Cobalt Metal Research Articles

Iridium-Cobalt Oxide from Modified Adam’s Fusion Synthesis Method as Electrocatalyst for Oxygen Evolution Reaction

Green hydrogen from water electrolysis is one of the leading energy carriers towards energy sustainability; however, cost reduction is necessary to make this technology more commercially viable. One of the most expensive components in an electrolysis cell are the iridium-based catalysts. To reduce cost, we propose to minimize iridium loading through alloying with a less-expensive cobalt (Co) metal. Here, we synthesized iridium-cobalt oxide (IrCo) using a surfactant-assisted Adam’s fusion synthesis technique as a scalable method. The in-house IrCo catalyst demonstrates improved performance than the commercial iridium oxide (IrOx_C) in both acidic and alkaline media. Further activity enhancement was achieved through acid etching (IrCo_ae), preferentially removing Co to generate more active sites. XPS and ICP-MS results reveal that the Ir:Co atomic ratio is increased from 1.0 to 5.5 after acid etching. The elemental distribution is also supported by EDX mapping. The effects of Ir/Co molar ratio, the use of surfactant and their interaction with the acid etching process were also investigated. The dependence of Ir valency on Ir/Co ratio and the possible influence of Ir3+ surface concentration to achieve high OER activity, especially in the acidic media, are highlighted in the study. In the absence of surfactant, the segregation of Ir and Co is much stronger forming a Co core and an Ir shell, and the OER activity is lower compared to its surfactant-assisted counterpart. The results confirm that surfactant improves the interaction of Ir and Co, leading to a better OER performance. This study proves an effective Ir utilization with the proposed synthesis method and could be tailored and enhanced to improve the catalyst stability for green hydrogen production.

Cobalt Encapsulated in Nitrogen-Doped Graphite-like Shells as Efficient Catalyst for Selective Oxidation of Arylalkanes.

Selective oxidation of ethylbenzene to acetophenne is an important process in both organic synthesis and fine chemicals diligence. The cobalt-based catalysts combined with nitrogen-doped carbon have received great attention in ethylbenzene (EB) oxidation. Here, a series of cobalt catalysts with metallic cobalt nanoparticles (NPs) encapsulated in nitrogen-doped graphite-like carbon shells (Co@NC) have been constructed through the one-pot pyrolysis method in the presence of different nitrogen-containing compounds (urea, dicyandiamide and melamine), and their catalytic performance in solvent-free oxidation of EB with tert-butyl hydrogen peroxide (TBHP) as an oxidant was investigated. Under optimized conditions, the UCo@NC (urea as nitrogen source) could afford 95.2% conversion of EB and 96.0% selectivity to acetophenone, and the substrate scalability was remarkable. Kinetics show that UCo@NC contributes to EB oxidation with an apparent activation energy of 32.3 kJ/mol. The synergistic effect between metallic cobalt NPs and nitrogen-doped graphite-like carbon layers was obviously observed and, especially, the graphitic N species plays a key role during the oxidation reaction. The structure-performance relationship illustrated that EB oxidation was a free radical reaction through 1-phenylethanol as an intermediate, and the possible reaction mechanistic has been proposed.

Efficient activation of peroxymonosulfate by molybdenum disulfide cocatalysis of Co and N co-doped porous carbon for degrading perfluorooctanoic acid: Synergistic effect of Co and N by molybdenum and its mechanism

In this study, precursor ultrathin molybdenum disulfide nanosheets and ZIF-67 was selected to prepare Co and N co-doped porous carbon by the support of Mo (MoS2/Co@NPC) to activate peroxymonosulfate (PMS) for perfluorooctanoic acid (PFOA) degradation. The morphology, crystal form and composition of MoS2/Co@NPC are studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and other methods. In MoS2/Co@NPC/PMS process, PFOA was completely degraded in 180 min at pH 7, 0.3 g/L catalyst, 0.1 mM PMS and reaction temperature of 25 °C. The degradation efficiency was much higher than that in other systems. The oxidative species for PFOA degradation was studied using free radical quenching experiments and electron paramagnetic resonance (ESR) tests. SO−4 plays a major role in the degradation of PFOA, OH plays an auxiliary role, and 1O2 contributes the least. The effect of different types and positions of cobalt‑nitrogen and molybdenum atoms on the electrocatalytic activity was investigated by density functional theory (DFT) calculations. The co-doping of Co and N into carbon-based materials can synergistically enhance by Mo for the activation of PMS. The unsaturated S atoms on the surface of metal sulfides can trap protons to form H2S while exposing the reducing metal active site, which also accelerates the rate-limiting step of the Co3+/Co2+ conversion. The core-shell structure of Co@NPC doped with Mo has the characteristics of improving the electron transfer ability of carbon, promoting the mass transfer of reactants, and preventing cobalt metal agglomeration and metal dissolution. The degradation pathways of PFOA were investigated and three possible pathways were proposed. In addition to PFOA, MoS2/Co@NPC-800/PMS system can also remove contaminant in pharmaceutical wastewater, indicating that the process has potential application value in practical wastewater treatment.

