Source Of Nickel Research Articles

Comprehensive extraction of V, Ni and Mo from black shale via selective leaching oxidation process

Black shale is one of the most representative sources of vanadium, nickel and molybdenum in China. Due to the poor endowment of minerals in black shale, V, Ni, Mo and other metals complex co-associated endowment state, extraction is difficult and long-term unused, resulting in a significant waste of resources. In this paper, it is shown that V, Ni and Mo can be obtained from black shale by a stepwise oxidation leaching process. In a first leaching process, V and Ni are effectively leached simultaneously. Mo is left in the residue. The leaching efficiency of V, Ni and Mo was 86.81%, 89.19% and 5.80% respectively under the leaching conditions of 35wt.% H2SO4, 4wt.% CaF2, 1.2:1 liquid to solid ratio (L/kg), 95℃ and 8h. The residue was then leached twice. The leaching efficiency of molybdenum was 91.10% under the leaching conditions of 25wt.% H2SO4, 8wt.% NaClO3, 1.5:1 liquid to solid ratio (L/kg), 45℃ and 7h. V2O5 products have been successfully prepared, the purity of V2O5 reaches 98.34%. A stepwise oxidation leaching method has been proposed to separate the vanadium, nickel and molybdenum in the leaching process. Vanadium, nickel and molybdenum can be effectively extracted from the black shale by the stepwise oxidation leaching process to maximize the utilization of the resources.

Assessment of an eco-efficient process for the optimization of metal recovery in lithium cobalt oxide and lithium nickel manganese cobalt oxide batteries

The expansion of technology motivates the increase of global demands for critical minerals. In this context, the exploration of secondary sources of these components is expanding. End-of-life batteries can be seen as potential sources of lithium, cobalt, nickel and manganese for electric vehicles or diverse applications in electronic equipments. This paper provides a comprehensive evaluation of the recovery of metals from waste batteries with diverse chemistry composition. Lithium cobalt oxide (LCO) and lithium nickel cobalt manganese oxide (NMC) batteries were co-treated with polyvinyl chloride (PVC) channels under supercritical water, varying reaction temperature (400–600 °C) and PVC/Battery composition (0–3 m/m) in a tubular continuous reactor. Results show high recovery rates for all metals, with up to 90% percentage recovery of lithium and cobalt in all cases. Temperature and feed composition were identified as determining factors for the recovery of lithium from LCO batteries. In the case of cobalt, temperature was identified as the most important factor that affects its recovery. The selected optimal conditions for cobalt recovery in the solid products of reactions were identified for batteries LCO and NMC: temperature of 600 °C and PVC/Battery ratio of 3.0 and temperature of 500 °C and PVC/Battery ratio of 1.5, respectively. Environmental impacts, primarily Global Warming Potential (GWP), were minimal, with 4.71·10−5 kg CO2 eq., indicating the benefits of the process as an eco-efficient and promising route for the recycling of valuable metals.

Binder-free Ni-doped In/Mn oxalate electrode for next-generation supercapacitors

The worth of electrochemical energy storage systems is significantly influenced by the nature of the electrode material. In this work, metal oxalates have emerged as cost-effective and robust candidates for application in supercapacitors. In this context, a binder-free electrode composed of in-situ Ni-doped In/Mn oxalate was synthesized. The nickel foam served a dual function, acting both as a structural framework and as a source of nickel. X-ray diffraction (XRD) analysis verified the crystalline nature of the in-situ Ni-doped In/Mn oxalate. Morphological assessment using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the presence of a hybrid one-dimensional/two-dimensional morphology within the in-situ Ni-doped In/Mn oxalate. Electrochemical evaluations indicated that the in-situ Ni-doped In/Mn oxalate electrode exhibits characteristics akin to those of a battery, maintaining 88.8 % of its initial capacity. Furthermore, it demonstrated a superior specific capacity, amounting to 1238.3 F g−1 at a current density of 1 A g−1. The inclusion of nickel during the material's synthesis process is posited to significantly augment its overall electrochemical performance and properties.

