Partitioning Of Nickel Research Articles

Redox effect on the partitioning of nickel in olivine

The fractionation of nickel by olivine in the Lower Zone of the Kiglapait Intrusion, in company with the olivine compositions compared to estimated liquid compositions, places stringent limits on the value of the olivine/liquid partition coefficient for Ni, estimated at 4.0± 0.8 at the base of the Lower Zone. Data from a strong Ni-MgO correlation in Mauna Loa picrites also require a low value of D, estimated at 5.8 ± 0.4. These values are much lower than usually considered normal for mafic magmas, and the effect is ascribed to the low oxygen fugacity of the magmas, estimated independently for the Kiglapait case to be near the wüstite-magnetite buffer. At this redox state, a significant amount (in this case about half) of the Ni in the melt is dissolved as Ni 0, which inflates the liquid concentration without entering the olivine. Because the analyzed values reflect only total Ni rather than the species, the partition coefficient decreases with reduction, as shown by recent experimental studies. The Mauna Loa data imply a reduced condition for that magma as well. Knowledge of the redox regime governing the partition coefficient is vitally important in modelling fractional crystallization and in discussing early planetary history. Conversely, knowledge of the Ni fractionation in a magma series can specify the redox regime of the magma, as at Mauna Loa.

Elemental partitioning and microstructural development in duplex stainless steel weld metal

A thermodynamic analysis which is capable of estimating the austenite/ferrite equilibria in duplex stainless steels has been carried out using the sublattice thermodynamic model. The partitioning of alloying elements between the austenite and ferrite phases has been calculated as a function of temperature. The results showed that chromium partitioning was not influenced significantly by the temperature. The molybdenum, on the other hand, was found to partition preferentially into ferrite phase as the temperature decreases. A strong partitioning of nickel into the austenite was observed to decrease gradually with increasing temperature. Among the alloying elements, average nitrogen concentration was found to have the most profound effect on the phase balance and the partitioning of nitrogen into the austenite. The partitioning coefficient of nitrogen (the ratio of the mole fraction of nitrogen in the austenite to that in the ferrite) was found to be as high as 7.0 around 1300 K. Consequently, the volume fraction of austenite was influenced by relatively small additions of nitrogen. The results are compared with the experimentally observed data in a duplex stainless steel weld metal in conjunction with the solid state δ → δ + γ phase transformation. Particular attention was given to the morphological instability of grain boundary austenite allotriomorphs. A compariso between the experimental results and calculations indicated that the instability associated with irregular austenite perturbations results from the high degree of undercooling. The results suggest that the model can be used successfully to understand the development of the microstructure in duplex stainless steel weld metals.

An experimental study on the effect of temperature and melt composition on the partitioning of nickel between olivine and silicate melt

Experiments in the simple system CaO-MgO-Al 2O 3-SiO 2-Na 2O-FeO were carried out to investigate the control of temperature and melt composition on the partitioning of nickel between olivine and silicate melt ( D oliv/liq Ni ). Eleven experiments determine the influence of changing forsterite (Fo) content on D oliv/liq Ni in this simple system. The equation of Hart and Davis (1978) that accounts for the variation of D oliv/liq Ni in terms of MgO content of the silicate liquid is tested using experimental data from ironbearing simple and natural systems and found to be inadequate to explain the observed variation of D oliv/liq Ni ( ±39% relative average error of prediction). Two different equations are formulated to describe the partitioning behavior of Ni between olivine and silicate melt. The first is similar to that of Hart and Davis (1978) and uses an expression for Ni-Mg exchange between olivine and silicate melt. The second uses an expression for the Ni-olivine formation reaction. The Ni-Mg exchange equation for D oliv/liq Ni depends on the forsterite content of the olivine and the mole fraction MgO liq, and predicts the experimentally determined values within ±13% relative average error. The Ni-olivine formation reaction equation for D oliv/liq Ni depends on temperature, mole fraction SiO liq 2, and melt compositional terms that arise from a symmetric, binary, Margules formulation of the activity coefficients for NiO liq and SiO liq 2. This equation predicts the experimentally determined values within ±9% relative average error.

