC — the middle of the second millennium BC in the Abashevo, Sintashta, Koptyakov-Seimino and the Alakul centers. The metal geochemical markers determination was performed by means of a local quantitative chemical composition analysis of 101 solid samples with an electron X-ray microanalyzer. The selection consisted of a representative series of copper and bronze items corresponding to various stages of metallurgical conversion process from the classic archaeological sites of the Trans-Urals. Systematization of the analytical data on the chemistry of items from each metal production center made it possible to identify stable compositions of micro-impurities associated with the base ores and alloys. The Abashevo and the Sintashta culture metal demonstrated a stable correlation of excess arsenic and nickel concentrations, which was partly due to the use of the Trans-Urals ores with a high content of these elements, however, the most significant concentration of arsenic (from 2 to 5 %) was observed in the finished items rather than in refined copper ingots or semi-finished products, which may indicate intentional alloying. Tin alloys in the Sintashta culture were quite rare; they demonstrated the same chemistry as the Seimin-Turbino metallurgical traditions. Large-scale use of tin for refined copper alloying was observed only in the Koptyakov-Seimino and the Alakul series. The Alakul series contained some high-tin alloying compositions close to the ideal tin bronzes (18 % Sn). It is possible that the sources of tin for them were the Kazakhstan and the Central Asia deposits. The only impurity integrating the entire ancient metal series, according to microprobe analysis, was sulfur, due to the sulfide feed stock. Sulfur was deposited in blister from the high-copper (above 20 % Cu) sulfide-silica-carbonate mineral blends that met the Bronze Age metal production criteria. The sources of raw materials were associated with the secondary sulfides of the ophiolite deposits hypergenesis zones in the Trans-Urals.

Archaeometallurgical characterization of Mediterranean discoidal shaped copper alloy ingots retrieved from sea environment

Five copper ingots from the National Archaeological Museum of Aquileia (NAMA nos. 2, 3, 4, 7, 8) and four copper ingots from the National Archaeological Museum of the Sea (NAMS nos. 1, 2, 3, 4), retrieved from a sea environment, were the subject of the current study. The aim of this research is to apply a metallurgical approach in order to add further information about these objects, including their composition, microstructure, manufacturing process, and if possible, their origin. Samples were examined by a variety of testing methods, including visual testing, XRF analysis, metallographic examination, digital 3D multi-focal light microscope observation, SEM-EDS analysis, and lead isotope measurements (LIA). Cast defects were observed on both sides of the NAMA and NAMS ingots. Metallographic examination of the ingots from both collections revealed a dendritic microstructure typical to as-cast products. All ingots have a slight step on one side, probably resulting from plastic deformation, perhaps developed as a result of lifting them with a wrecking bar tool. Both the NAMA and NAMS ingots were made of copper with a small percentage of lead, yet their general composition was different. The better preservation of the NAMS ingots may probably result from the 0.1–0.5 wt% zinc content according to the XRF results. The inclusions observed in the NAMA ingots included Cu, Pb, O, Cl, As, Sb and Sn, while the inclusions observed in the NAMS ingots included Cu, Pb, O, Cl, Fe and a high content of sulphur (up to 21.9 wt% S). Based on their dissimilar bulk composition, the NAMA and NAMS ingots were most likely manufactured in different workshops and from dissimilar ore sources. The lead isotope ratios measured on the NAMS no. 1 sample are compatible with Iberian deposits of the Ossa Morena zone, and they are consistent with the published data available on coeval wrecked ingots from the Western Mediterranean.

A royal wreck? Morpho-technological, elemental and lead isotope analysis of ingots from the Bang Kachai II shipwreck, Thailand

The Bang Kachai II wreck lies at 7–8 m depth in the Gulf of Thailand, just off the coast in the eastern Thai province of Chanthaburi. The ship, of which only the partial hull remains, probably sank in the early 17th century CE. It carried a cargo of ca. 20,000 billets, 10,000 kg, of sappanwood and, the focus of this paper, up to 3,000 kg of metal ingots. Sappanwood was an Ayutthaya state-controlled commodity, much prized abroad, China in particular, suggesting the vessel was possibly operating with Royal permission. Here we investigate the nature of the metal assemblage, to see if it supports or undermines this interpretation.Typo-technological analysis classified 195 copper ingots into four groups: layered bowl, bowl, plate, and irregular shape, but of non-standardised proportions. The five lead–tin alloy (pewter) ingots, on the other hand, share a single plano-convex shape. The ingots’ elemental compositions were likewise variable, with a majority in raw/black (sulphur content) copper but a substantial minority in leaded copper, of a range of alloy proportions, as well as bronze, leaded bronze, pewter and the intermetallic semi-product, matte. A representative group of 20 artefacts were sub-sampled for lead isotope analysis, the results of which separated into two main groups. The larger group, representing both leaded and unleaded alloys, does not correspond to any of the known Southeast Asian production signatures but does fall into the general field of regional consumption signatures. The smaller group corresponds to the five pewter ingots, and their LI signature is consistent with the Song Toh lead field, located ca. 200 km west of Ayutthaya.The copper’s physical and geochemical variability is not consistent with any known regional producers and thus their provenancing could not be resolved in this paper. However, this paper, based on sappanwood and lead-base ingots, opens new possibilities of copper being locally produced in Thailand, if not intra-regionally in Southeast Asia.

