Copper Slag Research Articles

Upscaling of Copper Slag-Based Geopolymer to 3D Printing Technology

Additive manufacturing using cement has evolved rapidly in recent decades, revolutionizing the construction industry. This technology automates building structures through computer-aided design, offering benefits such as reduced material waste, optimized material distribution, and the ability to use composite materials. This paper aims to examine the potential of using copper-slag-based geopolymers in 3D printing. Geopolymers have gained popularity as an alternative and more energy-efficient material to traditional building materials, while copper slag allows for reducing and managing mining industry waste. Moreover, samples formed in molds based on the same material were produced to evaluate the method of manufacturing on the mechanical properties of geopolymers. This paper presents an evaluation of the mechanical properties including the compressive, flexural, and shear strength of the layered material. It reveals promising results, with strength development mainly observed within the first 14 days. The results show that the compressive strength after 28 days of curing is 46.4 MP and 42.1 MPa for formed and printed samples, respectively. Furthermore, the average bending strength value ranges between 7.4 MPa and 7.8 MPa, regardless of the bending direction and forming method. The obtained results show that printed geopolymers demonstrate adequate layer bonding, confirming the profitability of the 3D printing technology. This research confirms that 3D printing technology enables the use of geopolymer binder materials based on copper slag, which opens the door to sustainable alternatives in construction practices.

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

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

Enhancing magnesium oxalate cements with copper slag and silica fume

Magnesium oxalate cement is an alternative binder made by reacting dead-burned magnesia and oxalic acid salts. Dead-burned magnesia, which has a high carbon footprint, was replaced at different levels (25–100 %) with copper slag, as a source of iron and thus a reactive component, or silica fume, as an inert or low-reactivity component. The powder mixtures contained ∼25–35 % oxalate, by mass. Physical and mechanical properties were investigated as well as changes in the mineralogy and morphology of paste and mortar specimens. Replacement of up to 50 % of dead-burned magnesia yielded strong (> 30 MPa) and water-resistant mortars with extended setting times, for mixtures with lower oxalate content. Mixtures with higher oxalate content and those without any dead-burned magnesia suffered significant strength loss in water. When copper slag was used, humboldtine, an iron oxalate, formed instead of or in addition to glushinskite, the main reaction product of magnesium and oxalate ions. Silica fume did not yield any crystalline reaction products.

Synergistic effect of carbothermal reduction and sodium salts leaching in the process of iron recovery from copper slag

Copper slag is mostly considered a waste material and around 41wt% of total iron content present in it is lost. Iron is mostly present in copper slag as fayalite (Fe2SiO4). In this study, Iron was recovered by the decomposition of Fe2SiO4 using the synergistic effect of carbothermal reduction and sodium salts leaching for the first time. The results showed that 68.39% of iron was recovered from copper slag by carbothermal reduction at 1000oC for 1hr. The iron recovery increased to 83.45, 93.39 and 97.8%, respectively, after further 1hr leaching by 2M NaOH, 1M Na2CO3 and 2M NaOH+1M Na2CO3 at 100oC. The leaching results indicated that the increased NaOH concentration from 1 to 2M improved the removal of silica, which in turn led to higher iron recovery. The increase of Na2CO3 concentration from 1 to 2M showed a negative effect on iron recovery. The combination of 2M NaOH and 1M Na2CO3, however, led to the highest iron recovery of 97.8% because NaOH+Na2CO3 gives Na2O that is easier to react with SiO2 with only -194.3kJ energy requirement. Mass balance calculations indicated that before the leaching process, 345kg mass was lost, whereas, after the leaching process the amount of discarded waste was only 260.8g. Therefore, the present study not only provides 97.8% iron recovery but also reduces the discharge of secondary solid waste due to no addition of additives.

Exploring the viability of copper slag geopolymer concrete in structural applications: A study on strength variability and seismic risk assessment

This study explores the use of copper slag (CS) as a sustainable alternative to natural sand (NS) in geopolymer concrete (GPC) for structural applications. Despite the potential of CS to promote environmental sustainability by repurposing industrial waste, its adoption in the construction industry remains limited. To address this gap, the study focuses on two main aspects: (i) modelling the uncertainty in the strength properties of CS-based GPC, and (ii) assessing the performance of CS-based GPC in seismic-resistant reinforced concrete (RC) framed buildings. The results show that the compressive strength of CS-based GPC is best represented by the Gumbel max and Gamma distributions, while the splitting tensile strength is well-modelled by Gamma and lognormal distributions. The flexural strength follows Gumbel max and Weibull distributions. These findings provide valuable data for probabilistic structural analysis and reliability-based design. Additionally, the seismic performance of RC frames made with GPC containing CS was found to be comparable to that of control frames with NS, confirming the viability of CS-based GPC in seismic-resistant structures. This research demonstrates that CS can be effectively utilized in GPC without compromising structural safety, contributing to more sustainable concrete construction practices.