Patch Testing With Nickel, Cobalt, and Chromium in Patients With Suspected Allergic Contact Dermatitis.

Background: Allergic contact dermatitis is frequently caused by metals, including multiple metals simultaneously. Objectives: To assess characteristics and associations of positive and clinically relevant patch test (PT) reactions with solitary and concurrent metal sensitization. Methods: A retrospective analysis of PT results for nickel, cobalt, and/or chromium from the North American Contact Dermatitis Group between 2001 and 2018 (n = 43,522). Results: 18.0% had a positive/allergic reaction to nickel sulfate hexahydrate, 7.3% to cobalt chloride hexahydrate, and 3.0% to potassium dichromate. 87.9% patients had a currently relevant reaction to 0, 9.4% to 1, and 2.7% to multiple metals tested. Patients with 1 versus no currently relevant reactions to metal were more likely to have a primary dermatitis site of trunk, feet, and ears; patients with currently relevant reactions to multiple metals had more dermatitis affecting the trunk and ears. Metal sources varied by co-reacting metal, especially for patients with cobalt and chromium allergy. Jewelry was the most commonly identified source of nickel and cobalt for both solitary and concurrent metal allergy. Conclusions: Sensitization to multiple metals occurred in 6% of patients. Allergen sources varied between patients with sensitivity to 1 metal versus those who had concurrent sensitivity to cobalt and/or chromium.

Synthesis and Characterizations of Fe-Doped NiO Nanoparticles and Their Potential Photocatalytic Dye Degradation Activities

Recently, the preparation of smart multifunctional hybrid nanoparticles has captured significant interest in versatile areas, including medicine, environment, and food, due to their enhanced physicochemical properties. The present study focuses on the synthesis of Fe-doped NiO nanoparticles by the coprecipitation method using the sources of nickel (II) acetate tetrahydrate and iron (III) nitrate nonahydrate. The prepared Fe-doped NiO nanoparticles are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV–visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and X-ray photon spectroscopic analysis. The XRD results clearly confirm the face-centered cubic structure and polycrystalline nature of the synthesized Fe-NiO nanoparticles. The Tauc plot analysis revealed that the bandgap energy of the Fe-doped NiO nanoparticles decreased with the increasing concentration of the Fe dopant from 2% to 8%. The XPS analysis of the samples exhibited the existence of elements, including Fe, Ni, and O, with the absence of any surplus compounds. The FE-SEM and TEM analyses proved the formation of nanostructured Fe-NiO with few spherical and mostly unevenly shaped particles. Further, the photocatalytic efficiency of the prepared Fe-doped NiO nanoparticles were identified by using the cationic dye rhodamine B (Rh-B). The photocatalytic results proved the 8% of Fe doped with NiO nanoparticles achieved 99% of Rh-B degradation within 40 min of visible-light irradiation. Hence, the results of the present study exemplified the Fe-doped NiO nanoparticles have acted as a noticeable photocatalyst to degrade the Rh-B dye.

Complexation leaching of critical and strategic metals from nickel converter slag using organic acids

Nickel converter slag is a waste product formed during the converting process in nickel production. In recent times the processing of nickel converter slag has gained attention as a secondary source of cobalt (Co) and nickel (Ni). Nickel and cobalt are considered critical and strategic metals that are essential for nations’ economy and defence, as well as high-technology industry. In particular, Co and Ni can be utilised in the batteries, superalloys, and automobiles. Extraction of critical and strategic metals from slag can be categorised as technospheric mining. In this study, the slag was characterised using combination of XRF, XRD, ICP-OES, FESEM and TIMA for better understanding of deportment of Ni and Co and texture of Ni converter (CV) slag. Complexation leaching by using a combination of citric acid and EDTA was undertaken to extraction by using the leaching agent and complexing agent. The preliminary test showed the most promising result. The leaching experiment was carried out with various parameters such as the reagent concentration, temperature, particle size, and pulp density. The optimum condition for extracting Co and Ni from CV slag is following; citric acid 1 M, EDTA 0.3 M, 80 °C, 6 hr, pulp density 2.5% (w/v), − 75 μm and 250 rpm, which recovered 85.29% of Co and 59.85% of Ni.