The Salcombe metal cargoes: New light on the provenance and circulation of tin and copper in Later Bronze Age Europe provided by trace elements and isotopes

Since the mid-1970s a Bronze Age assemblage of metal objects has been recovered from the seabed off the south Devon coast at Salcombe, southwest England. The assemblage spans two suspected shipwreck events and comprises nearly 400 pieces of raw materials and finished artefacts, primarily in copper, tin, bronze and gold. Among these are 280 copper and 40 tin ingots, by far the largest discovery of Bronze Age ingots in either metal from northwestern Europe. Research in recent years revealed the microstructural and chemical nature of the ingots and enabled some preliminary conclusions on the metals trade in Europe in the Later Bronze Age. The present study aims to extend this knowledge by determining the tin, copper and lead isotopic compositions of the ingots using HR-MC-ICP-MS. In addition, bronze artefacts (swords, rapiers, palstaves and weights) from the Salcombe site are included in the multi-proxy approach in order to investigate their history and the possible relationships between finished products and ingots. In combination with the available chemical data of previous studies, the current results of the tin metal show that most likely two tin sources in southwest Britain supplied the ore for their production. This also sheds light on Late Bronze Age tin ingots from Israel that share the same geochemical characteristics with one group of the finds from Salcombe. Although the tin in the bronzes is similar to the tin in the ingots, it is not certain that the latter were used to make the bronzes. Correlations of copper and tin isotopes and trace elements of the bronzes point to a mixing or even recycling of copper-tin alloys rather than the alloying of individual components of copper and tin. However, the copper ingots from the assemblage could have been an additional component in the mixing process given their impurity pattern and isotopic composition. At the same time, a close relationship between swords of the Rosnoën type and palstaves from the cargo is disclosed. Lead isotope ratios for their part suggest Sardinian and/or south Spanish copper ores as a source for both the copper ingots and the copper of the bronzes. This would mean long-distance metal trade in the Later Bronze Age in both cases and would provide new insights into the interpretation of the prehistoric networks in Europe.

A Metal Production Center on the Southwest Frontier of the Han Empire: An Archaeometallurgical Study of the Heimajing Cemetery Site in Gejiu, Yunnan Province, China

The Gejiu region in southeast Yunnan Province was an important metal and ore production area in China as early as the Han Dynasty (202 B.C. – A.D. 220). Past archaeological investigations in this region discovered an ancient smelting site. Large numbers of smelting-related relics including lead discs, copper ingots, and smelting wastes were also excavated from the Heimajing cemetery site nearby. These discoveries suggest that the burial occupants were probably involved in ancient mining, metal smelting, and the metal production industry. An archaeometallurgical analysis of smelting-related relics was conducted. The results demonstrated that lead, copper, and different copper-base alloys were produced in the region. The chemical compositional analysis and lead isotope studies of the samples collected from the Heimajing cemetery site suggest that there was probably a production and supply system and a demand for copper-base products in the Dian Kingdom (now central Yunnan) and Jiaozhi commandery (now northern Vietnam) through cross-regional resource allocation. The Gejiu region therefore might have had a complete industry chain on the southwest frontier of the Han Empire.

Shipping metal: Characterisation and provenance study of the copper ingots from the Rochelongue underwater site (Seventh–Sixth century BC), West Languedoc, France

The copper ingots from the underwater site off Rochelongue, near Cap d’Agde, on the coast of West Languedoc, offer an exciting means to investigate coastal mobility and cultural interaction between southern France and the broader western Mediterranean basin in the Early Iron Age. This paper presents the results of elemental and lead isotope analyses of a selection of copper ingots from the Rochelongue site, along with several ingots from the Iberian Peninsula, and for the first time demonstrates that their composition is consistent with Iberian and Alpine metalliferous mineral sources, and possibly some Mediterranean sources as well. The Rochelongue site also speaks to the likely role of indigenous societies of Languedoc in the movement of metals between Atlantic, Continental and Mediterranean circuits. The Rochelongue ingot metal thus provides a window into expansive networks of trade contacts that must be evaluated alongside typological and cultural data.

