Distribution Of Scandium Research Articles

Scandium distribution in the world-class Li-Sn-W Cínovec greisen-type deposit: Result of a complex magmatic to hydrothermal evolution, implications for scandium valorization

Scandium is a metal with specific industrial applications and its importance is expected to grow significantly in future. For its use in high-tech alloys and solid oxide fuel cells it is regarded as a strategic metal. The world-class Li-Sn-W Cínovec/Zinnwald greisen-type deposit contains significant amount of Sc which could be an interesting by-product in anticipated production of Li, Sn and W. We conducted systematic study of Sc abundances and mineralogical controls of its fractionation during magmatic and post-magmatic evolution of the Cínovec granite cupola and its greisen deposits. From the main accessory minerals found in (partially to strongly) metasomatized granites, the highest concentrations of Sc2O3 were found in columbite (≤3.0 wt%), zircon (≤2.5 wt%), and Nb-rutile (≤0.3 wt%) which are supplemented by wolframite (≤1.0 wt%), ixiolite (≤4.9 wt%) and cassiterite (≤0.3 wt%) in greisens and quartz-zinnwaldite veins. However, the major Sc-carrier in most rock types and especially in greisens is the common zinnwaldite (typically 40–85 ppm Sc) hosting up to 93% of the total Sc. Younger fluids causing zinnwaldite muscovitization and rare sulfidic overprint were significantly depleted in Sc and caused mobilization of Sc and/or its redistribution into secondary minerals.

Scandium Extraction with Benzo-15-crown-5 from Neutral Nitrate–Trichloroacetate Solutions

A systematic study for scandium extraction with benzo-15-crown-5 in chloroform from trichloroacetate solutions has been performed. The presence of free trichloroacetic acid in extraction system has been found to prevent scandium transfer into organic phase. Scandium is extracted from neutral trichloroacetate solutions as partially hydrolyzed trichloroacetate complexes, the extracted compound includes two crown ether molecules. The presence of nitrate anions has no effect on scandium distribution ratios and nitrate anion is not involved in extracted compound composition. Optimal process conditions for selective scandium recovery from concentrated solutions of rare-earth nitrates in the presence of lithium trichloroacetate with high separation factors (>100) on the use of B15C5 as extractant have been determined.

Scandium in the open ocean: A comparison with other group 3 trivalent metals

AbstractLittle is known about the distribution of scandium (Sc) in the open ocean. Since the 1970s there has been only one published depth profile of dissolved Sc. The work presented here reports depth profiles of dissolved Sc from GEOTRACES cruises in the North Atlantic, North Pacific, and South Pacific. This work also compares the reactivity of Sc with its trivalent periodic table groupmates in Group IIIB, yttrium (Y) and lanthanum (La), and Group IIIA, aluminum (Al) and gallium (Ga). Yttrium and La are classic nutrient‐type metals that increase in concentration in aging deep water; Al and Ga are classic scavenged‐type metals that do the opposite. Results indicate that Sc is a hybrid‐type metal with an inferred residence time on the order of 1000 years, and that Sc's inorganic speciation and reactivity are similar to Fe's and have the potential to give insights into the nonnutrient side of oceanic Fe cycling.

Melt growth, structure and properties of (ZrO2)1−x(Sc2O3)x solid solution crystals (x=0.035−0.11)

Crystals of (ZrO2)1−x(Sc2O3)x solid solutions with x=0.035, 0.06, 0.09 and 0.11 have been grown for the first time using the directional crystallization technique. Analysis of the scandium distribution along the crystal showed that the composition of all specimens is homogeneous, and the Sc2O3 concentration is almost identical to its content in the charge. All specimens exhibit a little decline in the scandium concentration along the crystal, this indicating that the effective distribution coefficient Sc is slightly greater than 1. The structure of as-grown crystals has been studied as a function of the Sc2O3 stabilising oxide concentration by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. Crystals containing 3.5mol% Sc2O3 are a mixture of the monoclinic and tetragonal phases, the crystals containing 6mol% Sc2O3 have a tetragonal structure, those with 9mol% Sc2O3 have the tetragonal phase with inclusions of the rhombohedral one and the specimens with 11mol% Sc2O3 represent the rhombohedral phase with inclusions of the cubic phase. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. The conductivity of the scandia stabilized crystals, in spite of their inhomogeneity, presence of stresses and low fracture toughness, is comparable with that of the yttria stabilized zirconia crystals.