Determination of Nickel in Selected Surface Waters of the Bonaberi Industrial Zone, Douala IV Council, Littoral Cameroon

Aims: To assess the source and level of Nickel in selected surface waters and its impact on the community of the Bonaberi industrial zone.
 Study Design: Cross-sectional study design that involved semi-quantitative and qualitative data collection method.
 Place and Duration of Study: This study was carried out in the area of Bonaberi industrial zone, Douala IV district between February 2019 to August 2020.
 Methodology: 25 Different surface water samples were collected from 5 sampling sites. Water samples were collected in polyethylene bottles previously washed with deionized water and rinsed with sample to be collected from different sites and acidified with 5 ml concentrated nitric acid. The contents of the metal were analyzed using Colorimetric merck microquant procedure. Two way ANOVA test and a P-value (<0.05) was considered significant.
 Results: Spring Water had a significant concentration of nickel in the various sites (0.06 mg/L), industrial waste (0.05 mg/L), River (0.04 mg/L), Well (0.03 mg/L), Tap waters (0.02 mg/L).
 Conclusion: Nickel is one of the most toxic naturally occurring metal(s) that is very dangerous to environmental sustainability when present in high concentrations. The study justifies the need to ascertain the long-term effects of Nickel contaminant(s) at waste dumping sites. Strengthening waste management systems and water quality monitoring should be implemented in the watersheds to minimize the health effects and deterioration of the aquatic ecosystem. Adequate measures should be taken to educate the community on heavy metals pollution on surface water and their effects to health and environment.

Mining on land or in the deep sea? Overlooked considerations of a reshuffling in the supply source mix

In a context of high global demand for energy transition minerals, the possibility of accessing the large resources in the deep sea appears to some as a supply and financial opportunity. This article posits that deep-sea mining (DSM) could become a significant part of the global supply mix for some of the metals required in battery manufacture, namely cobalt, copper, manganese, and nickel. Under a conceivable scenario, a reshuffling of global supply in favour of DSM would negatively affect other metal suppliers, and particularly the terrestrial mining sector. This would have negative implications for mining jurisdictions and localities. After laying out the current state of knowledge, the paper provides a preliminary analysis that assesses current and future vulnerabilities in extractive locations. We characterise the terrestrial sources of cobalt, copper, manganese and nickel and the social, political, and economic contexts in which resources are located. Factors considered include the jurisdiction's economic dependence on mining and governance score; mining communities’ remoteness; and mining projects’ relative position in the cost curve. More predictive macro-economic analyses are needed to assess the scale of the indirect effects DSM supply could trigger.

Study of the Synthetic Characteristics of Pure Cobalt - Tinged Nickel Oxide (Nio) Membranes (Co)

The pure nickel oxide ((NiO) doped with cobalt (Co) in different atomic ratios (at.% 3.6.9.12) were prepared by spraying on glass bases at a temperature of (550ºC), where a solution of nickel nitrate (Ni(NO3) 2.6H2O) is a source of nickel (Ni) with a molar concentration (0.2mol/L) and a cobalt chloride solution (CoCl 2.6H2O) with the same molar concentration as the previous source of the grafting element (Co), The effect of cobalt grafting on the structural Characteristics has been studied. The results of the X-ray examinations showed that the prepared Devices were of polycrystalline cubic structure, and the predominant orientation (111) for all the prepared Devices. It was found that cobalt grafting led to an increase in the intensity of the top of the trend (200) and its relative stability relative to the top of the preferential direction in the X-ray diffraction pattern, while there is a discrepancy in the values of the grain size with an increase in the proportion of cobalt grafting, as the results of the (FTIR) assays showed the emergence of the two chemical bonds (Ni-O) and (Co-O) which appear in the wavelength range (400-500 nm).

