Copper Cobalt Research Articles

Impact of effluents from a copper–cobalt processing plant in the environment

Abstract The new concentrator of Kipushi (NCK) in Katanga province is located in the southeast of the Democratic Republic of the Congo. This processing plant produces a concentrate of copper and cobalt, and it also generates a large amount of effluents equivalent to 2,500 m3/h. The complex nature of these effluent has become a threat to human lives, vegetation, as well as to freshwater resources in the surrounding areas. During this investigation, it was found that NCK effluents have high turbidity and high levels of sulphates compared with EPA standards. These sulphates originate from acid mine water used as one of the components for the flotation process. Also, high chlorides compared with EPA standards and hardness levels due to high concentrations of calcium and magnesium were recorded. Furthermore, the effluents contain heavy metals such as zinc, copper, cobalt, lead, ion, cadmium, and arsenic. Water used during flotation and downstream processes to produce copper and cobalt concentrates was a mixture of raw water from Kamalenge pond and acid mine water from Kipushi mine in a volume ratio of 70/30 respectively. However, it was found that the mine water is the major contributor to the effluent contamination.

Nanostructured copper–cobalt based spinel for the electrocatalytic H2O2 reduction reaction

Nanostructured copper–cobalt based spinel [(Cu0.30Co0.70)Co2O4] was employed as an electrocatalyst in the hydrogen peroxide (H2O2) reduction reaction (HRR). Both nanoparticles and nanoneedles co-existed in the (Cu0.30Co0.70)Co2O4 spinel, which exhibited a high intrinsic electrical conductivity and surface-to-volume ratio, resulting therefore in a large electrochemically active surface area for the HRR. In addition, (Cu0.30Co0.70)Co2O4 showed an onset potential at approximately −0.14 V in the HRR, with a limiting current density of ∼104 mA/cm2 at −0.43 V. The synthesised material followed the direct HRR pathway and exhibited good stability. In addition, the HRR activity of (Cu0.30Co0.70)Co2O4 was comparable to that of commercial Pt/C electrodes. The present results therefore demonstrate the significant potential of (Cu0.30Co0.70)Co2O4 for future applications in fuel cells as a cathode catalyst.

Using phytostabilisation to conserve threatened endemic species in southeastern Democratic Republic of the Congo

AbstractOutcrops in the southeastern Democratic Republic of the Congo (DRC) are recognized as some of the largest copper–cobalt orebodies in the world. They support a unique vegetation with nearly 600 metallophytes that include rare and endemic species. Mineral exploitation has increased considerably in the region since the 1900s, affecting both environmental and public health. Phytostabilisation of polluted areas represents an opportunity to decrease the bioavailability of heavy metals in the highly polluted soils that result from ore extraction. Such a technique has been successfully implemented near Lubumbashi with the grass Microchloa altera. However, long‐term maintenance requires a good understanding of interspecific relationships, such as competition and facilitation. This study tested the establishment success of four herbaceous species from the Katangan Copperbelt by assessing the potential role of Microchloa altera as a nurse species. Two annual and two perennial species were sown in an experiment designed to study the influence of soil amendment and vegetation cover on seedling emergence, growth, and survival. These variables were monitored during the vegetation growing season as well as resprouting success for perennials. Microchloa altera showed a distinct effect on the emergence and survival of annual and perennial species and negatively affected the growth of individuals belonging to both groups of species.

Comparative Evaluation of Optical Properties, Photoluminescence of Copper Oxide and Cobalt Oxide Nanoparticles Synthesized by O. Sanctum Mediated and Solvent Free Mediated Approach Under Microwave Irradiation

Comparative Evaluation of Optical Properties, Photoluminescence of Copper Oxide and Cobalt Oxide Nanoparticles Synthesized by O. Sanctum Mediated and Solvent Free Mediated Approach Under Microwave Irradiation

Effect of reaction temperature on the amorphous-crystalline transition of copper cobalt sulfide for supercapacitors