Biomonitoring of Exposures to Solvents and Metals in Electronics Manufacturing Facilities in Batam, Indonesia.

Concerns about chemical exposure in the electronics manufacturing industry have long been recognized, but data are lacking in Southeast Asia. We conducted a study in Batam, Indonesia, to evaluate chemical exposures in electronics facilities, using participatory research and biological monitoring approaches. A convenience sample of 36 workers (28 exposed, 8 controls) was recruited, and urine samples were collected before and after shifts. Five solvents (acetone, methyl ethyl ketone, toluene, benzene, and xylenes) were found in 46%-97% of samples, and seven metals (arsenic, cadmium, cobalt, tin, antimony, lead, and vanadium) were detected in 60%-100% of samples. Biological monitoring and participatory research appeared to be useful in assessing workers' exposure when workplace air monitoring is not feasible due to a lack of cooperation from the employer. Several logistical challenges need to be addressed in future biomonitoring studies of electronics workers in Asia in factories where employers are reluctant to track workers' exposure and health.

Effects of heavy metals on bacterial growth parameters in degradation of phenol by an Antarctic bacterial consortium.

Antarctica has often been perceived as a pristine continent until the recent few decades as pollutants have been observed accruing in the Antarctic environment. Irresponsible human activities such as accidental oil spills, waste incineration and sewage disposal are among the primary anthropogenic sources of heavy metal contaminants in Antarctica. Natural sources including animal excrement, volcanism and geological weathering also contribute to the increase of heavy metals in the ecosystem. A microbial growth model is presented for the growth of a bacterial cell consortium used in the biodegradation of phenol in media containing different metal ions, namely arsenic (As), cadmium (Cd), aluminium (Al), nickel (Ni), silver (Ag), lead (Pb) and cobalt (Co). Bacterial growth was inhibited by these ions in the rank order of Al < As < Co < Pb < Ni < Cd < Ag. Greatest bacterial growth occurred in 1 ppm Al achieving an OD600 of 0.985 and lowest in 1 ppm Ag with an OD600 of 0.090. At a concentration of 1.0 ppm, Ag had a considerable effect on the bacterial consortium, inhibiting the degradation of phenol, whereas this concentration of the other metal ions tested had no effect on degradation. The biokinetic growth model developed supports the suitability of the bacterial consortium for use in phenol degradation.

Intermetallic compounds as oxygen evolving anodes for metal electrowinning: Electrochemical dealloying and effects of scale in practical electrochemistry

Electrochemical dealloying has recently been highlighted as a promising technique for developing active electrodes for water electrosplitting. Intermetallic compounds of a base metal with passive film-forming element are effective oxygen evolution anodes for metal electrowinning. Cobalt- manganese-silicon alloys and titanium-nickel intermetallics are demonstrated as examples and related to the proposed paradigm of electrochemical dealloying. These systems illustrate the effects of scale in practical electrochemistry, where ‘scale’ has multiple meanings: the transition to practise; formation of surface deposits; and the evolution of the interface in extended use. In the case of cobalt-silicon-manganese alloys, the microstructure of the metal is critical. A highly porous surface layer is developed, within which the active phase is ‘nanostrands’ of cobalt metal in ‘nanoconfinement’ within a slowly-dissolving silicide matrix. Within the confined environment, a saturated solution of cobalt salt causes a salt film over the cobalt metal under which an oxygen-evolving cobalt anodic oxide is stabilised. In the case of TiNi, a nickel-rich surface forms over a thin titanium anodic oxide. Oxygen evolution occurs by field-assisted electron tunnelling to the surface nickel titanium oxide states. Field-driven ion migration both leads to these active states and leads to a slow dissolution of the metal. There is a useful range of composition between 51 and 55 wt% Ni (46 – 50 at%) which balances ductility against dissolution rate: excess titanium leading to a continuous phase of Ti2Ni results in a very brittle material; separation of TiNi3 leads to more rapid dissolution. In practise however, intrusion of oxygen during casting of large plates segregated Ti as the oxide Ti4Ni2O leading to separation of TiNi3 . The more rapid dissolution of this phase, in association with formation of MnO2 from Mn salts present in plant electrolyte, led in association with oxidation of cobalt salts to deposition of an adherent surface scale under which the solution became strongly acidic. The accelerated anode dissolution led to an under-scale of TiO2 which further increased acidification. Impractically rapid destruction of the anode resulted. The work illustrates how mass-transport and microstructure in the evolving interphase between electrode and electrolyte can interact in subtle ways important for practical application.