Synthesis of nickel coated graphene and analysis of the efficacy of its reinforcement on the hyper eutectic AlSi alloys that are grain modified and refined

Investigation on the impact of grain refiners and modifiers on the mechanical characteristics of Aluminium Silicon alloys is an ongoing subject. It is understood that the mechanical properties of AlSi alloys can be significantly improved by refining and modifying the grains and by adding the solid lubricants. In the present work, synthesis of nickel coated graphene particles is carried out. The die cast hyper eutectic AlSi alloys are subjected to grain refinement and modification with simultaneous reinforcement of nickel coated graphene powder. Nickel coated graphene particles are synthesised by electroless plating. After graphene is pre-treated, electroless plating was conducted in a bath having nickel nitrate as source of nickel along with sodium borohydrate as a reducing agent. During this procedure, ultrasonic agitation was used to improvise the coating properties. The coated graphene powder was characterised by EDAX which revealed the Ni coating on the surface of graphene. AlSi alloys of three distinct compositions are synthesised using die casting method. The first alloy comprises of aluminium silicon as the base alloy. The second alloy comprises of the nickel coated graphene reinforced aluminium silicon alloy. The third alloy comprises of aluminium silicon alloy which is grain refined, modified and further reinforced with the nickel coated graphene powder. The three different compositions of AlSi alloys thus casted, are tested for the mechanical properties like tensile strength and Vicker's hardness test. They are also tested for the microstructure by scanning electron microscopy and optical microstructure. The tensile strength and hardness are the highest for that alloy that is simultaneously grain refined, modified and nickel coated graphene reinforced. The microstructure of the third alloy displayed a clear transition of the plate like silicon to globular shaped eutectic silicon with uniformly distributed graphene. • Synthesis of Nickel coated Graphene powder (NCG). • Examine the coating of Nickel on the Graphene. • Preparation of the metal composites by die casting the Aluminium Silicon alloys. • Study the properties of alloys prepared using grain refiners, modifiers and NCG. • Report the tensile, micro hardness values and microstructure of the casted alloys.

Removal of heavy metals from stormwater runoff using granulated drinking water treatment residuals

Stormwater runoff is a significant source of heavy metals, including cadmium (Cd), chromium (Cr), and nickel (Ni), which pose ecological and human health problems. Various filter media have been evaluated for heavy metal removal from stormwater via adsorption, most involving chemical- or energy-intensive processes. Aluminum-based drinking water treatment residuals (WTR), a non-hazardous byproduct of drinking water treatment, are an inexpensive sorbent for heavy metals. However, the low permeability of WTR is a problem and requires mixing with sand and carbon materials to improve flow; but such amendments also reduce its sorption capacity. To overcome this problem, a granulated WTR sorbent was generated using a green technique involving organic materials and a low-energy process. Batch studies showed that WTR granules remove Cd, Cr, and Ni simultaneously. Metal removal was adequately described by pseudo-second-order kinetic models and Langmuir and Freundlich isotherm models. The overall removal performance was Cr > Cd > Ni. The presence of divalent cations in solution negatively affected metal removal; anions had a strong effect on Cd removal. A triple-layer surface complexation model adequately described metal removal. Results demonstrated the strong potential of the WTR granules to emerge as green filter media for the removal of heavy metals from stormwater runoff. • WTR granules are sustainable sorbents that can simultaneously remove Cd, Cr, and Ni. • WTR granules were made from a waste byproduct and organic material with low energy. • The environmental parameters affected the removal of Cd, Cr, and Ni. • Surface complexation model could adequately describe the removal of Cd, Cr, and Ni.

Elaboration of the Al-Al3Ni Alloy Eutectic by a Carbothermal Process.

The present study develops an elaborate method of materials Al-Al3Ni by carbothermic reduction of nickel oxide from the decomposition of Ni(NO3)2.4H2O mixed with aluminum powder. This nitrate salt represents the source of nickel for an elaboration of these materials. The thermodynamic parameters adopted in the experimental study were defined based on the liquid-solid phase equilibrium diagram of the binary system Al-Ni and the Ellingham approach. Throughout this study, the metal Ni is elaborated by carbothermic reduction of nickel oxide resulting from nitrate salt decomposition at 900°C under a nitrogen atmosphere. The heat treatment at 900 °C of a mixture of nitrate salt with aluminum powder under an inert gas atmosphere leads to the formation of phases Al2O3, Al4C3, Al, and Ni. The annealing of these obtained phases during 1 h and under a nitrogen flow atmosphere at the temperature of 600°C allowed us to obtain the Al-Al3Ni alloy devoid of oxides. The characterization of these obtained solid phases was carried out by the XRD analysis, the SEM-EDS, the DTA, and the DSC.

