Copper Smelter Research Articles

Evaluation of the Applicability of Rotating Cylindrical Anodes for Higher Speed Copper Electrolytic Refining

With the aim of increasing the overall speed of conventional copper smelting, in which a dry process and an aqueous electrolysis are connected in series, the challenge is to increase the speed of the electrolysis by increasing the current density, since the electrolysis is the rate-determining step in the series. However, electrolysis at high current density causes passivation of the anode due to a significant increase in the copper ion concentration near the anode, which inhibits electrolysis. The use of forced convection (stirring or jetting) has been considered to suppress passivation. However, it is not easy to apply the effect of forced convection uniformly across the electrode surface in the conventional electrolysis method, in which plate electrodes are arranged in a dense array. In this study, we proposed a method to obtain forced convection by rotating the cylindrical electrode (anode) as shown in the figure. The diffusion of copper ions from the anode surface can be promoted efficiently and uniformly by using this method. As a first step in the evaluation of the applicability, we performed numerical simulations of the tertiary current distribution to investigated the effects of the cylindrical anode rotation on the correspondence between the current density and the copper ion concentration near the anode. Figure 1

Surface sulfidization mechanism of difficult to enrich copper oxide in copper smelting slag and its response to recycling performance

Copper oxide (CuO) is a key component of the oxidized fraction of copper slag (CS). The recovery of CS has been targeted only at the sulfide fraction, with the recovery of the oxidized fraction not sufficiently studied. CuO has chemical properties analogous to but different from copper oxide minerals. Sodium sulfide (Na2S) is a typical activator of copper oxide minerals. The sulfization mechanism of Na2S on CuO and its effect on collection adsorption were investigated in this study. The primary mechanism of CuO activation is an increase in the Cu active sites, yielding a more effective activated surface by using an appropriate Na2S concentration. When the Na2S concentration is extremely high, S continues to adsorb onto CuO surface, which covers the Cu sites, resulting in its depression. The recyclability of the modified CuO is improved owing to the improved adsorption of sodium butyl xanthate (SBX) and the enhanced interaction force between CuO particles and bubbles. At an extremely high Na2S concentration, the SBX adsorbed on CuO surface was weakens and reduced interaction force between CuO particles and bubbles. This study clarifies the activation mechanism of CuO and its effect on CuO recyclability, providing a theoretical basis for practical applications, and provide guidance for the recycling and utilization of copper resources in CS.

Effect of Bi(III) on flotation of copper sulfide from leaching residue of copper smelting dust

Flotation is a potential method for extracting residual copper sulfide (CuS) from the acid-leaching residue of copper smelting dust; however, the inhibitory impact of Bi(III) in the flotation pulp significantly hampers its practical application. In this study, we systematically investigated the inhibition mechanism of Bi(III) on CuS flotation and propose a method to prevent inhibition. Microflotation test results show that a pulp environment with pH 3 and a Bi(III) concentration greater than 1 × 10–2 mol/L significantly depresses the floatability of CuS. Scanning electron microscopy and energy-dispersive spectroscopy results confirmed that Bi(III) hydrolyzes on the surface of CuS to form a precipitate cover layer, which adsorbs onto the surface of CuS. This precipitate was confirmed by X-ray photoelectron spectroscopy analysis and thermodynamic calculations to be BiOCl. Fourier transform infrared analysis revealed that BiOCl reduces the recovery of CuS by hindering the adsorption of xanthate. Finally, the pre-treatment of the leaching residue with H2SO4 + NaCl solution can dissolve BiOCl precipitates on the surface of CuS, eliminate the influence of Bi(III), and result in efficient flotation recovery of CuS from leaching residue.

