Copper Smelter Research Articles

Correlations between levels of essential metals and arsenic in the urine of exposed copper smelter workers

Correlations between levels of essential metals and arsenic in the urine of exposed copper smelter workers

Novel Strategy for Efficient Recovery of CuO-Based Multiple-Metals from Copper Smelter Dust toward CO2 Electrocatalytic Reduction.

Copper smelter dust, a typical hazardous waste that is abundant in valuable heavy metals, holds the potential to be regarded as a promising resource. This study introduces a new approach that integrates chlorination roasting and cascade condensation to efficiently recover heavy metals from copper smelter dust. The findings demonstrate the successful separation of heavy metals (Cu, Pb, and Zn) as chlorides at nearly 100% efficiency while also effectively converting trivalent arsenic (As(III)) into pentavalent arsenic (As(V)) and immobilizing it in the roasting residues, thereby reducing environmental risk. Through the utilization of thermogravimetric mass spectrum analysis and thermodynamic equilibrium calculations, the chlorination process for heavy metals was investigated, revealing both direct and indirect chlorination processes. Additionally, the study resulted in the development of a CuO-based multiple-metals electrocatalyst from the oxidized roasting-recovered heavy metal chlorides, exhibiting significantly enhanced catalytic activity and faradaic efficiency for the electroreduction of CO2 into CO and CH4 compared to pure CuO electrocatalyst under similar electrocatalytic conditions. Overall, this work presents a sustainable and scalable method and new insights for addressing environmental risks while repurposing copper smelter dust.

The sulfurization precipitation and competition mechanisms of Cu(II) and As(V) in electrolyte towards efficient recovery of copper

The sulfide precipitation has been widely used to recover Cu(II) and remove As(V) in copper smelting electrolyte based on the Cu(II)-As(V) separation. However, the recovery efficiency was undesirable due to the inaccurate control of process parameters. It was necessary to investigate the process and mechanisms of sulfurization precipitation for accurate adjustment. Herein, under the single and mixed solutions of Cu(II) and As(V), the process parameters were investigated and the precipitation mechanisms were explored. And when using actual electrolytes, the corresponding sulfurization process and mechanisms were also revealed. The sulfurization results of single component solutions suggested that Cu(II) was rapidly precipitated in one step, but As(V) firstly generated intermediate, then it was gradually reduced to As(III) for a longer time and quickly precipitated in the form of amorphous. This phenomenon caused the significantly faster removal speed of Cu(II) than that of As(V). For their mixed solutions, only a small amount of As(V) were removed by adsorbing the precipitate at the low S/Cu molar ratios (RS/Cu), and Cu(II) and As(V) could achieve a good separation. Simultaneously, it revealed that the sulfidation competitive mechanisms were related to the solubility product constant (Ksp) and initial As(V) concentrations. In addition, the similar rules were also observed in actual electrolytes. Moreover, under RS/Cu = 1.2 and reaction time of 10 min, the arsenic content of sulfide precipitates in the actual electrolyte was less than 2.5%, which showed a great separation also could be obtained for the actual electrolyte. This result met the requirement of Cu(II) recovery. It can provide a good reference for adjusting sulfidation parameters in the actual process to achieve efficient copper recovery, reduce the production of hazardous waste containing arsenic at the source and realize the cleaner production of copper smelting system.

Reassessing Bronze Age Metallurgy in Upland Southwest China on the Basis of Excavations at Longbohe, Yunnan

Longbohe is a newly discovered copper mining, smelting and production site located strategically beside the Red River on the China–Vietnam border in Southeast Yunnan, China. Recent excavations have dated it from the second half of the second millennium to the end of the first millennium BC, making it the earliest copper mining and processing site in Upland Southwest China and Southeast Asia. The metallurgical production tradition in Upland Southwest China and Southeast Asia is recognized and detailed with reference to the chaîne opératoire revealed at the Longbohe site. The location of Longbohe provides evidence for a route along which metallurgy was introduced from Southwest China into Southeast Asia. Current evidence further suggests that metallurgy probably arrived on the Yunnan–Guizhou Plateau along the eastern Qinghai–Tibet Plateau corridors, and then entered Southeast Asia along south-flowing rivers. The Longbohe site is thus a most significant find in the southward dissemination of metallurgical technological systems into Southwest China and Southeast Asia in the later second millennium BC.