In situ TEM study of Ni-silicides formation up to 973K

Low-temperature solid-state reactions between Ni and Si were studied using in situ transmission electron microscopy (TEM). In the experiments thin amorphous silicon (a-Si) films were laid on Ni micro-grids and heated up to 973 K. In our approach the supporting Ni-grid serves as an unlimited source of nickel to successively form the whole range of Ni-silicide phases while diffusing into amorphous silicon. Unlike other thin film experiments where Ni and Si are layered on top of each other, our arrangement enables lateral diffusion of Ni along the Si layer and therefore enables the formation and study of successive Ni-Si phases side by side. That allowed us to observe in situ α-NiSi2 as the first reaction product, in contrast to most studies that had reported either δ-Ni2Si or θ-Ni2Si as the first phase to form. α-NiSi2 was continuously present at the reaction front propagating into the a-Si film. The phase sequence followed the increasing Ni concentration from a-Si towards the Ni-grid: α-NiSi2, NiSi, Ni3Si2, δ-Ni2Si, γ-Ni31Si12 and Ni3Si. Almost all known Ni-silicide phases were found to form at relatively low temperatures except the θ-Ni2Si, β-NiSi2 and β3-Ni3Si. The dominant phase was γ-Ni31Si12 which appeared in three structural modifications, differing in lattice periodicity along the c-axis. The periodicity of the basic γ-Ni31Si12 structure along the c-axis is ~12 Å (c0 = 12.288 Å) and that of the other two modifications were ~18 Å and ~36 Å, denoted by S12, S18 and S36 respectively. Of the three, only S12 has a structural model, S18 had been previously observed by Chen, but S36 had not been documented in previous works. During our in situ heating experiments, in addition to the Ni-silicide layer formation a new phenomenon was observed, namely the appearance, growth and transformation of Ni-silicide whiskers which was attributed to the accumulation of compressive stress in the thin layer.

An alternative route to extract nickel and cobalt from non-commercial laterite ore

Laterite ores, which represent around two-thirds of nickel reserves, became an important source of nickel and cobalt metals. The objective of the present study was to investigate the efficiency of a hybrid route to extract nickel and cobalt present in a laterite ore sample which was not commercially attractive to be processed through the current routes. The process efficiency was investigated through the application of different test conditions, such as roast temperature, ore sample comminution, and moisture. Chemical analysis by atomic absorption was used to quantify the metals. The solid phase’s identification and characterization were accomplished by X-ray diffraction and Scanning Electron Microscopy. The Rietveld Method was used for the mineral’s phase quantification. In terms of nickel and cobalt extractions, the most favorable condition was: particle size smaller than 38 µm, 50% sulfuric acid (wt.%), and 10% moisture (wt.%), which permitted nickel, cobalt, magnesium, and iron recoveries of 84.5%, 92.0%, and 93.0%, 27.0% respectively. These results indicate the successful application of the route. In addition, it was found that chlorite, chromite, hematite, and goethite were identified as the main nickel and cobalt carriers present in the process residue.

Morphology and Particle Size of a Synthesized NMC 811 Cathode Precursor with Mixed Hydroxide Precipitate and Nickel Sulfate as Nickel Sources and Comparison of Their Electrochemical Performances in an NMC 811 Lithium-Ion Battery

