Nickel Precipitate Research Articles

Nucleation of Nickel Disilicide Precipitates in Float‐Zone Silicon: The Role of Vacancies

Nickel is one of the fast diffusion transition metal impurities in silicon that tends to form precipitates during cooling from processing temperature. The typically observed NiSi2 plate-shaped precipitates are well-understood from structural and electrical perspectives with the exception of the initial stages of particle nucleation. Herein, the fact that excess vacancies bound into nitrogen-vacancy complexes react with interstitial nickel to form substitutional nickel atoms, Nis is exploited. Furthermore, excess vacancies can be removed by thermal annealing thus providing a scheme, where nickel precipitation can be studied with and without the presence of Nis. It is shown by deep-level transient spectrocopy (DLTS) that Nis considerably enhances nickel precipitate nucleation by reducing the nucleation barrier by about 1.7 eV and that Nis is consumed by precipitate formation. Simple energy considerations and an atomistic model of particle nucleation will be discussed.

Recovery of nickel from spent electroplating solution by hydrometallurgical and electrometallurgical process

Recovery of nickel from spent electro nickel plating solution has been investigated via hydro-metallurgical and electrometallurgical processes. Experimental consisted of 3 steps, including precipitation of nickel from spent solution, leaching of nickel precipitate, and electrowinning of nickel. Nickel precipitation was performed using sodium hydroxide. Leaching parameters such as 1 M to 3 M sulfuric acid concentration, 100 g×L-1 to 300 g×L-1 solid to liquid ratio, and 30 min to 180 min leaching time were investigated. The leachate from the optimal leaching condition was further used as an electrolyte in electrowinning process. Effects of 3.3 V to 3.7 V cell voltage on recovery and purity of nickel and current efficiency of the electrowinning process were investigated. The results showed that nickel precipitation could be performed by using 2 M sodium hydroxide to adjust the solution to pH ³13. For leaching, dissolution of nickel precipitate of higher than 90% was achieved at the optimum leaching condition of 2 M sulfuric acid, solid to liquid ratio of 100:1 g×L-1 and leaching time of 60 min. Electrowinning of nickel applying the cell voltage of 3.5 V for 24 h showed the greatest nickel recovery of about 61%, giving nickel purity of 99% while the current efficiency of electrowinning cell of approximately 16% can be achieved.

Geokimia Endapan Nikel Laterit di Tambang Utara, Kecamatan Pomalaa, Kabupaten Kolaka, Provinsi Sulawesi Tengara

Pomalaa is administratively located in Kolaka Regency, Southeast Sulawesi Province. The nickel mining business area in Pomalaa is managed by State-Owned Enterprises and Private Enterprises. Pomalaa is a sub-district that has natural resources in the form of nickel. Nickel Laterite deposits is a result weathering of ultramafic rock that is leaching process and accumulates in the supergen enrichment zone. The lateritization factor is controlled by lithology, morphology, and structure. In general, the profile of laterite nickel deposits in the North Mine area from top to bottom consists of top soil, limonite, saprolite, and bedrock zones. The laterite nickel precipitate in the North Mine shows varying thickness, based on color, texture, size and mineral composition. Laterite deposits from drilling results reaches an range of 25 - 30 meters. Soil and rocks sampling from each laterite zone every meter resulting from drilling are carried out by laboratory testing using XRF (X-Ray Fluorescence) analysis method with 283 total sample. High Ni element show enrichment in the saprolite zone, whereas in the high Fe (iron) element in the limonite zone.Keywords: nickel, laterite, geochemical, Pomalaa

Geokimia Endapan Nikel Laterit di Tambang Utara, Kecamatan Pomalaa, Kabupaten Kolaka, Provinsi Sulawesi Tengara

Pomalaa is administratively located in Kolaka Regency, Southeast Sulawesi Province. The nickel mining business area in Pomalaa is managed by State-Owned Enterprises and Private Enterprises. Pomalaa is a sub-district that has natural resources in the form of nickel. Nickel Laterite deposits is a result weathering of ultramafic rock that is leaching process and accumulates in the supergen enrichment zone. The lateritization factor is controlled by lithology, morphology, and structure. In general, the profile of laterite nickel deposits in the North Mine area from top to bottom consists of top soil, limonite, saprolite, and bedrock zones. The laterite nickel precipitate in the North Mine shows varying thickness, based on color, texture, size and mineral composition. Laterite deposits from drilling results reaches an range of 25 - 30 meters. Soil and rocks sampling from each laterite zone every meter resulting from drilling are carried out by laboratory testing using XRF (X-Ray Fluorescence) analysis method with 283 total sample. High Ni element show enrichment in the saprolite zone, whereas in the high Fe (iron) element in the limonite zone.Keywords: nickel, laterite, geochemical, Pomalaa

Geokimia Endapan Nikel Laterit di Tambang Utara, Kecamatan Pomalaa, Kabupaten Kolaka, Provinsi Sulawesi Tengara