Flash sintering mechanism in multiphase materials system of copper smelting slags

Flash sintering (FS) is of great interest today, as it allows the production of high-density ceramics in seconds at lower temperatures than conventional sintering. In this study, the effects of conventional sintering at 1250°C for 4 h and FS at various electric fields (12.5, 25, 50 and 75 V/mm) on copper smelting slag (CSS), which is a multiphase material system, are investigated. The results show that FS occurs at substantially lower temperatures with much shorter times than conventional sintering, in conjunction with improved density and hardness values for CSS. The optimum condition for better densification is observed for the sample applied the 25 V/mm electric field in 554 s, and the maximum power density of about 76.49 mW/mm3. On the other hand, the shortest FS duration is achieved with the sample applied 75 V/mm in 114 s. Flash sintering at lower temperatures also stabilizedthe magnetite-hematite the phase transition, which arouses at higher temperatures. Overall, FS has made a huge contribution to reducing sintering time and temperature while providing better microstructure integrity and mechanical properties in multiphase materials systems.

Boosting peroxymonosulfate activation via Fe–Cu bimetallic hollow nanoreactor derived from copper smelting slag for efficient degradation of organics: The dual role of Cu

Valorization of iron-rich metallurgical slags in the construction of Fenton-like catalysts has an appealing potential from the perspective of sustainable development. For the first time, copper smelting slag (CSS) was utilized as the precursor to synthesize hollow sea urchin-like Fe–Cu nanoreactors (Cu1.5Fe1Si) to activate peroxymonosulfate (PMS) for chlortetracycline hydrochloride (CTC) degradation. The hyper-channels and nano-sized cavities were formed in the catalysts owing to the induction and modification of Cu, not only promoting the in-situ growth of silicates and the formation of cavities due to the etching of SiO2 microspheres, but also resulting the generation of nanotubes through the distortion and rotation of the nanosheets. It was found that 100 % CTC degradation rate can be achieved within 10 min for Cu1.5Fe1Si, 75 times higher than that of Cu0Fe1Si (0.0024 up to 0.18 M−1‧min−1). The unique nanoconfined microenvironment structure could enrich reactants in the catalyst cavities, prolong the residence time of molecules, and increase the utilization efficiency of active species. Density functional theory (DFT) calculations show that Cu1.5Fe1Si has strong adsorption energy and excellent electron transport capacity for PMS, and Fe-Fe sites are mainly responsible for the activation of PMS, while Cu assists in accelerating the Fe(II)/Fe(Ⅲ) cycle and promotes the catalytic efficiency. The excellent mineralization rate (83.32 % within 10 min) and efficient treatment of CTC in consecutive trials corroborated the high activity and stability of the Cu1.5Fe1Si. This work provides a new idea for the rational design of solid waste-based eco-friendly functional materials, aiming at consolidating their practical application in advanced wastewater treatment.

Practical experience to theoretical innovation: A model for recovering metal resources from industrial solid waste − A case study of copper smelting slag

Industrial solid waste (ISW), a byproduct of modern industrial production, poses significant challenges to sustainable development due to limitations in economic and technical capabilities. Despite containing valuable metal resources, the lack of a coherent approach to its treatment has hindered progress in addressing this longstanding issue. In response, we introduce an innovative model for metal resource recovery from ISW (ISWMRR), with a specific focus on copper smelting slag (CSS) as a prevalent example. This study underscores the efficacy of mineral phase reconstruction technology in converting CSS from a liability to an asset, thereby ensuring a sustainable stream of high-quality raw materials for green steel production amid declining iron ore reserves. Experimental findings indicated that employing the ISWMRR model enabled the successful production of iron products from CSS, yielding an iron concentrate with a TFe (total iron) fraction of 87.21 wt% and iron recovery of 91.24%. This approach facilitated the cost-effective, environmentally friendly, and efficient recovery of iron resources from CSS. By furnishing a novel theoretical framework, our research seeks to guide scientists and industry stakeholders engaged in ISW management.

