Copper Sulfide Research Articles

Trojan Horse Bioheterojunction Empowers Adhesive Hydrogel with Robust Antibacterial Activity and Sensing Capacity for Infected Cutaneous Regeneration.

Strategic integration of adhesive hydrogels with phototherapy-based antibacterial properties has been extensively leveraged in infected tissue repair. Nevertheless, the interference of bacterial heat shock proteins and antioxidant defense systems attenuates the bactericidal potency of phototherapy. To address this imposing predicament, a Trojan horse bioheterojunction (Th-bioHJ) incorporating liquid metal and copper sulfide is devised to confer an adhesive hydrogel with multimodal and comprehensive antibacterial properties for remedying infectious wounds. Th-bioHJ generates phototherapeutic effects and interrupts the electron transport chain with the Trojan horse strategy, achieving rapid and robust sterilization. Additionally, Th-bioHJ promotes cell migration and angiogenesis. In vivo studies elucidate the remarkable efficacy of Th-bioHJ hydrogel in rapidly eradicating bacteria, promoting angiogenesis and boosting infectious cutaneous regeneration. Meanwhile, the Th-bioHJ hydrogel demonstrates exceptional biointerface adhesion and sensing capabilities for real-time motion monitoring. This study provides groundbreaking insights into the innovative application of an adhesive hydrogel in the management of infected wounds.

A General Strategy for Tumor-Specific In Situ Synthesis of Copper Sulfide for Gas Therapy and Surface Plasmon Resonance Enhanced Phototherapy

A General Strategy for Tumor-Specific In Situ Synthesis of Copper Sulfide for Gas Therapy and Surface Plasmon Resonance Enhanced Phototherapy

Gold Recovery from Smelting Copper Sulfide Concentrate

Gold is a significant revenue source for custom copper smelters facing profitability challenges due to low treatment and refining charges, stricter regulations, and rising costs. Gold is also often blended with copper concentrates, but precise recovery rates from smelting processes are poorly documented despite gold critical economic importance. This paper aims to provide the first comprehensive estimates of gold first-pass recovery across various operational units within the copper sulfide concentrate processing flowsheet. It evaluates the effectiveness of different copper smelting and converting technologies in recovering gold. Optimizing gold first-pass recovery is especially important to enhance immediate financial returns and responsiveness to market dynamics, allowing companies to capitalize on favorable gold prices without delays. Given the absence of direct measurements for gold recovery rates, this research develops an estimation method based on understanding gold loss mechanisms during smelting. This study identifies and analyzes key input and output parameters by examining data from various copper producers. By correlating these parameters with gold loss, the research estimates gold first-pass recovery rates within the copper smelting process. Among integrated smelting-converting routes, the flash smelting to Peirce–Smith converting route achieves the highest gold first-pass recovery (98.8–99.5%), followed by the Mitsubishi continuous smelting and converting process (94.3–99.8%), bottom-blowing smelting to bottom-blowing converting (95.8%), flash smelting to flash converting (95.5%), Teniente smelting to Peirce–Smith converting (95.2%), and the Noranda continuous smelting and converting process (94.8%). The final recovery rates are expected to be higher considering the by-products’ internal recirculation and post-processing within the copper flow sheet. Additionally, superior gold recoveries are attributed to advanced metallurgical practices and control systems, which vary even among companies with similar technologies. This research demonstrates that copper smelting can effectively recover over 99% of gold from sulfide concentrates. Gold accumulates up to 1000 times its original concentration in anode slime during electrolytic refining, generating 5–10 kg of slime per ton of copper, which is further processed to recover gold and other by-products. Major smelters operate precious metal plants where recovering gold from highly concentrated anode slime is both cost-effective and efficient.

Metallurgical technology and resources mobility in the El Argar culture: An archaeometallurgical study at Laderas del Castillo (Callosa de Segura, Alicante)