Optimization of Tessier Procedure for Metal Solid Speciation in River Sediments

Abstract Optimization of Tessier procedure for trace metal partitioning in sediments is studied. Firstly simplex optimization method is applied and the results indicate that the volume of extractant solution/weight of sediment ratio (V/m) is the main variable. Optimization of V/m ratio for second, third and fourth fractions of Tessier scheme is studied on two different river sediments. The optimum values of V/m ratio obtained are applied for copper, lead, chromium and nickel partitioning. The results obtained are compared with those obtained using Tessier procedure. Some conclusions about the behaviour of each fraction are presented.

Contrasting behaviour of dissolved and particulate nickel and zinc in a polluted estuary

The distributions of dissolved and particulate nickel and zinc in the Mersey estuary have been studied in a series of surveys covering the period 1980–1984. Sampling exercises were conducted over a range of tidal and river flow conditions. For both elements, metal versus salinity plots indicate inputs of dissolved nickel and zinc in the middle and upper estuary. We suggest that the influx of nickel originates from industrial discharges to the narrow upper estuary, while discharges of untreated domestic wastewater account for the pronounced maximum in the zinc distribution at salinities in the region 20–25%. The influence of release of dissolved zinc by physical disturbance of sediments and mixing of interstitial waters is also recognised. Dispersion of the zinc anomaly appears to be controlled by hydrological, meteorological and tidal conditions. Particulate metal distributions reflect the different partitioning of nickel and zinc in suspended solids, nickel being associated more with refractory components while zinc occurs in association with organic phases.

Copper and nickel partitioning in iron meteorites

Trace element analyses using proton induced x-ray emission (PIXE) and synchrotron x-ray fluorescence (SXRF) have been made on metal and troilite from 9 iron meteorites representing 5 geochemical groups. Nickel and copper distribution coefficients D ( troilite metal ) vary by factors of 600 and 20, respectively, correlate positively with kamacite band width and correlate negatively with bulk nickel content. Meteorites with bulk Ni < 10% have Cu-enriched troilite ( D Cu > 1) while those with Ni > 10% have Cu-depleted troilite ( D Cu < 1). Since magmatic evolution and partial melting will produce Cu-enriched troilite only, the observation of Cu-depleted troilite in Ni-rich meteorites is evidence for subsolidus re-equilibration, a process which reduces D Cu by transfer of Cu to exsolving metal. Elemental redistribution may have played an important role in establishing the present chemical trends in iron meteorites.

Metal Precipitation in Two Landfill Leachates

Leachate from solid‐waste landfills poses a significant environmental threat to groundwater supplies, warranting capture and treatment. Treatment prior to biological co‐production to reduce heavy metal concentrations via sorption onto in situ precipitated hydrous ferric and manganese oxides may provide adequate reductions while minimizing hazardous residuals. This investigation studied the partitioning of cadmium, copper, zinc, and nickel with iron and manganese solid phase formed from leachate constituents at pH 9. Batch‐type partitioning experiments were conducted using sodium hydroxide and calcium hydroxide for pH control. Naturally produced leachate was obtained from the Snohomish County and King County solid‐state disposal facilities in Washington state. The cadmium‐sorbent ratios of this investigation were well below those found by previous researchers; however, removal rates were somewhat below those found in organic‐free systems. These lower removal rates might be attributed to the “complexation” of cadmium by leachate organic constituents. Copper‐sorbent ratios were also well below those found by previous researchers; conversely, removal rates were significantly below those found for organic‐free systems. Lower copper removal rates could be attributed to the complexation by organics and the formation of uncharged and negatively charged species at pH 9. Zinc‐sorbent ratios were much higher than those found by previous researchers; however, removal rates were similar. The mechanism of zinc partitioning was probably the formation of a zinc oxide solid phase. Nickel‐sorbent ratios were well below those found by previous researchers, while removal rates were far below those of organic‐free systems. Lower nickel removal rates cannot be attributed to either organic complex formation or speciation effects.