Reißscheiben from shipwrecks as an indicator for copper qualities produced in the major middle and North European mining districts during the late medieval and early modern period 15th–17th Century AD

Major advances in maritime archaeology in the last 20 years resulted in the discovery of several shipwrecks carrying copper slab ingots, so-called Reißscheiben. With the interest in early modern metal trade growing, geochemical analysis of these raw copper ingots represents invaluable merit for understanding the various qualities produced in the major mining regions in Europe. Here, we present ICP-MS trace elemental and lead isotope data for 52 Reißscheiben ingots salvaged at three different findspots in northern European waters dating to the 15th and 16th century. Our results reveal the Reißscheiben to originate from two different mining centres, Slovakia and the southern Harz foreland. Copper produced in these regions shows significantly different trace elemental patterns probably affected by both different kinds of copper ores used and smelting processes applied. The analytical results reveal the difficulties that early modern copper smelters may have had to deal with when processing sulfidic copper ores, as it seems that refining processes were not understood sufficiently. On the other hand, the written historical sources suggest that early modern brass makers already had a proper understanding of which regions produced the most suitable copper qualities. This paper underlines the potential of using geochemical characterisation of early modern period metals for solving historical questions.

On the investigation of reuse potential of SnPb-solder affected copper subjected to work-hardening and thermal ageing

The reuse potential of SnPb-solder affected old/waste copper is investigated under the influence of work hardening and thermal treatments. In fact, the urge of using old copper to manufacture new components necessitates useful characterization of various properties to explore its reuse potential. In this context, a number of physico-mechanical properties of interest, namely, hardness, conductivity, thermal stability, structure, etc. are chosen here to characterize the solder-affected copper materials as well as analyze their possible changes/improvements under the influence of work-hardening and thermal treatments. Since the old/waste copper usually contains little amount of lead and tin, three additional sample materials, such as, copper ingots, copper‑tin alloy, and copper‑lead alloy are taken into consideration to ascertain the influence of individual solder elements on the properties of the copper alloy. It is observed that addition of trace amount of tin and lead can significantly influence micro-hardness, conductivity, thermal capacity, etc. Micro-hardness values of all four sample materials have been found to be increasing in curvilinear pattern with the rise of cold-rolling level up to 50– 55% and then get flatten, and cold-rolled work-hardening level of ~35% is found to be a critical deformation level where the hardness of CuPb alloy supersedes pure Cu and Cu-Sn-Pb alloy supersedes CuSn alloy. Electrical conductivity of Cu falls drastically with the addition of only about 1% Sn or 1% Pb, which increases little initially after cold-rolled deformation up to ~35% and start falling again with the rise of deformation levels. Shifting of endothermic peak has occurred and thereby recrystallization temperature of Cu is transformed as an effect of alloying due to inclusion of SnPb-solder in Cu as well as work hardening. Micrographs have confirmed the structural changes responsible for the variation of electro-mechanical properties.

Copper from banks of the Volkhov River

This paper presents the results of an experiment for smelting of copper from the ore revealed in the riv- erside limestone deposits on the Volkhov River. This experiment has demonstrated the ease of processing the Volkhov ore, while investigations of the chemical composition (microprobing, ICP-MS) showed the high purity of the smelted metal. These investigations were carried out in order to identify the traces of the use of local ore in mediaeval metalworking. Copper ingots found during excavations at Zemlyanoye Gorodishche in Staraya Ladoga were used for comparison

Metallic Fuel Fabrication Process Development in Remote Fuel Fabrication Mock-Up at KAERI

This paper presents a remote testbed for metallic fuel fabrication using surrogates or depleted uranium. The testbed named “remote fuel fabrication mock-up (RFFM)” was created at the Korea Atomic Energy Research Institute and specifically designed to incorporate remote operation and maintenance. The subsystems of the RFFM are described, and test results regarding remotely conducted metallic fuel slug fabrication at the RFFM are also presented. After fabricating fuel slugs using copper ingots, their specifications and properties were analyzed and evaluated using chemical analysis, radiographic tests, and diameter and weight measurements. Analysis results showed that the fabricated metallic fuel slugs have an acceptance rate of more than 90% and a casting ratio (ratio of weight of injected metal to charged metal) of more than 0.7. Moreover, operations involving remote handling of in-cell equipment were also satisfactory.

Tracking Alpine copper—analysis of Late Bronze Age copper ingot hoard from South Bohemia

We present the results of a complex archaeometric study of Late Bronze Age copper ingots from the Stare Hodějovice hoard (South Bohemia). In order to understand the origin of the copper and describe the metallurgical process, we use modern analytical methods (metallography analyses, major/trace element and lead isotope analyses) to describe the samples. Within this study, a representative dataset of trace element composition and lead isotope ratios of non-alloyed and non-recycled corpus of copper ingots from the Late Bronze Age was created. We assume that most of the ingots were not altered by alloying, mixing or recycling. Based on lead isotope ratios and major/trace element composition, we suppose that the origin of the copper could be mostly Alpine ores from the Trentino and Mitterberg regions and possibly the Valais region. By this study, it was proved that copper smelted by a matte smelting process was transported in the form of flat or plano-convex ingots from multiple sources to South Bohemia, where it was subsequently refined and alloyed. Obtained analytical results refute the idea of prevailing copper recycling in the Late Bronze Age.