Amorphous and crystalline copper cobalt sulfides are successfully synthesized via a hydrothermal method at different temperatures and researched as electrode materials for supercapacitor. The reaction mechanisms during the sulfidation and hydrothermal processes are investigated and clarified. It is demonstrated that the hydrothermal temperature is a crucial factor for the crystallinity, morphology and electrochemical performance of CuCo2S4. Among all the samples, the CuCo2S4 synthesized at 150 °C shows the highest specific capacitance of 515 F g-1 at 1 A g−1 as well as good cycling stability with ∼93.3% capacitance retention after 10000 cycles at 5 A g−1. An asymmetric device which is assembled by using optimized CuCo2S4 electrode as positive electrode and activated carbon as negative electrode material is able to deliver an ultrahigh energy density of 50.56 Wh kg−1 at a power density of 4.6 kW kg−1, and remains 20.93 Wh kg−1 at a high power density of 22.5 kW kg−1, with ∼99% capacity retention after 10000 cycles. Based on the results above, the CuCo2S4 materials prepared by our method possess a considerable potential as electrode materials for supercapacitor applications.

Copper–Cobalt–Cerium Ternary Oxide as an Additive to a Conventional Platinum‐Group‐Metal Catalyst for Automotive Exhaust Catalysis

AbstractRecently, we reported on a ternary mixed‐oxide catalyst that showed low‐temperature CO oxidation activity under lean exhaust conditions without inhibition by hydrocarbons such as propene. However, the hydrocarbon oxidation activity of this Cu–Co–Ce (CCC) catalyst cannot be considered as a stand‐alone solution to low‐temperature automotive exhaust catalysis. To achieve both low‐temperature oxidation of pollutants and a reduction in the total platinum‐group‐metal (PGM) content, we examined a 50 % physical mixture of traditional Pt/Al2O3 and our CCC catalyst in two simulated exhaust protocols. Using this physical mixture, we were able to obtain equivalent or better hydrocarbon activity than the baseline Pt/Al2O3 catalyst with half the total PGM content as well as increased sulfur tolerance for the CCC component of the mixture. Diffuse reflectance infrared Fourier transform spectroscopy data confirmed that despite exposure of sulfur‐sensitive CCC to SO2, Cu+‐carbonyl binding sites could still be seen if the catalyst was mixed with Pt/Al2O3.

Three-Dimensional Dendrite Cu–Co/Reduced Graphene Oxide Architectures on a Disposable Pencil Graphite Electrode as an Electrochemical Sensor for Nonenzymatic Glucose Detection

Three-dimensional (3D) copper–cobalt (Cu–Co)/reduced graphene oxide (rGO) hierarchical architectures are electrochemically deposited over a pencil graphite electrode (PGE), and the modified PGE is directly exploited as a binder-free and disposable electrode for high performance nonenzymatic glucose sensors. The morphological features substantiate that the Cu–Co nanostructures display a 3D, open, porous, interconnected network architecture, in which the rGO layers are tightly pinned among the nanofeelers. Owing to the benefits of dendrite architectures and optimized composition, Cu–Co/rGO/PGE demonstrates better glucose oxidation behavior under alkaline conditions. Being a nonenzymatic glucose sensor, Cu–Co/rGO/PGE demonstrates excellent gluose detection properties with considerable chloride poisoning resistance. The excellent analytical performance of Cu–Co/rGO/PGE comprehends its application in human serum samples. Thus, this report paves constructive opportunities for the development of disposable, envi...

Tailoring magnetic and dielectric properties of Co0.9Cu0.1Fe2O4 with substitution of small fractions of Gd3+ ions

This paper describes the structural, magnetic, and dielectric properties of Gd3+ substituted cobalt–copper ferrite. The influence of Gd3+ substitution on the structural, magnetic and electrical properties of cobalt–copper ferrite was investigated through various characterization techniques. Thermal analysis was carried out on the prepared gel to know the combustion and calcination temperature. The detailed structural analysis suggests that the substitution of a Fe3+ ion with a Gd3+ ion at B site results in lattice distortion, modification in crystallite size and grain size of the material. X-ray photoelectron spectroscopy confirmed the oxidation states of the elements present. Magnetic measurement performed at 300 and 50 K depicts the decrease in saturation magnetization (Ms) and increase in coercivity (Hc) with Gd3+ substitution in the cobalt–copper spinel ferrite. The dielectric measurements acquired over a wide range of frequencies and temperature showed an increase in dielectric constant with increasing Gd3+ concentration.

