Nickel Sulfate Solution Research Articles

Effect of TiO2–ZrO2 composition on catalytic activity of supported NiSO4 for ethylene dimerization

A series of catalysts: NiSO4/TiO2–ZrO2, having different TiO2–ZrO2 compositions, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. No diffraction line of nickel sulfate was observed up to 30 wt%, indicating good dispersion of nickel sulfate on the surface of the supported NiSO4 catalysts. The surface area and acidity of TiO2–ZrO2 binary metal oxide increased remarkably compared with the values for single metal oxides, TiO2 or ZrO2. The binary oxide TiO2–ZrO2 calcined above 600 °C resulted in the formation of a crystalline orthorhombic phase of ZrTiO4. Therefore, NiSO4/TiO2–ZrO2 calcined at 500 °C exhibited a maximum catalytic activity, and then the catalytic activity decreased with the calcination temperature. NiSO4 supported on 50TiO2-50ZrO2 (TiO2/ZrO2 ratio = 1) exhibited the highest catalytic activity for ethylene dimerization among TiO2–ZrO2 binary oxides. The catalytic activities of supported NiSO4 catalysts were correlated with the acidity of catalysts measured by the ammonia chemisorption method, regardless of the kind of support (TiO2, ZrO2, or TiO2–ZrO2).

Preparation of ultrafine nickel powder by wet chemical process

The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53–73 °C) and flow rate of nickel sulfate solution (50–100 mL/min). Moreover, temperature below 60 °C and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm 3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.

Characterization of nickel sulfate supported on SiO 2 for ethylene dimerization and promoting effect of Al 2O 3 on catalytic activity

A series of catalysts, NiSO 4/SiO 2, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. No diffraction line of nickel sulfate was observed up to 20 wt%, indicating good dispersion of nickel sulfate on the surface of SiO 2 and SiO 2–Al 2O 3. The addition of Al 2O 3 to NiSO 4/SiO 2 improved the thermal stability of catalyst and increased the number of acid sites on the surface of catalyst. Consequently, the Al 2O 3-promoted catalyst exhibited remarkably higher catalytic activity than non-promoted NiSO 4/SiO 2. The catalytic activities of supported NiSO 4 catalysts were correlated with the acidity of catalysts measured by the ammonia chemisorption method, regardless of the kind of support (SiO 2 or SiO 2–Al 2O 3).

Electrochemical behaviour and electrocatalytic activity of a novel nickel aquapentacyanoferrate modified electrode

A new electroactive polynuclear inorganic compound, namely nickel aquapentacyanoferrate was prepared chemically by mixing equimolar solutions of nickel sulphate and sodium aquapentacyanoferrate. It was characterized using FTIR spectroscopy. The complex was then mechanically immobilized on the surface of a paraffin impregnated graphite electrode. The cyclic voltammetric behaviour of the nickel aquapentacyanoferrate (NAPCF) mechanically immobilized to the surface of the graphite electrode was well defined and exhibited a pair of redox peaks with the formal potential of 0.33 V vs SCE at a scan rate of 20 mV s −1 in 0.1 M NaNO 3 solution. A preliminary investigation has been carried out to study the catalytic effect of the NAPCF modified electrode for the electrocatalytic oxidation of a few analyte components with clinical and environmental importance. The electrode showed excellent electrocatalytic activity for the oxidation of all the analytes studied. The electrode was highly stable and its response to the analytes also remained relentless.

The Effect of Tungsten Content on Nanocrystalline Structure of Ni-W Alloy Electrodeposits

The effects of tungsten content on the nanocrystalline structure of Ni-W alloy electrodeposits were investigated. Direct current electrodeposition was conducted with various W mole fractions in a nickel sulfate solution containing citric acid as a complexing agent. Current efficiency was an almost constant value of 52% up to W mole fraction of 0.58. However, it was sharply decreased owing to severe H2 evolution with increasing cathode overvoltage at a W mole fraction higher than 0.74. The X-ray diffraction peak was decreased and broadened with increasing W content, and an amorphous pattern appeared clearly at 49 wt.% W. It was confirmed that Ni-W alloy deposit was transformed from crystalline to amorphous structure between 41 and 49 wt.% W. This result was also verified through a TEM analysis.