Possibility of metallic cobalt formation in the oxide scale during high-temperature oxidation of Co-27Cr-6Mo alloy in air

Abstract Co-based alloys are known to be high oxidation-resistant material and used in several high temperature applications. During high temperature oxidation, duplex oxides containing Co and Cr were formed. It was thermodynamically elucidated that when the growing scale was thick enough, the partial pressure of O2 in the scale dropped. Then, the reduction of CoO occurred for promoting O2 which was responsible for Cr2O3 production. This work experimentally proved this point by in situ characterising Co-27Cr-6Mo at high temperatures in air by X-ray diffractometer in a grazing incident mode and metallic Co was confirmed to be formed by the reduction of CoO consistent with the image taken and analysed by field emission scanning electron microscope, energy-dispersive X-ray, and electron backscatter diffraction. Furthermore, the change in lattice parameter and the phase transition were observed when the temperature was altered.

Potential environmental and human health menace of spent graphite in lithium-ion batteries

The growing demand for lithium-ion batteries for portable electronics and electric vehicles results in a booming lithium battery market, leading to a concomitant increase in spent graphite. This research investigated the potential impacts of spent graphite on environmental and human health using standardized toxicity extraction and Life Cycle Impact Assessment models. The spent graphite samples were classified as hazardous waste due to the average nickel content of 337.14 mg/L according to Chinese regulations. Besides, cadmium and fluorine were the other elements that exceeded the regulations threshold. Easily ignored aluminum and heavy metal cobalt are other harmful elements according to the results of Life Cycle Impact Assessments. All the metallic harmful elements mainly exist in a transferable state. Thermogravimetry infrared spectrometry coupled with mass spectrometry was employed to recognize the emitted gases and explore gas emission behavior. Inorganic gases of CO, H2S, SO2, SO3, oxynitride, HCl, and fluoride-containing gases were detected. Sulfur-containing gases released from spent graphite were contributed by the residual sulfuric acid after leaching. The correlation between the evolution of emitted gases and the heating schedule was established simultaneously. The research comprehensively illustrates the pollution of spent graphite and provides assistance for the design of green recycling schemes for spent graphite.

Optimizing phosphate removal by manipulating manganese and cobalt levels in soil aquifer treatment system

Manganese (Mn2+) and cobalt (Co2+) metals have been reported to exhibit complex interactions with phosphate (PO43-) ions, which can influence their mobility, reactivity, and removal behavior in soil aquifer treatment system (SAT). This study aimed to investigate the role of manganese (Mn2+) and cobalt (Co2+) in phosphate (PO43-) removal within a soil aquifer treatment system. A lab-scale column experiment was conducted using sand as the filtration media, and a synthetic wastewater containing 20 mg/L PO43-, 60 mg/L Mn2+, and 40 mg/L Co2+ was used. The breakthrough curves showed efficient removal of PO43- during the infiltration process, with concentrations reaching as low as 1 mg/L. The regression analysis revealed that Mn2+ had a strong negative correlation effect on PO43- concentration, indicating its stimulatory role in PO43- removal. Conversely, Co2+ showed a strong positive correlation effect, suggesting its promoting effect on PO43- concentration. Optimization analysis identified optimal concentrations of 57.4 mg/L for Mn2+ and 4.8 mg/L for Co2+ that interacted with lower PO43- concentrations, achieving the desired outcome of reducing PO43- levels. These findings highlight the importance of considering Mn2+ and Co2+ concentrations in soil aquifer treatment systems for effective phosphate removal.