Improving device access efficiency using a device protocol matching model

The connectivity of devices and systems in the Industrial Internet of Things (IIoT) enables interoperability and collaboration between industrial systems. Device access is the pathway to achieve connectivity, while protocol matching is the basis for device access. Protocol matching is a complex task due to the diverse range of device types, numerous protocols, the issues related to protocol privatization, and the reliance on domain knowledge. These complexities result in inefficient device access. To improve the device access efficiency, a Device Protocol Matching Model (DPMM) is proposed in this paper, which uses only the basic device information to find the best-matched protocol, including protocol identification and basic data. The DPMM adopts a two-stage strategy, consisting of an ontology creation stage and a protocol matching stage. In the ontology creation stage, a simplified device ontology is built to enable the uniform expression of device information and the representation of domain knowledge. In the protocol matching stage, a protocol matcher based on the Two-layer Cooperative Iteration (TCI) algorithm is designed to find the best-matched protocol. In the TCI, to achieve the global optimization of protocol matching efficiency, a penalty mechanism-based weight update method and learning-based matcher evolution are designed. Experiments in two scenarios: a communication base station and a copper smelting production line, are conducted to validate the effectiveness of the DPMM. The experimental results demonstrate that the DPMM can achieve automatic protocol matching with an average matching index of 80.3% and an average hit rate of 35.1%. Moreover, it significantly reduces network resource consumption by up to 96.7%, and increases the hit rate by up to 12.1 times compared with the existing methods.

Antimony Vaporization and Condensation in Simulated Flash Smelting Off-Gas Train Conditions

Antimony is one of the most deleterious impurity elements in copper smelting and has a strong tendency to vaporize in the smelting furnace resulting in an enrichment of antimony in smelter flue dusts. The vaporization and condensation behavior of antimony species was studied in dust-free conditions simulating the off-gas train of a Flash Smelting Furnace at temperatures below 1273 K (1000 °C). The influences of the oxygen partial pressure and the condensate formation temperature on the characteristics of the precipitated antimony species were determined. It was found that practically all the vaporized antimony species precipitated between 853 K and 546 K (580 °C and 273 °C) and that a higher oxygen partial pressure favored precipitation at higher temperatures. The formation of antimony sulfate, which thermodynamically is the most stable antimony species in the studied conditions at temperatures below approximately 723 K (450 °C), was found to be kinetically constrained and the vaporized antimony species precipitated as oxides or sulfides depending on the oxygen partial pressure and the precipitate formation temperature.

Contribution of Copper Slag to Water Treatment and Hydrogen Production by Photocatalytic Mechanisms in Aqueous Solutions: A Mini Review.

Hydrogen has emerged as a promising energy carrier, offering a viable solution to meet our current global energy demands. Solar energy is recognised as a primary source of renewable power, capable of producing hydrogen using solar cells. The pursuit of efficient, durable, and cost-effective photocatalysts is essential for the advancement of solar-driven hydrogen generation. Copper slag, a by-product of copper smelting and refining processes, primarily consists of metal oxides such as hematite, silica, and alumina. This composition makes it an attractive secondary resource for use as a photocatalyst, thereby diverting copper slag from landfills and generating 0.113 μmol/g h of hydrogen, as noted by Montoya. This review aims to thoroughly examine copper slag as a photocatalytic material, exploring its chemical, physical, photocatalytic, and electrochemical properties. Additionally, it evaluates its suitability for water treatment and its potential as an emerging material for large-scale solar hydrogen production.

Diversified competitive sulfuration behaviors of concomitant heavy metal ions on copper recovery from copper smelting waste acid