Performance and mechanism of arsenic-metal separation in copper smelting flue gas regulated by chalcopyrite

To reduce the release of arsenic from non-ferrous metal (especially copper) smelting flue gases as well as to recover arsenic, the dry quenching process has been successfully applied to remove arsenic. However, the formation of arsenate hindered the separation of arsenic, thus reducing the collection efficiency. To tackle the bottleneck, the strategy of mineral phase regulation was proposed by the conversion from arsenate to sulfate, metal sulfate and gaseous arsenic were formed and separated each other. Chalcopyrite served as a potential sulfation regulator due to the gradual production of active sulfur (S2 dimer and S monomers) at high temperatures. At a chalcopyrite dosage of 60 %, the separation efficiency of arsenic from the metals reached 93.78 % and the residual arsenic content in the arsenic-copper particulate matter was decreased from 40.38 % to 3.12 % at 700 °C. The separation of arsenic and metal was attributed to the release of active sulfur from chalcopyrite, which enhanced the conversion of arsenate to sulfate. The separated arsenic enters the following section in the form of gaseous As2O3, which is beneficial to the dry quenching collection of arsenic. This provides theoretical and technical support for the clean production of nonferrous metal smelting and the control of arsenic pollution in flue gas.

Metallography of tailings from the Mansfeld copper mining area

Abstract The copper slate deposit of the Mansfeld copper mining area was mined in the 19th and 20th century. Mineral collectors can still find traces of copper smelting activities on the slag heaps of the various copper smelters. A piece from the Krug smelter slag heap mainly consists of Cu and Fe sulfides. The piece in question might be the intermediate product copper matte. The pieces from Hettstedt and the August Bebel smelter contain clearly visible metallic copper. The Hettstedt specimen might be a piece of furnace lining with adhering slag. Cr and Mg could be found, suggesting that chromium magnesia was used as refractory material. The piece from the August Bebel smelter contains up to 18 wt. % Cu. It does, however, not contain any sulfur. It is most likely Fe2SiO4 slag (fayalite) with a high proportion of FeO. The presence of Sn and Zn suggests that this slag was formed during the processing of bronze or brass.

Assessment of Palladium Recovery from Spent Pd-Al2O3 Catalyst: Comparative Analysis Using Copper and Iron Metal Smelting Methods

Assessment of Palladium Recovery from Spent Pd-Al2O3 Catalyst: Comparative Analysis Using Copper and Iron Metal Smelting Methods

Extraction of arsenic from fine dust of copper smelters by reduction roasting with natural gas

One of the current trends in the complex processing of fine dust from copper smelters is their direct leaching with sulfuric acid. As practical results show, high reliable technological parameters are not achieved due to the high content of arsenic in dust. During sulfuric acid leaching of dust, arsenic is distributed between the lead cake and the solution at a ratio of 40 and 60%, respectively. The redistribution of arsenic between leaching products significantly reduces the technological performance and leads to the accumulation of arsenic in the technological scheme. The paper presents the results of comprehensive studies of the elemental and phase composition of fine dust from one of the copper smelters in Kazakhstan. In the initial dust, along with the main phases presented in the form of lead and zinc sulfate, the following typical components were found: oxides of copper, lead, zinc and copper and zinc ferrites. Arsenic is found in two forms—As(III) and As(V). The laboratory installation and technique for conducting reduction roasting of dust with natural gas are presented. The influence of roasting duration, temperature and natural gas consumption on the extraction of arsenic from dust was studied. It has been established that almost complete, up to 99%, extraction of arsenic from dust is achieved with optimal technological roasting parameters: duration τ = 40 min.; natural gas consumption is 1.5 times higher than the stoichiometrically required amount for the reduction of As2O5, and temperature 500 °C.

Landscape, chronology and function of Bronze Age terrace-shaped settlements: A case study from the Youzhashan site in Yangxin County, Hubei Province, China