Synthesis of cobalt doped nickel titanate nanomaterials for enhanced photocatalytic reduction of chromium

A series of cobalt doped nickel titanate nanomaterials where cobalt % is varied from 1 to 10% have been successfully synthesized by solvothermal method followed by calcination at 600 °C. Synthesized materials are characterized by XRD, FE-SEM, HR-TEM, BET surface area, DRS UV-Vis-NIR, XPS and PL spectroscopy. XRD and HR-TEM confirm the existence of NiTiO3 ilmenite structure with crystallite size in the range of 20–30 nm. HR-TEM of cobalt doped NiTiO3 shows the presence of tiny single atom cobalt metal sitting on NiTiO3, surface which induces the surface plasmon resonance effect. XPS of the doped NiTiO3 exhibits Ti3+ formation accompanied with oxygen vacancies resulting in the extended light absorption in the Vis-NIR region. The photocatalytic efficiency is studied monitoring the photoreduction of carcinogenic Cr (VI) under visible light. 3% cobalt doped NiTiO3 achieves 100% reduction of 30 ppm Cr (VI) solution within 60 min whereas pristine NiTiO3 shows only 50% efficiency under identical conditions. The trapping experiment shows the direct transfer of photogenerated electrons for the reduction of Cr (VI) following a first order kinetics. The two-fold enhanced activity of cobalt doped NiTiO3 is due to the collective effect of oxygen vacancies, efficient Vis-NIR absorption and surface plasmon resonance effect.

Facile synthesis of cobalt, nickel and manganese-based metal organic framework derived layered double hydroxides on Ni foam as effective binder-free electrodes of energy storage devices

Metal organic framework (MOF) derivatives have attracted intensive attention as the active material of energy storage devices. Layered double hydroxide (LDH) with large surface area, high redox capability and good cycling stability is regard as one of efficient active materials. Developing MOF-derived LDH with multiple metals can possibly achieve excellent surface properties, high electrical conductivity and abundant redox reactions. However, synthesizing MOF-derived LDH is time-consuming and requires high temperature environments. In this work, a simple and time-effective precipitation and etching process is proposed to synthesize MOF-derived LDH on nickel foam (NF) as binder-free electrodes of energy storage devices. The cobalt, nickel and manganese are utilized to design MOF-derived LDH with different metal species and numbers. The trimetallic MOF-derived LDH based on Co, Ni and Mn presents a high specific capacitance (CF) of 1113.7 F/g at 20 mV/s, due to abundant electroactive sites and multiple redox states for carrying out large numbers of redox reactions. The energy storage device composed of the trimetallic MOF-derived LDH and carbon on NF as electrodes presents the maximum energy density of 61.5 Wh/kg at the power density of 750 W/kg, and the CF retention of 92.5% and Coulombic efficiency of 95% after 10,000 charge/discharge cycles.

Sustainable Hierarchically Porous Reusable Metal–Organic Framework Sponge as a Heterogeneous Catalyst and Catalytic Filter for Degradation of Organic Dyes

Advanced oxidation processes based on sulfate radical are considered one of the most promising wastewater treatment technologies currently. Among heterogeneous catalysts, cobalt metal–organic framework (MOF) has been widely reported. However, the inherent powder form of MOF hinders its practical application and reusability. Therefore, innovative methods to increase the loading capacity and the accessibility of MOF active sites in monolithic materials are required. Therefore, a simple and scalable method of fabricating a stable, hierarchical porous zeolitic imidazolate framework (ZIF‐67) 3D sponge by growing MOF on a short electrospun fiber network is shown. The sponge can efficiently activate peroxymonosulfate and rapidly degrade an exemplary organic dye (Rhodamine B) with a degradation efficiency of 100%. The resulting multilevel, hierarchical porous structure is beneficial to the mass transfer of reagents making the catalytic process efficient. This also enables the use of the ZIF‐67 as an efficient catalytic filter for continuous removal of dye. The sponge can be recycled and reused for several cycles due to its robustness without loss in efficiency. The proposed research strategy provides a new way to design MOF 3D monolithic materials.