Currently, sulfuration is widely used for the Cu(II) recovery from copper smelting waste acids (CSWA). However, the abundant concomitant heavy metal ions (HMIs) seriously obstruct Cu(II) recovery. In this paper, we find that the precipitation difficulty of HMI sulfide is determined by solubility product constant (Ksp), H+ concentration and S(−II) concentration, resulting in the diversified competitive sulfuration behaviors of concomitant HMIs on Cu(II) recovery. For concomitant HMIs without S(−II)-consuming ability, the positive-side competitive sulfuration behaviors on Cu(II) recovery are in the order of In(III) > Zn(II) > Ni(II) > Fe(II) > Mn(II). However, with the formation of concomitant HMIs sulfides, the negative-side competitive sulfuration behaviors on Cu(II) recovery are in the order of Fe(III) > As(III) > Bi(III) > Cd(II). According to the results of diffusion-growth-dissolution model, the S(−II)-combining process on HMIs surface is divided into S(−II)-capturing and S(−II)-consuming stages, related to Ksp value and HMIs precipitation, respectively. In actual CSWA, 5000 ∼ 15000 mg/L As(III) seriously inhibits the recovery efficiency of 500 ∼ 2000 mg/L Cu(II), and other concomitant HMIs (e.g., 250 ∼ 1200 mg/L Zn(II), 300 ∼ 450 mg/L Cd(II), 10 ∼ 200 mg/L Bi(III) and 20 ∼ 200 mg/L Fe(II)) will further affect Cu(II) recovery. Besides, ignoring these diversified competitive sulfurations of concomitant HMIs induces unreasonable S(−II) concentration for complete Cu(II) recovery, resulting in Cu(II) recovery issues: As(III) precipitation and Cu(II) residue. Thus, timely information in instantaneous Cu(II) concentration is a feasible strategy to accurately adjust S(−II) concentration via Cu(II) quantitative model. This work is devoted to the efficient and controllable recovery of Cu resources and the reduction of As-containing hazardous wastes in sulfuration treatment of actual CSWA.

Sustainability assessment with the green retrofitting concept for building: A study case in the Gresik regency, Indonesia

In green construction, sustainable resources are essential. One such material is copper, which is widely utilized in electronics, transportation, manufacturing, and residential buildings. As a very useful material, it has many beneficial impacts on human life. Observed from the recent demand spike is in line with the overall trend and the current growing smelter construction in Indonesia. Researchers intend to adapt the existing Copper Smelting Plant Building into an environmentally friendly building as a part of the production chain, in addition to reducing public and environmental concerns about the consequences of this development. We have identified a disparity in cost, where the high cost of green buildings is an obstacle to its implementation to enhance the cost performance with increased renewable energy of the Smelter Construction Building, this study investigates the application of LEED parameters to evaluate green retrofit approaches through system dynamics. The most relevant features of the participant assessments were identified using the SEM-PLS approach, which is used to build and test statistical models of causal models. We have results for this Green Retrofitting study following significant variables according to the following guidelines: innovation, low-emission materials, renewable energy, daylighting, reducing indoor water usage, rainwater management, and access to quality transit.

The effect of copper slag as a precursor on the mechanical properties, shrinkage and pore structure of alkali-activated slag-copper slag mortar

Copper slag, an industrial by-product produced in large quantities during copper smelting and refining, has the potential to be used as an alternative precursor for alkali-activated materials. This approach not only reduces the environmental impact of copper slag but also addresses the growing scarcity of conventional precursors, such as ground granulated blast furnace slag. In this research, copper slag was used as an alternative precursor for alkali-activated slag-copper slag mortars. Sodium hydroxide and water glass served as the activators. The workability, mechanical properties, autogenous shrinkage and drying shrinkage were investigated to evaluate the influence of copper slag content. Furthermore, the reaction products and pore structure of hardened mortar were analysed to gain deeper insights into its performance. The results show that the incorporation of copper slag effectively prolongs the setting time and increases the fluidity. Copper slag reduces the autogenous shrinkage, but it also results in an undesirable increase in drying shrinkage. While copper slag delays strength development and reduces the strength, incorporating copper slag at a 50 % ratio still results in strength comparable to that of mortars utilizing 100 % ground granulated blast furnace slag as the precursor. The incorporation of copper slag alters the composition of calcium aluminosilicate hydrate and promotes the formation of ferro-silicate. Although it reduces the proportion of macropores in the total pore volume, it simultaneously increases the amount of capillary pores. Copper slag alters pore solution, and although heavy metal leaching remains minimal, risks in complex environments require further study.