The Middle and lower reaches of the Yangtze River, constituting a region rich in metal resources, played an important role in the formation and early development of the Bronze Age civilization in China, mainly including mainly the southeastern part of Hubei Province, the northern part of Jiangxi Province and the southern part of Anhui Province. Geological surveys have revealed that this region, which stretches for 500 km along the Yangtze River, is rich in mines, and archaeological institutions have discovered a large number of Bronze Age mining and metallurgical sites in the region over the past three decades. This region is an important area for studying the rise and prosperity of the Chinese Bronze Age civilization. Therefore, exploring the production pattern of the bronze industry in the copper mining area in the middle and lower reaches of the Yangtze River, as well as the resource circulation network between this region and the northern part of China, has become a hot issue in Chinese archaeological research in recent years.From March to July 2023, Wuhan University and the Cultural Relics Bureau of Yangxin County formed a joint archaeological team to carry out an archaeological survey of mining and metallurgical sites in an independent geographic unit in the northern part of Yangxin County, Hubei Province, covering an area of 120 km2, and a total of 60 mining and metallurgical sites were discovered during the survey, and approximately two-thirds of the 60 sites exhibited the landscape with a more typical terrace-shaped site. In this study, we have carried out systematic archaeological exploration and drone mapping of the Youzhashan site, a typical terrace-shaped site in this region, and reconstructed the process of terrace-shaped site accumulation formation using materials from archaeological excavation, exploration and survey. In addition, scientific and technological tests were conducted on the metallurgical relics collected from the Youzhashan site, which revealed the occurrence e of copper smelting activities at the Youzhashan site, and we analyzed the processing system. In addition, the carbon samples excavated from the Youzhashan site were carbon dated to determine the exact date of the formation of the Youzhashan site.

Enhanced Generative Adversarial Networks for Isa Furnace Matte Grade Prediction under Limited Data

Due to the scarcity of modeling samples and the low prediction accuracy of the matte grade prediction model in the copper melting process, a new prediction method is proposed. This method is based on enhanced generative adversarial networks (EGANs) and random forests (RFs). Firstly, the maximum relevance minimum redundancy (MRMR) algorithm is utilized to screen the key influencing factors of matte grade and remove redundant information. Secondly, the GAN data augmentation model containing different activation functions is constructed. And, the generated data fusion criterion based on the root mean squared error (RMSE) and the coefficient of determination (R2) is designed, which can tap into the global character distributions of the copper melting data to improve the quality of the generated data. Finally, a matte grade prediction model based on RF is constructed, and the industrial data collected from the copper smelting process are used to verify the effectiveness of the model. The experimental results show that the proposed method can obtain high-quality generated data, and the prediction accuracy is better than other models. The R2 is improved by at least 2.68%, and other indicators such as RMSE, mean absolute error (MAE), and mean absolute percentage error (MAPE) are significantly improved.

Green leaching and predictive model for copper recovery from waste smelting slag with choline chloride-based deep eutectic solvent

This research was performed to investigate the optimization of copper recovery from copper smelting slag (CSS) with a deep eutectic solvent as green reagent. The effect of important parameters on leaching efficiency of copper and zinc (as well as dissolution of iron), such as leaching time, leaching temperature, liquid/solid ratio, and particle size was studied. In order to model the copper recovery, an optimization method was used. According to the chemical analysis of CSS, the slag contains 0.9% copper, 3.3% zinc, and 36.7% iron. Also, it was found that the CSS is mainly composed of Fe2SiO4, Fe3O4, and SiO2. Copper-containing structures were determined as CuO and CuS. As a result of leaching experiments, 80% copper and 61% zinc recoveries were obtained at 48 h, 95 °C, 1/25 g·ml–1, and -33 μm. It is noted that the iron and silicon dissolution remained negligible under the selected conditions. According to the mathematical model, the highest copper leaching efficiency (up to 100%) could get under optimum working conditions as 48.5 °C leaching temperature, 40.1 hours leaching duration, and 62.3 ml·g–1 liquid/solid ratio. Also, the proposed model revealed that wide range of experimental levels can be used as leaching parameter to get desired metal leaching efficiency.

Study on the mechanism of copper and arsenic separation in copper smelting acidic solution by arsenic sulfide residue

A large amount of acidic solution containing arsenic and copper is produced in the hydrometallurgical treatment process of arsenic-containing solid waste in copper smelting. It is necessary to develop an economical and efficient separation technology of arsenic and copper from the solution. In this paper, according to the difference of solubility product between As2S3 and CuS, arsenic sulfide residue (ASR) was used as copper precipitant to realize the efficient separation of copper and arsenic in acidic solution, so as to achieve the purpose of “treating waste with waste”. It is found that the copper precipitation reaction is a more sensitive reaction. With the increase of temperature and time, the precipitation efficiency of copper first increases and then decreases, mainly because CuS will react with AsO43- in the solution, and then re-dissolution occurs. With the increase of pH value, As and Fe precipitate, resulting in incomplete separation of Cu and As. Under the optimum conditions, the precipitation efficiencies of Cu, Sb, Cd, Fe and Zn reached 97.39 %, 46.31 %, 2.04 %, 2.59 % and 0.65 %, respectively. The content of Cu in the precipitated residue reaches 50.47 wt%. The precipitated residue can be used as raw material for copper smelting.

