scholarly journals The substitution mechanism of Au in In-, Fe- and In-Fe-bearing synthetic crystals of sphalerite, based on the data from EPMA and LA-ICP-MS study

LITOSFERA ◽  
2019 ◽  
pp. 148-161 ◽  
Author(s):  
D. E. Tonkacheev ◽  
D. A. Chareev ◽  
V. D. Abramova ◽  
E. V. Kovalchuk ◽  
I. V. Vikentyev ◽  
...  
Keyword(s):  
Depositional Environments ◽  
Salt Flux ◽  
Research Subject ◽  
Trace Impurities ◽  
Valuable Component ◽  
Experimental Conditions ◽  
Icp Ms ◽  
Substitution Mechanism ◽  
Synthetic Crystals ◽  
Good Agreement

Research subject.Sphalerite (ZnS) is a widespread mineral that can be found in various depositional environments. During formation, this mineral can accumulate minor and trace impurities, with gold being one of the most valuable component. The issue of the chemical state of Au in sphalerite has been much discussed recently.Methods.Samples of In-, Fe- and In-Febearing sphalerite with a composition ranging from 0 to 2.5 mol.% In2S3 and 0 – 40 mol.% FeS were synthesized in an Ausaturated system using gas transport and salt flux techniques. The resulting products were subsequently investigated using EPMA and LA-ICP-MS.Results.All the elements under investigation are found to be homogeneously distributed within the sphalerite matrix. After quenching, sphalerite is shown to retain Au. Our data indicates that the observed increase in Au concentration is caused by the presence of In (up to 1.02 wt % Au) and, to a lesser extent, by that of Fe (up to ≈600 ppm Au). These elements substitute Zn in the crystal structure of sphalerite following the scheme Au+ + In3+(Fe3+) ↔ 2Zn2+, which is in good agreement with previous data obtained using the XAS method.Conclusions.A higher sulphur fugacity in the system leads to a more significant accumulation of Au in sphalerite. The concentration of Au in pure sphalerite does not exceed 10 ppm under our experimental conditions and does not depend on the activity of sulphur in the system.

Determination of V, Cr, Cu, As, and Pb Ions in Water and Biological Samples by Combining ICP-MS with Online Preconcentration Using Impregnated Resin

2015 ◽  
Vol 98 (1) ◽  
pp. 218-224 ◽  
Author(s):  
Shuo Wang ◽  
Xv Dong ◽  
Bingye Dai ◽  
Mingfei Pan ◽  
Shaoyuan He ◽  
...  
Keyword(s):  
Biological Samples ◽  
Inductively Coupled Plasma ◽  
Environmental Water ◽  
Experimental Conditions ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Improved Accuracy ◽  
Water And Biological Samples ◽  
Good Agreement

Abstract A method was developed for detection of V, Cr, Cu, As, and Pb in water and biological samples by combining online flow injection and preconcentration with inductively coupled plasma-MS. The 2-nitroso-1-naphthol-4-sulfonic acid (Nitroso-S) impregnated MCI GEL CHP20P resin was prepared as an enrichment sorbent. Some parameters affecting the efficiency of the preconcentration process were investigated in the experiment, including the pH and volume of sample solution, the flow rate for sample loading, the type and concentration of eluent, and the influence of co-existing ions. Under the optimal experimental conditions, the enrichment factor and LOD (3s) of chosen metal ions V, Cr, Cu, As, and Pb were in the ranges of 71–268 and 4.89–23.76 ng/L, respectively. Based on 11 repeated measurementsof standard solutions (1.0 μg/L), the RSD ofthe ions ranged from 1.2 to 2.9%. The detection procedure was also performed for analyzing two certifiedreference materials, GBW 08607 (water) and GBW 10052 (green tea), as well as environmental water and biological samples. Good agreement with certified valuesand high recoveries have demonstrated improved accuracy of the proposed method.

scholarly journals Laser ablation ICP-MS of size-segregated atmospheric particles collected with a MOUDI cascade impactor: a proof of concept

2017 ◽  
Vol 10 (5) ◽  
pp. 1823-1830 ◽  
Author(s):  
Marin S. Robinson ◽  
Irena Grgić ◽  
Vid S. Šelih ◽  
Martin Šala ◽  
Marsha Bitsui ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Submicron Particles ◽  
Good Precision ◽  
The Novel ◽  
Proof Of Concept ◽  
Image Mapping ◽  
Icp Ms ◽  
Elemental Image ◽  
Elemental Maps ◽  
Good Agreement

