Copper Scrap Research Articles

The Geochemistry of Unalloyed Copper Metallurgical Group Indicates Copper Ore Sources in the Late Bronze and Early Iron Ages of the Urals

Trace elements in copper artifacts from Late Bronze and Early Iron Age sites in the Urals, formerly attributed to the metallurgical group of “chemically pure” copper, were analyzed using the method of laser ablation inductively coupled plasma mass spectrometry. The metal of which artifacts included in this group are made reveals geochemical markers suggesting that “pure” copper actually falls into several subgroups. The PCA analysis of the results identifies 11 clusters corresponding to various sources of copper ores and their mixtures. At least seven principal associations can be linked to copper deposits of different geological types and origin: Au-Te-Bi, Au-Se-Te-Sb, Fe-Co-Ni-As-Sb, Fe-Co-Ni -Zn, Se-Co-Fe, Ag-Pb-Ni, and Sb-Pb-Zn-As. Also, several mixed associations reflect the fusion of copper items and metal scrap initially obtained from different sources: Sn-Pb, Fe-Co-Ni-Zn + Sn, Fe-Co-Ni + Au-Te-Bi-Ag, Fe-Co-Ni + Au-Te-Bi + Sn. A separate association, for which the ore source remains unknown, consists of artifacts characterized by a low content of trace elements, jointly making up less than 0.01 wt%. The largest sample in the Late Bronze Age “pure copper” group falls within the Sn-Pb cluster representing a mixture of local copper and imported Sn-containing copper scrap. Judging by trace elements, the main sources of ore in the “pure copper” group of the Itkul and Sarmatian cultures were the Gumeshki mine and another unidentified source. Both could have been used already in the Final Bronze Age.

Effect of Surface Condition on the Results of Chemical Composition Measurements of Scrap Copper Alloys

The processing of copper-bearing scrap makes it possible to reduce the costs and energy consumption of obtaining copper alloy products compared to producing them from primary raw materials. To achieve this, it is necessary to quickly and accurately determine the content of alloying elements in individual scrap elements. However, the copper-bearing scrap obtained at secondary raw materials collection points consists of elements with various surface conditions (due to contamination, shape, paint coatings, roughness, etc.). The paper contains research results on the influence of surface roughness and paint coatings on the measurement result of the content of alloying elements in copper-bearing scrap. Three mobile spectrometers were used for measurements: spark-induced optical emission spectroscopy (OES), X-ray fluorescence spectrometry (XRF) and laser-induced breakdown spectroscopy (LIBS). The tests used elements with different surface roughness (from Ra = 0.03 μm to 6.7 μm) and covered with various types of varnish (alkyd, water-based, oil-phthalic, acrylic, oil-alkyd). It was found that the roughness of Ra < 2 μm does not significantly affect the results of the measurements with the OES and LIBS spectrometers, and a larger scatter of measurement results was observed for the XRF spectrometer compared to OES and LIBS. For Ra > 2 μm, a significant impact of roughness was found on the measurement results (this may result in the erroneous classification of the scrap as an incorrect material group). The influence of paint coatings on the measurement is much stronger compared to surface roughness. Even a single layer of paint can cause a change in the measurement result of the content of alloying elements by more than 10%. In the case of an OES spectrometer, paint coatings may prevent the measurement from being performed (which means that no measurement result can be acquired).

Examining the Seventeenth-Century Copper Trade: An Analysis of Smelted Copper from Sites in Virginia and North Carolina

AbstractWhen the colonists who made up the Virginia Company of London established James Fort on the banks of the James River in 1607, they brought with them sheets of scrap copper. Based in large part on the experience of the earlier Roanoke Colony, the English knew that copper was a highly prized material among Native peoples of the Chesapeake, and they brought it with them as a trade item. Artifacts made from European smelted copper (impure copper and copper alloy) have been found at contact period sites (ca. AD 1607–1680) throughout Virginia, and James Fort has long been hypothesized to be the primary distribution point for that material. To test this hypothesis, we analyzed the elemental composition of a sample of smelted copper artifacts from James Fort (1607–ca. 1625), as well as samples of copper artifacts from five Native sites in central Virginia. We also analyzed a sample of copper artifacts from another well-known European fort site—Fort San Juan (1567–1568) in North Carolina. The results suggest that although a portion of the smelted copper that circulated through Native networks in Virginia came from James Fort, the rest of it possibly came from English, French, or Dutch distribution points to the northeast.

