Small Amount Of Mn Research Articles

Electrochemical Studies on the Ca-Based Hydrogen Storage Alloy for Different Milling Times

The CaNi4.8Mn0.2 powder was synthesized by mechanical alloying, under an atmosphere of argon at room temperature, at different milling times (2, 10, 20, 30, 40, 50 and 60 h) with ball to powder weight ratio of 8:1. The structural and morphological characterizations of the CaNi4.8Mn0.2 powder were carried, respectively, by scanning electron microscopy and X-ray diffraction. After 2 h, all the alloys had a biphasic structure, two major phases, Ni and Ca2Ni7, remained virtually unchanged when a small amount of Mn was added. After more than 40 h of milling, the same peaks of the Ni and Ca2Ni7 phases appeared, while the intensity of the peaks decreased, indicating an additional amorphization process. After 50 h of milling, this damping was followed by the crystallization amorphization. The electrochemical properties of CaNi4.8Mn0.2 electrodes were studied at different milling times (10, 20, 30, 40, 50 and 60 h) and in KOH electrolyte concentrations (1 M and 6 M) at ambient temperature, as anodes in the Ni–MH battery. Different techniques were used, such as galvanostatic polarization, potentiostatic polarization and potentiodynamic polarization.

Improvements of CoPx Stability By Cathodic Protection in Discontinuous and Interrupted Operations of Alkaline Water Electrolysis

This paper presents a study of the degradation phenomena of Cobalt phosphides (CoPx), which is attracted as the hydrogen evolution reaction (HER) electrode for alkaline water electrolysis cells(AWEs).1-9 Although the HER activity of CoPx showed 100-fold HER activity enhancements over a nickel catalyst, the kinetic current for the HER after discontinuous and interrupted operations was observed to decrease as shown in Figure 1. During the shut-down of the AWEs, the cathode potential changed from -1.03V to -0.8V (vs. Hg/HgO), which is close to the equilibrium potential of Co oxidation reaction to Co(OH)2. Once Co(OH)2 was formed on CoPx electrode, the kinetic degradation was not recovered even though voltage sweep was applied. We employed cathodic protection to mitigate degradation of the CoPx electrode by shifting the potential of the electrode below the open circuit voltage of Co(OH)2. For the cathodic protection case, Mn was co-deposited with the CoPx electrode as a sacrificial species, which reduces the electrode degradation rate by negative polarization of the electrode. The results showed that by the co-depositing even small amount of Mn into the CoPx electrode could restrain HER performance loss during the repeat of discontinuous operation of the AWEs. That is, controlling the performance loss with the cathodic protection is applicable to ensure the stability of the CoPx electrodes of the AWE system for the integration with renewable powers. Figure 1. Stability improvements for CoPx HER electrodes in 5 h discontinuous operation by the cathodic protection Acknowledgements The authors gratefully acknowledge financial support for this work by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science and ICT (NRF-2015M1A2A2074657). R eferences [1] A. Goryachev L. Gao, Y. Zhang, R. Y. Rohling, René. H. J. Vervuurt, A. A. Bol, J. P. Hofmann, E. J. M. Hense, ChemElectroChem 2018, 5, 1230-1239[2] Q. Liu, J. Tian, W. Cui, P. Jiang, N. Cheng, A. M. Asiri, X. Sun, Angew., Chem. Int. Ed. 2014, 53, 6710–6714.[3] E. J. Popczun, C. G. Read, C. W. Roske, N. S. Lewis, R. E. Schaak, Angew. Chem. Int. Ed. 2014, 53, 5427–5430.[4] N. Jiang, B. You, M. Sheng, Y. Sun, Angew. Chem. Int. Ed. 2015, 54, 6251–6254.[5] Z. Huang, Z. Chen, Z. Chen, C. Lv, M. G. Humphrey, C. Zhang, Nano Energy 2014, 9, 373–382.[6] F. H. Saadi, A. I. Carim, E. Verlage, J. C. Hemminger, N. S. Lewis, M. P. Soriaga, J. Phys. Chem. C 2014, 118, 29294–29300.[7] F. H. Saadi, A. I. Carim, W. S. Drisdell, S. Gul, J. H. Baricuatro, J. Yano, M. P. Soriaga, N. S. Lewis, J. Am. Chem. Soc. 2017, 139, 12927–12930[8] S. Oh, H. Kim, Y. Kwon, M. Kim, E. Cho and H. Kwon, J. Mater. Chem. A, 2016, 4, 18272-18277[9] J. F. Callejas, C. G. Read, E. J. Popczun, J. M. McEnaney and R. E. Schaak, Chem. Mater., 2015, 27, 3769–3774. Figure 1