Abstract. A widely used instrument for collecting size-segregated particles is the micro-orifice uniform deposit impactor (MOUDI). In this work, a 10-stage MOUDI (cut-point diameter of 10 µm to 56 nm) was used to collect samples in Ljubljana, Slovenia, and Martinska, Croatia. Filters, collected with and without rotation, were cut in half and analyzed for nine elements (As, Cu, Fe, Ni, Mn, Pb, Sb, V, Zn) using laser ablation ICP-MS. Elemental image maps (created with ImageJ) were converted to concentrations using NIST SRM 2783. Statistical analysis of the elemental maps indicated that for submicron particles (stages 6–10), ablating 10 % of the filter (0.5 cm2, 20 min ablation time) was sufficient to give values in good agreement (±10 %) to analysis of larger parts of the filter and with good precision (RSE < 1 %). Excellent sensitivity was also observed (e.g., 20 ± 0.2 pg m−3 V). The novel use of LA-ICP-MS, together with image mapping, provided a fast and sensitive method for elemental analysis of size-segregated MOUDI filters, particularly for submicron particles.

scholarly journals Lutetium oxide analysis by direct arc atomic emission spectrometry

2021 ◽  
Vol 25 (2) ◽  
pp. 70-83
Author(s):  
E. S. Koshel ◽  
◽  
A. A. Arkhipenko ◽  
V. B. Baranovskaya ◽  
◽  
...  
Keyword(s):  
Atomic Emission ◽  
Emission Spectrometry ◽  
Experimental Conditions ◽  
Impurity Composition ◽  
Operating Modes ◽  
Lutetium Oxide ◽  
Icp Ms ◽  
Wide Range ◽  
Sample Dissolution ◽  
Dc Arc

The requirements for the composition of initial oxides for the lutetium orthosilicate crystals are quite stringent: the content of the basic substance Lu2O3 is 99.999 wt%. Critical are coloring impurities: Fe, Ni, Cr, Co, Cu, V, Mn, the content of each should be no more than 0.0005 - 0.0010 wt%, Pr, Nd, Sm, Er, Tb, Yb no more than 0.0005 wt% for each one. It is also necessary to control the content of Al, As, Bi, Cd, Mg, Mo, Pb, Sb, Si, Sn, Ti, Zn, Y, La, Ce, Sc, Eu, Gd, Dy, Ho, Tm. To determine the impurity composition of lutetium oxide, one of the promising methods of analysis is direct arc atomic emission spectroscopy (DC Arc). The advantages of this method are the determination of the chemical composition without sample dissolution, a wide range of concentrations (10-6 - 10-1% wt%), a large number of determined elements. To realize the potential analytical capabilities of the method, the experimental conditions were studied: the interelectrode distance, the shape and size of graphite electrodes, the ratio of Lu2O3 to the spectral buffer, the type of carriers and operating modes of the generator. For most elements, the limits of determination are n ∙ 10-6 - n ∙ 10-4 wt%, that is significantly lower than in the current methods of DC Arc. The trueness of results is controlled by ICP-MS. The complex application of new approaches and modern capabilities of spectral equipment made it possible to develop a method with improved metrological characteristics.

scholarly journals OPTIMIZATION OF LEVOFLOXACIN REMOVAL FROM AQUEOUS SOLUTION USING ELECTROCOAGULATION PROCESS BY RESPONSE SURFACE METHODOLOGY

2021 ◽  
Vol 52 (1) ◽  
pp. 204-217
Author(s):  
Mohammed & Mohammed-Ridha
Keyword(s):  
Aqueous Solution ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Correlation Coefficient ◽  
Iron Hydroxide ◽  
Second Order ◽  
Experimental Results ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Good Agreement