Sustain China's copper resources with domestic mining, trading, and recycling

Rapid urbanization and industrialization made China the world's largest refined copper producer and consumer. Insufficient copper ore reserves necessitated significant imports and scrap copper recycling. Using material flow and scenario analysis, this study examined historical copper supply and assessed future supply-demand balance. The results show that China's refined copper consumption soared from 2.3 Kt in 1949 to 14.43 Mt in 2020, with imports rising from 1.5 Kt to 11.77 Mt, resulting in a 75 % external dependence. In addition, primary copper importers were concentrated in the Americas. In 2020, China accumulated around 120 Mt of in-use stocks, enabling urban mineral resource development. Forecasted results indicate a persistent copper supply deficit. Recycling copper scrap is crucial to bridge the supply-demand gap. This study enhances understanding of copper's historical supply and consumption, providing policymakers with suggestions for sustainable copper resource management.

Sustaining the United States’ copper resource supply

A secure supply of copper resource is crucial for socio-economic development. To better understand the relationship between urban mining and resource security, it is essential to conduct an integrated analysis of above-ground and underground copper supply, demand, and import/export at the national level. The study quantified the copper resource from multiple sources in the U.S. spanning from 1950 to 2021. Above-ground copper reserves exceed underground reserves by 1.8 times. Net-import dependence of refined copper has risen to 45%. Only 6% of EOL scrap was recycled, and the collection rate declined to 38% by 2021. To prepare for potential bans in China and Malaysia, the U.S. should boost its domestic copper scrap smelting capacity. The current recycling condition poses a challenge for the U.S. to achieve a sustainable supply of copper resource. Future predictions indicate that copper demand would steadily rise to approximately 5 Mt annually by the second half of this century. However, scenario analysis indicates that the total U.S. copper resources can be sustainably supplied by increasing the rate of copper scrap recovery, reducing scrap exports, and exploiting hibernating copper.

Dynamic relationship between refined and scrap copper prices

Dynamic relationship between refined and scrap copper prices

Co-treatment of copper electrolytic sludges and copper scraps for the recycled utilization of copper and arsenic

The Cu electrolytic sludge is a hazardous waste because of its high Cu and As contents. In contrast, As content in Cu scraps is low but causes massive floating slime to be formed during its electrolytic refining, thus decreasing quality of the obtained cathode Cu. In this study, an innovative process was developed to transfer As from the electrolytic Cu sludge into Cu scraps, realizing the recycled utilization of As and Cu from them. The Cu electrolytic sludge was firstly subjected to oxidization roasting in the presence of Ca(OH)2, where the As2O3, Cu3As, and elemental As from the sludge were oxidized and immobilized into Cu3(AsO4)2 and Ca3(AsO4)2. The Cu3(AsO4)2 and Ca3(AsO4)2 retained in the roasted residue. The As volatilization efficiency was only 3.7% under the optimized roasting condition. In the next co-fire-refining of the roasted residue and Cu scraps, the As in Cu3(AsO4)2 and Ca3(AsO4)2 was reduced and transferred into the refined Cu at a content of 0.17 wt%. Although a volatile As2O3 could be generated in this co-fire-refining, the molten Cu scraps restricted As volatilization by forming a Cu–As alloy. With the obtained As-containing refined Cu used in electrolytic refining, the formation of floating slime could be decreased and consequently the quality of the cathode Cu would be increased. This research provided an alternative technology for Cu and As recycling by co-treating Cu electrolytic sludges and Cu scraps.

Microscopic X-ray fluorescence analyses (μ-XRF) of copper-based and silver alloy coins minted in Rhodes, Greece, from the fourth century BCE to the second century CE

The present study provides new data from the analysis of 111 copper-based and 11 silver-alloy coins from the ancient city of Rhodes, Greece. This is the first time that an elemental analysis has been carried out on copper-based coins issued by the Rhodian mint from the mid-4th c. BCE to the 2nd c. CE. Based on the μ-XRF results, three different groups of copper-based alloys are formed, with tin and lead as their major alloying components. The elemental composition shows that most of the coins are binary, leaded and ternary bronzes, while two samples—confirmed as imports—belong to a different technological tradition. All impurities present, such as iron, nickel, cobalt, antimony, or lead, are typical of copper ores, while the diminutive amounts of tin, lead and/or arsenic in some coins could indicate the use of alloys made from copper scrap. Based on a complex and extensive set of compositional data and using silhouette analysis for k-means clustering, we identified the existence of four distinct groups clustered on the basis of similar trace element values. The groups give indication to the raw materials used for minting and provided valuable insights into the technological and origin-related aspects of Rhodian coin production. In the silver coins, four groups of different silver grades can be identified on the basis of the most important alloying elements. Overall, the differences in the composition of the silver coins become clear, but a more extensive sample is needed to better understand the evolution of Rhodian silver coinage.