Enhancing sustainability in concrete construction: Utilizing copper slag for improved properties of geopolymer concrete

Geopolymer concrete (GPC), utilizing aluminosilicate precursor materials as binders, stands as an eco-friendly alternative to Portland cement concrete. These precursors commonly include natural resources like metakaolin, volcanic ash, and industrial solid waste such as fly ash (FA) and ground granulated blast furnace slag (GGBFS). However, despite not utilizing cement, GPC still faces environmental challenges due to the use of natural aggregates, leading to resource depletion. To mitigate this issue, researchers have explored replacing natural aggregates with waste materials, aiding both resource conservation and waste management. Copper slag (CS) is one such waste material with potential as fine aggregate in GPC. This study conducts a comprehensive evaluation of FA-GGBFS-based GPC incorporating CS as fine aggregate, revealing notable enhancements in transport, durability, and strength properties. The optimal replacement of 60 % natural sand with CS in GPC resulted in a 20–25 % increase in compressive strength, a 10–15 % improvement in slake durability, an 18–40 % reduction in water absorption, a 30–39 % decrease in permeable voids, and a 26–47 % reduction in depth of wear, all in comparison to the control specimen made with natural sand only. Thus, incorporating CS as a fine aggregate in GPC is recommended as an effective approach to enhance mechanical performance and durability, while contributing to sustainable construction practices.

Partial replacement of cement with marble powder and fine aggregate with copper slag

Concrete is the biggest utilized material around the world. With the expanding pace of populace development, framework to should be grown quickly to satisfy the necessities of individuals and for all these an enormous measure of assets are required. The significant one of them is total. In any case, the inordinate utilization of these assets will make an ecological awkwardness. Hence, we have chosen to supplant these significant element of the development business with marble powder and copper slag individually. As we know Concrete is the largest material after food and water. The main constituents of concrete are Cement and Fine aggregate. Many studies have been done to know the environmental impact of cement and concrete. Seeking the adverse effect of high production of cement on environment, we have thought of partial replacement of cement with marble dust and fine aggregate with copper slag in this research.

Organic and Inorganic Modifications to Increase the Efficiency in Immobilization of Heavy Metal (Zn) in Cementitious Composites-The Impact of Cement Matrix Pore Network Characteristics.

This research investigated the properties of modified cementitious composites including water purification from heavy metal-zinc. A new method for characterizing the immobilization properties of tested modifiers was established. Several additions had their properties investigated: biochar (BC), active carbon (AC), nanoparticulate silica (NS), copper slag (CS), iron slag (EAFIS), crushed hazelnut shells (CHS), and lightweight sintered fly ash aggregate (LSFAA). The impact of modifiers on the mechanical and rheological properties of cementitious composites was also studied. It was found that considered additions had a significantly different influence over the investigated properties. The addition of crushed hazelnut shells, although determined as an effective immobilization modifier, significantly deteriorated the mechanical performance of the composite as well as its rheological properties. Modification by iron slag allowed for a significant increase in immobilization properties (five-fold compared to the reference series) without a substantial impact on other properties. The negative effect on immobilization efficiency was observed for nanoparticulate silica modification due to its sealing effect on the pore network of the cement matrix. The capillary pore content in the cement matrix was identified as a parameter significantly influencing the immobilization potential of most considered modifications, except biochar and active carbon.

Prediction of Mechanical and Tensile Properties of Self-Compacting Concrete Incorporating Fly Ash and Waste Copper Slag by Artificial Neural Network-ANN

Prediction of Mechanical and Tensile Properties of Self-Compacting Concrete Incorporating Fly Ash and Waste Copper Slag by Artificial Neural Network-ANN

Performance evaluation of fly ash–copper slag-based geopolymer bricks

This study investigates the production and evaluation of geopolymer bricks made from a blend of fly ash, copper slag, soda ash activator, and sand as fillers. Locally abundant industrial and mining waste materials were selected as the primary components. The bricks were synthesized using two binders: 60% fly ash with 40% copper slag, or 70% fly ash with 30% copper slag. Both were milled with the activator at a 0.2 soda ash-to-precursor ratio. Fine sand was added to the mixes at 1:2 and 1:3 binders-to-sand ratios. The bricks’ physical, mechanical, and durability properties were examined through compressive strength, modulus of rupture, density, water absorption, drying shrinkage, and efflorescence test, and their performance was compared to established industry standards. The experimental findings indicate that bricks made with 60% fly ash, 40% copper slag, and a 1:2 binder-to-sand ratio exhibited optimal compressive strength (9.64 MPa) and water absorption (7.5%) at 28 days of curing age. Conversely, there was only a marginal increase of up to 4.7% in the strength of the formulation with 70% fly ash and 30% copper slag, attaining a compressive strength of 4.9 MPa between the curing ages. Furthermore, the results indicated a positive correlation between the density and compressive strength of the geopolymer bricks at similar curing ages. The bricks’ density showed minimal variation with curing age and the highest modulus of rupture value observed was 2.5 MPa. The optimal bricks also exhibited relatively low linear shrinkage, good resistance to efflorescence, and met the relevant industry standards.