Volatilization and cleaning recovery of Pb, Se and Hg in acid sludge of copper smelting system during vacuum distillation

The high lead acid sludge, containing a small amount of selenium and mercury, is a hazardous waste product of the copper smelting system. Improper disposal of this waste can cause serious harm to the environment. In this study, the method of vacuum distillation was proposed for treating the high lead acid sludge. The study aimed to investigate the volatilization rule of selenium, mercury, and lead in the acid sludge during vacuum distillation, as well as to purify PbSe and metallic lead. The results indicated that under 5 Pa, Hg and Se commence volatilizing at 300 ℃, the content of Hg in volatile substances remains relatively constant after reaching 400 ℃, demonstrating nearly complete volatilization at this temperature with a ratio of 92.93 %. Similarly, selenium almost completely volatilizes at 800 ℃ with a ratio of 96.74 %, while lead does so at around 1000 ℃ with a ratio of approximately 99.27 %. Mercury at 400 ℃ can be recovered as mercury selenide. Lead selenide can be achieved at 800 ℃, while lead sulfate can be decomposed and purified at 1000 ℃ to obtain metallic lead with a purity higher than 99 %. The method can properly treat and recover mercury, selenium, lead and other elements in the acid sludge with short process and no pollution, which provides a new cleaning approach for high lead acid sludge.

To the problem of processing of waste slag from copper smelting plants in Kazakhstan

Дана характеристика отвальным медным шлакам, рассчитан их рациональный состав. Для эффективной переработки подобных шлаков предложено применение процесса выщелачивания растворами серной кислоты, не требующего затрат тепловой энергии извне, вследствие экзотермичности протекающих реакций. Выполнен расчет термодинамических характеристик реакций, возможных при выщелачивании отвальных медных шлаков растворами серной кислоты. Проведен анализ фазового равновесия процесса выщелачивания шлака при различных расходах серной кислоты, оценено влияние температуры на изменение состава фаз, построены диаграммы фазового равновесия. Выполнены исследования по сернокислотному выщелачиванию отвальных медных шлаков при комнатной температуре и при 80 °С. Выявлены проблемы сгущения и фильтрования пульпы после выщелачивания, связанные с образованием кремниевой кислоты Үйінді мыс шлактарына сипаттама беріліп, олардың рационалды құрамы есептелді. Мұндай шлактарды тиімді өңдеу үшін жүретін реакциялардың экзотермиялық болуына байланысты жылу энергиясының сырттан шығынын қажет етпейтін күкірт қышқылының ерітінділерімен шаймалау процесін қолдану ұсынылады. Үйінді мыс шлактарын күкірт қышқылының ерітінділерімен шаймалау кезінде мүмкін болатын реакциялардың термодинамикалық көрсеткіштері есептелді. Күкірт қышқылының әр түрлі шығындарында шлакты шаймалау процесінің фазалық тепе-теңдігіне талдау жүргізіліп, температураның фазалар құрамының өзгеруіне әсері бағаланды, фазалық тепе-теңдік диаграммалары тұрғызылды. Үйінді мыс шлактарын бөлме және 80 °С температураларда күкірт қышқылымен шаймалау бойынша зерттеулер жүргізілді. Кремний қышқылының түзілуіне байланысты шаймалаудан кейін пульпаның қоюланып сүзуге кедергі жасайтыны анықталды The characteristic of dump copper slag is given, their rational composition is calculated. For the effective processing of such slags, it is proposed to use the leaching process with sulfuric acid solutions, which does not require the expenditure of heat energy from outside, due to the exothermicity of the ongoing reactions. Calculation of thermodynamic characteristics of reactions possible at leaching of waste copper slags with solutions of sulphuric acid is carried out. The phase equilibrium of the slag leaching process was analysed at different sulphuric acid flow rates and the influence of temperature on the change of phase composition was evaluated, phase equilibrium diagrams were constructed. Studies on sulfuric acid leaching of waste copper slag at room temperature and at 80 °C. Problems of pulp thickening and filtration after leaching associated with the formation of silicic acid have been identified

Occupational health risk assessment of exposure to major hazardous chemicals in copper and nickel smelting enterprises

Objective: To evaluate the risk of major chemical exposure positions in copper and nickel smelting enterprises, and provide a basis for risk assessment and prevention control measures. Methods: From September to October 2023, two copper nickel ore smelting enterprises in Xinjiang Uygur Autonomous Region were selected as the research objects. Relevant information on chemicals was collected through occupational hazard field investigations. Qualitative analysis and exposure index methods were used in GBZ/T 298-2017 "Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazardous Factors in the Workplace" to conduct risk assessments on the main chemical exposure positions. The qualitative risk assessment results were checked for consistency using the Weighted Kappa coefficient. Results: The positions with high risk of exposure to hazardous chemicals in copper nickel smelting enterprises are saponification positions exposed to hydrochloric acid in refining processes, black nickel positions exposed to sodium hydroxide, and tail suction positions. The consistency between the two occupational health risk assessment results is poor (Kappa=0.14) . Conclusion: The amount of major hazardous chemicals in copper-nickel smelting enterprises is large, and the occupational health risks caused by exposure are complex and diverse, so the effects of chronic occupational health should be strengthened.