Metallurgy has been defined as a pivotal activity in understanding of the development of El Argar society. Nonetheless, comprehensive studies of extractive metallurgical processes based on archaeometallurgical analyses remain lacking. This article examines the production remains found at the El Argar site of Laderas del Castillo, documented from 2150 to 1950 cal BC, including samples of slag, crucibles, copper prills and artefacts. Laderas del Castillo emerges as a key site for understanding the technology and organization of metallurgical production in the El Argar world. There are few sites with archaeometric analysis of metallurgical remains, and the present case allows for an almost complete view of the entire metallurgical chaîne opératoire in this period. Microstructural analyses of smelting remains by SEM-EDS reveal a technological tradition that mirrors the previous Copper Age one and the direct exploitation of complex arsenical copper ores with occasional copper sulphides. Despite the existence of closer mineralizations, lead isotope analyses show the exploitation of various copper resources and sources far from the settlement (Linares, the Interior of the Baetic Cordilleras and Almagrera, about 300, 200 and 140 km respectively). These active exchange networks in Laderas del Castillo reflect the same pattern found in the rest of the El Argar territory, which is based on the intensive exploitation of mineralizations in the interior of the Baetics and the Southeast of the peninsula. Some of these sources have also been observed in Copper Age metallurgy, suggesting that the mobility and exchange networks operating in the southeast during the El Argar period were rooted in earlier archaeological phases, indicating a wide and complex exchange network in the region.

Role of grain boundary passivation in the enhancement of efficiency of copper chalcogenides thin film photovoltaic devices: A schematic review

Photovoltaic devices are expected to display peak performance if fabricated with perfect single crystals. Since surfaces break the periodicity of a single crystal, there are regions of defects, which give rise to states inside the forbidden energy gap. In polycrystalline thin films, the main structural defect is the grain boundary. The presence of grain boundaries affects the optical absorption, carrier mobility and lifetime of the semiconductor. This review focuses on grain boundary passivation in thin film photovoltaic devices based on copper chalcogenides. Achieving enhanced performance in copper chalcogenide thin film Photovoltaic devices requires effective grain boundary passivation. This approach aims to mitigate the adverse effects of grain boundaries on the optoelectronic properties of the material, leading to improved efficiency and stability in Photovoltaic devices. The abstract discusses recent developments, methodologies and outcomes related to grain boundary passivation strategies, shedding light on their significance in advancing the performance of copper chalcogenide thin film Photovoltaic devices. The exploration of grain boundary passivation in this context contributes valuable insights to the ongoing efforts in optimizing the performance of thin film Photovoltaic technologies.

Polymer stabilized cholesteric liquid crystals enhanced by functional nanofibers loaded with CuS NPs and ATO NPs for efficient smart windows and advanced infrared camouflage/anti-counterfeiting technologies

The development of multifunctional smart windows with infrared anti-counterfeiting capabilities is a key research priority. However, achieving both high visible light (VIS) transparency and effective near-infrared (NIR) blocking remains a significant challenge. In this study, a multi-field responsive polymer stabilized cholesteric liquid crystal (PSCLC) smart window was successfully prepared. By adjusting the electric field, the smart window enables controlled adjustment of incident VIS and NIR light for temperature control. Optimization of polymerization conditions and nanofiber loading enhanced the bandwidth reflectance from 256 to 507 nm. The smart window employs an optimized drive scheme for coordinated IR modulation via direct current (DC). The copper sulfide (CuS) and antimony tin oxide (ATO) nanoparticles were loaded in the PSCLC system using electrostatic spinning technique. The loading of nanoparticles using nanofibers greatly increased the number of nanoparticles compared to direct doping of nanoparticles. Therefore, the nanofibers loaded with nanoparticles greatly enhanced the infrared shielding ability and electrical response of the system. In addition, the enhancement of nanofibers also improves the thermal and electrical durability of the PSCLC smart window, and the controlled distribution of nanofibers results in a highly flexible and reliable infrared anti-counterfeiting smart window. This research provides the development of multifunctional liquid crystal smart windows with infrared light modulation, camouflage and anti-counterfeiting functions.

CuS enabled efficient Fenton-like oxidation of phenylarsonic acid and inorganic arsenic immobilization

Herein, copper sulfide (CuS) was introduced to the Fenton-like (Fe(III)/H2O2) system for the efficient removal of phenylarsonic acid (PAA). Results of reactive oxygen and Fe/Cu species showed that CuS preferentially reacted with Fe(III) and H2O2 to generate Cu(I) and superoxide anion (•O2-). These reductive species could efficiently promote the Fe(III)/Fe(II) and Cu(II)/Cu(I) cycles, and are beneficial to the sequential Fenton reaction to generate •OH. The organoic/inorganic arsenic species detected in the CuS/Fe(III)/H2O2 system confirmed that PAA was oxidized by •OH to hydroxylated organoarsenic and phenolic intermediates, which were further mineralized to oxalate and formic acid. Meanwhile, the inorganic As(III)/As(V) released during PAA degradation were efficiently immobilized by CuS. The PAA removal efficiency remained as high as 92.9 % after 5 cycles of the CuS-mediated Fenton-like process. These results demonstrate an innovative method for the treatment of organoarsenic-contaminated water, and provide new insights into the enhanced Fenton-like process utilizing sulfide minerals.

