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Manganese alloys are used in steel industry as deoxidizing, desulfurizing and alloying agents. The alloys are commonly produced through high temperature reduction by using coke as reductant with the addition of fluxes / additives. A series of experiments have been performed to investigate the reduction behavior of manganese ore using sub-bituminous coal without the presence of flux. The reduction experiments were carried out at maximum holding temperatures between 1450, 1500 and 1550 °C. The macroscopic appearances, microscopic features and chemical compositions of the reduction products were analyzed using Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS). The influences of coal addition and maximum holding temperatures on the reduction products were discussed and compared to those calculated using FactSage thermodynamic software. The results showed that the manganese alloy can be formed through a fluxless high temperature reduction by utilizing sub-bituminous coal as a cost-effective reductant. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of a filter made from a composite of ore manganese and granular activated Carbon of coconut shells to remove iron and manganese from groundwater. At the first stage of research, ore manganese and activated Carbon were sieved, then the composite was performed in comparison from 20: 60 mess, 20:100 mess, 60:60 mess, to 100:60 mess of ore manganese and activated Carbon. These composites were tested filtration processes to remove iron from groundwater and the effectiveness of iron removal were achieving 94.05% sizing in 100:60 mess. With using particle size of 100 mess manganese and 60 mess of activated carbon coconut, the composite was performed by mass comparison of ore manganese and activated Carbon with combination 25:75, 40:60, 50:50, 40:60, and 75:25. The effectiveness of manganese removal ranges from 74.16 % to 84.5 % and iron removal range from 76.31% to 88.73%, along with the increase in the amount of manganese concentration in the composite. The morphology of manganese was measured by using SEM-EDX, range from diameter 1.06 µm to 671.02 µm, and activated carbon range from 1.3 µm to 55.02 µm. [ABSTRACT FROM AUTHOR]

NMC is a lithium-ion battery that combines three primary metals, namely Nickel, Manganese, and Cobalt. Manganese metal is used in the form of manganese sulfate (MnSO4). This research has studied the effect of adding alkali in the precipitation of impurities from the solution of manganese ore leaching on the crystals of MnSO4 as raw material for the manufacture of NMC. Some manganese ores are leached using oxalic acid as a reducing agent in a sulfuric acid atmosphere. Then, the impurities (mainly iron) precipitation from pregnant leached solution was carried out with pH adjustment using various alkalis. The alkalis used in this study were NaOH, NH4OH, and Ca(OH)2. The MnSO4 products were characterized using XRF and XRD. The results showed that the use of Ca(OH)2 in the precipitation of iron and other impurities from the pregnant leached solution could provide better MnSO4 crystals than the use of NaOH and NH4OH. [ABSTRACT FROM AUTHOR]

The Li-NMC cathode battery production usually applies carbonate precipitation processes. Manganese compound used is in the form of manganese sulfate (MnSO4) and precipitate using carbonate to produce manganese carbonate. This research has studied the synthesis of manganese carbonate from Indonesian manganese ore as raw material for the manufacture of NMC cathode precursor. Some manganese ores are leached using oxalic acid as a reducing agent in a sulfuric acid atmosphere. This leaching process was conducted using sulfuric acid with a concentration of 6%, leaching temperature 80oC, for 6 hours, oxalic acid used 30 g/liter, with a ratio of ore to the sulfuric acid solution was 52.63 gr/l. Then, the impurities (mainly iron) precipitation from pregnant leached solution was carried out with pH adjustment using various alkalis. The alkalis used in this study were NaOH, Na2CO3, and NH4OH. Manganese carbonate products were characterized using XRF and XRD. The results showed that manganese carbonate with high purity (>95%) can be synthesized from Indonesian manganese ore using leaching and precipitation method. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the physicochemical characteristics of a high-quality sinter when it is reduced in a mixture with manganese ore in a hydrogen atmosphere sequentially at temperatures of 500 °C, 700 °C, and 1050 °C under constant static load. At the initial stages of the experiment, an intensive reduction of relatively easily dissociating higher oxides of manganese ore proceeded. At temperatures of 500–700 °C, the reduction rate of a mixture consisting of 90% sinter and 10% manganese ore was 2.3 times on average higher than the sinter reduction rate due to the reduction of fragile higher manganese oxides and a low initial degree of reduction. An increase in mass losses and in the hydrogen utilization rate slowed as the reduction degree increased and the amount of higher oxides of iron and manganese available for reduction correspondingly decreased. A mixture of sinter and manganese ore was characterized by lesser resistance to the passage of gas through the sample layer when it was reduced in with hydrogen at temperatures of 500–1050 °C compared to the reduction of individual sinter by an average of 8.3%. [ABSTRACT FROM AUTHOR]