Synthesis and dual-channel optical properties of Mn-doped ZnSe quantum dots

We have successfully demonstrated the colloidal hot-injection process to easily obtain the Mn-doped ZnSe quantum dots (QDs) with a size of about 4–5 nm, and d-spacing is 0.31 nm, corresponding to the (1 1 1) lattice plane of ZnSe. Experimental results show that UV–vis absorption and fluorescence spectra were recorded to elucidate the role of Mn2+ ions substituted into ZnSe, which resulted in the carrier transfer of luminescent sites by a small amount of Mn2+ dopant. The small size of the Mn-doped ZnSe QDs offers intriguing opportunities for their application in photonic, bioimaging, and spintronics devices.

Preparation of Wasted Rock Dust Catalyst and its Catalytic Ozonation Properties for the Treatment of Oxalic Acid Containing Wastewater

MnOx/wasted rock dust catalyst (WZ01) and modified wasted rock dust catalyst (WZ02) were prepared by impregnation method and hydrothermal method as the wasted rock dust (WRD) generated in stone processing plants was used as carriers. The structure of the two catalysts were characterized by energy dispersive spectrometer (EDS), X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Their removal efficiencies and reaction mechanisms of oxalic acid were compared and analyzed, which could provide an innovative perspective for catalytic efficiency improvement and cost reduction. The results showed that the WRD contained O, Si, Al, K, Mg, Fe, Ca and Na elements. Mn was amorphous in WZ01 and loaded on the surface of WRD, and Mn was in the form of orthorhombic Mn2O3 in WZ02. WZ02's surface morphology showed obvious changes and was wrinkled with many microchannels. The specific surface area, total pore volume and average pore size of WZ02 had been improved. After 30 minutes of reaction at room temperature, the removal efficiencies of oxalic acid with an initial concentration of 500 mg·L-1 were 40.6% and 54.6% by using WZ01 and WZ02 as catalysts with catalyst dosages of 2 g·L-1 and O3 concentration of 4.92 mg·L-1, respectively. The removal efficiency of oxalic acid decreased greatly after WZ01 recycling and Mn, which acted as active components, was massively washed out. The removal efficiency of oxalic acid was stable after WZ02 was triply recycled as only a small amount of Mn was washed out. The removal efficiency of oxalic acid reduced after tert butanol was introduced into the two reaction systems, and a large amount of •OH was detected by using coumarin fluorescence technology. The removal of oxalic acid by WZ01 and WZ02 catalyzed ozonation were achieved by the combination of adsorption and hydroxyl radical reaction.

Comparison of Structural and Electrical Behaviour of Phospho-Olivine LiNiPO<sub>4</sub> and LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>PO<sub>4</sub> for High Voltage Rechargeable Li-Ion Batteries

Phase pure olivine LiNiPO4 and doped LiNi0.8Mn0.1Co0.1PO4 powders have been prepared by conventional solid state route. X-ray diffraction (XRD) combined with Rietveld refinements analysis reveals the formation of LiNiPO4 and doped LiNi0.8Mn0.1Co0.1PO4 with high crystalline nature at high temperature of 950 °C and 1000 °C. The lattice parameters of doped LiNi0.8Mn0.1Co0.1PO4 are significantly larger than LiNiPO4. It has been found out that the estimated crystallite size is in the order of nanometres for both samples. SEM analysis confirms that the particles have connected with each other in random shape and sub-microns size. The particle size has increased as small amount of Mn and Co are doped into LiNiPO4. The AC impedance spectroscopy measurements have revealed that the conductivity of LiNiPO4 is enhanced by around one order of magnitude by doping Mn and Co.