Synergetic catalysis of bimetallic copper–cobalt nanosheets for direct synthesis of ethanol and higher alcohols from syngas

The reaction scheme of CO hydrogenation to ethanol under the synergetic catalysis of uniformly dispersed bimetallic copper–cobalt nanosheets.

铜钴硫纳米材料的合成及应用研究概述

铜钴硫纳米材料的合成及应用研究概述

125 Effect of Complexed Trace Minerals on Oocyte and Embryo Production

The objective of this experiment was to evaluate the impact of trace mineral supplementation on reproductive performance in lactating beef cows. Thirty days before AI (Day –30), 68 postpartum cows were stratified by weight, body condition score, and parity before being equally and randomly assigned to either a treatment or a control group. Each group received a weekly mineral supplement allotment of 1.2 kg/week per cow-calf pair for 15 weeks. Cows in the treatment group received a mineral supplement that contained zinc, copper, and manganese amino acid complexes as well as cobalt glucoheptonate (Availa® Plus; Zinpro Corp., Eden Prairie, MN, USA), whereas cows assigned to the control group received a mineral supplement that contained the same concentrations of these trace minerals from inorganic sources. All cows were submitted to a 7-day CO-Synch + CIDR protocol on Day –10 and bred using fixed time AI on Day 0. Pregnancy diagnosis was performed via transrectal ultrasound on Day 28. Cows diagnosed as nonpregnant were then removed from the experiment. Pregnant cows were divided into 10 groups of 3 or 4 cows per group: 5 treatment groups (20 total cows) and 5 control groups (18 total cows). On Day 52 and 67, all pregnant cows were subjected to an ovum pick-up (OPU). Collected oocytes were evaluated before performing in vitro fertilization. Number of oocytes cleaving (dividing into more than one cell) and developing to blastocyst stage was recorded. Analysis of variance was conducted using PROC GLIMMIX (SAS 9.4; SAS Institute Inc., Cary, NC, USA) to determine differences between treatment and control, and group was the experimental unit. Mineral consumption did not differ (P = 0.48) between treatments (average of 1.16 ± 0.065 v. 1.09 ± 0.065 kg/week per cow-calf pair, for treatment and control, respectively). Pregnancy per AI was numerically higher in mineral-supplemented cows versus controls (64.7% v. 52.9%, respectively; P = 0.33). Consumption of the complexed trace mineral supplement increased (P = 0.06) total oocyte yield (22.6 ± 1.44 mean ± SEM v. 16.4 ± 2.04 oocytes/group for treatment and control, respectively). Moreover, groups receiving the complexed trace minerals had more (P = 0.05) culturable oocytes (grades A through C) compared with control groups (15.9 ± 1.6 mean ± SEM v. 11.8 ± 1.01 oocytes/group, respectively). In addition, production of transferable embryos (grades 1 through 3) was greater (P = 0.04) for groups receiving complexed trace minerals than inorganic trace minerals (4.2 ± 0.64 mean ± SEM v. 2.6 ± 0.65 embryos/group, respectively). In summary, supplementing with zinc, manganese, and copper amino acid complexes plus cobalt glucoheptonate improved oocyte production and embryo development in pregnant beef cows when compared with cows supplemented with inorganic forms of these trace minerals.

Effects of the Addition Points of Reducing Agents on the Extraction of Copper and Cobalt from Oxidized Copper–Cobalt Ores

One of the key issues facing cobalt producers is to effectively use reducing agents to maximize cobalt extraction while minimizing operating costs. In addition to reducing cobalt(III), reducing agents like sodium metabisulfite (SMBS) and sulfur dioxide may also react with previously dissolved elements such as copper and magnesium that precipitate. The amount of reducing agents could be optimized and the parasitic reactions reduced if the most suitable points of addition of the reducing agents during leaching are determined. In this study, leaching tests on oxidized copper–cobalt ore were performed in order to determine the effects of SMBS addition points on the extraction behaviors of copper and cobalt. SMBS was added to various aqueous solutions at time t = 0 and t = 3 h. Regardless of the addition period, results showed that the addition of SMBS significantly improved cobalt extraction. However, a little amount of loss of copper by precipitation was observed when SBMS was added at t = 3 h than at t = 0 h.