Insights over the in-situ grown copper sulfide/NiFe-LDH composites for alkaline and urea water electrolysis

Harnessing hydrogen fuel through electrocatalytic water splitting offers an eco-friendly alternative to the traditional fossil fuels. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are the two half-cell reactions, that make up the electrocatalytic water splitting. Replacing the sluggish OER in the electrocatalytic water splitting with less energy demanding urea oxidation reaction (UOR) might benefit overall water splitting with reduced cell voltages. On the other hand, developing electrodes based on non-precious metals is essential for cost-effective and efficient water splitting. Herein, composites comprising non-precious nickel iron layered double hydroxide (NiFe-LDH) and copper (II) sulfide (CuS) are grown over the nickel foam and subjected to electrochemical measurements for alkaline water electrolysis (AWE) and urea water electrolysis (UWE). Structural and morphological investigations reveal that the 10 wt% CuS composited NiFe-LDH (NFCS10) is supposed to have effective catalytic features for water electrolysis. The electrochemical investigations in the three-electrode system with silver/silver chloride (Ag/AgCl, reference electrode) and platinum (Pt, counter electrode) revealed that the NFCS10 requires only a minimal overpotential (Ƞ50) of 235 mV for UOR and 400 mV for OER respectively. For bifunctional performance, NFCS10 requires an overall cell potential (OCP) of 1.65 V and 1.50 V to reach 10 mA/cm2 current density in AWE and UWE, respectively. X-ray photoelectron spectroscopy identifies the enrichment of oxygen vacancies in NiFe-LDH:CuS heterostructure, which could influence the charge transport and stability of the proposed electrode. This study emphasizes the interfacial interactions between the LDH and metallic sulfide, as well as their impact on the electrocatalytic activity in alkaline and urea water splitting.

Dual-Role of Thiourea for Synthesis of Copper Sulfide Decorated on Reduced Graphene Oxide/Graphitic Carbon Nitride for Advanced Photocatalysis

Dual-Role of Thiourea for Synthesis of Copper Sulfide Decorated on Reduced Graphene Oxide/Graphitic Carbon Nitride for Advanced Photocatalysis

Nguba Group hosted the Lonshi Copper Deposit: Perspective for the discovery of new deposits in the vicinity of the Lonshi Mine

The Lonshi is a newly discovered copper deposit located in the southeastern region of the Central African Copperbelt, in the Democratic Republic of Congo. The deposit is hosted in the Nguba Group of the Katanga Supergroup. This paper analyzes the lithostratigraphy of the Nguba Group, structures, ore host rock, and mineralization characteristics of the Lonshi deposit. The lithostratigraphy of the Lonshi area is comprised of the Mwashya sandstone of the Roan Group; conglomerate, dolostone, shale, mudstone, and siltstone of the Nguba Group; and conglomerate, pink dolostone, and siltstone of the Kondelungu Group. Geological structures identified within the mining zone encompass the N-S and W-E trending folds, the NW-trending fault, E-W sinistral shear structures, and various fractures and veins. The Lonshi deposit exemplifies a characteristic of hydrothermal stratiform mineralization, comprising two main orebodies situated within the Mwale conglomerate (lower orebody) and the underlying Lonshi dolostone (upper orebody). The ore deposited during three mineralization stages, wherein the first hydrothermal stratigraphically-controlled stage that deposited chalcocite 1, bornite, chalcopyrite and pyrite. The structurally-controled stage 2 is further divided into chalcocite 2 and bornite stage 2a, and chalcopyrite, bornite and native copper stage 2b; and the supergene alteration stage 3 results in the formation of chalcocite 3, malachite, cuprite, azurite, and native copper 2. The gangue minerals associated with copper sulfide minerals consist of ankerite, feldspar, quartz, muscovite/sericite, kaersutite, barite, and illite. The sulfide minerals associated with ore stages display zonation both vertically and laterally, transitioning from chalcocite to bornite to chalcopyrite to pyrite±sphalerite. Copper sulfide minerals manifest as fine- to coarse-grained disseminations within the conglomerate, exhibiting a replacement texture. The mineralizing fluids at the Lonshi deposit were likely enriched in Fe, Ca, Mg, Si, S, and Cu, with additional magnesium within the ore hosted dolostone and cobalt and potassium within the ore hosted conglomerate.The Nguba Group shows the distinct lithologies of light-gray conglomerates and dolostone, provide valuable insights for potential new deposits near the Lonshi mine. The observed mineral zoning, hydrothermal alterations, and multi-stage mineralization events suggest favorable conditions for copper mineralization. Targeting similar stratigraphic settings and alteration signatures in the vicinity could enhance the likelihood of discovering new deposits, particularly in areas exhibiting similar geological characteristics and structural features.