The influence of calcination temperature on the PTCR effect in (Bax-0.002Sm0.002) TiO3 ceramics prepared by the reduction sintering-reoxidation method

We investigate the effect of calcination temperature on the positive temperature coefficient of resistivity (PTCR) characteristics in (Bax-0.002Sm0.002)TiO3 ceramics that were fired at 1250 °C for 30 min in a reducing atmosphere and reoxidized at 800 °C for 1 h in air. The results indicate that the room-temperature resistivity first decreased and then increased as calcination temperature increased from 1000 °C to 1200 °C. Moreover, the critical calcination temperature of 1150 °C is experimentally determined. The samples have a low room-temperature resistivity of 38.4 Ω·cm and exhibit a significant PTCR effect with a resistance jump of 2.1 orders of magnitude. Furthermore, the room-temperature resistivity of the S7 samples doped with a small amount of Mn(NO3)2 is much higher than that of the S3 specimens not doped with Mn(NO3)2 in our work.

Effects of Mn2+ doping on the microwave dielectric properties of Ti1−xCux/3Nb2x/3O2 ceramics

In this study, undoped and Mn 2+ doped Ti 1-x Cu x/3 Nb 2x/3 O 2 (TCN, x = 0.2, 0.25, 0.3, 0.35) ceramics were prepared using a solid-state reaction method. The phase composition and microstructure of the TCN ceramics were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the density and permittivity of the TCN ceramics increase with the increasing of the Cu and Nb content. However, Q × f value of the undoped TCN ceramics decreases with an increase in the sintering temperature. A small amount of Mn 2+ doping has no effect on the permittivity, but improves the Q × f value. X-ray photoelectron spectroscopy (XPS) analysis indicated that the transition of Cu 2+ to Cu + during the sintering process could be inhibited by Mn 2+ doping, which suppresses the formation of oxygen vacancies, as a result, the improvement of Q × f value. Excellent microwave dielectric properties with a permittivity of 95 and Q × f value of 20800 GHz (@3.50 GHz) were achieved from the 0.6 at% Mn 2+ doped TCN (x = 0.25) ceramics sintered at 1025 °C for 5 h.

TiC supported Pt-based nanoparticles: Facile sonochemical synthesis and electrocatalytic properties for methanol oxidation reaction

In this study, we synthesized Pt nanoparticles (NPs) with small amounts of Mn (≤11.4 at%) included, hence Pt(Mn) NPs, on titanium carbide (TiC) support (denoted as Pt(Mn)/TiC) in three different Pt loadings (16.0–33.2 wt%) and investigated their electrocatalytic performance for methanol oxidation reaction (MOR) in acidic media. The syntheses were achieved via one-pot sonochemical reactions of Pt(acac)2 and Mn(acac)2 (acac = acetylacetonate) in ethylene glycol in the presence of TiC particles and without any other additives. The Pt(Mn) NPs were uniform in size (4–6 nm) and were evenly deposited on the TiC surface. The electronic structure of Pt in Pt(Mn)/TiC samples, probed by X-ray photoelectron spectroscopy (XPS) and other techniques, is systematically changed with the Pt loading, by which enhanced electrocatalytic properties from pure Pt are expected. In addition, the TiC support contributes to enhancing the electrocatalytic properties of Pt(Mn) NPs through its high conductivity, chemical resistance to corrosion, and the TiO2 formed on the surface which exerts the bifunctional mechanism to reduce the CO poisoning on Pt. The electrochemical performance of Pt(Mn)/TiC was investigated by the rotating disk electrode (RDE) technique. The specific and mass MOR currents are, respectively, 1.6–2.2 and 0.9–1.4 times higher in Pt(Mn)/TiC samples than in commercial Pt/C. All Pt(Mn)/TiC samples show 93–98% of the initial electrochemical surface areas after 3000 potential cycles, superior electrochemical stability to commercial Pt/C (86%).

Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides

Oxidation of Mn(II) is an important process that controls the mobility and bioavailability of Mn, as well as the formation of Mn (oxyhydr)oxides in natural systems. It was found that the surfaces of minerals, such as iron (oxyhydr)oxides, can accelerate Mn(II) oxidation to a certain degree, but the underlying mechanism has not been clearly understood. This study explores the reaction pathways and mechanisms of Mn(II) oxidation on ferrihydrite surfaces at neutral pH, commonly found in natural environments, by comparisons with montmorillonite, amorphous Al(OH)3, goethite, and magnetite using macroscopic experiments and spectroscopic analyses. Results show that when Mn(II) concentrations are below 4mM, macroscopic Mn(II) adsorption on the three iron (oxyhydr)oxide surfaces conforms well to the Langmuir equation, with ferrihydrite showing the highest adsorption capacity. With Mn(II) concentrations ranging within 6–24mM, the adsorbed Mn(II) is mainly oxidized into manganite (γ-MnOOH) and/or feitknechtite (β-MnOOH) by dissolved O2, and Mn(II) removal on a unit mass basis in the presence of magnetite is the highest compared with ferrihydrite and goethite. Ferrihydrite, a semiconductor material, shows stronger catalytic ability for Mn(II) oxidation on the same surface area than insulator minerals (i.e., montmorillonite and amorphous Al(OH)3). Additionally, the products of Mn(II) oxidation in the presence of semiconductor iron (oxyhydr)oxides (i.e., ferrihydrite, goethite, or magnetite) at the same Fe/Mn molar ratio include both manganite and a small amount of Mn(IV) minerals, and the Mn average oxidation states (Mn AOSs) of these products follow the order: magnetite>goethite>ferrihydrite. Magnetite and goethite, with relatively smaller SSAs and lower band gap energies, exhibit greater catalysis for Mn(II) oxidation than ferrihydrite at the same Fe/Mn ratio, which goes against the conventional interfacial effect and is related to the electrochemical properties. Thus, the Mn(II) catalytic oxidation by O2 on ferrihydrite surfaces should include an electrochemical pathway, i.e., electron transfer (ET) in the Mn(II)-Conduction Band (CB)Ferrihydrite-O2 complexes, in addition to the conventional two interfacial catalytic pathways, i.e., ET in the Mn(II)-Fe(II, III)-O2 complexes and direct ET in the Mn(II)-O2 complexes. These results reveal new implications for understanding the processes and mechanisms of Mn(II) oxidation on iron (oxyhydr)oxide surfaces and the abiotic formation of Mn (oxyhydr)oxides in surface environments.

Effect of Annealing on Valence Electronic States Related to Mn Ions of La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> Films

La0.67Sr0.33MnO3 (LSMO) films were prepared on SrTiO3 single-crystal substrates by the pulsed laser deposition method. X-ray photoelectron spectra (XPS) were measured for the LSMO films as-prepared and annealed in vacuum, respectively. Multiple peak fitting for Mn 2p3/2 XPS spectra shows that Mn3+ and Mn4+ proportionally decrease on the surface of the LSMO film annealed in vacuum compared with the as-prepared film. And the saturation magnetization (Ms) slightly decreases. Analysis indicates that a small amount of Mn2+, as surface defects of LSMO films, hardly changed after vacuum annealing. The total of Mn3+, Mn4+ and the low-binding energy peak (LEP) remains unchanged before and after annealing in vacuum, which suggests that LEP should be related with Mn3+ and Mn4+ when the magnetic properties are considered.

Microstructure of Coal Gangue and Precipitation of Heavy Metal Elements

The microstructure and mineral composition of the gangue play a decisive role in the precipitation of heavy metal elements. In this study, the microstructure, mineral composition, and precipitation of heavy metal elements of coal gangue with different weathering degrees were analyzed through electron microscopy, X-ray diffraction, and static immersion leaching experiments. The following results were derived. (1) After the weathering of the coal gangue, its compactness and integrity changed significantly. The coal gangue structure transformed from relatively dense to relatively loose, and the development of large pores and fractures changed from basically no development to significant development. (2) After weathering, the contents of kaolinite and illite significantly increased, while that of feldspar significantly decreased. Coal gangue contains a small amount of Mn, Cu, Zn, Ti, Ba, Cl, and other elements. After weathering, the contents of each element were reduced. (3) Under the same conditions, a higher number of heavy metal elements precipitated from the weathered coal gangue than from the fresh coal gangue. The results of this research have significant importance in revealing the precipitation mechanism of heavy metals from coal gangue and in perfecting the theory of underground water environmental protection during solid backfilling mining.