Improving the Efficiency of Refining Copper Scrap Melt Via Steam-Air Oxidation Based on Mathematical Modeling and Experimental Investigations

Improving the Efficiency of Refining Copper Scrap Melt Via Steam-Air Oxidation Based on Mathematical Modeling and Experimental Investigations

The effect of advanced electrodeposited Ni-P-Cu coatings obtained with scrap cu plates on the tribological performance of Al powder metallurgy products

With the increasing demand for even higher levels of wear resistance in various applications, researchers and manufacturers have been working on developing enhanced coatings for Al to enhance its wear properties even further. The aim of this research was to investigate the impact of electrodeposited Ni-P-Cu coatings derived from scrap copper, as well as coatings of pure NiP, comparatively, on the wear resistance of Al samples. The study involved a detailed examination of the effect of these coatings on the wear properties of Al, and the findings were analysed in depth. In this context, the relationship between the morphology, phase analysis, hardness and wear performance of the obtained coatings has been revealed in detail. In Al substrate materials, the adhesive wear mechanism is the primary mechanism, whereas in NiP and Ni-P-Cu coatings, the abrasive wear mechanism is more dominant due to the presence of a hard coating layers. In Ni-P-Cu coatings, the wear performance was increased by increasing the hardness of the coating despite the amorphous microstructure thanks to the Cu obtained from scrap Cu. At the end of the sliding distance of 100 m, it was determined that the wear resistance of Al samples increased by about 60 times thanks to Ni-P-Cu coatings. Specifically, the current work focused on the potential benefits of these coatings in enhancing the abrasion resistance of Al, which is a crucial aspect of its performance in many industrial applications. By comparing the wear properties of coated and uncoated Al samples, the durability and longevity of this material was highly improved by the role of developed Ni-P-Cu coatings including Cu ions from scraps.

Effectiveness application of Chitosan/Alginic/Copper–organic framework beads on removal of carbaryl carbamate from wastewater

In this study, we concentrated on creating copper-benzene dicarboxylate metal organic frameworks (Cu-BDC MOFs) utilizing scrap copper metal that was obtained from used copper electrical wires. For practical applications, powdered forms of MOFs are typically poorly processed; as a result, Cu-BDC/chitosan/alginic beads were created by cross-linking chitosan, alginic acid, and Cu-BDC MOF. The carbaryl pesticide adsorption from wastewater still challenge due to its low adsorption capacity. Therefore, Copper-BDC/chitosan/alginic beads were compared to chitosan/alginic beads, and the results showed that the latter had a more effective adsorption capacity (225.51 mg g−1) than the former (95.71 mg g−1). Through the use of X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), and Brunauer-Emmett-Teller (BET), the physical and chemical properties of chitosan/alginic and Cu-BDC/chitosan/alginic beads were examined. It's interesting to note that the Cu-BDC/chitosan/alginic beads' morphology is homogeneous and has sizable holes. The uniqueness of the produced materials lends itself to desirable characteristics for the targeted isolation of carbaryl from wastewater. As a result of the current work, MOFs materials for the selective removal of pesticides from wastewater will commercially available and easily process.

Metals and pigments at Amara West: Cross-craft perspectives on practices and provisioning in New Kingdom Nubia

This paper presents the results of elemental and lead isotopic analysis of copper alloys, copper-based pigments and an extremely rare tin-based alloy from the town of Amara West (Sudan), the centre for pharaonic control of occupied Upper Nubia between 1300 and 1070 BCE. It is the first assemblage of its kind to be analysed for Upper Nubia during this period. This research examines the selection and consumption of alloys in a colonial context, in light of earlier and contemporaneous practices and patterns in both Egypt and Nubia, to assess broader systems of resource management and metal production. Drawing on the complementary information obtained from pigment analysis, novel insights into interactions between different high-temperature crafts are obtained, particularly in terms of shared provisioning systems. From this unique perspective, pigment analysis is used for the first time to illuminate copper sources not reflected in metal assemblages, while scrap copper alloys are identified as a key colourant for Egyptian blue manufacture. The integrated application of strontium isotope analysis further highlights the potential for identifying links between glass, faience and Egyptian blue production systems within Egypt and for distinguishing these from other manufacturing regions such as Mesopotamia. The analysis of a tin artefact further expands our understanding of potential tin sources available during the New Kingdom and their role in shaping copper alloy compositions. Overall, this holistic approach to copper alloys and their application in other high-temperature industries ties together different strands of research, shaping a new understanding of New Kingdom technological practices, supply networks and material stocks circulating throughout the Nile Valley.