Ideal mixing of divalent cations in mafic magma. II. The solution of NiO and the partitioning of nickel between coexisting olivine and liquid

Using both high- and low-NiO starting materials, a set of aluminosilicate liquids are equilibrated with metallic nickel under controlled oxygen fugacity at 1400°C to contour a Matrix-NiO-MgO ternary system for a NiO. The ternary contains a synthetic analog of standard diabase W-1. The results demonstrate that the relation a ternary NiO = a Mg-free NiO × Ni (Ni + Mg) accounts for the variation of a NiO at constant mole fracti of Matrix ( X Matrix = 1 − X Nio − X MgO ) in the ternary system. This suggests that the divalent cations of Ni and Mg mix ideally on the sites that they occupy in mafic magmas. Using Doyle and Naldrett's (1986) simple mixing model for aluminosilicate liquids, the compositional dependence of a NiO in a wide range of mafic and intermediate magmas is strongly temperature sensitive. The data are consistent with CaAl 2Si 2O 8 being a component of the Matrix and the remaining Ca mixing ideally with the divalent cations of Fe, Mn, Mg and Ni. These findings are used to understand better the controls on the partitioning of Ni between coexisting olivine and mafic or intermediate liquid.

The oxygen content of "sulfide" magma and its effect on the partitioning of nickel between coexisting olivine and molten ores

The oxygen content of "sulfide" magma and its effect on the partitioning of nickel between coexisting olivine and molten ores

Partitioning of nickel during pearlite growth

Partitioning of nickel during pearlite growth

Chemical Partitioning of Cadmium, Copper, Nickel and Zinc in Soils and Sediments Containing High Levels of Heavy Metals

AbstractThree soils and a sediment which had undergone prior massive additions of heavy metals were sequentially extracted so that Cd, Cu, Ni, and Zn could be partitioned into five operationally defined geochemical fractions: exchangeable, bound to carbonates, bound to Fe‐Mn oxides, bound to organic matter, and residual. Metal recoveries were within ± 10% of the independently measured total Cd, Cu, Ni, and Zn concentrations. The highest amount of Cd (ca. 37%) was foand in the exchangeable fraction, and Cu was the only metal significantly associated with the organic fraction. The Fe‐Mn oxide fraction contained 23, 24, 26, and 39%, and the residual fractions 15, 34, 55, and 14% of the Cd, Cu, Ni, and Zn, respectively. The amount of Cd in the residual fraction was 50 times higher than typical for unpolluted soils. Assuming that mobility and biological availability are related to the solubility of the geochemical form of the metals and decreases in the order of extraction, the apparent mobility and potential metal bioavailability for these highly contaminated soils and sediment is: Cd &gt; Zn &gt; Cu ≅ Ni.

The partition of nickel between olivine, magma and immiscible sulfide liquid

The Ni contents of glasses in products of earlier experiments on the Ni partition between olivine and immiscible sulfide liquid have been determined, allowing the distribution coefficients for Ni Fe 2+ exchange between sulfide and silicate ( K D 1), and olivine and silicate ( K D 2) to be calculated. Ni is relatively enriched in S-bearing Mg-silicate liquids by complexing with dissolved S. In consequence, K D 1 and K D 2 are systematically dependent on both silicate liquid and sulfide liquid composition. The present study re-affirms the reliability of the existing Ni partition data for coexisting olivine and sulfide and, therefore, supports the earlier conclusion that an immiscible sulfide liquid cannot be a normal product of upper-mantle magmatic processes. In S-bearing systems K D 2 will be somewhat lower than the value for the corresponding S-free system, and this may account for the discrepancies between previously reported partition data.