Effect of Mn-substituted SnO2 particle toward photocatalytic degradation of methylene blue dye

SnO2 and Mn-doped SnO2 were successfully prepared by wet chemical synthetic route. The understanding of substituted Mn into SnO2 leads to transfer the energy band gap by small amount of metal dopant. Fourier transform infrared and X-ray diffraction were used to determine chemical bonding and crystal structure, respectively. It showed that small amount of Mn can be completely substituted into SnO2 lattice. 40%wt of Mn was completely substituted. EDX was used to confirm the existence of Mn-doped SnO2. Scanning electron microscope revealed that their particles exhibits blocky particle with irregular sharp. The efficiency of SnO2 and Mn-doped SnO2 was investigated on the photocatalytic activity on methylene blue degradation for 4h. The photocatalytic activity of SnO2 and Mn-doped SnO2 exhibited the excellent performance in wastewater treatment in textile industry.

Synthesis and optical properties of turquoise- and green-colored brownmillerite-type Ba2In2−x−y Mn x Al y O5+x codoped with manganese and aluminum

Brownmillerite-type oxides Ba2In2−x−yMnxAlyO5+x (0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5) were prepared at 1300°C through solid-state reaction. X-ray diffraction (XRD) analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl2O4 and Ba2InAlO5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn (x ≤ 0.3), the Ba2In2−x−yMnxAlyO5+x samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba2In2−x−yMnxAlyO5+x was confirmed to be +5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba2In2−x−yMnxAlyO5+x samples is rooted in the existence of Mn5+; thus, the introduction of Al does not affect the optical properties of the compounds.

The Enhancement of Mg Corrosion Resistance by Alloying Mn and Laser-Melting.

Mg has been considered a promising biomaterial for bone implants. However, the poor corrosion resistance has become its main undesirable property. In this study, both alloying Mn and laser-melting were applied to enhance the Mg corrosion resistance. The corrosion resistance, mechanical properties, and microstructure of rapid laser-melted Mg-xMn (x = 0–3 wt %) alloys were investigated. The alloys were composed of dendrite grains, and the grains size decreased with increasing Mn. Moreover, Mn could dissolve and induce the crystal lattice distortion of the Mg matrix during the solidification process. Mn ranging from 0–2 wt % dissolved completely due to rapid laser solidification. As Mn contents further increased up to 3 wt %, a small amount of Mn was left undissolved. The compressive strength of Mg-Mn alloys increased first (up to 2 wt %) and then decreased with increasing Mn, while the hardness increased continuously. The refinement of grains and the increase in corrosion potential both made contributions to the enhancement of Mg corrosion resistance.

Solidification microstructures of the undercooled Co–24at%Sn eutectic alloy containing 0.5at%Mn

Abstract Solidification samples of undercooled Co–24 at%Sn eutectic alloy containing a small amount of Mn (

Interaction of gold nanoparticles mediated by captopril and S-nitrosocaptopril: the effect of manganese ions in mild acid medium.

We report herein results regarding reactivity and assembly of citrate-capped gold nanoparticles (AuNPs) mediated by captopril (cap) and S-nitrosocaptopril (NOcap), two angiotensin converting enzyme inhibitors and antihypertensive agents. The results were compared with that of cysteine (Cys), a thiol-containing amino acid found in plasma. The interparticle interactions were characterized by monitoring the evolution of the surface plasmon resonance band using the spectrophotometric method. The original gold nanoparticles were efficiently modified by small amounts of Mn(+2) ions, which are adsorbed onto the surface of 15.4 nm citrate-capped gold nanoparticles, giving rise to manganese-gold nanoparticles (Mn-AuNPs) that, in mild acid medium, have proved to be highly sensitive and a rapid colorimetric detection method for thiols. Depending on the concentration of the Mn(+2) ions the aggregation of AuNPs can be rapidly induced. The kinetics of the assembly process has been studied. Good first-order kinetics has been observed, with the exception of captopril-mediated nanoparticle aggregation at low concentration of either cap or acid. The rate of Cys-mediated assembly of gold nanoparticles in aqueous 10 mM acetic acid is more than 20-times faster than pure AuNPs and concentrations of Cys as low as 34 nM can be detected in less than 40 min under conditions of stable Mn-AuNPs. Similar effects were observed with cap or NOcap. The assembly-disassembly reversibility is shown with cap and NOcap and depends highly on pH.