Microrod and Microtube Formation by Electrodeposition of Metal into Ordered Macropores Prepared in p-Type Silicon

Copper and nickel electrodeposition into ordered macropores prepared in p-type silicon has been studied in aqueous solutions containing cupric and nickel ions, respectively. When a macroporous silicon template was cathodically polarized in 0.1 M cupric sulfate solution, copper was deposited preferentially at the pore bottom in the dark, whereas the deposition was found to proceed not only at the pore bottom but also partially on the pore wall under the back side illumination. In contrast, the deposition of nickel in 0.1 M nickel sulfate solution was not possible in the dark, while deposition occurred uniformly on the entire surface of the pore wall under the back side illumination. Dissolution of silicon templates by the alkaline etching process led to the formation of copper microrods and nickel microtubes. The deposition behavior of both metals was compared and this discrepancy was discussed.

Micro-gear fabrication using optical projection lithography on copper-clad plastic substrates and electroplating of nickel

Nickel micro-gears were fabricated using optical projection lithography on copper-clad plastic substrates and nickel electroplating. Adopting low numerical-aperture projection exposure, large depth-of-focus was secured, and SU-8 resist moulds with vertical sidewalls were fabricated. In addition, cost was greatly reduced by using copper-clad plastic substrates instead of silicon wafers. After nickel was electroplated in nickel sulfate solution, nickel gears with modules of 0.026–0.04 and pitch diameters of 760–1100 μm were stripped from the substrates when the resist moulds were dissolved in hot remover.

Recovery of nickel from Orimulsion fly ash by iminodiacetic acid chelating resin

Macroporous resins containing imminodiacetic acid (IDA) groups (Lewatit TP-207, Purolite S-930 and Amberlite IRC-748) were studied under dynamic conditions for uptake of nickel ions from the sulphate solution at pH 4 deriving from preliminary acid leaching of Orimulsion fly ash and subsequent vanadium recovery and impurities removal stages. The effects of temperature and ionic medium on the Ni adsorption were investigated. The Lewatit TP-207 showed higher Ni uptake capacity in all operating conditions examined with an adsorption capacity of 1.32 mmol of Ni/g at 40 °C using the real process solution at pH 4. The extraction of Ni adsorbed on the resin was obtained using 10 wt.% H 2SO 4; the resultant concentrated solution of nickel sulphate, containing about 13 g/L of nickel, can be suitable for elettrowinning, precipitation etc.

Ion Association and Hydration in Aqueous Solutions of Nickel(II) and Cobalt(II) Sulfate

Aqueous solutions of nickel(II) and cobalt(II) sulfate have been investigated at 25 ∘C by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 ≤ ν (GHz) ≤ 89) and salt concentrations (0.025 ≤ c(mol-L−1) ≤ 1.4). The spectra indicate, as for MgSO4(aq) studied previously, the simultaneous presence of double solvent-separated, solvent-shared and contact ion pairs in both NiSO4(aq) and CoSO4(aq). The stepwise formation constants for each ion-pair type and the overall association constant, obtained from the data are in good agreement with ultrasonic relaxation and other estimates. The DR spectra at higher concentrations (c ≥ 0.5 mol-L−1) suggest the existence of a nonlinear triple ion M2SO42+(aq). Consistent with the very strong hydration of the salts, which have ‘effective’ hydration numbers approaching 27 at infinite dilution, there are no significant differences in any of the relaxation or thermodynamic parameters for NiSO4(aq) and CoSO4(aq), except that the triple ion appears to be somewhat more stable for the latter.

Solvent extraction of aluminium in the presence of cobalt, nickel and magnesium from sulphate solutions by Cyanex 272

The extraction and separation of aluminium from cobalt, nickel and magnesium sulphate solutions have been carried out using the organo-phosphinic extractant Cyanex 272. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of extraction pH at equilibrium, temperature, extractant concentration and organic to aqueous phase ratio. A statistically designed experiment was also carried out in order to study the stripping of the aluminium loaded Cyanex 272 organic phase by sulphuric acid solution. The number of stages required for both extraction and stripping processes of aluminium was also evaluated. The results of the continuous counter current, mini plant tests demonstrated the recovery of aluminium from cobalt, nickel and magnesium sulphate solution.