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.

Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia

Mine slag dumps could be point-sources of possible pollutants to the surrounding water and soils. The purpose of this study was to investigate the leaching behavior of zinc, lead and nickel from Nkana copper slag dump of Kitwe in Zambia. To assess the toxicity and hazardous nature of the slag, Bath Leaching EN 12,457–2:2002, Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) were employed. The results from these techniques revealed that the copper slag was inert in the open or natural environment. Sequential extraction analysis was conducted to analyze the fractionation of the zinc, lead and nickel using a seven-step procedure. The sequential extraction analysis showed that the 3 metals were predominantly present in the residual fraction. The risk assessment code (RAC) showed that zinc and lead's mobility could pose an environmental risk categorized as low risk, with RAC values of 1.31 % and 1.50 %, respectively. Nickel's mobility fell within the no-risk category with a RAC of 0.32 %. Additionally, the effect of pH, particle size and contact time on the release of the 3 metals were investigated. The results showed that the highest concentrations of zinc and nickel were observed for longer period of exposure (>33 days), in acidic environments (pH 2.2 and pH 3.0), for particle size distribution (<75 μm). However, lead leaching was not affected by the variation of pH or particle size distribution but mostly by duration of exposure. X-ray diffraction (XRD) analysis revealed that diopside (CaMgSi2O6) and quartz (SiO2) constitute the primary phases within the sample. It is recommended to limit the exposure of slag material to acidic environments and minimize the fragmentation of the slag into finer particles as these conditions would promote increased release of zinc, lead and nickel to the surrounding environment.

Experimental Investigation on the Properties of Concrete Containing Waste HDPE Plastic and Copper Slag as Coarse and Fine Aggregates Replacement

Resource concerns have become apparent globally, particularly in the construction sector due to the exploitation of resources for developing globalized infrastructures. This has led to challenges, especially in sourcing construction materials. Consequently, numerous studies have focused on waste management strategies with eco-efficient parameters, particularly in the realm of construction aggregates. While previous research has explored alternatives for these aggregates, there remains ample opportunity for further investigation on the effectiveness and potential of alternative materials in construction projects to promote sustainable resource management. The research aims to fill this gap by examining the impact of using alternatives for both fine and coarse aggregates, specifically copper slag and waste HDPE. This study investigates the effects of partially incorporating waste HDPE plastic and Copper slag on the strength and sustainability of concrete, with the goal of evaluating their viability as sustainable alternatives in construction materials in the construction sector. Three percentages of High-Density Polyethylene (HDPE) Plastic (10%, 20%, and 30%) and Two Percentages (30% and 40 %) of copper slag were incorporated with the weight of Coarse aggregate and Fine aggregate respectively. Comparisons of conventional concrete with concrete incorporating HDPE waste &amp; copper slag as coarse aggregate and fine aggregates were conducted. From investigation it was found that concrete incorporating 10% of HDPE and 40% of copper slag cured for 7 and 28 days had 10% increase in compressive strength compared to the nominal mix and flexural strength 25% and 40% more than nominal mix. The concrete incorporating 10% of HDPE and 30% of copper slag had 18% reduction in split tensile strength for cylinders cured for 7 days and 55% increase in split tensile strength for cylinders cured for 28 days.

Sustainable Green Industry Work: Recovery of Copper Slag with Mill Scale Leaching Reactant Optimized by Response Surface Methodology (RSM)

Sustainable Green Industry Work: Recovery of Copper Slag with Mill Scale Leaching Reactant Optimized by Response Surface Methodology (RSM)

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.

Utilizing copper waste to develop silicon-carbon anode materi als for lithium-ion batteries

This study dedicated to a novel method for synthesizing silicon-carbon (Si/C) and silicon dioxide-carbon (SiO2/C) nanocomposite anodes for lithium-ion batteries, utilizing industrial copper slags from the Almalyk Mining and Metallurgical Complex as a cost-effective source of SiO2. The synthesized nanocomposites address key challenges in lithium-ion battery anodes, including the volumetric expansion of silicon and its low conductivity, by leveraging the high lithiation capacity of silicon combined with the structural stability and conductivity of carbon. Amorphous SiO3 was extracted from copper slags via ammonium fluoride (NH4F) treatment and subsequently reduced to metallurgical-grade silicon through carbothermal reduction. The resulting SiO2/C and Si/C composites were thoroughly characterized using SEM, XRD, and electrochemical analyses, demonstrating improved electrochemical performance, favorable particle size distribution, and stability. This approach not only reduces material costs but also promotes environmental sustainability by repurposing industrial waste, offering promising candidates for high-performance lithium-ion battery anodes.