Development of the supercapacitor efficiency of the two-dimensional graphene oxide decorated by nano magnetite through building novel nanocomposites using nanoparticles of cobalt, manganese, vanadium, and zirconium oxides

The targeting of the current work is enhancing the supercapacitor efficiency of the magnetite nanocomposite with graphene oxide (GO) nanostructure via the addition of metal oxide nanoparticles (NPs) such as cobalt, manganese, vanadium, and zirconium for building a novel nano combination. The sol/gel method is utilized to fabricate the nanocomposites, and the potentiostat device measures the electrochemical performances. The supercapacitors of the magnetite (Fe3O4) NPs that decorate the graphene oxide (GO) surface and the modified electrode building have been examined by different tests for supercapacitor applications, and are studied via the impedance spectroscopy (EIS) data that confirm the building progress of the electron transfer and surface structure that enable it to be a favorable candidate for supercapacitors applications. The areal capacitance (Carea) of NCPs was measured and presented at 622.65 mFcm−2 (GO@Fe3O4), 62.428 mFcm−2 (GO@ Fe3O4.Co3O4), 388.4 mFcm−2 (GO@ Fe3O4.Mn3O4), 851.1 mFcm−2 (GO@Fe3O4.V4O7), 966.4 mFcm−2 (GO@Fe3O4.ZrO2). The NCPs have capacitance values related to CPE (C = 9.404 nF/cm2), GO@Fe3O4 (C = 40.886 nF/cm2), GO@Fe3O4.Co3O4 (C = 13.17 nF/cm2), GO@Fe3O4.Mn3O4 (C = 17.56 nF/cm2), GO@Fe3O4.V4O7 (C = 126.9 nF/cm2), and GO@Fe3O4.ZrO2 (C = 183.6 nF/cm2). By adding cobalt, manganese, vanadium, and zirconium metal oxide NPs, the new building electrodes have capacitance at 13.17, 17.56, 183.6, and 126.9 nF/cm2, respectively. The capacitance retention finished at 100 cycles is recorded and exhibited good cycle stability. From the results, the fabricated NCPS electrodes are a promising candidate for supercapacitor manufacturing applications and other applications such as water treatment.

Coloration and Fire Retardancy of Transparent Wood Composites by Metal Ions.

Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 × 100 × 1 (l × b × h) mm3.

Efficient Interfacial Sites between Metallic and Oxidized Cobalt for Propene Hydroformylation.

Currently, the hydroformylation of short olefins is operated almost exclusively by using Rh catalysts. Considering the high cost and scarcity of rhodium resources, it is important to develop non-noble metal catalysts toward hydroformylation. Herein, we report an efficient cobalt-based catalyst rich in interfacial sites between metallic and oxidized cobalt species for the hydroformylation of short olefin, propene, under a moderate syngas pressure. The catalyst exhibited a high specific activity of 252 mol molCo-1 h-1 in toluene under 2 bar of propene and 40 bar of CO/H2 mixed gas (CO/H2 = 1:1) at 160 °C. According to mechanistic studies, the interface of metallic and oxidized cobalt species promoted the adsorption of CO and propene. Moreover, the interfacial sites lowered the energy barrier for CO* hydrogenation and C-C coupling compared with metallic cobalt.

Triggered lattice-oxygen oxidation with active-site generation and self-termination of surface reconstruction during water oxidation.

To master the activation law and mechanism of surface lattice oxygen for the oxygen evolution reaction (OER) is critical for the development of efficient water electrolysis. Herein, we propose a strategy for triggering lattice-oxygen oxidation and enabling non-concerted proton-electron transfers during OER conditions by substituting Al in La0.3Sr0.7CoO3-δ. According to our experimental data and density functional theory calculations, the substitution of Al can have a dual effect of promoting surface reconstruction into active Co oxyhydroxides and activating deprotonation on the reconstructed oxyhydroxide, inducing negatively charged oxygen as an active site. This leads to a significant improvement in the OER activity. Additionally, Al dopants facilitate the preoxidation of active cobalt metal, which introduces great structural flexibility due to elevated O 2p levels. As OER progresses, the accumulation of oxygen vacancies and lattice-oxygen oxidation on the catalyst surface leads to the termination of Al3+ leaching, thereby preventing further reconstruction. We have demonstrated a promising approach to achieving tunable electrochemical reconstruction by optimizing the electronic structure and gained a fundamental understanding of the activation mechanism of surface oxygen sites.