Characterization of scandia doped pressed cathode fabricated by spray drying method

Scandia doped pressed cathode was prepared by a new method of spray drying combined with two-step hydrogen reduction process. The Sc 2O 3 and barium–calcium aluminate co-doped powders have sub-micrometer size in the range of 0.1–1 μm and scandium oxide and barium–calcium aluminate are distributed evenly in the powders. The cathodes sintered by powder metallurgy at 1600 °C b have a smooth surface and sub-micrometer grain structure with homogeneous distribution of scandium, barium, calcium and aluminum which are dispersed over and among the tungsten grains. This cathode has good emission, e.g., the current density of this cathode reaches 31.50 A/cm 2 at 850 °C b. After proper activation, the cathode surface is covered by a Ba–Sc–O active substances layer with a preferable atomic ratio, leading to its good emission property. The evaporation activation energy of SDP cathode with 4.58 eV is the highest among the Ba–W, M-type and SDP cathodes, and the average evaporation velocity v t of SDP cathode with 1.28 × 10 −8 g cm −2 s −1 at 1150 °C b is the lowest one.

Effect of scandia on tungsten oxide powder reduction process

Scandia doped tungsten powders were prepared by spray drying combined with two-step hydrogen reduction. The particle size of doped tungsten powder, powder morphology and doped tungsten matrix were characterized by scanning electron microscope, X-ray diffraction and laser diffraction particle size analyzer, respectively. The reduction behavior of Sc 2O 3 doped tungsten oxide and the effect of Sc 2O 3 on the property of tungsten powder were studied by the temperature programmed reduction. The experimental results showed that the precursor powders prepared by spray drying had spherical shape. The addition of Sc 2O 3 could decrease the reduction temperature of tungsten oxide. The scandia doped tungsten powder had sub-micrometer size in the range of 0.1 to1 μm and scandium distributed evenly in the powder. By using this kind powder, sub-microstructure cathode matrices with semispherical grains and homogenous distribution of scandium were obtained.

Scandia doped tungsten matrix for impregnated cathode

As a matrix for Sc-type impregnated cathode, scandia doped tungsten with a uniform distribution of Sc 2O 3 was obtained by powder metallurgy combined with the liquid-solid doping method. The microstructure and composition of the powder and the anti-ion bombardment behavior of scandium in the matrix were studied by means of SEM, EDS, XRD, and in-situ AES methods. Tungsten powder covered with scandium oxide, an ideal scandium oxide-doped tungsten powder for the preparation of Sc-type impregnated cathode, was obtained using the liquid-solid doping method. Compared with the matrix prepared with the mechanically mixed powder of tungsten and scandium oxide, Sc 2O 3-W matrix prepared with this kind of powder had smaller grain size and uniform distribution of scandium. Sc on the surface of Sc 2O 3 doped tungsten matrix had good high temperature stability and good anti-ion bombardment capability.

Vertical distribution of scandium in the north central Pacific

The concentrations of scandium (Sc) in seawater, which have remained unreported since the early 1970s, were determined together with those of yttrium (Y) and lanthanides (Ln) with samples from the north central Pacific Ocean (St. BO‐3). The Sc concentration shows a so‐called nutrient‐like profile: it increases gradually from the surface (about 2 pmol/kg) to the ocean floor (about 20 pmol/kg). That pattern closely resembles those of Y and Ln (correlation coefficient (r) > 0.92). Some light‐to‐middle Ln (Pr–Tb) exhibit a closer correlation with Sc than do Y, La, or heavy Ln (Ho–Lu). In contrast, Y/Sc and Ln/Sc ratios (elemental abundance ratios) indicate that Sc is depleted compared to either Y or Ln in seawater more than in loess, which represents chemical compositions of crustal material. These observations offer a conflicting view of chemical reactivity related Y, Ln, and Sc: r values show that the chemical reactivity of Sc resembles those of Y and Ln, but differences of Y/Sc and Ln/Sc ratios in seawater and in loess suggest that the chemical reactivity of Sc differs from those of Y and Ln. More Sc data for seawater are necessary to clarify the chemical reactivity of Sc in the ocean. We also propose that comparative studies of vertical profiles of Sc and such elements as Fe, Ti, Zr, and Hf showing so‐called nutrient‐like profiles at the same oceanic stations would be helpful and effective for clarifying the behavior of Sc in the ocean.

Local environment of scandium in aluminophosphate laser glasses: structural studies by solid state NMR spectroscopy

The first NMR study of a scandium oxide containing glass system is reported. The influence of scandium substitution for aluminium in the sodium aluminophosphate glass system (NaPO3)0.83–(Al2O3)0.17−x(Sc2O3)x (0 ≤ x ≤ 0.11) has been studied in detail by multinuclear high-resolution NMR experiments. Introduction of scandium into this glass system results in a systematic change in the aluminium speciation: as the substitutional parameter x is increased, aluminium is successively converted from six- to four-coordination. This result suggests that the scandium ions require more non-bridging oxygen atoms for coordination than aluminium in these glasses. 45Sc chemical shifts are consistent with isolated six-coordinated scandium species. 31P{45Sc} rotational echo adiabatic passage double resonance (REAPDOR) curves show a monotonic increase in slope with increasing x, indicating that the number of 31P–45Sc dipole–dipole couplings increases, consistent with a random spatial distribution of scandium. These results rule out the possibility of rare-earth clustering in these glasses. Both the 45Sc MAS-NMR spectra and 45Sc{31P} rotational echo double resonance (REDOR) data indicate that the scandium species adopt a constant, compositionally independent local environment dominated by phosphorus in the second coordination sphere.