Green Synthesis, Characterization of Copper Sulfide Nanoparticles and Antibacterial Activity Evaluation

This study focused on the eco-friendly and economical synthesis of copper sulfide nanoparticles at certain temperatures using myrtle leaf extract. Green synthesis methods are mostly considered to be safe and efficient in the nanoparticle synthesis field. The nanoparticles were characterized using FT-IR, AFM, UV-visible spectrophotometer, FESEM with EDX, and XRD. where the crystal size in XRD was 21.4 nm. The antibacterial properties of CuS nanoparticles were evaluated against two bacterial strains, namely, Staphylococcus aureus and Escherichia coli, using various concentrations. The Minimum Inhibitory Concentration (MIC) was determined for both bacteria at a range of CuS NPs conc. from 0.5229 × 10-1 M to 0.3268 × 10-2 M.

Fabrication of high-performance asymmetric supercapacitor device based on CuS with marigold flower like framework

A solvent regulated approach was utilized for creating copper sulfide of distinct morphologies and employed as an electrode in three and two electrode configurations. X-ray diffraction, FESEM and TEM revealed the crystalline structure and marigold flower like morphology of copper sulfide in ethylene glycol. The marigold flower like CuS outperforms in terms of electrochemical performance, with an excellent capacitance of 631.2 F/g at 1 A/g of current density. Furthermore, a supercapacitor device has been constructed with a potential window of 1.4 V, exhibited 301.23 F/g of capacitance at 10 A/g. This device displays a desired 82 Wh/kg of energy density when the power density is 2.9 kW/kg. The device maintained cyclic stability of 82 % during 2500 GCD cycles at 20 A/g. Two devices connected in series light up different colours of LEDs. These favourable electrochemical results strongly suggest that the marigold flower-like CuS electrode has excellent potential for use in energy storage applications.

Comprehensive Assessment of In Vivo Toxicity and Safety Profile of PEGylated Copper Sulfide Nanoparticles in a Rat Model (Sprague Dawley)

Comprehensive Assessment of In Vivo Toxicity and Safety Profile of PEGylated Copper Sulfide Nanoparticles in a Rat Model (Sprague Dawley)

Portable paper-based microfluidic devices with Cu1-xAgxS NPs modification for multiplex intelligent visualized detection of adrenaline and glucose simultaneously

BackgroundAdrenaline and glucose are essential biomarkers in human body for maintaining metabolic balance. Abnormal levels of adrenaline and glucose are associated with various diseases. Therefore, it is important to design portable, on-site devices for rapid adrenaline and glucose analysis to safeguard health. Traditional paper-based analytical devices (μPADs) for multiplexed detection typically required multiple recognized probes, increasing the cost and complexity. Moreover, non-uniform color distribution, caused by lateral chromatographic elution effect, reduced results accuracy. Hence, it is necessary to construct visualized μPADs with controlled flow capability using single sensing probe for simultaneous adrenaline and glucose analysis in point-of-care testing (POCT). ResultsThe portable multiplexed 3D-folded μPADs have been developed for the visualized, accurate and simultaneous detection of adrenaline and glucose, employing Ag-doped copper sulfide nanoparticles (Cu1-xAgxS NPs) as multifunctional sensing probe. The μPADs integrated the sampling entrance layer, buffer layer and test layer into a single device through wax printing, allowing the analyte solution to flow vertically from buffer zones to detection zones, thereby minimizing lateral chromatographic elution effect. Cu1-xAgxS NPs, exhibiting laccase-like and peroxidase-like multi-enzyme activities, were modified on various detection zones of μPADs for multiplex colorimetric analysis of adrenaline and glucose. Based on Cu1-xAgxS-induced colorimetric reactions, the orange-red and blue colors were generated in adrenaline and glucose detection zones, respectively. Subsequently, color signals were converted into RGB values via smartphone application (APP) for rapid and intelligent results analysis. The Cu1-xAgxS-incorporated μPADs exhibited colorimetric uniformity and accuracy with limit of detection (LOD) of 10.2 nM and 11.5 μM, respectively. SignificanceThe adjustable laccase-like and peroxidase-like activities of Cu1-xAgxS NPs induced by Ag doping provide a new perspective for multiple biomarkers analysis. Benefiting from the excellent multienzyme activity of Cu1-xAgxS NPs, μPADs can perform on-site, visual and multiplex analysis using a single probe, demonstrating their potential for POCT in personal healthcare. The 3D folded Cu1-xAgxS-incorporated μPADs with integrated horizontal and vertical flows exhibit uniform color signals for obtaining accurate detection results.