Cathode precursors of lithium-NMC 811 were synthesized by the coprecipitation method using two different nickel sources, namely mixed nickel–cobalt hydroxide precipitate (MHP) and nickel sulfate. The characteristics of the synthesized precursors were compared with the characteristics of the commercial NMC 811 cathode precursor obtained from the international market. The XRD analyses identified that the diffraction peaks of the three precursor materials were in close agreement to that of Li0.05Ni0.75Co0.1Mn0.1O2, with the figure(s) of merit (FoM) of 0.81, 0.88, and 0.9, respectively, for the synthesized precursor that used MHP as the source of nickel (SM-LNMCO-811), nickel sulfate as the source of nickel (SX-LNMCO-811), and the commercial precursor (K-NMC-811). The elemental analysis of the synthesized precursors revealed the Ni:Mn:Co mol ratios of 0.8:0.08:0.12 and 0.76:0.11:0.13 for SM-LNMCO-811 and SX-LNMCO-811, respectively. The SEM analysis revealed that SX-LNMCO-811 and K-NMC-811 showed a similar particle morphology with a spherical shape; the SM-LNMCO-811 exhibited an irregular particle morphology. The particle size analysis showed that SM-LNMCO-811 had the largest average particle size (285.2 μm) while K-NMC-811 and SX-LNMCO-811 samples had almost the same average values (i.e., 18.28 and 17.16 µm, respectively). The results of the charge–discharge measurement of the fabricated battery cylindrical cells with SM-LNMCO-811, SX-LNMCO-811, and K-NMC-811 as cathode materials showed the best discharge value of the SX-LNMCO-811 sample at 178.93 mAh/g with an initial efficiency of 94.32%, which is in line with the electrochemical impedance measurement results that showed the largest ion conductivity and lithium ion diffusion coefficient value of the SX-LNMCO-811 sample that utilized the synthesized nickel sulfate as the source of the nickel.

Awaruite, a new large nickel resource. Part 1: Physicochemical properties and their implication for mineral processing

Nickel is an important component of stainless steel and a wide range of applications which are critical for the transition to clean energies including electric vehicle batteries. Awaruite is a native nickel–iron alloy that has gained interest as a possible new economic source of nickel. In the last decades, there have been discoveries of awaruite, mostly with more significant amounts of nickel sulphides, that have demonstrated the potential for awaruite to contribute to the economics of a deposit. This study is focused on the very large Baptiste deposit in central British Columbia, Canada where awaruite is the primary nickel mineral. Most of published data on awaruite are focused on geology, and important fundamental physiochemical properties have still not been determined. These properties are fundamental for the set-up of a flowsheet that will enable its large-scale processing. The limited information available of this nickel–iron alloy can be complemented with the available information of a synthetic alloy with the same elemental composition. The synthetic awaruite alloy has demonstrated remarkable magnetic properties, and based on those properties, it was named permalloy. In this study, physicochemical properties of native and synthetic awaruite were measured including chemical composition, crystallographic structure, and magnetic properties. The native awaruite composition from the Baptiste deposit averages 77.3 % nickel, 21.0 % iron, 1.1 % cobalt and 0.6 % copper. Natural and synthetic awaruite have the same crystallographic characteristics and similar ferromagnetic behaviour. The measured initial volumetric magnetic susceptibility for native awaruite was 14.4 and the saturation magnetization was 750kA/m. Awaruite has the potential to be concentrated in a unique and valuable nickel concentrate of distinctive characteristics including its very high nickel content, which lowers both the downstream costs and the carbon intensity. Furthermore, the negligible content of sulphur and penalty trace elements, such as mercury, antimony, and arsenic in a potential awaruite concentrate, minimizes the costs of refining it. The physicochemical data in this study provides information to reliably set up a mineral processing flowsheet, which is discussed in this work.

Microwave one-step controllable synthesis of NiSb materials for high-performance energy storage

Energy depletion has led to the demand for new versatile materials with energy transmission and storage properties. Therefore, in this study, adhesive-free film structure of the NiSb alloy materials was obtained in one step through a simple and economic microwave synthesis technology using nickel foam as the source of nickel. X-ray analysis confirmed the successful preparation of NiSb nano-structures. In addition, electrochemical studies indicated that the adhesive-free film structure has a high capacity (4633 F g−1) and good cycle stability, and the capacitance value of this material was higher than that of previously reported alloy electrode materials such as MnCo and NiSn. In addition, we assembled an asymmetric supercapacitor with NiSb and activated carbon as the positive and negative electrode, respectively. The solid-state asymmetric supercapacitor had a working voltage of 1.7 V, and it exhibited a maximum energy density of 481.7 μWh cm−2 at 1630 μW cm−2, indicating the good energy transmission and storage properties of the NiSb nanomaterials.