This study was aimed to investigate the response surface methodology (RSM) to evaluate the effects of various experimental conditions on the removal of levofloxacin (LVX) from the aqueous solution by means of electrocoagulation (EC) technique with stainless steel electrodes. The EC process was achieved successfully with the efficiency of LVX removal of 90%. The results obtained from the regression analysis, showed that the data of experiential are better fitted to the polynomial model of second-order with the predicted correlation coefficient (pred. R2) of 0.723, adjusted correlation coefficient (Adj. R2) of 0.907 and correlation coefficient values (R2) of 0.952. This shows that the predicted models and experimental values are in good agreement. The results of the kinetic study showed that the second-order kinetic model was in good agreement with the experimental results and suggested that the mechanism of chemisorption controlled the LVX adsorption. The experimental results indicated that the adsorption of LVX on iron hydroxide flocs follows Sips isotherm with the value of the correlation coefficient (R2) of 0.937. Sips isotherm shows that both homogenous and heterogeneous adsorption can occur.

scholarly journals Прямой магнитоэлектрический эффект в двухслойных керамических композитах на основе ферримагнетика Mn-=SUB=-0.4-=/SUB=-Zn-=SUB=-0.6-=/SUB=-Fe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- и сегнетоэлектрика PbZr-=SUB=-0.53-=/SUB=-Ti-=SUB=-0.47-=/SUB=-O-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (7) ◽  
pp. 888
Author(s):  
А.В. Калгин
Keyword(s):  
Magnetoelectric Effect ◽  
Powder Materials ◽  
Heterogeneous Environment ◽  
Effective Parameters ◽  
Experimental Conditions ◽  
Good Agreement

Under different experimental conditions, the direct magnetoelectric effect was studied in two-layer composites prepared both by joint sintering of layers of powders of ferrimagnet Mn0.4Zn0.6Fe2O4 and ferroelectric PbZr0.53Ti0.47O3 and by gluing plates pre-sintered from powder materials of Mn0.4Zn0.6Fe2O4 and PbZr0.53Ti0.47O3. It was found that sintered composites show greater values of the magnetoelectric effect than composites prepared by gluing sintered plates together. The revealed regularities are in good agreement with the conclusions from the theoreti-cal model of the effective parameters of the heterogeneous environment.

Numerical Simulation of Scouring in Overtopping Dam-break Flow

2021 ◽  
Author(s):  
Can Huang ◽  
Xiaoliang Wang ◽  
Qingquan Liu
Keyword(s):  
Numerical Simulation ◽  
Empirical Relationship ◽  
Dam Break ◽  
Experimental Conditions ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dam Break Flow ◽  
Scouring Process ◽  
Overtopping Erosion ◽  
Good Agreement

&lt;p&gt;Overtopping dam-break flow has great harm to the earthen embankments due to the hydraulic erosion. Some researchers have carried out relevant model experiments, but it is difficult to achieve the experimental conditions for the actual situation. The common numerical simulation is to express the scouring process through the empirical relationship, which obviously could not reflect the real scouring process. In this paper, a new overtopping erosion model using Smoothed Particle Hydrodynamics (SPH) is proposed. When the shear stress on the sediment SPH particle exceeds the critical stress, the erosion process begins. Then, when a sediment SPH particle is completely eroded, it will begin to move and is described as a non-Newtonian fluid. The un-incipient sediment particles are treated as boundary. This model is well validated with plane dike-breach experiment, and has also achieved a good agreement with erodible bed dam-break experiment.&lt;/p&gt;

scholarly journals STH/CFD Coupled Simulation of the Protected Loss of Flow Accident in the CIRCE-HERO Facility

2020 ◽  
Vol 10 (20) ◽  
pp. 7032 ◽  
Author(s):  
Pucciarelli Andrea ◽  
Galleni Francesco ◽  
Moscardini Marigrazia ◽  
Martelli Daniele ◽  
Forgione Nicola
Keyword(s):  
Thermal Stratification ◽  
Outlet Section ◽  
Experimental Conditions ◽  
Ansys Fluent ◽  
Internal Loop ◽  
Fuel Pin ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd ◽  
The University ◽  
Good Agreement

The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident (PLOFA). The facility consists of an internal loop, equipped with a fuel pin simulator and a steam generator, and an external pool. In this coupling application, the System code RELAP5 is adopted for the simulation of the internal loop while the CFD code ANSYS Fluent is used for the sake of simulating the pool. The connection between the two addressed domains is provided at the inlet and outlet section of the internal loop; a thermal coupling is also performed in order to reproduce the observed thermal stratification phenomenon. The obtained results are promising and a good agreement was obtained for both the mass flow rates and temperature measurements. Capabilities and limitations of the adopted coupling technique are discussed in the present paper also providing suggestions for improvements and developments to be achieved in the frame of future applications.