According to the results of the experiments, it was found that the possibility of selective reduction of iron in the composition of complex oxides with carbon monoxide gas. The samples used were Brazilian mono-manganese ore rich in manganese oxide, ferromanganese ore from the Selezenskoye deposit (Russia) with a high phosphorus content and concentrate from the Zhayremsky GOK (Kazakhstan). Experiments have shown the possibility of selective reduction of iron from complex manganese ores to a metallic state not only with solid carbon, but also with carbon monoxide. According to the results of experiments at a temperature of 1000 °C in the CO atmosphere, iron and phosphorus can be selectively reduced without reducing Mn, and the use of solid carbon as a reducing agent promotes the transition of manganese to the metal part. In all experiments, the oxides of manganese, silicon, and calcium remain mainly in the oxide part. [ABSTRACT FROM AUTHOR]

Manganese silicate is one of manganese mineral which is barely exploited for mineral processing and extraction compared to other manganese minerals such as pyrolusite, psilomelane and rhodochrosite. Manganese silicate ore could not directly be leached out in the hydrometallurgical extraction process due to strong bonding between silicon and manganese. At the same time, traditional high-temperature treatment (pyrometallurgy) was unfavorable in terms of high consumption of energy and additives (flux). Therefore, in this research fusion pre-treatment would be proposed to break Mn-silicate bonding using NaOH, in a relatively lower temperature than the traditional pyrometallurgical process for common manganese ore. Fusion pre-treatment of manganese silicate would produce intermediate compound sodium manganate (Na2MnO4), which is easily leached using a mildly alkaline solution. The effect of manganese silicate ore/NaOH mass ratio, fusion temperature, fusion time, leaching pulp density, and leaching time on the Mn recovery would be investigated and discussed. Optimum parameters for Mn recovery (94 %) obtained were manganese silicate ore/NaOH ratio 1, fusion temperature 500 °C, fusion time 1 h, leaching pulp density 7 %, and leaching time 5 min. [ABSTRACT FROM AUTHOR]

The beneficiation of manganese ore from Sumbawa, West Nusa Tenggara, Indonesia has been carried out by leaching method using sulfuric acid (H2SO4). The effects of sulfuric acid concentration, leaching temperature, and reaction time were optimized. The leaching parameters were set based on Box-Behnken Design and optimized using Response Surface Methodology (RSM). The beneficiation product was prepared for the synthesis of lithium manganese oxide (LiMn2O4) that will be applied as lithium ion battery cathode material. X-Ray Flouroscense (XRF), X-Ray Diffraction (XRD) and Atomic Absoption Spectroscopy (AAS) were performed for characterization of manganese ore and lithium manganese oxide that obtained. The optimum of manganese ore leaching yield was 79.57%. The optimum yield was produced by leaching of manganese ore in sulfuric acid 2.5 M, leaching temperature of 70 °C and leaching time of 9 hours. [ABSTRACT FROM AUTHOR]