Microstructure of large ingots of aluminum alloy 01570

The use of hollow cylindrical ingots instead of solid ones simplifies considerably the manufacturing process of parts. In order to determine the quality of the ingots and predict and analyze the mechanical properties of parts made from them, the authors compare the parameters of the microstructure of hollow and solid cylindrical ingots and determine the distribution of scandium and zirconium among the structural components of the alloy.

Enrichment and distribution of elements in flood-plain soils of the bitterfeld industrial area—studied by neutron activation analysis

Bitterfeld is an industrial area of central Germany which has been exposed to extraordinarily high concentrations of anthropogenic environmental pollutants for many decades. High concentrations of organic (e.g. PCB and hydrocarbons) as well as inorganic (e.g. heavy metals) pollutants are present in the soils. The major objectives of this study were the quantification of inorganic components in the soils and the verification of the analytical results through different analytical methods. The origin of the anthropogenic heavy metal input in the study area is twofold: first, at present, industrially produced fly ash is deposited upon flood-plain sediment and second, sedimentation processes during the flood periods of the Mulde river over the past number of years. Flood-plain soil profiles were studied and characterized by four horizons, designated as A h, B v, Gor and D. Samples were taken at 10-cm intervals down to a total depth of 170 cm. All components studied were analyzed using activation methods with reactor neutrons and accelerator-produced high energy bremsstrahlung photons. Thirty-four elements and their vertical distributions throughout the profile were examined. The results are interpreted in relation to geochemical and soil-related physical parameters, e.g. pH, clay content, density and organic components. We conclude that for a number of elements, estimations of the anthropogenic input and their mobility behaviour can be made. For instance, the distribution characteristics of calcium, nickel, zinc, molybdenum, arsenic, antimony, lead and uranium indicate mainly an anthropogenic input, whereas the distribution of scandium, titanium, rubidium, yttrium, zirconium, tin, cesium and the rare earths are obviously to a large extent of geogenic origin. For the classification of the depth distribution of the elements studied, a hierarchic cluster analysis was carried out, the results of which were correlated subsequently with the help of canonic discriminance functions.

Application of Monoalkyl Methanephosphonates to Extraction of Selected Metals

The distribution of scandium and hafnium between 0.1 or 1.0 mol l-1 HNO3 and solutions of monoalkyl methanephosphonates (HA; alkyl = methyl, propyl, butyl, isobutyl, pentyl, 2-methylbutyl, cyclohexyl, 1,2,2-trimethylpropyl) in chloroform and 1,1,2,2-tetrachloroethane has been studied. The organic solvents mentioned allow to obtain the optimum values of partition coefficients of the two metals. The corresponding extraction constants of the ScA3(HA)x and Hf(NO3)4(HA)4 complexes have been calculated.

Studies on the scandium distribution in organs of fattened chicken by neutron activation analysis

Tissues samples of chicken /blood, liver, spleen, fat, pancreas, kidney, lung, breast muscle, brain, femur, faeces, egg yolk, white of egg/, were analyzed for scandium concentration. ScCl3 was applied intravenously /1 mg kg−1 body weight/. High scandium concentrations were found in the liver /34. 35 ppm/, spleen /15.46 ppm/, and lung /15.52 ppm/ three days after application. This experiment shows that accumulation of scandium occurs in the yolk of egg but not in the white of the egg.

Liquid phase epitaxial growth of Y 3(Al, Sc) 2Al 3O 12 on (111)-oriented Y 3Al 5O 12 substrates

Epitaxial layers of Y 3(Sc x Al 1- x ) 2Al 3O 12 for which x = 0–1 were grown on (111)-oriented Y 3Al 5O 12 substrates to investigate the variation of the scandium distribution coefficient with composition for growth from supercooled solutions of PbO-B 2O 3. Lead incorporation from PbO is negligible at the growth temperature of 1050 °C, which allowed determination of the scandium content of the layers by lattice constant measurement with reference to the terminal compositions. Layer growth at compressive strain greater than about 0.5% resulted in layers with the “facet” defect. The distribution coefficient of scandium was found to decrease linearly from 2.3 to 1.1 as the scandium content of the melt [Sc/(Sc + Al)] increased from 0 to 0.35. The lattice constant of the Y 3Sc 2Al 3O 12 terminal composition (1.2263 nm) is somewhat larger than for Czochralski grown crystals as reported by Brandle and Barns, possibly due to a difference in the site selectivity of scandium at lower growth temperatures.