Awaruite (Ni3Fe), a new large nickel resource: Electrochemical characterization and surface composition under flotation-related conditions

Awaruite is a native nickel–iron alloy (Ni3Fe), found in serpentinized ultramafic rocks, that has gained interest as a possible source of nickel. FPX Nickel is advancing a very large awaruite deposit in central British Columbia, Canada, on which this work is based. To date there is limited information available regarding the flotation conditions to selectively concentrate awaruite from gangue minerals in serpentinite ores. The aim of this work was to investigate the floatability of awaruite in different solution conditions with a xanthate collector. Awaruite readily floated in acidic solution with a xanthate collector but not in neutral and alkaline solutions. Voltammograms on awaruite indicated that the alloy shows an active passive transition behaviour in acidic solution and passive behaviour in neutral and alkaline solutions. The passivation layer formed in neutral and alkaline solutions showed to inhibit the interaction between xanthate and awaruite surface. Infrared spectra on awaruite showed the presence of xanthate compounds attached to the surface in acidic condition at potentials higher than the reversible potential of xanthate/dixanthogen. Based on experimental results, it was postulated that xanthate chemisorbs on awaruite and then it oxidizes to form dixanthogen. Also, it was demonstrated that when passivated, awaruite quickly activates in acidic solution, good flotation performance was achieved with 10 min of conditioning, and similar performance was obtained after 30 min of conditioning. This work serves as a confirmation that is possible to float awaruite using xanthate, a well-known collector that offers selectivity over oxides and silicate minerals, which are the main gangue minerals in serpentinite ores.

Intricate Road to Linear Anionic Nickel(I) Hexamethyldisilazanide [Ni(N(SiMe3)2)2

In this report, we present intricate pathways for the synthesis of linear nickel(I) silylamide K{m}[Ni(NR2)2] (NR2 = -N(SiMe3)2). This is achieved first via the reduction of nickel(II) trisamide Li(donor)4[Ni(NR2)3] (Li(thf)x[1]) with KC8 in the presence of 18-crown-6 or crypt.222. In due course, the behavior of Li(donor)4[Ni(NR2)3] as a source of masked two-coordinate nickel(II) hexamethyldisilazanide is explored, leading to the formation of nickel(I) and nickel(II) N-donor adducts, as well as metal-metal-bonded dinickel(I) trisamide K(toluene)[Ni2(NR2)3] (K(toluene)[5]). Finally, a convenient and reliable synthesis of K{m}[Ni(NR2)2] by ligand exchange of phosphines in [Ni(NR2)(PPh3)2] with K{m}(NR2) is presented. This allows for the comprehensive analysis of its electronic properties which reveals a fluxional behavior in solution with tight anion/cation interactions.

Synthesis and Characterization of Nickel oxide thin films by spray Pyrolysis method: Effect of Nickel source nature

Nickel oxide (NiO) material had been reported as one interesting candidate for transparent conductive oxides (TCO) applications, given their specific properties. In this work, we have synthesized un-doped nickel oxide (NiO) thin films by using the spray pyrolysis method deposited on heated glass substrates at 500°C. The effect of the Nickel source on the optical and electrical properties of the prepared films had been reported. We have used two sources of nickel: nickel nitrate (Ni (NO3)2.6H2O) and nickel Chloride (NiCl2.6H2O). The characterization techniques such as UV–visible spectroscopy and the two-point probe technique were used to investigate the prepared NiO thin films. The optical analyses show that all the samples exhibit averaged optical transparency between 52% and 61% in the visible region. The evalueted optical gap- the energy of the NiO thin films between 3.59 and 3.84eV with the change of nickel source. Refractive index and extinction coefficient values were decreased with a variation of nickel source. From Electrical measurement, it was observed that the minimum resistivity of the NiO films are 0.106 Ω from films prepared with nickel nitrate source.