One-step synthesis of copper-cobalt carbonate hydroxide microsphere for electrochemical capacitors with superior stability

Copper cobalt carbonate hydroxide (Cu-Co CH) microspheres were synthesized as a pseudocapacitive electrode material via a simple one-step hydrothermal method. Morphological characterization of the Cu-Co CH microspheres was carried out by scanning electron microscopy and transmission electron microscopy, showing their dandelion-like structure with the size approximately 4–7μm. The crystalline structure, morphology and electrochemical performances of Cu-Co CH materials could be readily dominated by the molar ratio of Cu to Co. Among various stoichiometries of Cu-Co CHs, sample Cu0.48Co1.52 CH delivered the highest specific capacitance of 397.3Fg−1 at 1Ag−1 with a good rate capability. Cu0.48Co1.52 CH electrode material also exhibited a remarkably excellent cycling stability, ~99% of initial capacitance retention even after 10,000 charge/discharge cycles at 2Ag−1. An asymmetric energy storage device was assembled by using Cu0.48Co1.52 CH as positive electrode and activated carbon as negative electrode in 2M KOH electrolyte. The hybrid capacitor device could deliver an energy density of 26.3Whkg−1 at a power density of 400.2Wkg−1, and remain 16.7Whkg−1 at 8374.2Wkg−1. Meanwhile, it also showed amazing stability with ~99% capacity retention after 10,000cycles. Based on the above results, Cu-Co CH microspheres possessed practical application as electrode materials for electrochemical capacitors due to their good structural stability in KOH electrolyte.

Incorporation of matte-slag thermochemistry into sulphide smelter discrete event simulation

ABSTRACTDiscrete event simulation (DES) is a suitable framework to evaluate and optimise the dynamics of sulphide smelters. In particular, iron–nickel–copper–cobalt sulphides undergo continual oxidation within a roasting or smelting operation, followed by batch oxidation within the converting operation, thus producing iron-free Bessemer matte (or blister copper, in the case of copper smelters); this semi-finished product undergoes further processing to produce nickel, copper and cobalt products, and to recover precious metals. The juncture between continuous smelting and batch converting is often an appropriate focus for the earliest phases of DES development, since it is typically a major bottleneck within nickel and copper smelters; later phases may include increasing levels of detail for auxiliary unit operations, as well as plant logistics. Moreover, DES can support matte-slag chemistry, including Gibbs free energy balances to determine the iron speciation within the slag. DES is therefore capable of linking the fundamentals of oxidation reactions to the intricacies of plant dynamics.

Influence of synthesis conditions on the surface properties of cobalt copper nanoferrites

Copper cobalt ferrite nanoparticles are prepared through two coprecipitation methods as well as two sol–gel auto combustion methods, and a comparison is made by studying the structural properties of nanoparticles produced. The effect of heat treatment is studied by calcining the obtained samples at two different temperatures. The obtained nanoparticles are characterized by different standard techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and surface area and pore diameter studies. XRD patterns reveal the spinel structure of the prepared nanocomposites. FTIR spectra confirm the spinel structure by revealing two characteristic absorption bands in the range 400–450 and 550–600 cm−1 respectively due to the vibrations of oxide ions with the divalent and trivalent metal ions in octahedral and tetrahedral sites in the spinel lattice. TEM images disclose the spherical nature of the particles. The acid site distribution of the prepared samples quantified using temperature-programmed desorption (TPD) of ammonia depict the presence of moderate and strong acid sites. Temperature-programmed reduction (TPR) experiments suggest the potential use of cobalt copper nanoferrites in catalytic applications.