FCC and BCC Solidification Products in a Rapidly Solidified Austenitic Steel.

ABSTRACTThe microstructures and local composition variations in centrifugally atomized high-sulfur stainless steel powder are investigated. Both fcc and bcc are found to be primary solidification phases in the as-solidified powder of this nominally austenitic steel where the smaller powder particles (≲ 70 micron diameter) tend to be bcc.Cellular solidification structures, with sulfide precipitates (100 to 200 nm diameter in size) at the cell walls, are observed in both fcc and bcc particles. The bcc structure, however, has many small sulfide precipitates (10 to 20 nm diameter) in the cell interior with few larger sulfide precipitates at the cell walls. The small precipitates, observed only in the bcc structures, form on cooling from a supersaturated solid solution that results from reduced solute partitioning during solidification. Partitioning of chromium and nickel is minimal in these cellular structures. A non-cellular bcc structure is also observed with small sulfide precipitates throughoutthe entire structure. This non-cellular bcc structure results from smooth-front massive solidification. Analysis of the nucleation process for solidification indicates that a transition from fcc nucleation to bcc nucleation occurs with increasing wetting angle in heterogeneous nucleation. Thus bcc should nucleate in the smaller droplets of a liquid dispersion where catalytic surfaces of low potentcy (large wetting angle) tend to be the only heterogeneous nucleants available.

Partitioning of chromium, manganese, cobalt and nickel between olivine and basaltic liquid: an experimental study

Partitioning of chromium, manganese, cobalt and nickel between olivine and basaltic liquid: an experimental study

Nickel partitioning between olivine and liquid in natural basalts: Henry's Law behavior

Equilibrium, reversal experiments on natural mid-ocean ridge olivine basalt 527-1-1 were performed to determine whether Ni behaves according to Henry's Law when partitioned between olivine and liquid. The results indicate that nickel obeys dilute solution behavior in both olivine and liquid at the concentration ranges found in most natural basalts (100–300 ppm Ni in glass). The partition coefficient K d Ni (O1/L) at the liquidus temperature (1267°C) was bracketed at 10.25 ± 0.50. In addition, it was determined that the apparent partition coefficients in experiments with amounts of nickel in the ppm range are extremely sensitive to the loss of nickel to metal containers during runs. The electron microprobe can be used successfully to determine natural nickel concentrations in both olivine and basaltic liquid.

Comments on: “The partitioning of nickel between olivine and silicate melt” by S.R. Hart and K.E. Davis

Comments on: “The partitioning of nickel between olivine and silicate melt” by S.R. Hart and K.E. Davis

Determination of crystallization temperatures in fractional crystallization series by nickel partitioning equations

Representative crystallization temperatures for five basaltic series are calculated by use of Ni partitioning equations using the Neuman equation, which expresses the bulk partition coefficient in terms of mineral-liquid coefficients and mineral weight fractions. Bulk partition coefficients are calculated using the Rayleigh distribution law. Mineral compositions of the precipitating solid are determined from a computer program which allows us to calculate the mineral composition of the solid subtracted from the liquid, and from judgements based on the petrography of the samples. We use the empirical equations for Ni mineral-liquid partitioning with temperature for restricted SiO 2 compositions calculated by Hart and Davis (1978) , Leeman (1974) , D.J. Lindstrom (unpublished, 1976) and Hakli and Wright (1967) and Hakli (1968) . These are substituted into the Neumann equation in place of the mineral-liquid partition coefficients, and this equation is then solved to determine the temperature. These calculations have been made for volcanic series in Terceira (1200–1270°C) and Flores (1050–1225°C) Islands in the Azores, Miocene plateau basalts in northwest Iceland (1180–1270°C), Cape Verde Islands (970–1180°C) and Grenada Island (1200–1240°C), Lesser Antilles arc. The extremes of the temperatures in the brackets represent the differences between the sets of equations used; however, the calculated error on each temperature is only about ±2% or 20–25°C despite much larger errors on the calculated bulk partition coefficient and mineral fractions. The results have been counterchecked for Terceira and Flores by calculating plagioclase temperatures based on the method of Drake (1976) . The plagioclase temperature for Terceira (1270°C) agrees almost exactly with the Hart-Leeman-Lindstom calculations. The plagioclase temperature for Flores (1130°C) lies in between those calculated by the partitioning equations, but this may be due to the error in the orthopyroxene equation.