Design towards recyclable micron-sized Na2S cathode with self-refinement mechanism

Sodium sulfide (Na2S) as an initial cathode material in room-temperature sodium-sulfur batteries is conducive to get rid of the dependence on Na-metal anode. However, the micron-sized Na2S that accords with the practical requirements is obstructed due to poor kinetics and severe shuttle effect. Herein, a subtle strategy is proposed via regulating Na2S redeposition behaviours. By the synergistic effect from both conductive structure and cuprous sulfide (Cu2S) catalysis, the micron-sized Na2S particles are broken down and redeposited to nano-size during the initial cycle which can be fully utilized in subsequent cycles. Consequently, the Na2S/CPVP@Cu2S||Na cell delivers excellent cyclability (670 mAh gS−1 after 500 cycles) with a remarkable average Coulombic efficiency over 99.7% and rate capability (480 mAh gS−1 at 4 A gS−1). Besides, the Na-free anodes are used to prove the application prospects. This work provides an innovative idea for utilizing micron-sized Na2S and offers insights into its conversion pathway.

Multifunctional Copper Sulfide Urchin‐Like Nanostructures for Adsorption and Photocatalysis of Water Contaminants

AbstractWe reported here a one‐step chemical route to prepare nanocomposites comprising CuS nanophases supported on GO sheets with magnetic properties. The synthesis reported here combines such materials in single‐nanostructures that show morphological features well‐suited for wastewater treatment. The photocatalytic performance of CuS/GO nanocomposites was first investigated towards the removal of a common organic dye (rhodamine B) and sulfamethoxazole (SMX), which is an antibiotic considered a water contaminant of emerging concern. The RhB and SMX adsorption efficiency of CuS/GO and Fe3O4/GO/CuS hybrids, as well as of CuS particles, was significantly higher than GO or Fe3O4/GO. Overall, the CuS‐based magnetic and CuS/GO hybrids have shown the capacity to uptake more than 80 % of RhB or SMX, after 120 minutes. Under blue‐led irradiation, almost complete degradation of RhB was achieved in the presence of CuS/Fe3O4/GO, after 180 minutes; and higher than 85 % degradation of SMX, after 240 minutes of irradiation. The photocatalytic behaviour of nanocomposites was best described by the first–order kinetic model, for which k values for degradation of RhB and SMX followed the order: CuS/Fe3O4/GO>CuS/GO>CuS. The tricomponent CuS/Fe3O4/GO can be easily recovered after use and be reused maintain their high photocatalytic performance, thus providing a sustainable and cost‐effective hybrid solution for water treatment.

Development of a hybrid CuS-ICG polymeric photosensitive vector and its application in antibacterial photodynamic therapy

At the present time, owing to the extremely high growth of microbial resistance to antibiotics and, consequently, the increased healthcare associated costs and the loss of efficacy of current treatments, the development of new therapies against bacteria is of paramount importance. For this reason, in this work, a hybrid synergetic nanovector has been developed, based on the encapsulation of a NIR (near infrared) photosensitive molecule (indocyanine green, ICG) in biodegradable polymeric nanoparticles (NPs). In addition, copper sulfide nanoparticles (CuS NPs), optically sensitive to NIR, were anchored on the polymeric nanoparticle shell in order to boost the generation of reactive oxygen species (ROS) upon NIR irradiation. As a result, the nanohybrid synthesized material is capable to generate ROS on demand when exposed to a NIR laser (808 nm) allowing for the repeated triggering of ROS production upon NIR light exposure. After each irradiation, the ROS generated were able to eliminate pathogenic bacteria, as it was demonstrated in-vitro with three bacterial strains, Staphylococcus aureus ATCC 25923 used as a reference strain (S. aureus), S. aureus USA300 (methicillin-resistantstrain, MRSA) and GFP-expressing antibiotic-sensitive S. aureus (methicillin-sensitive strain, MSSA). Finally, the effect of the hybrid NPs in the skin bed was tested on a plasma-derived in vitro skin model. Fluorescence and histological images showed the presence of CuS NPs all over the dermal layer lacking epidermis of the skin construct. Thus, the in vitro model facilitated the prediction of the nanovector’s behavior in a human skin equivalent, showcasing its potential application against topical infections after wounding.