In this work, lithium ion battery cathode material (LiMn2O4) has been synthesized from Li2CO3 as a source of Li and manganese ore (pyrolusite) as a source of MnO2. Manganese ore was characterized using X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD). XRF results showed that manganese ore contains 89.35% MnO. XRD diffractogram showed MnO2 peaks in accordance with JCPDS no. 24-0735. Manganese ore was leached using hydrofluoric acid and nitric acid to remove silica and other impurities. Leaching optimization was carried out using Response Surface Methodology (RSM) with Box-Bahken Design. The optimization showed that the highest MnO2 recovery from acid leaching was 95.73%. All the leaching residue contain MnO2 at 100% ranges. The optimum acid leaching condition was obtained by leaching 0.5 grams of manganese ore in 20 mL HNO3 at 80°C for 6 hours. LiMn2O4 was synthesized using a solid state reaction at 900 °C. The LiMn2O4 that obtained was applied as cathode materials characterized using cyclic voltammetry (CV), charge-discharge (CD) and Electrochemical Impedance Spectroscopy (EIS). [ABSTRACT FROM AUTHOR]

The MnO2:NH4F system is a component of the widely used Leclanche electrochemical cell. In addition, pyrolusite is among the main components of manganese ores. Quite promising is the chloride technology used for processing manganese-containing feed. In this paper, the interaction between manganese dioxide and ammonium chloride was studied. Final products of the interaction between MnO2 and NH4Cl are not only manganese(II) chloride, but also chloromanganates, nitrides and oxychlorides as the most thermodynamically favorable products. To understand the multistep nature of the process, the TGA-DSC analysis was carried out. The products were characterized by IR spectroscopy and XRD. [ABSTRACT FROM AUTHOR]

The incorporation of renewable energy sources in high temperature industrial processes has the potential to reduce energy costs as well as greenhouse gas emissions. The current study forms part of an evaluation of the opportunities to integrate concentrating solar thermal energy into the sintering of manganese ores. The study includes the results of direct irradiation of manganese ore pellets with concentrating solar flux in combination with the closed-loop forced convection of air. The results of this study will be of interest to the fields of high temperature solar thermal process heat and solar thermal materials processing as well as manganese ore sinter production. [ABSTRACT FROM AUTHOR]

In this study, the k0-NAA standardization method was applied to determine manganese concentrations in commercial manganese ores that collected different mining sites in Turkey. The samples were grinded, sieved and filled into Teflon tubes with a thickness of 1mm and then irradiated in one irradiation cell of the 37GBq 241Am–Be isotopic neutron source. The activities of the irradiated manganese-ore samples were produced via 55Mn(n,γ)56Mn reaction and were measured by using a n-type coaxial HPGe detector with 78.5% relative efficiency. The peak area analysis of the 846.8 keV (98.85%) and 1810.7 keV (26.9%) gamma-ray lines of 56Mn product radionuclide were performed. Experimental data of the 197Au(n,γ)198Au standard monitor reaction, the neutron flux parameters in the irradiation cell and related nuclear data were used together to determine manganese concentrations in the samples. The manganese contents in five different mining sites were found to be 2.63 ± 0.23(%) for MH (Malatya Hekimhan), 13.78 ± 0.98(%) for EA (Elazığ-Akboğa), 21.53 ± 1.52(%) for AK (Ankara Kalecik), 34.09 ± 2.38(%) for AB (Adiyaman Besni), 41.36 ± 2.89(%) for AG (Adıyaman Gölbaşı). The results indicated that k0-NAA method with use of an isotopic neutron source can be successfully applied to the analysis of manganese ores. [ABSTRACT FROM AUTHOR]

Solar thermal treatment of manganese ores can potentially lower energy costs and reduce greenhouse gas emissions. The solar thermal treatment of three manganese ores resulted in thermal decomposition and reduction of the ores. Empirical results compared to thermodynamic equilibrium models and numerical heat transfer models informs the next steps towards proving the concept. The study provides information regarding the bulk thermal conductivity of manganese ores as determined by optimization of the heat transfer model parameters. Changes observed in the mass of the solar treated samples confirm thermal decomposition and reduction of manganese and iron minerals. [ABSTRACT FROM AUTHOR]

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate. [ABSTRACT FROM AUTHOR]