Thermoelectric properties in Ca3Co4−xMnxOy ceramics

Ca3Co4−xMnxOy polycrystalline thermoelectric ceramics with small amounts of Mn have been prepared by the classical solid state method. X-ray diffraction data have shown that Ca3Co4O9 is the major phase, with small amounts of the Ca3Co2O6 one. Moreover, they show that the Mn has been incorporated into these two phases. Electrical resistivity decreases, compared with the values for undoped samples, with Mn content until a minimum for the 0·03 doped ones, increasing for higher Mn substitution. Seebeck coefficient does not change in all the measured temperature range, independently of Mn content. The improvement in electrical resistivity leads ∼30% higher power factor values for the 0·03 Mn doped samples than that obtained in the undoped ones. The maximum power factor at 800°C, ∼0·28 mW K−2 m−1, is close to that obtained in much higher density samples, clearly indicating the good thermoelectric properties of these samples.

Effect of Mn loading onto MnFeO nanocomposites for the CO2 hydrogenation reaction

This work describes the preparation of mesoporous xMnFe oxide (x=0, 0.05, 0.1, 0.2, 0.3 and 0.5 molar ratios) nanocomposites through a one-step sol–gel process in the presence of a triblock copolymer as a structure-directing agent. The prepared oxides were used as catalysts in the CO2 hydrogenation via Fischer–Tropsch reactions for the production of valuable hydrocarbons. Among the catalysts, the 0.05MnFe catalyst performed best under the selected reaction conditions: a reaction temperature of 340°C, overall pressure of 20bar, reactant mixture of 23% CO2/69% H2/8% N2 and flow rate of 20mLmin−1. This catalyst provided a much higher conversion of CO2 to hydrocarbons (63.2%C2–C5, 3.9% to C6+ and 3.6% to oxygenates) and the lowest levels of CO and methane formation among the xMnFe series. Moreover, 0.05MnFe was the only catalyst with a mesoporous structure, and it had a substantially lower reduction temperature than did the other members of the series. The enhanced catalytic activity of the 0.05MnFe catalyst, which contains only a small amount of Mn, appears to result primarily from its high specific area and relatively easy reduction.

Immiscibility of magmatic fluids and their relation to Mo and Cu mineralization at the Bangpu porphyry deposit, Tibet, China

The coexistence of aqueous fluid inclusions and silicate melt inclusions in quartz phenocrysts from porphyrites at the Bangpu porphyry Mo–Cu deposit, Tibet, China were examined to characterize the immiscibility processes during the magmatic to hydrothermal transition. The physical and chemical environment during crystallization of the magmas has been reconstructed on the basis of microthermometric experiments and trace element microanalysis. Compositions of melt and brine fluid phases are determined using Synchrotron radiation X-ray fluorescence analysis, SEM–EDS and Laser Raman spectroscopy analyses. Brine fluids were directly exsolved by a crystallizing melt, and the simultaneous entrapment of volatile-rich (brine fluid) and volatile-poor immiscible phases (silicate melt) occurred at 670–700°C and 1.6–1.95kbar when the magma had H2O contents between 5 and 6wt% and crystal contents of 60–80%. A later low-density fluid with a higher Mo concentration exsolved after about 80–90% crystallization had occurred. This fluid contained significant concentrations of Cl, Na, K, Ca, Fe, Cu, Zn, Rb, and small amounts of Mn, Br and Pb. Immiscibility of magmatic fluids can lead to different metal partitioning behaviors between residual melt and volatile phases, which generate variable metal ratios. Copper was partitioned preferentially into the brine phase, in contrast to the behavior observed in other porphyry Cu deposits. Ore deposition by a dense brine could explain the partially deep Cu mineralization. Condensation of brine from a later low-density parental fluid could be an efficient mechanism to concentrate shallow Cu mineralization and broadly distributed Mo mineralization. The source of the Mo mineralizing fluids probably was a particularly large magma chamber that crystallized and fractionated at depth greater than upper continental crust level.

SEM, EDX, Infrared and Raman spectroscopic characterization of the silicate mineral yuksporite

The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH)⋅H2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087cm−1 and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668cm−1. A very sharp band is observed at 3668cm−1 and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628cm−1 are assigned to water stretching vibrations.