Purification of Cu–Zn melt based on the migration behavior of lead and bismuth under pulsed electric current

The recovery and regeneration of waste brass can alleviate the pressure of ore resource demand, and can also obtain considerable economic profits from the regenerated alloy products. However, excessive lead and bismuth residues in brass will lead to severe high temperature brittleness of the alloy, and chemical separation will complicate the separation process due to the difference in activity between elements. In this study, the physical separation of Pb and Bi from brass was realized by applying pulse current based on the electrical conductivity difference between Pb, Bi and brass melt, overcoming the limitation of using metal activity difference for oxidation refining. For 10 kg melt, the distribution of current line is adjusted by designing current intensity, frequency and electrode position to explore the migration behavior of Pb and Bi in brass melt under the action of pulse current. After pulse current treatment, Pb and Bi accumulate on the surface of the melt, especially at the bottom of the melt, forming a region rich in Pb or Bi. Based on the numerical calculation, Pb and Bi migrate in the direction perpendicular to the current line driven by the current density gradient, and the migration direction is the direction of the current density gradient decreasing. Pulse current separation technology has the characteristics of shortening the recovery steps, green energy saving, which provides a new solution for the difficult recycling of scrap copper and has great commercial value.

Microstructure and properties of Cu-Zn-Cr-Zr alloy treated by multistage thermo-mechanical treatment

A high-strength and high-conductivity Cu-0.4Zn-0.35Cr-0.2Zr alloy was designed and prepared by adding galvanized scrap copper into Cu-Cr-Zr alloy. The effects of multistage thermo-mechanical treatment involving the microstructure and properties of the alloy were investigated by some means, e.g. mechanical property, conductivity testing and transmission electron microscopy observation. After multistage thermo-mechanical treatment, the Cu-Zn-Cr-Zr alloy had tensile strength of 672 MPa, yield strength of 670 MPa, hardness of 201 HV, and electrical conductivity of 72.1 %IACS. Zn was uniformly dissolved in the Cu matrix, and the nano-Cr phase was the main precipitation phase. The strengthening mechanism of the alloy was combination of strain strengthening, fine grain strengthening, precipitation strengthening and solid solution strengthening. Adding an appropriate amount of Zn can improve the strength of the alloy without significantly reducing the electrical conductivity in combination with the appropriate thermo-mechanical treatment. The novel formulation could present an idea for high-quality reuse of waste copper containing Zn to fabricate high-performance copper alloys.

Potential for Increased Use of Secondary Raw Materials in the Copper Industry as a Countermeasure Against Climate Change in Japan

The copper industry faces serious challenges in achieving the dual goals of mitigating climate change and developing a circular economy, as the increased use of secondary raw materials could increase CO 2 emissions during the smelting stage. This study aimed to examine the possibility of increased use of secondary raw materials (copper scrap and waste from electrical and electronic equipment (WEEE) substrates) in the Japanese copper industry as a countermeasure to climate change. We comprehensive analyzed the changes in CO 2 emissions and costs associated with increased use of secondary raw materials compared to the use of primary copper resources by establishing an intensity at each stage within the system boundary. The analysis results established that CO 2 emissions can be reduced but costs may increase, and that purchasing carbon credits is economically more advantageous. It was also established that the results will vary depending on how CO 2 emissions and costs are allocated because multiple metals can be recovered from WEEE substrates and that the carbon footprint of all‑copper allocation will be significantly lower in the future because of the expected development of decarbonization technologies, including transportation. The study results indicate the potential of the copper industry to expand its use of secondary raw materials from a climate change perspective. CO 2 emissions resulting from the increased use of secondary raw materials in the Japanese copper industry.

Comprehensive utilization of valuable elements in brass alloy rods production through recovery of copper scraps

Brass alloys that meet ASTM C36000 standard were prepared from scrap copper alloys in this study. The mechanical properties of these brass alloy products were measured, and the results showed that yield strength, elongation, tensile strength, and hardness were respectively 164 N/mm2, 37.7%, 383 N/mm2, and 87.7 HV. The flow of elements in the brass alloy production process was also investigated using thermodynamic calculations and microstructural observations. It was discovered that elements such as Al, Mg, Pb, and Cd were easily oxidized as slag; Cd was easily volatilized at high temperatures, and impurities such as Fe, S, and P were precipitated as ZnS and Fe3P inclusions.