Synergistic environmental benefits from copper slag recycling in China: Pollutant mitigation and carbon reduction

In response to the dual challenges of climate change and environmental degradation, China is prioritizing efforts to manage both pollution and carbon emissions. Given China's leadership in global copper smelting, recycling substantial amounts of copper slag is considered a key strategy for environmental improvement. This study applies life cycle assessment (LCA) to evaluate the environmental benefits of three copper slag recycling strategies. Building on the LCA results, we introduced a synergistic reduction index system that assesses the combined effects of pollution mitigation and carbon reduction. Findings indicate that utilizing recycled copper slag in building materials not only significantly reduces local industry emissions but also demonstrates substantial synergistic effects. This strategy optimally reduces both air pollution and carbon emissions, largely due to the substitution of high-pollution materials with recycled copper slag. Based on these insights, we propose targeted recycling strategies tailored to regional needs and capacities, thereby offering practical suggestions for the sustainable management of copper slag.

The number of seedlings from the soil seed bank of pine forests with differently dated fires near the Karabash copper smelter

We tested the hypothesis that the number of seedlings from the soil seed bank (SSB) in forests polluted by heavy metals and disturbed by recent fires decreases. It was also assumed that the consequences of pollution and fires for the soil seed bank are additive. We estimated the number of seedlings from the SSB of pine forests located near the Karabash copper smelter (KCS) (contaminated by Cu, Zn, Pb, and Cd) and from uncontaminated forests of the Ilmen State Reserve (ISR). In both areas, samples of the forest litter and humus horizon were taken from forests recently exposed to ground fires and long-term unburned forests. Samples were exhibited from June to September, conducting seven rounds of counting seedlings. Small peculiarities of the emergence of seedlings on the samples of the forest litter and the humus horizon were established. However, the regularities of the reaction of SSB to pollution and fire disturbances did not depend on the soil horizon. The number of seedlings on substrates from contaminated forests was 5–8 times lower than the number of seedlings on substrates from background forests. A decrease in the number of seedlings on polluted substrates was accompanied by an increase in the share of dicots in the total number of seedlings. The relationship between the number of seedlings and the age of fires was not found. The additivity of the consequences of pollution and fires has also not been established. Of the two types of damage, pollution and fires, the pollution factor is of leading importance for SSBs. The results indicate a low recovery capacity of the herb-shrub layer of polluted forests.

Stay with the green: New insights into ancient copper smelting in the Tonglüshan site, China

This paper presents new archaeometallurgical analyses from the Tonglüshan site, a famous ancient mining and smelting site in China. Results show that the primary phases in slag samples from two sites (Sifangtang and Lujia’nao) are all of a vitreous matrix, interspersed with fayalite crystals, wüstite, and hercynite. The trapped metallic particles in the slag are mainly raw copper with few sulfides present, which indicates a direct reduction process of oxidic ore. Iron-rich minerals were likely to be added as flux implied by the few unreacted inclusions in the slag samples. The extremely low copper content in the slag samples demonstrates a high rate of copper recovery, indicating that the copper smelting technology in the region had reached a considerably advanced level. In the meantime, the variations in metal content in slag samples from different periods reveal the diachronic changes in this copper smelting technology. The Tonglüshan site, with its millennia of ancient mining and metallurgical activities, provides an excellent material base for detailed studies on technological evolution.