Simultaneous solvent extraction of cobalt and magnesium in the presence of nickel from sulfate solutions by Ionquest 801

AbstractThe simultaneous extraction of Co(II) and Mg(II) from nickel sulfate solutions has been carried out using the organophosphonic extractant Ionquest 801 diluted in Exxsol D‐80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction parameters, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic/aqueous phase ratio. A statistically designed experiment was also carried out to study the stripping of the Ionquest 801 organic phase loaded with cobalt and magnesium by sulfuric acid solution. The number of stages required for both extraction and stripping processes of cobalt and magnesium was evaluated. The results of continuous counter‐current mini‐plant tests demonstrated the simultaneous recovery of cobalt and magnesium from nickel sulfate solution. Copyright © 2005 Society of Chemical Industry

Correlation between acidic properties of nickel sulfate supported on TiO2-ZrO2 and catalytic activity for ethylene dimerization

A series of catalysts, NiSO4/TiO2-ZrO2, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. For NiSO4/TiO2 -ZrO2 sample, no diffraction line of nickel sulfate was observed up to 30 wt%, indicating good dispersion of nickel sulfate on the surface of TiO2-ZrO2. The addition of nickel sulfate to TiO2-ZrO2 shifted the phase transition of TiZrO4 from amorphous to orthorhombic to a higher temperature because of the interaction between nickel sulfate and TiO2-ZrO2. The number of acid sites of NiSO4/TiO2-ZrO2 increased in proportion to the nickel sulfate content up to 20 wt% of NiSO4. Nickel sulfate supported on TiO2-ZrO2 was found to be very active even at room temperature, giving a maximum in both activity and acidity when the catalyst containing 20% NiSO4 was calcined and evacuated at 500°C The asymmetric stretching frequency of the S=O bonds for NiSO4/TiO2-ZrO2 samples was related to the acidic properties and catalytic activity. That is, the higher the frequency, the higher both the number of acid sites and the catalytic activity for ethylene dimerization.

Active Facilitated Transport and Separation of Co in Co–Ni Sulfate Solution by Hollow Fiber Supported Liquid Membrane Containing HEH(EHP)

The active facilitated transport and separation of cobalt in mixed solution of cobalt and nickel sulfate were studied using hollow‐fiber supported liquid membrane (HF‐SLM). The HF‐SLM contained 2‐ethylhexylphosphonic acid mono‐2 ethylhexyl ester [HEH(EHP)], which was diluted in kerosene as a carrier. The permeation rates and separation factors were found to be dependent on the operational variables such as the concentrations of metal and hydrogen ions in the feed solution, the carrier concentration in the liquid membrane, and the flow rate of feed solution. The permeation rate of cobalt was 10−6–10−7 mol/m2 s and the separation factor of Co/Ni was 10–220 under the experimental conditions. By recirculating the strip solution, a tenfold enrichment of cobalt was possible and cobalt with 95% purity was recovered from the low concentration solution in which the concentrations of both cobalt and nickel were 17 mol/m3.

Conductometric study of ion association of divalent symmetric electrolytes: I. CoSO 4, NiSO 4, CuSO 4 and ZnSO 4 in water

Electric conductivities of cobalt, nickel, copper and zinc sulfate solutions in water were measured from 5 to 35 °C (steps of 5 °C) in the concentration range 10 −4< c/(mol dm −3)<4×10 −3. Data analysis, based on the chemical model of electrolyte solutions including short-range interactions, yields the limiting molar conductivity Λ ∞ and the association constant K A . The standard Gibbs energy, enthalpy and entropy of the ion-pairing process were calculated from the temperature dependence of the ion-association constants.

Process for the recovery of cobalt and nickel in the presence of magnesium from sulphate solutions by Cyanex 272 and Cyanex 302

The simultaneous extraction and separation of Co(II) and Mg(II) from nickel sulphate solutions was carried out using the phosphinic extractant Cyanex 272. Nickel, which remained in the aqueous phase, was concentrated by Cyanex 272 and then stripped by synthetic nickel spent electrolyte in order to produce a solution suitable for nickel electrowinning. Subsequently, cobalt and magnesium separation was achieved by the thiophosphinic acid Cyanex 302. Statistical design and analysis of experiments were used, in all cases, in order to determine the main effects and interactions of the solvent extraction factors, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic to aqueous phase ratio. A statistically designed experiment was, also, carried out in order to study stripping of the loaded, with cobalt and magnesium, Cyanex 272 organic phase by diluted sulphuric acid. Cobalt was recovered from the loaded Cyanex 302 by a synthetic cobalt spent electrolyte, in order to produce a solution suitable for cobalt electrowinning. The slope analysis method was used to determine the nature of the cobalt and nickel complexes extracted by both extractants. The number of stages required for the extraction and stripping processes was also evaluated. Finally, the results of the continuous, counter-current, mini-plant tests clearly demonstrated the feasibility of the simultaneous recovery of cobalt and magnesium from nickel sulphate solutions by Cyanex 272, as well as their separation by Cyanex 302.