scholarly journals Gold Partitioning in a Model Multiphase Mineral-Hydrothermal Fluid System: Distribution Coefficients, Speciation and Segregation

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 890 ◽  
Author(s):  
Sergey Lipko ◽  
Vladimir Tauson ◽  
Valeriy Bychinskii
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluid Phase ◽  
Distribution Coefficients ◽  
Crystal Defects ◽  
Geothermal Systems ◽  
Fluid System ◽  
Experimental Conditions ◽  
Inductively Coupled ◽  
Ms Analysis ◽  
Icp Ms

The characteristics of Au partitioning in a multiphase, multicomponent hydrothermal system at 450 °C and 1 kbar pressure were obtained using experimental and computational physicochemical modelling and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. Sphalerite and magnetite contained 0.1–0.16 ± 0.02 µg/g Au and coexisted with galena and bornite which contained up to 73 ± 5 and 42 ± 10 µg/g Au, respectively. Bornite and chalcopyrite were the most effective Au scavengers with cocrystallization coefficients Au/Fe and Au/Cu in mineral-fluid system n–n × 10−2. Sphalerite and magnetite were the weakest Au absorbers, although Fe impurity in sphalerite facilitated Au uptake. Using the phase composition correlation principle, Au solubility in minerals was estimated (µg/g Au): low-Fe sphalerite = 0.7, high-Fe sphalerite = 5, magnetite = 1, pyrite = 3, pyrite-Mn = 7, pyrite-Cu = 10, pyrrhotite = 21, chalcopyrite = 110, bornite = 140 and galena = 240. The sequence reflected increasing metallicity of chemical bonds. Gold segregation occurred at crystal defects, and on surfaces, and influenced Au distribution due to its segregation at crystal interblock boundaries enriched in Cu-containing submicron phases. The LA-ICP-MS analysis of bulk and surficial gold admixtures revealed elevated Au content in surficial crystal layers, especially for bornite and galena, indicating the presence of a superficial nonautonomous phase (NAP) and dualism in the distribution of gold. Thermodynamic calculations showed that changes in experimental conditions, primarily in sulfur regime, increased the content of the main gold species (AuCl2− and AuHS0) and decreased the content of FeCl20, the prevailing form of iron in the fluid phase. The elevation of S2 and H2S fugacity affected Au partitioning and cocrystallization coefficients. Using Au content in pyrite, chalcopyrite, magnetite and bornite from volcanic-sedimentary, skarn-hosted and magmatic-hydrothermal sulfide deposits, the ranges of metal ratios in fluids were estimated: Au/Fe = n × 10−4−n × 10−7 and Au/Cu = n × 10−4−n × 10−6. Pyrite and magnetite were crystallized from solutions enriched in Au compared to chalcopyrite and bornite. The presence of NAP, and associated dualism in distribution coefficients, strongly influenced Au partitioning, but this effect does not fully explain the high gold fractionation into mineral precipitates in low-temperature geothermal systems.

Interfacial Energy-Dispersive Spectroscopy Profile X-Ray Resolution Measurements in Variable Pressure SEM

2014 ◽  
Vol 20 (5) ◽  
pp. 1565-1575 ◽  
Author(s):  
Abdelhalim Zoukel ◽  
Lahcen Khouchaf ◽  
Jean Di Martino ◽  
David Ruch
Keyword(s):  
Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Shape Change ◽  
High Vacuum ◽  
Energy Dispersive ◽  
Variable Pressure ◽  
Experimental Conditions ◽  
X Ray ◽  
Scanning Electron ◽  
Good Agreement

AbstractA procedure has been developed to follow degradation of energy-dispersive spectroscopy (EDS) X-ray lateral resolution in a variable pressure scanning electron microscope. This procedure is based on evaluation of the EDS profile shape change for different experimental conditions. Some parameters affecting the X-ray resolution in high-vacuum mode have been taken into account. Good agreement between the simulated and experimental EDS profiles shows the reliability of the proposed procedure. A significant improvement in measurement of the EDS profile interfacial distance (DINT) has been achieved.

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