The Number of Seedlings from the Soil Seed Bank of Pine Forests with Differently Dated Fires Near the Karabash Copper Smelter

The Number of Seedlings from the Soil Seed Bank of Pine Forests with Differently Dated Fires Near the Karabash Copper Smelter

Separation of halogens and recovery of heavy metals from secondary copper smelting dust

The separation of halogens and recovery of heavy metals from secondary copper smelting (SCS) dust using a sulfating roasting−water leaching process were investigated. The thermodynamic analysis results confirm the feasibility of the phase transformation to metal sulfates and to gaseous HF and HCl. Under the sulfating roasting conditions of the roasting temperature of 250 °C and the sulfuric acid excess coefficient of 1.8, over 74 wt.% of F and 98 wt.% of Cl were volatilized into flue gas. Approximately 98.6 wt.% of Zn and 96.5 wt.% of Cu in the roasting product were dissolved into the leaching solution after the water leaching process, while the leaching efficiencies of Pb and Sn were only 0.12% and 0.22%, respectively. The mechanism studies indicate the pivotal effect of roasting temperature on the sulphation reactions from various metal species to metal sulfates and the salting out reactions from various metal halides to gaseous hydrogen halides.

Chemical Composition of PM10 in a Classroom near the Copper Smelter in Bor, Serbia

Chemical Composition of PM10 in a Classroom near the Copper Smelter in Bor, Serbia

Kinetics analysis of copper extraction from copper smelting slag by sulfuric acid oxidation leaching

Copper smelting slag (CSS) is generally produced from the pyrometallurgy of copper sulfide concentrate, the current storage disposal methods of CSS not only occupy precious land and pollute the environment, but also waste resources. To recover copper from the CSS and explore the atmospheric pressure oxidative leaching kinetics of copper extraction from CSS with sulfuric acid was investigated intensively. In this study, the effect of particle size, sulfuric acid concentration, temperature, liquid-to-solid ratio, and hydrogen peroxide added amount were investigated comprehensively. The results indicated that the decrease of particle size and increase of other parameters can significantly promote the leaching of copper. Under the optimum conditions, 90.7 % of the copper in the CSS was effectively leached, other copper in the leaching slag mainly existed in the form of fine-grained embedded copper sulfide. The dominant phase of the leaching slag is magnetite, which could be further recovered by conventional magnetic separation. Moreover, the kinetics of copper atmospheric pressure oxidative leaching in CSS were further expounded. The results indicated that the copper leaching kinetic conforms to the shrinking core model, and the overall leaching reaction was controlled by the internal diffusion control with an activation energy of 11.22 KJ/mol. The apparent reaction order of sulfuric acid and particle size are determined to be 0.965 and 0.478 respectively. Finally, the kinetics model equation is established for copper at normal pressure as:1-23η-1-η2/3=0.032·CH2SO40.965·r0-0.956·t. This research could provide an alternative solution for the efficient utilization of CSS.

Recovery of Cu from waste smelting slag through extraction with novel deep eutectic solvents (DESs)

ABSTRACT This study reports on the recovery of copper, zinc, and iron from the copper smelting slag (CSS) of Saindak Copper and Gold Project, Baluchistan, Pakistan using novel deep eutectic solvents (DESs) and Sulfuric acid. Sorbic acid, citric acid, and urea were each mixed with tetrabutylammonium chloride (TBAC) to prepare three DESs. Leaching experiments were performed in batch mode under a constant stirring speed of 300 revolutions per minute (rev min−1) and contact time of 2 h, under different liquid to solid ratios (L/S 1.5–3) and different temperatures (60–90°C). Results showed that the DES2 (TBAC & citric acid) recovered about 77% copper, 49% zinc, and 1% iron among other two prepared DESs at 3 L/S and 90°C. Sulphuric acid recovered 94% copper, 2% zinc, and 4.7% iron under the same conditions. The same DES also showed selectivity in the recovery of copper, as compared to iron.