A Bibliometric Analysis and Review on Applications of Industrial By-Products in Asphalt Mixtures for Sustainable Road Construction

The growing consumption of natural resources to meet the needs of road construction has become a significant challenge to environmental sustainability. Additionally, the increase in industrial by-products has raised global concerns due to their environmental impacts. The utilization of industrial by-products in asphalt mixtures offers an effective solution for promoting sustainable practices. The objective of this article is to conduct a bibliometric analysis and citation-based review to characterize and analyze the scientific literature on the use of steel slag aggregates, copper slag, phosphorus slag, bottom ash, fly ash, red mud, silica fume, and foundry sand in asphalt mixtures. Another aim is to identify research gaps and propose recommendations for future studies. The bibliometric analysis was conducted using VOSviewer software version 1.6.18, focusing on authors, co-authorship, bibliographic coupling, and countries. A total of 909 articles were selected for the bibliometric analysis. The findings indicate that more effort is needed to expand the application of industrial by-products in asphalt mixtures. Furthermore, these by-products should be utilized in different types of asphalt mixtures. The incorporation of industrial by-products into asphalt mixes also requires field validation and further laboratory investigations, particularly concerning aging and moisture resistance. In addition, the effects of chemical reactions involving industrial by-products on the long-term performance of asphalt layers should be evaluated. Finally, this article encourages engineers and researchers to intensify their efforts in utilizing industrial by-products for environmental sustainability.

Mineralogical Analysis of Copper Slag Treated Expansive Soil Using X-Ray Diffraction

Mineralogical Analysis of Copper Slag Treated Expansive Soil Using X-Ray Diffraction

Numerical simulation for heat transfer behavior of copper slag ladle under air-cooling mechanism

Copper slag ladle cooling process is divided into two stages: air-cooling and water-cooling, is one of the important processes in copper production process from copper slag flotation recovery of valuable metals. This study investigates the transient heat transfer behavior of copper slag ladle during air-cooling mechanism based on the finite-volume method. The innovative aspect of this research lies in development of a 1:1 scale 3D model of slag ladle based on industrial-scale dimensions, obtaining the relevant thermophysical parameters of copper slag by experiment, and validating simulation results against actual industrial production data. The results of study show that: (i) The temperature distribution of copper slag within slag ladle exhibits a “concentric circle” pattern with the formation of a “liquid core” zone, indicating that the temperature is significantly higher in central region compared to periphery, revealing a notable temperature gradient during the air-cooling process; (ii) The heat flux is most concentrated in the central region of slag ladle, suggesting that the heat transfer intensity is the greatest in this area, the temperature variation of copper slag in proximity to this region is the most pronounced; (iii) The cooling path of copper slag proceeds from outer layers to inner layers, with the cooling rate decreasing from fast to slow, reflecting the temperature change trend of copper slag during air-cooling, which transitions from rapid to gradual cooling. This study provides new perspectives and data support for exploring air-cooling process of copper slag ladle and contributes to the further advancement of this field.

Mineralogical Characterisation of Copper Slag and Phase Transformation after Carbocatalytic Reduction for Hydrometallurgical Extraction of Copper and Cobalt

Copper smelting slag is a significant potential resource for cobalt and copper. The recovery of copper and cobalt from copper slag could significantly augment the supply of these metals, which are essential to facilitating the transition to green energy while simultaneously addressing environmental concerns regarding slag disposal. However, the complex mineral composition of copper slag poses an enormous challenge. This study investigated the mineralogical and chemical characteristics of copper slag, which are vital for devising the most effective processing techniques. XRD and FESEM-EDS were employed to examine the morphologies of copper slag before and after the reduction process. The effects of borax and charcoal (carbocatalytic) reduction on phase transformation were evaluated. The XRD analysis revealed that the primary phases in the copper slag were Fe2SiO4 and Fe3O4. The FESEM-EDS analysis verified the presence of these phases and yielded supplementary details regarding metal embedment in the Fe2SiO4, Fe3O4, and Cu phases. The carbocatalytic reduction process expedited the transformation of copper slag microstructures from crystalline dendritic to amorphous and metallic phases. Finally, leaching experiments demonstrated the potential benefits of carbocatalytic reduction by yielding high extractions of Cu, Co, and Fe.