Pomalaa is administratively located in Kolaka Regency, Southeast Sulawesi Province. The nickel mining business area in Pomalaa is managed by State-Owned Enterprises and Private Enterprises. Pomalaa is a sub-district that has natural resources in the form of nickel. Nickel Laterite deposits is a result weathering of ultramafic rock that is leaching process and accumulates in the supergen enrichment zone. The lateritization factor is controlled by lithology, morphology, and structure. In general, the profile of laterite nickel deposits in the North Mine area from top to bottom consists of top soil, limonite, saprolite, and bedrock zones. The laterite nickel precipitate in the North Mine shows varying thickness, based on color, texture, size and mineral composition. Laterite deposits from drilling results reaches an range of 25 - 30 meters. Soil and rocks sampling from each laterite zone every meter resulting from drilling are carried out by laboratory testing using XRF (X-Ray Fluorescence) analysis method with 283 total sample. High Ni element show enrichment in the saprolite zone, whereas in the high Fe (iron) element in the limonite zone.Keywords: nickel, laterite, geochemical, Pomalaa

Synergistic effect of organic acid on the dissolution of mixed nickel-cobalt hydroxide precipitate in sulphuric acid solution

The synergistic effect of an organic acid on the dissolution of nickel and cobalt from a mixed nickel-cobalt hydroxide precipitate (MHP) in sulphuric acid solution was studied. The effects of sulphuric acid concentration, the type of organic acid, leaching time, leaching temperature and stirring speed on the dissolution of the metals were experimentally investigated. It was observed that there is no beneficial effect of leaching temperature and stirring speed on the dissolution of the metals from the used MHP product which contains 37.7% Ni, 2.1% Co and 5.6% Mn. It was found that citric acid was more effective than oxalic acid for the dissolution of nickel and manganese, whereas oxalic acid was more effective than citric acid for the dissolution of cobalt. The addition of oxalic acid into the leaching system, however, affected the dissolution of nickel negatively because nickel precipitate as nickel oxalate. Therefore, the use of citric acid as synergist for sulphuric acid leaching of MHP product is more promising. After 60 min of leaching, 90.9% Ni, 84.2% Co and 98.1% Mn were dissolved under the following conditions: 0.75 M sulphuric acid, 2 g citric acid, 1/10 solid-to-liquid ratio, 400 rpm stirring speed and 30 °C temperature. The experimental results demonstrate that the addition of citric acid as a synergist for sulphuric acid leaching of a MHP product provides beneficial effect for the dissolution of nickel, cobalt and manganese.

Radiation-resistant magnetic field sensors based on SiO2(Ni)/Si structures

Structures containing a nickel precipitate in the pores of silicon oxide were obtained by ion-track technology. The SiO2(Ni)/Si structures were exposed under irradiation with 60Co gamma quanta with energy of 1.25 MeV at the dose up to 1.5 × 105 Gy. The electrophysical and galvanomagnetic characteristics of the SiO2(Ni)/Si structures before and after irradiation were studied and the influence of ionizing radiation on their electrical resistivity and magnetoresistance was discussed. The use of SiO2(Ni)/Si structures as a sensitive element of radiation-resistant magnetic field sensors was proposed.

Separation and Recovery of Nickel from Spent Electroless Nickel-Plating Solutions with Hydrometallurgical Processes

A method of recovering nickel from spent electroless nickel-plating solutions has been investigated through the electrowinning method, following the precipitation of nickel by adding alkali and then dissolving this nickel precipitate with sulfuric acid. When sufficient caustic soda was added to a spent electroless nickel-plating solution to increase the pH to higher than 13, fine nickel particles, below 4 microns in size, along with nickel hydroxide were formed. After filtering the nickel precipitate, it was dissolved with a sulfuric acid solution of over 2 vol%, with which more than 95% of the nickel precipitate could be dissolved. For nickel recovery by electrowinning, the pH of the nickel solution required an adjustment of nearly 2.0.

Recovery of nickel from aqueous samples with water-soluble carboxyl methyl cellulose–acetone system

A simple and efficient method, which involves carboxyl methyl cellulose (CMC) and acetone, was developed for recovery of trace nickel from aqueous solutions. This method was based on the fact that Ni 2+ could react with CMC and form water-soluble complexes, which would solidify in excess acetone. After centrifugation, the solid mass consisting of the nickel complex and free CMC was easily dissolved with water and the nickel was determined by flame atomic absorption spectrometry (FAAS). Several factors influencing the recovery of nickel were thoroughly investigated and the optimized conditions were as follows: 5.00 mL water sample, 0.50 mL 0.5% CMC, 1.00 mL of 3.0 mg mL −1 KNO 3 and 20 mL acetone. Under the optimized conditions, the loading capacity of CMC for nickel was 20.6 mg Ni/g polymer. The linear range was 0.025–3.0 μg mL −1, the limit of detection was 0.019 μg mL −1 and the pre-concentration factor was 4. Ni(II) can be well recovered in this CMC–acetone system from binary ions mixtures containing Zn(II), Ba(II), Ca(II), Mo(VI), Co(II), Cd(II), Mg(II), Mn(II) and Cr(III). The developed method had been applied to the recovery of trace nickel in water samples with satisfactory results. A possible mechanism for the nickel precipitate was proposed. The efficient, convenient and affordable method provides an alternative method for the recovery of nickel from environmental waters.