Extraction of lead from sulfate cakes of copper smelter dust leaching

Extraction of lead from sulfate cakes of copper smelter dust leaching

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

Copper slag, a bulk non-ferrous solid waste, is critical in establishing a closed-loop cycle in the copper metallurgy industry. Currently, the processing techniques for copper slag are characterized by prolonged procedures, secondary waste discharge, limited value utilization, and high energy consumption. A novel approach was proposed to harness the thermal energy inherent in molten copper slag for producing copper-bearing weathering steel and cement while simultaneously synergistically recovering lead and zinc. The results indicate that under the conditions of smelting temperature of 1500 °C, alkalinity of 1.06, smelting time of 60 min, and mechanical stirring, the recovery rates of copper, iron, lead, and zinc in copper slag reached 98.83%, 99.59%, 97.45%, and 98.51%, respectively. Furthermore, the feasibility of this approach was validated by laboratory-scale preparation of Q355GNH-grade copper-bearing weathering steel and S95-grade cement clinker. Computational analysis for the direct carbothermal reduction of molten copper slag in its thermal state reveals that, compared to the traditional flotation process, this approach saved 1177 MJ of thermal energy per metric ton of copper slag, equivalent to a reduction of 147 kg of carbon dioxide emissions. This study facilitates the zero-waste, high-value, and sustainable development of the copper smelting industry.

Effect of chemical pollution on the fertility of male rodents from natural populations: сomparing the response of sperm morphology, motility, and concentration

The results of studies of epididymal spermatozoa of three species of rodents (bank vole Clethrionomys glareolus, northern red-backed vole Cl. rutilus, and herb field mouse Sylvaemus uralensis) living under long-term exposure to atmospheric emissions from two large copper smelters in the Middle Urals are summarized (Middle Ural and Kirovgrad copper smelters). The impact of pollution (including at the individual level on the accumulation of Cu, Zn, Pb, and Cd in the liver) was assessed for indicators characterizing the quality of sperm from different aspects: morphology (proportion of cells with head and tail defects), motility (proportion of motile cells, velocity, and straightness of movement) and concentration. Sperm motility responds to pollution: in impact zones, the proportion of motile cells and their velocity were lower than in background zones. The occurrence of abnormal cells and sperm concentration were not statistically significantly different between impact and background zones. The reaction of sperm to chemical pollution is species-specific: voles react more strongly than the herb field mouse. The consistency of changes in sperm parameters (in the direction of their deterioration) in response to increased pollution was found only in the bank vole. Effect sizes for sperm parameters are much smaller compared to those for liver Cd accumulation and animal abundance. In general, the reaction of sperm to pollution turned out to be weak, none of the studied indicators can be a reliable marker of industrial pollution.

Proportion of birch leaves damaged by insects along the pollution gradient of the Middle Ural copper smelter

The proportion of leaves of downy birch (Betula pubescens Ehrh.) damaged by insects at ten sites of coniferous forest along the pollution gradient of the Middle Ural copper smelter was analyzed. The study was conducted during periods of moderate (2009) and low (2019) emissions in early and late summer. The proportion of damaged leaves was higher in 2019 and increased towards the end of the growing season but was not associated with distance to the smelter and lead concentration in leaves.

QURAYYAH PAINTED WARE OUTSIDE THE HEJAZ: EVIDENCE OF A COMMUNITY OF PRACTICE IN THE LATE BRONZE AND EARLY IRON AGES?

SummaryQurayyah Painted Ware (QPW) is the most solid evidence of contacts between the Hejaz and the southern Levant in the Late Bronze and Early Iron Ages. However, even after decades of research, there is still much uncertainty regarding the chronology of these contacts and their nature. Here, we present an exceptionally rich collection of QPW fragments documented recently in the copper smelting sites of the Timna Valley. We argue that the distribution of this painted ware in the southern Levant extended from the early thirteenth to ninth centuries BC and that its prominent presence in industrial contexts in the Aravah Valley is related to the transmission of metallurgical ‘know‐how’ from the Hejaz, which included rituals in which QPW vessels took part. While the original exchange probably involved craftspeople from the Hejaz in the Aravah's metalworking, the continuous use of QPW throughout several centuries in the southern Levant is best explained as a reflection of an enduring community of practice of the local populations with the metalworkers of the Hejaz.