Development of Self-Compacting Concrete Incorporating Rice Husk Ash with Waste Galvanized Copper Wire Fiber

This research work is devoted to the experimental investigation of both rheological and mechanical properties of self-compacting concrete (SCC) produced with waste galvanized copper wire fiber and rice husk ash (RHA). In the study, three different volume fractions of 0.5 p to 0.75 percent, 1 percent of scrap copper wire fiber as reinforcing material, and 2 percent RHA as cement replacement were used. To evaluate the fresh characteristics of SCC, the slump flow, J-ring, and V-funnel experiments were conducted for this investigation. Compressive strength, splitting tensile strength, and flexural strength of the concrete were conducted to assess the hardened properties. The test was carried out to compare each characteristic of plain SCC with this modified SCC mixture, containing RHA as pozzolanic materials and copper fiber as reinforcing material. Incorporating copper fiber in the SCC leads to a drop in fresh properties compared to plain SCC but remains within an acceptable range. On the other hand, the inclusion of 2% RHA makes the SCC more viscous. Although adding 2% RHA and 1% copper wire in SCC provide the highest strength, this mix has an unacceptable passing ability. The SCC mix prepared with 2% RHA and 0.75% copper fiber is suggested to be optimum in terms of the overall performance. According to this study, adding metallic fiber reinforcement like copper wire and mineral admixture like RHA can improve the mechanical properties of SCC up to a certain level.

Selective separation of base metals and high-efficiency enrichment of precious metals from scrap copper anode slime

In this study, a clean and effective integrated process for selectively separating base metals and high-efficiency enriching precious metals from scrap copper anode slime was investigated. O2-enriched roasting combined with H2SO4-NaCl leaching was used in the decopperized process to avoid the scattered distributions of As & Sn and enhance the selective leaching efficiencies of Cu, Ni, and As. The obtained leachate containing Cu, Ni, and As can be sent to the existing electrolyte purification process. Then, alkaline xylitol leaching was applied to selectively separate Pb greatly avoiding its negative impact on the subsequent process, and Pb-containing leaching solution was used to prepare lead electrodeposition electrolyte. Sn was recovered in the form of sodium stannate by soda roasting-alkaline leaching. Results of scale-up experiment showed that the direct leaching efficiencies of Cu, Ni, As, Pb, and Sn under the optimum conditions were 99.3 %, 96.9 %, 98.6 %, 98.1 %, and 98.9 %, respectively. Ag and Au were maximally remained in the residue. Furthermore, three leaching solutions generated in the proposed process can be treated in an environmentally friendly way. Therefore, it was a high-efficiency and eco-friendly method for SCAS to realize the comprehensive utilization of the base metals and reduced risks of secondary pollution.

Efficient separation of impurities in scrap copper by sulfurization-vacuum distillation

Scrap copper is a vital source to make up for the supplement of copper resources in China. However, during the recovery process, due to the wide range of sources and extensive processes, many impurities, such as Pb, Sn, Zn, etc., are mixed in the raw materials, resulting in the inability to be used directly. In this study, a sulfurization-vacuum distillation method for impurities separation has been developed. The separation feasibility was determined by the difference in saturated vapor pressure of Cu and the impurities, which was based on the thermodynamic analysis. At the vacuum degree close to industrial production, laboratory experiments investigated the effects of temperature, time and dosage of sulfurizing agent (cuprous sulfide) on the separation of impurities, and revealed the reaction mechanism. Lastly, the impurities separation ratio reached more than 98.50 wt. % under the optimal conditions: the temperature was 1050 °C, the holding time was 60 min, and the mass ratio of the cuprous sulfide to scrap copper was 10%. A novel method was provided to solve the impurities in scrap copper resources. The process turned urban solid waste into treasure and realized green and clean production.

An efficient and clean method for the selective separation of arsenic from scrap copper anode slime containing high arsenic and tin

As the different properties of conventional copper anode slime and scrap copper anode slime (SCAS), the disposal of arsenic before the extraction process is very important. There was simultaneous leaching of As and Sn when the hydrometallurgical process or the sulfation roasting-leaching was applied to treat arsenic in the SCAS. It was difficult to achieve the effective separation of arsenic and tin by these methods. Therefore, an effective and clean pretreatment method for selectively separating arsenic from scrap copper anode slime containing high arsenic and tin via oxygen-enriched roasting followed by acid leaching was proposed. The volatilization rate of arsenic was only 1.13% under the optimum oxygen-enriched roasting parameters. The results of acid leaching showed that the leaching efficiencies of Cu and As were above 97%, and the elements of Sn, Pb, and Ag were enriched in the leaching residue. It is a promising method which can not only obtain selective leachable compounds (such as insoluble SnO2) but also restrict the volatilization of arsenic by forming (MeO)x(As2O5)y or As2O5 to solve the problem of easy dispersion of arsenic, both of which were good for sulfuric acid leaching. Meanwhile, there was no need to develop a new process for treating the leachate, which can be directly sent to the electrolyte purification process.