Lead isotopes link copper artefacts from northwestern Botswana to the Copperbelt of Katanga Province, Congo

Copper was highly valued in sub-Saharan Africa for jewellery and as a store of wealth, but was rarely used for tools or weapons. The Central African Copperbelt is one of the world's largest copper deposits, and is known to have been mined since at least 400–600 cal CE, but has seen very little archaeological investigation. We measured lead isotope ratios and trace element concentrations in 20 copper objects, dating between ca. 650 cal CE and ca. 1200 cal CE, from two sites in the Tsodilo Hills in northwestern Botswana. The results show unequivocally that almost all derive from Copperbelt ore deposits in Katanga Province, Democratic Republic of the Congo, at least 1050 km from Tsodilo. Our results are very similar to those recently obtained for a suite of 45 copper ingots, dated between 9th and 18th centuries cal CE, most of which are from cemeteries in the Upemba Depression, about 200 km north of the Copperbelt (Rademakers et al., 2019).

Structure of copper shaped charge liner evolution law based on die forging process

Numerous studies have addressed the effect of grain size of materials on the overall penetrating performance of warheads. However, the use of the forging process to illustrate the grain heat-treatment refining technology has not been reported. In this experiment, the grain size of copper was observed and evaluated during the main processes of preparing copper shaped charge liners using the die forging process. Through this study, the evolution law for the structure of copper shaped charge liners was examined. In the as-cast condition, the grains of the copper ingots were mostly evenly distributed large flaky equiaxed crystal. Pre-forging and die forging make the grains appear more like strips. After the recrystallization heat treatment, the grain size of the copper shaped charge liner was refined and more uniform. Using these results, this study presents an evolution curve for copper shaped charge liners prepared using the forging process. The results can be used as a technical reference to solve the problem of grain size deviation in the production process of copper shaped charge liners.

Study on the copper and iron alloy from the Bronze Age unearthed from the Yangtze River area in Anhui Province, China

In the 1980s and 1990s, dozens of diamond-shaped ingots were unearthed from the Western Zhou Dynasty to the Warring States Period (1046–256 BC) from the ancient copper mining and metallurgy sites along the Yangtze in Guichi, Tongling, Nanling, and Fanchang in Anhui Province. These rust-colored metal ingots showed significant differences from the copper ingots unearthed in the area and were even designated as iron ingots or copper matte ingots when unearthed. Based on the previous work, the article analyzes these kinds of ingots unearthed in Nanling and Guichi by XRF, XRD, SEM and EDS, and OM (optical microscope). The result shows that the segregation of the copper-iron alloy samples analyzed is obvious, and the copper or iron phase in the supersaturated solid solution with dispersed state distribution can be seen in the samples. Therefore, these are not copper ice copper ingots, but iron supersatured copper-iron mixtures (alloys), which may be the earliest known artificial smelting of copper-iron alloys. It is produced by environmental control when smelting copper oxide ore containing iron by solid reduction.

Non-ferrous metal artefacts from the northern Lowveld, South Africa, ca. 1000 CE to ca. 1880 CE

We report metallographic studies of copper ingots and metal artefacts recovered during sporadic surface surveys and excavations over the past fifty years in the northern Lowveld of South Africa. These include primary copper ingots, copper droplets or prills, a nodule of tin bronze, a bimetallic copper/iron ingot, cast copper bars and rods, and finished items like finger rings and beads. Metallographic study of these items shows that copper smelters had difficulty in controlling reducing conditions sufficiently to prevent the co-reduction of iron, despite the use of smaller furnaces for copper smelting than local iron production. Copper probably was refined by melting in crucibles, allowing the iron contaminant to float to the surface, where it was skimmed off. Despite former suggestions to the contrary by geologists, brass could not have been produced locally by smelting of zinc‑copper ores from the Murchison Range. Bronze and brass first appeared in this region at the end of the thirteenth century CE, probably as imports from the Islamic world.

Le bois de l’Enfer à Saint-Sauveur-le-Vicomte (Manche, France) : un nouveau dépôt de lingots plano-convexes et quelques éléments de réflexion sur la présence d’indicateurs spatiaux au-dessus des dépôts métalliques

Le bois de l’Enfer à Saint-Sauveur-le-Vicomte (Manche, France) : un nouveau dépôt de lingots plano-convexes et quelques éléments de réflexion sur la présence d’indicateurs spatiaux au-dessus des dépôts métalliques