Electron microscopy study of the interaction of Ni, Pd and Pt with carbon: I. Nickel catalyzed graphitization of amorphous carbon

The aggregation of nickel supported on amorphous carbon during heating in vacuum and at how hydrogen pressures in the temperature range 1000 K was investigated by means of high resolution electron microscopy, electron diffraction and microdiffraction. It was established that the interaction of highly dispersed nickel with amorphous carbon substrates is strong enough to break away carbon atoms from the bulk at relatively low temperatures (∼ 700 K) Carbon atoms dissolved in nickel precipitate as graphite. As a result the aggregation of nickel is accompanied by the conversion of the amorphous carbon substrate to graphitic carbon.

Effect of dipolar aprotic permeability enhancers on the basal stratum corneum

The effect of dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide on the basal stratum corneum of excised nude mouse skin was investigated. All of these dipolar aprotic solvents caused a swelling of the basal stratum corneum cells and a disruption of the normal keratin pattern. This behavior suggests that dipolar aprotic solvents might alter the barrier properties of the basal stratum corneum cells. To test this hypothesis, the distribution of topically applied, electron-dense divalent metal ions (Hg2+ and Ni2+) was studied in excised nude mouse skin which had been perturbed by the application of dipolar aprotic solvents, and in controls which had not been so treated. In control skin membranes, Hg2+ and Ni2+ were located almost exclusively in the intercellular space of the stratum corneum. However, with the application of a dipolar aprotic solvent, Hg2+ and Ni2+ were found in the intercellular spaces and inside the basal stratum corneum cells, where they appeared to be primarily associated with the cytoplasmic filaments. Sulfide precipitation allowed for the localization of Hg2+ and Ni2+, and subsequent chemical identification by energy-dispersive X-ray microanalysis. The spatial resolution of X-ray microanalysis studies was ∼0.5–0.75 μm. The spatial alteration in mercury and nickel precipitate distribution, which occurs when the skin is pretreated with a dipolar aprotic solvent, is consistent with the hypothesis that the pathway of Hg2+ and Ni2+ diffusion through the basal stratum corneum has also been modified.

The microstructure and fracture properties of MgO crystals containing a dispersed phase

MgO crystals containing up to 40% by volume of magnesioferrite and up to 2% by volume of iron and nickel were produced by a diffusion technique followed by appropriate heat treatments. Magnesioferrite precipitate did not significantly change the effective surface energy of a crack as measured by the double cantilever beam technique. Iron and nickel precipitate was produced in the form of platelets lying on {100}MgO planes whose orientation relationships were [001]MgO ∥[001]Fe, [110]MgO ∥[100]Fe with a spread of +10°, approximately, and [001]MgO ∥[001]Ni, [010]MgO ∥[010]Ni with negligible spread. Despite the crystallographic orientation relationships, the metal-MgO interface appeared to be very weak; the reasons for this are discussed. The effect of the metal precipitate on crack propagation was to markedly increase the density of cleavage steps. For a volume fraction of precipitate of 0.02, this led to a small increase in the effective surface energy, on the order of 1 Jm−2.

鐵鋼中コバルトの存在に於けるニッケルの定量に就て

The ordinary process for the determination of nickel in iron and steel is precipitation by Dimethylglyoxime. This method is very accurate in the presence of all other elements except cobalt. When more than traces of cobalt are present, the method must be slightly modified. of modifications, the one apparently in most general use is the Methods of U.S. Steel Corporation that is based upon the oxidation of cobalt by sodium or potassium chlorate in ammoniacal solution. By this method the author determined nickel in iron and steel in the presence of varying amounts of cobalt. And he found the fact that this is an excellent process giving good results when the amount of cobalt in the solution of the sample does not exceed about 0·02 grams but when it is in excess of this limit the precipitate of the nickel glyoxime obtained may not have its true scarlet color owing to the contamination with cobalt and iron and too high results are obtained. So any remedy for this effect of cobalt is necessary if the solution of the sample contains more than 0·02 grams of cobalt. Some experiments were made to study the methods applicable in such a case. and of these the following method proved most successful:-Proceed as for nickel as in the Methods of U.S. Steel Corporation obtaining the impure nickel precipitate. The precipitate is dissolved off the filter with nitric acid allowing the solution to run into the beaker in which the precipitate of nickel was made. Heat and destroy any remnant of dimethylglyoxime. Cool and make the solution ammoniacal. Boil and filter the iron hydroxide. The precipitated iron hydroxide willcarry out with it a small amount of nickel. This iron hydroxide is redissolved in hot I; I nitric acid and again precipitated with ammonia. From the combined fitrate the pure nickel precipitate can readily be obtained.