On the scandium distribution in indium arsenide crystals grown by the Czochralski method

AbstractIn this paper the behaviour of scandium in n‐type monocrystalline indium arsenide grown by Czochralski method in sealed ampoule is studied. The crystals have been grown in [111] direction under different conditions: crystallization rate, As‐partial pressure and scandium initial concentration in the melt. The effect of the above factors on the scandium distribution along the crystals have been investigated. Using these results and by means of the equation of normal freezing the effective Sc distribution coefficient (k) in InAs under different technological conditions has been determined. It has been found that k < 1 in all experiments. In order to find the equilibrium coefficient (k0) at fixed growth conditions the Burton‐Prim‐Slichter model has been used. On the basis of Hall measurements and atomic absorption analysis of Sc‐doped InAs it is concluded that connected with Sc electrically active centers behave as shallow donors, most probably monovalent ones.

The distribution coefficient of scandium in czochralski grown Gd3ScχGa5- χO12 and Y3ScχGa5- χO12 Garnets

The lattice parameter values of Czochralski grown single crystals and solid state reacted ceramic samples from the two garnet systems Gd 3 Sc χ Ga 5- χ O 12 and Y 3 Sc χ Ga 5- χ O 12 are presented. The crystallographic site preferences of the ions are discussed. The scandium distribution coefficient of the Czochralski grown single crystal is calculated. It is found to vary from greater to less than unity with increasing scandium concentration in the melt. The congruent compositions of the two systems are shown to be Gd 3Sc 1.6Ga 3.4O 12 and Y 3Sc 1.4Ga 3.6O 12 respectively.

Lanthanum and Scandium Distribution in Three Glacial Soils of Western Wisconsin

AbstractNeutron activation analysis was used to deterimne the total La and Sc content of three soils developed from loess‐capped glacial till. The profiles were classified as Gray‐Brown Podzolics (Hapludalfs) overlying paleosols developed in Rockain till. The total La content in the less than 250µ fraction of these soils ranged from 18.1 to 37.1 ppm, with an average content of 23.7 ppm in the loess and 28.5 ppm in the glacial till. Total Sc in the soils ranged from 5.1 to 10.9 ppm with average contents of 6.5 and 9.0 ppm in the loess and glacial till, respectively. Translocation by pedogenic processes was indicated by the accumulation of these elements in the argillic B horizons. Correlation coefficients of La and Sc with clay percentages in the profiles were 0.79 and 0.88, respectively.

Regularity on the distribution of scandium chelate in TTA-alcohol system

The distribution of scandium chelate with thenoyltrifluoroacetone (TTA) between 11 alcohols and the aqueous perchlorate solution of ionic strength of 0·1 was studied. After it has been confirmed that the extractable chelate is the same species shown as ScA 3 in all alcohol systems, except in 1-butanol and 2-methyl-1-propanol, the distribution coefficient of scandium chelate ( P M) and that of TTA ( P HA) were compared, and it was found that there is an evident correlation expressed as log P M = n log P HA + const. This correlation is the same with the one obtained in the so-called inert solvent systems.

Extraction of Scandium(III) with Tri-n-butyl Phosphate from Chloride Solutions

Abstract The distribution of scandium(III) between tri-n-butyl phosphate and aqueous solutions containing chloride has been measured using 46Sc as a tracer. The extraction of anionic scandium chlorocomplexes seems to be unimportant in the systems studied and it appears that different solvates of the trichloride ScCl3 can exist in tributyl phosphate extracts.

Adsorption of the rare-earth elements on an anion-exchange resin from nitric acid-acetone mixtures

The distribution coefficients on Dowex I-X8 anion-exchange resin were determined for all the rare earths at various proportions of concentrated nitric acid and acetone, using radioactive tracers of the metallic ions. In the range 4–40% nitric acid, the distribution coefficients decrease with increasing content of nitric acid, and at a given ratio of acid to acetone, they decrease with increasing atomic number in the lanthanum series. The value for yttrium is close to that of thulium; scandium is much less adsorbed. Literature data for aqueous systems and other mixed solvent systems are discussed. The distribution of scandium between Dowex I-X8 and conc. nitric acid-methanol, ethanol or acetone systems is described. The separation power of the nitric acid-acetonc system at different acid concentrations is analysed. Dowex I-X8 resin with a nitric acid-acetone solvent is shown to be sufficient for separation of the rare-earth elements by ion-exchange chromatography.