Biocatalyst enhanced biogas production from food and fruit waste through anaerobic digestion

In recent years, the world has faced the adverse effects of global warming and waste management issues. Food waste is one of the major constituents of solid waste. Currently, the world is in the throes of finding an alternative source of fossil fuels, which could lower the energy demand and bring about a pollution-free environment. The stability of anaerobic digestion is significantly influenced by trace elements (TE), which are micronutrients for microbes. Experimental measurements were made of the effects of trace metals (cobalt (Co), nickel (Ni), magnetite (Fe2+Fe3+2O4) and biochar) on mesophilic and thermophilic anaerobic digestion of food waste. The study's major significance is identifying the potential catalyst for the anaerobic digestion system and achieving the best production efficiency. Adding micronutrients increased biogas generation, but it was hampered by the excessive addition of trace metalsthe excessive addition of trace metals hampered it. More biogas was produced when Co was added. We have achieved 42% of methane production with 28 days of hydraulic retention time. The findings can provide quantitative data on the replenishment of trace metals for efficient anaerobic digestion. This work presents novel information about the trace elements and their enhancement inside the biodigester for kitchen and fruit wastes.

Rational Molecular Design of Redox-Active Carbonyl-Bridged Heterotriangulenes for High-Performance Lithium-Ion Batteries.

Carbonyl aromatic compounds are promising cathode candidates for lithium-ion batteries (LIBs) because of their low weight and absence of cobalt and other metals, but they face constraints of limited redox-potential and low stability compared to traditional inorganic cathode materials. Herein, by means of first-principles calculations, a significant improvement of the electrochemical performance for carbonyl-bridged heterotriangulenes (CBHTs) is reported by introducing pyridinic N in their skeletons. Different center atoms (B, N, and P) and different types of functionalization with nitrogen effectively regulate the redox activity, conductivity, and solubility of CBHTs by influencing their electron affinity, energy levels of frontier orbitals and molecular polarity. By incorporating pyridinic N adjacent to the carbonyl groups, the electrochemical performance of N-functionalized CBHTs is significantly improved. Foremost, the estimated energy density reaches 1524Wh kg-1 for carbonyl-bridged tri (3,5-pyrimidyl) borane, 50% higher than in the inorganic reference material LiCoO2 , rendering N-functionalized CBHTs promising organic cathode materials for LIBs. The investigation reveals the underlying structure-performance relationship of conjugated carbonyl compounds and sheds new lights for the rational design of redox-active organic molecules for high-performance lithium ion batteries (LIBs).

Cobalt in the regolith upon Nui Nua ultramafic Massif

Cobalt (Co) Metal plays an increasingly important role in the battery and engine manufacturing industry for electric cars. Previously most of Co was mined as by-product in copper ore deposits in Central Africa. Recently, the proportion of Co extracted from other sources such as weathering-derived mines on ultramafic rocks is increasing. In Vietnam, Cobalt has been discovered in Cu-Ni ore deposits in the Northeast and Northwest Regions. The literature shows that cobalt is found in small amounts in ultramafic rocks. During the weathering process of ultramafic rocks, Co ions will be priority adsorbed in the hydroxide colloids of Mn and Fe (goethite and asbolan). In the regolith upon Nui Nua Masif, Ni content increased dramatically (several times) from 0.19% in bedrocks up to 1% in some locations, while cobalt content just increased only slightly (from 0.02% in bedrock to 0.05 regolith, rarely up to 0.1%). The results of the previous analysis of weathered crust samples of ultramafic rocks of Nui Nua massif by several authors show that, unlike Ni which is presented in both silicate minerals and Fe-Mn oxide/hydroxide, cobalt ions tend to be concentrated in Fe-Mn oxides/hydroxides. Our SEM analyses combined with EDS show some remarkable results: the Co content in some specific minerals is quite high from 1.12÷4.67% (denominator). This is only a preliminary result and it is necessary to conduct more work to further detailed studies defining the Co potential in weathering products of ultramafic rocks of Nui Nua massif as well as in the areas where other ultramafic rocks are developed. Recently, research confirmed that there is a significant Co-Ni occurrence discovered in Mau Lam Valley (Southwest of Nui Nua Massif).

Facile Synthesis of Spherical Porous Tricobalt Tetroxide and Metal Cobalt for High Quality Cobalt Production and Recycling

Facile Synthesis of Spherical Porous Tricobalt Tetroxide and Metal Cobalt for High Quality Cobalt Production and Recycling