Study of the Structure and Hardness of Alloys of the Sn – Cu – Co System Used as Diamond Abrasive Tool Binders

The effect of the chemical composition of alloys of the Sn – Cu – Co system used as a binder for diamond abrasive tools on their structure and hardness is studied. It is shown that in the range of concentrations of the elements studied alloy structure is represented by three phases, i.e., β-Co, a solid solution of tin and cobalt in copper (Cu), and an e (Cu3Sn) intermetallic phase. The lowest microhardness of the three phases is exhibited by β-Co, as a result of which with an increase in cobalt content alloy macrohardness decreases.

Synthesis and properties of a copper(I) cobalt(II) double sulfite

The Pourbaix diagrams of the Cu–H2SO4–H2O and Co–H2SO4–H2O systems have been refined and the stability regions of sulfite phases in the diagrams have been identified. Phase diagrams of copper(I) copper( II) and copper(I) cobalt(II) double sulfites have been mapped out. The double sulfites Cu2SO3 · СuSO3 and Cu2SO3 · СoSO3 have been isolated from an aqueous solution saturated with sulfur dioxide. We have obtained electron paramagnetic resonance spectra of the double sulfite Cu2SO3 · СoSO3 and characterized it by X-ray diffraction, IR spectroscopy, particle size analysis, and thermogravimetry. A foundation has been laid for the thermodynamic prediction of the synthesis of the Cu2SO3 · MSO3 (M = Cu, Co) double sulfites.

Synthesis of graphene oxide supported copper–cobalt ferrite material functionalized by arginine amino acid as a new high–performance catalyst

A novel Cu0.5Co0.5Fe2O4@Arg–GO catalytic system was successfully prepared by immobilization of copper substituted cobalt ferrite nanoparticles on arginine–grafted graphene oxide nanosheets, in which ferrite moiety acts as an oxidation catalyst and arginine has the role of base catalyst. Also, arginine amino acid was used to modify the surface of graphene oxide nanosheets which the prepared support can improve dispersion and uniform loading of nanoparticles. The prepared nanocomposite was characterized by flame atomic absorption spectroscopy (FAAS), inductively coupled plasma optical emission spectrometer (ICP–OES), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT–IR), ultraviolet–visible spectroscopy (UV–vis), Raman spectroscopy, thermogravimetric analysis (TGA), x–ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. The prepared Cu0.5Co0.5Fe2O4@Arg–GO nanocomposite was used as an efficient catalyst for one–pot tandem oxidative synthesis of 2–phenylbenzimidazole derivatives in good yields.

Polyol Synthesis of Cobalt–Copper Alloy Catalysts for Higher Alcohol Synthesis from Syngas

Novel catalysts for the selective production of higher alcohols from syngas could offer improved pathways towards synthetic fuels and chemicals. Cobalt–copper alloy catalysts have shown promising results for this reaction. To improve control over particle properties, a liquid phase nanoparticle synthesis based on the polyol method was selected to synthesize Co2.5Cu particles, which were then supported onto a variety of metal oxide supports (Al2O3, SiO2, TiO2, ZrO2). The catalysts were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy before and after catalytic testing in a flow reactor at 250 °C and 40 bar. The results show alloyed phases were obtained using the polyol method, resulting in selectivity towards higher alcohols, as high as 11.3% when supported on alumina. Segregation of cobalt and the formation of cobalt carbide were observed in the catalysts after catalytic testing, which may limit performance compared to the desired alloy phase.

Cellulose-based copper–cobalt solid dispersed composite catalysts and their physicochemical and catalytic properties in alcohol synthesis

The physicochemical and catalytic properties of pyrolyzed cellulose-based Cu–Co solid dispersed composite catalysts synthesized by matrix isolation under the action of IR radiation have been studied. It has been shown that alcohols can be produced from CO and H2 in the presence of the synthesized composite catalysts comprising Cu–Co solid dispersed phase nanoparticles. The effect of synthesis conditions on the structure of the composite catalysts and their activity in synthesis gas conversion to alcohols has been studied by X-ray diffraction analysis, ATR-FTIR spectroscopy, and in situ magnetometry.