In this investigation, manganese lias been produced from medium grade manganese ore from Karangnunggal mine (West Java, Indonesia). The effects of weighed amount of banana peels on the structural and leaching properties have been studied. Hie material's properties have been characterized on the basis of the experimental data obtained using X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectroscopy. It has been found that an increase of the weighed amount of banana peels up to 4 g leads to an increase of the leaching efficiency of manganese from manganese ore. Above 4 g, however, the leaching efficiency does not change significantly. The analysis based on the interpretation of both XRD patterns and FTIR spectrum allows one to explain the increase in the leaching efficiencies of manganese by the reduction of Mn02 minerals and by the removal of hemicelluloses groups of banana peel in the samples. [ABSTRACT FROM AUTHOR]

The beneficiation of two different low-grade manganese ores had been done by gravity separation and reduction-roasting process followed by the magnetic separation to improve their Mn/Fe ratio. The effect of particle size and temperature of reduction-roasting in this beneficiation process had been investigated clearly. XRF and XRD analyzer were used to characterize the as-received and beneficiated of these low-grade manganese ores. From the result, the manganese oxide in the form of pyrolusite (MnO2) was easier to beneficiate for enhancing the Mn/Fe ratio than in the form of pyroxmangite (MnSiO3) and grossular manganoan (Ca1.3Mg0.1Mn0.8 Fe0.8 Al2 (SiO4)3. The optimum beneficiation resulted from the reduction-roasting process of low-grade manganese ore in -40+60 mesh at temperature 700°C followed by the magnetic separation process. It had improved the Mn/Fe ratio of this low-grade manganese ore from 1.39 into 4.0. [ABSTRACT FROM AUTHOR]

Indonesia is known to have a large low-grade manganese ore reserve. Nevertheless, it could not be used optimally in producing ferromanganese due to their low Mn/Fe ratio. In this present study, the beneficiation process had been applied to the low-grade manganese ore. Reduction roasting was conducted to this manganese ore at 700°C for an hour and then continued with low-intensity magnetic separation. This process had improved the Mn/Fe ratio from 1.39 to 6.11. The effect of basicity on ferromanganese production from this beneficiated low-grade manganese ore had been investigated clearly in this experiment by using mini submerged arc furnace (SAF). Several basicities for 0.7 and 1.0, was used and it was controlled by the addition of limestone in this smelting process. From this experiment, the ferromanganese containing 60% Mn was obtained from smelting the beneficiated low-grade manganese ore with the optimum basicity 0.7. [ABSTRACT FROM AUTHOR]

In this study we report the effect of the sintering temperature of polycrystalline La0.67Ba0.33MnO3 (LBMO) manganites synthesized via solid state reaction method. LBMO have been sintered at 900 to 1200 °C in intervals of 100 °C. X-ray diffraction spectrum confirms that LBMO phase formation starts at 900 °C accompany by a minor second phase of BaMnO3 and fully forms into single phase of LBMO at 1200 °C. SEM images showed that, the grain size increased with sintering temperature and leading to densifications or lower porosity. The Tp was not affected by the sintering temperature. However, the electrical resistances of samples were decreased with the sintering temperature. At higher sintering temperature, due to grain growth and reduction of insulating BaMnO3 phase, the intergrain connectivity has been improved and the resistance drops. [ABSTRACT FROM AUTHOR]

We report the fabrication of composites made of La2/3Sr1/3MnO3 and two comb-type polysiloxane-based copolymers, polysiloxane-g-styrene and polysiloxane-g-(styrene-co-butyl-acrylate), in an attempt to improve the elastic properties of the polymer-based composites. The composites were obtained by the co-precipitation of a polymer solution mixed with the lanthanum manganite followed by sintering at appropriate temperatures. The rheological properties of the composites before as well as the magnetic and transport properties after sintering process are presented. [ABSTRACT FROM AUTHOR]

Perovskite manganites La1-xSrxMnO3 (x = 0.075, 0.10, 0.125, 0.15, 0.17, 0.185, 0.30, 0.50, 0.60, 0.75) have been studied as a function of temperature (1 K<=T<=20 K) by means of a Rigid Ion Model (RIM) for the determination of specific heat, Debye temperature, cohesive energy, restrsahlen frequency and Grüneisen parameter. The specific heat values revealed by us are in reasonably good agreement with the available experimental data at low temperature The Debye temperatures obtained by us from the lattice contributions are found to be in closer agreement with the experimental data [ABSTRACT FROM AUTHOR]