Transport Properties of Doped Wide Band Gap Layered Oxychalcogenide Semiconductors Sr2GaO3CuCh, Sr2ScO3CuCh, and Sr2InO3CuCh (Ch = S or Se).

The structural, electrical, and optical properties of a series of six layered oxychalcogenides with the general formula Sr2 MO3CuCh, where M = Ga, Sc, or In and Ch = S or Se, have been investigated. From this set, we report the structure and properties of Sr2GaO3CuSe for the first time, as well as the full structural details of Sr2ScO3CuSe, which have not previously been available. A systematic study of the suitability of all of the Sr2 MO3CuCh phases as p-type conductors has been carried out, after doping with both sodium and potassium to a nominal composition of A 0.05Sr1.95 MO3CuCh, (A = Na or K), to increase the hole carrier concentration. Density functional theory calculations were used to determine the electronic band structure and predict the transport properties, while optical properties were determined using UV-vis spectroscopy, and structures were confirmed using Rietveld refinement against powder X-ray diffraction data. Room-temperature conductivity measurements were carried out on both pristine samples and doped samples, 18 compositions in total, using four-point probe measurements. We found that the most conductive sample was K0.05Sr1.95GaO3CuSe, with a measured conductivity of 0.46 S cm-1, collected from a sintered pellet. We have also been able to identify a relationship between the conductivity and the geometry of the copper chalcogenide layer within the Sr2 MO3CuCh series of compounds. As this geometry can be controlled through the material composition, the identification of this structure-property relationship highlights a route to the selection and identification of materials with even higher conductivities.

Exploring the phase composition and crystal structure of potassium-doped copper sulfide

This study investigates the phase composition, crystal structure, and phase transitions of potassium-substituted copper sulfide (KxCu1.97-xS), focusing on the effects of potassium doping on the material’s properties. Using X-ray diffraction analysis, we identified the structural characteristics of potassium-doped variants, confirming their retention of the monoclinic chalcocite structure (P21/c) with slight modifications in lattice parameters. The incorporation of potassium ions resulted in observable changes in the unit cell dimensions, suggesting enhanced ionic interactions and potential impacts on electronic conductivity. The thermoelectric coefficient, electro-conductivity, and thermoelectric power were also examined, revealing that potassium doping could stabilize certain phases under varying temperature conditions. This work provides valuable insights into the structure-property relationships in copper sulfides, highlighting the potential for tailored materials in thermoelectric applications and other advanced technologies. Future studies will explore the implications of these findings for optimizing the performance of potassium-doped copper sulfides in practical applications.

Further Results on the Effects of the Grinding Environment on the Flotation of Copper Sulphides

Grinding conditions affect the flotation of copper sulphide minerals as changes in the properties of the grinding media and their interactions with the sulphide minerals, and between sulphide minerals themselves, affect the chemical environment in the flotation pulp. Galvanic interactions between steel grinding media and sulphide minerals, and between sulphide minerals, can lower the pulp potential, decrease the dissolved oxygen concentration in the mineral slurry, and lead to the dissolution of iron and copper from the media and the minerals. As a result, the formation of hydrophilic iron hydroxides and their adsorption on the copper sulphide minerals can be deleterious to copper flotation while pyrite (when present) can be activated to flotation by dissolved copper lowering the grade of the copper concentrate. Electrochemically less active grinding media (e.g., chrome alloy balls rather than mild steel media) can have beneficial effects on flotation performance due to the lower oxidation of the grinding media and consequently the lower production of oxidised iron species in the pulp. Copper activation of pyrite can be decreased by chemical additions to the pulp. In this paper, relevant experimental data published in the last 15 years are discussed.