Acidic properties of nickel sulfate supported on TiO 2–ZrO 2 and catalytic activity for acid catalysis

A series of catalysts, NiSO 4/TiO 2-ZrO 2, was prepared by the impregnation method using an aqueous solution of nickel sulfate. Calcination at 300–600 °C of co-precipitated Ti(OH) 4–Zr(OH) 4 resulted in the formation of an amorphous phase and further heating at 700 °C and above resulted in the formation of crystalline ZrTiO 4 compound. For NiSO 4/TiO 2-ZrO 2 sample, no diffraction line of nickel sulfate was observed up to 30 wt.%, indicating good dispersion of nickel sulfate on the surface of TiO 2–ZrO 2. The addition of nickel sulfate to TiO 2–ZrO 2 shifted the phase transition of ZrTiO 4 from amorphous to orthorhombic to higher temperature because of the interaction between nickel sulfate and ZrTiO 4, and the acid amount of NiSO 4/TiO 2-ZrO 2 increased in proportion to the nickel sulfate content up to 20 wt.% of NiSO 4. The high catalytic activity of NiSO 4/TiO 2-ZrO 2 was related to the increases of acid amount and acid strength due to the addition of NiSO 4. The catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation, were correlated with the acid amounts of catalysts measured by on ammonia chemisorption method. The asymmetric stretching frequency of the SO bonds for NiSO 4/TiO 2-ZrO 2 samples was related to the acidic properties and to the catalytic activity for acid catalysis. That is, the higher the frequency, the larger the acid amount and catalytic activities for 2-propanol dehydration and cumene dealkylation.

Activity Coefficients of HCl in the Nickel Sulfate Solution

Activity Coefficients of HCl in the Nickel Sulfate Solution

The effect of temperature on structural changes of NI55CO45 amorphous powder

Cobalt and nickel alloy powders were obtained by electrochemical deposition on a titanium cathode from an ammonium solution of cobalt and nickel sulfate. Powders of a specific chemical structure and composition, particle shape and size were obtained by an appropriate choice of electrolysis parameters, current density, deposit growth rate and solution temperature and composition. Within the current density range of 5 - 450 mAcm-2, the current density did not significantly affect the chemical composition of the powders, but had a significant effect on the particle structure, shape and size. Crystal particles formed at a current density lower than 30 mAcm-2. Amorphous powders were obtained at a current density higher than 50 mAcm-2. Structural changes of the obtained amorphous powder of 55mol.% Ni, 45 mol.% Co, pressed under the pressure of 100 MPa, were investigated by measuring the temperature dependence of electrical resistance in isothermal and non-isothermal conditions varying from room temperature to 750?C. The process of thermal stabilization of defects that appeared during pressing occurred within the temperature range of 200-390?C. The DSC method was used to determine that the powder crystallization process occurred in two stages with peak temperatures of the exothermal maximum in the first and second stage of T1 = 438?C and T2 = 573?C, respectively. A distinct correlation between the change of electrical resistance and the crystallization process was established. The reduction of electrical resistively occurs during each crystallization stage.

Hydrothermal deposition of nickel on Teflon substrate

Nickel coating with large surface area has been formed by a hydrothermal deposition on Teflon (PTFE) substrate. The hydrothermal reduction from nickel sulphate and ammonia solution at 150 °C results in the formation of uniform nickel layer (20–30 μm) on Teflon surface. Ni-coated Teflon samples were characterized using X-ray diffraction and scanning electron microscopy (SEM). It was found that nickel was homogeneously distributed on Teflon surface.

Electrodeposition of Ni/SiC contacts

We report on the fabrication and characterization of n-type 4H–SiC/Ni contacts formed by electrodeposition from nickel sulfate solutions. We show that the nickel ion states overlap the conduction band of n-type 4H–SiC so that electrodeposition occurs by electron injection from the conduction band into the nickel ion acceptor states. Nickel deposition on n-type 4H–SiC is characterized by nucleation followed by diffusion-limited growth of three-dimensional clusters. As-deposited n-type 4H–SiC/Ni contacts are rectifying with ideality factors of 1.5–2. After annealing, the contacts are Ohmic due to the formation of Ni2Si.