The magneto-impedance (MI) effect of polycrystalline La0.7Ba0.25Sr0.05MnO3 Manganites measured at 300 K gives a value of ∼51% at 500 Oe under the working frequency of 50 KHz. The field dependence of MI nearly saturates at ∼55% in a magnetic field of 1KOe, MI decreases sharply with increase in frequency upto 200 KHz and saturates at higher frequencies. MI is linear between ±20 and ±250 Oe and varies from 2% to 45% depending upon the working frequency. The present investigation reveals that the polycrystalline La0.7Ba0.25Sr0.05MnO3 manganite can be used as a potential magnetic sensor for near room temperature application. [ABSTRACT FROM AUTHOR]

The properties of manganites, exhibiting colossal magnetoresistance, and high critical temperature cuprates are studied numerically using a variety of microscopic and phenomenological models. Inhomogeneous ground states are discovered in many regions of parameter space. It is shown how colossal magnetoresistance arises in manganites due to the peculiar reaction of complex inhomogeneous states to small disturbances. Comparison with experimental data lends support to our theoretical results. Based in similar inhomogeneous characteristics observed in models for high Tc cuprates, as well as in real materials using novel experimental approaches, we predict the possibility of colossal effects in the cuprates. The interplay of magnetic, charge and lattice degrees of freedom in the cuprates is also discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

To elucidate the similarities and differences between the physics displayed by orbital and spin degrees of freedom, we analyze an orbital-Hubbard model with two orbital flavors, corresponding to pseudospin 1/2, and contrast its behavior with that of the familiar (spin-1/2) Hubbard model. The orbital-Hubbard model describes a partly filled spin-polarized eg band on a cubic lattice, as occurs in ferromagnetic manganites. We demonstrate that the absence of SU(2) invariance in orbital space has important implications — superexchange contributes in all orbital ordered states, the Nagaoka theorem does not apply, and the kinetic energy is enhanced as compared with the spin case. As a result orbital-ordered states are destabilized by doping, and instead a strongly correlated orbital liquid with disordered orbitals is realized. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

We review the frustrated magnetic interactions in spin-orbital models which describe superexchange in transition metal oxides with orbital degeneracy, and analyze the reasons for the symmetry breaking in cubic perovskites. The superexchange in eg systems is dominated by orbital interactions responsible for the orbital ordering, and the A-type antiferromagnetic ordering follows at lower temperatures. Instead, a generic tendency towards dimerization, found already in the degenerate Hubbard model, occurs in t2g systems. In this case the quantum orbital fluctuations may stabilize orbital liquid states along one directions even in some undoped t2g systems, leading to the C-type antiferromagnetic order. The orbital liquid in manganites is triggered by doping. The present understanding of the spectroscopic parameters provides reliable information on the magnetic interactions, as shown on the example of magnons in ferromagnetic cubic and bilayer manganites. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Electrolytic manganese is conventionally produced through low-grade manganese ore leaching in SO2, with the combustion of high sulfur coal. Subsequently the coal ash and manganese slag, produced by the combustion of high sulfur coal and preparation of electrolytic manganese, can be used as raw ingredients for the preparation of sulphoaluminate cement. In order to realize the ‘coal-electricity-sulfur-manganese-building material’ system of complementary resource utilization, the conditions of material inflow and outflow in each process were determined using material flow analysis. The material flow models in each unit and process can be obtained by analyzed of material flow for new technology, and the input-output model could be obtained. Through the model, it is possible to obtain the quantity of all the input and output material in the condition of limiting the quantity of a substance. Taking one ton electrolytic manganese as a basis, the quantity of other input material and cements can be determined with the input-output model. The whole system had thusly achieved a cleaner production level. Therefore, the input-output model can be used for guidance in practical production. [ABSTRACT FROM AUTHOR]