Experimental determination of nickel partition coefficients between liquid, pargasite, and garnet peridotite minerals and concentration limits of behavior according to Henry's law at high pressure and temperature; erratum

Experimental determination of nickel partition coefficients between liquid, pargasite, and garnet peridotite minerals and concentration limits of behavior according to Henry's law at high pressure and temperature; erratum

Pressure dependence of nickel partitioning between forsterite and aluminous silicate melts

Nickel partitioning between forsterite and aluminosilicate melt of fixed bulk composition has been determined at 1300°C to 20 kbar pressure. The value of the forsterite-liquid nickel partition coefficient is lowered from >20 at pressures equal to or less than 15 kbar to <10 at pressures above 15 kbar. Published data indicate that melts on the join Na 2O-Al 2O 3-SiO 2 become depolymerized in the pressure range 10–20 kbar as a result of Al shifting from four-coordination at low pressure to higher coordination as the pressure is increased. This coordination shift results in a decreasing number of bridging oxygens in the melt. It is suggested that the activity coefficient of nickel decreases with this decrease in the number of bridging oxygens. As a result, the nickel partition coefficient for olivine and liquid is lowered. Magma genesis in the upper mantle occurs in the pressure range where the suggested change in aluminum coordination occurs in silicate melts. It is suggested, therefore, that data on nickel partitioning obtained at low pressure are not applicable to calculation of the nickel distribution between crystals and melts during partial melting in the upper mantle. Application of high-pressure experimental data determined here for Al-rich melts to the partial melting process indicates that the melts would contain about twice as much nickel as indicated by the data for the low-pressure experiments. If, as suggested here, the polymerization with pressure is related to the Al content of the melt, the difference in the crystal-liquid partition coefficient for nickel at low and high pressure is reduced with decreasing Al content of the melt. Consequently, the change of D Ni ol-andesite melt is greater than that of D Ni ol-basalt melt , for example.

Partitioning of manganese, iron, copper, zinc, lead, cobalt, and nickel in black coatings on stream boulders in the vicinity of the Magruder mine, Lincoln Co., Georgia

Abstract Sequential digestions of Fe-Mn oxide coated boulders collected upstream and downstream from the Magruder mine, Lincoln Co., Georgia, indicate probable partitioning relationships for Zn, Cu, Pb, Co, and Ni with respect to Mn and Fe. Initial digestion with 0.1M hydroxylamine hydrochloride (Hxl) in 0.01M HNO3 selectively dissolyes Mn oxides, whereas subsequent digestion with 1:4 HCl dissolves remaining Fe oxides. The results indicate that partitioning is not constant, but varies systematically with respect to the location of metal-rich waters derived from sulfide mineralization. Upstream from the mineralized zone Zn and Ni are distinctly partitioned to the Fe oxide component and Co and Cu are partitioned to the Mn oxide component. Immediately downstream from the mineralized zone, Mn oxides become relatively more enriched in Zn, whereas Fe oxides are relatively more enriched in Cu, Co, and Ni. Analytical precision for Pb is poor, but available data suggests it is more closely associated with Fe oxides. For routine geochemical surveys utilizing coated surfaces, a one-step digestion method is probably adequate. Parameters useful for detecting sulfide mineralization are metal concentrations normalized to surface area or various ratios (e.g. Zn/(Mn + Fe), Cu/Mn, Pb/Fe). Ratios can be obtained much faster, and at lower analytical costs than conventional analysis of stream sediment.