Ratio Of Manganese Research Articles

A novel method for the separation of zinc and cobalt from hazardous zinc–cobalt slag via an alkaline glycine solution

• Introducing a novel separation method of zinc and cobalt with the glycine solution. • Highly separation efficiency was done by the selective dissolution of zinc. • Purification of the oxides of cobalt and manganese in residue was realized. • The recovery of Zn 2+ from glycine solution was performed by using oxalic acid. Zinc–cobalt slag, a hazardous waste from hydrometallurgical zinc smelting, is an important secondary source of cobalt; however, the separation of zinc and cobalt is a serious problem in cobalt recovery. A novel approach was proposed to separate zinc and cobalt via an alkaline glycine solution. This innovative method selectively dissolves zinc and cadmium from the slag with a high yield, leaving most of the cobalt and manganese in the residue. The dissolution ratios of zinc and cadmium are 93.81% and 87.64%, respectively, under optimal conditions (pH 10, 45 °C, glycine concentration of 100 g/L, L/S ratio of 40:1, and a reaction time of 180 min). In contrast, the dissolution ratios of cobalt and manganese are almost negligible. Substantial separation of zinc and cobalt occurred as the separation factor reached a value of 736.8. The recovery of zinc and cadmium from the glycine leachate was accomplished by precipitation with an oxalic acid solution, and the precipitation ratios were 97.7% and 99.0%, respectively. The use of glycine as the leaching agent successfully separated zinc and cobalt, which allowed for the recovery of cobalt, and also enabled the recovery of zinc and cadmium.

Source Apportionment of Inorganic Solutes in Surface Waters of Lake Baikal Watershed

The aim of this study was to obtain a detailed picture of the origin of the anthropogenic and natural inorganic solutes in the surface waters of the Lake Baikal watershed using limited data on solute sources. To reveal the origin of solutes, the chemical composition of water was considered as a mixture of solutes from different sources such as rocks and anthropogenic wastes. The end-member mixing approach (EMMA), based on the observation that the element ratios in water uncorrelated with one another are those that exhibit differences in values across the different types of rocks and anthropogenic wastes, was used for source apportionment. According to the results of correlation analysis, two tracers of sources of most abundant ions present in riverine waters were selected. The first tracer was the ratio of combined concentration of calcium and magnesium ions to concentration of potassium ion ((Ca2+ + Mg2+)/K+), and the second tracer was the ratio of sulfate and bicarbonate ion concentrations (SO42−/HCO3−). Using these tracers, three sources of main ions in water, such as sulfide-bearing silicate rocks, non-sulfide silicate rocks and carbonate rocks, were apportioned. The results of cluster analysis showed the possibility of using the ratios of strontium, iron, manganese, molybdenum, nickel, and vanadium concentrations (Sr/Fe, Sr/Mn, Ni/V, Mo/V) as tracers of the trace element sources. The use of these tracers and the obtained data on sources of main ions showed the possibility of identifying the natural trace element sources and distinguishing between natural and anthropogenic trace element sources.

Study of synergetic effects of ternary transition metal in the electrochemical performance of metal oxides anode for lithium-ion battery

Synergistic effect improves the electrochemical properties of metal oxide anode materials for lithium ion-batteries. The influence of different ratios of nickel and manganese on the microscopic morphology and the contribution of pseudocapacitance were investigated. The ternary Prussian blue analog NixMny[Fe(CN)6]2(x + y = 3) manufactured by adjusting the ratio of Ni-Mn mixed salt was used to obtain the ternary transition metal oxide. When the ratio of Ni and Mn is 8:2 or 2:8, the synergistic effect of oxide anode materials between the ternary transition metals is strong. The corresponding materials have excellent cycle stability, higher reversible capacity, lower charge transfer resistance and higher proportion of pseudocapacitance contribution. The calcined product is NiFe2O4-FeMnO3, which has a core-shell structure when the ratio of Ni and Mn is 2:8, and the first cycle discharge capacity is 1697.6 mAh/g. It can provide a reversible capacity 536.1 mAh/g after 500 cycles at 500 mA/g. The analysis of electrode dynamics shows that the pseudocapacitance contribution can reach 46.8% at 0.1 mV/s.

Synthesis of manganese ore/Co3O4 composites by sol–gel method for the catalytic oxidation of gaseous chlorobenzene

Manganese ore/cobalt oxide composites were synthesized by using natural manganese ore and Co(NO3)2·6H2O via oxalic acid-assisted sol–gel method and applied in the catalytic oxidation degradation of gaseous chlorobenzene. The catalytic properties of the manganese ore/Co3O4 composites were investigated by X-ray diffraction (XRD), the electron microscopy technique (FE-SEM), N2 adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS) and H2-temperature programmed reduction (H2-TPR), respectively. The results showed that the composite catalyst with the mass ratio of manganese ore/cobalt oxide was 0.4 and calcined at 450 °C had the optimal catalytic performance. It could achieve 94% conversion of chlorobenzene, 83% selectivity of CO2 and over 36 h sustainability at 300 °C for the gaseous chlorobenzene with the initial concentration of 1200 mg m−3. The composite catalyst had the abundant surface oxygen species, good anti-chlorine poisoning performance and strong redox properties of composites, which were due to the interaction between manganese ore and Co3O4, and played a key role in degradation of chlorobenzene.

Effects of B-Site Modification of Bi-Ru Based Oxide on Catalytic Activity for Oxygen Reactions

An aqueous air secondary battery uses oxygen in air as the active mass of the air electrode, at which the reactions are oxygen reduction during discharge and oxygen evolution during charge. The polarization of the air electrode is known to be large and a highly active bi-functional oxygen catalyst is needed to reduce the polarization. We have been developing a metal hydride/air secondary battery using KOH solutions and have found that bismuth and ruthenium based oxide (BRO) can suppress the polarization of oxygen reactions [1]. Although BRO has a good bi-functionality, there is still an issue that the polarization of oxygen reduction is ca. 100 mV larger than that of oxygen evolution. In this work, we aimed to improve the catalytic activity of BRO with modification of B-site element by substituting ruthenium with manganese. Then, the modified BRO (MBRO) was examined by titanium disk method (TDM) developed by our group [2], which is very useful to know the activity of oxygen catalyst, because no oxygen reactions on titanium occur in the examined potential range so that no oxygen current from the substrate is excluded. The electrochemical polarization data was analyzed to obtain some kinetic parameters such as Tafel slope and exchange current density.MBRO was prepared by co-precipitation method, in which the calcination of the precipitates obtained by adding excess NaOH solutions into the metal salt solution containing bismuth, ruthenium, and manganese. BRO was also synthesized for comparison. The obtained oxides were characterized by XRD, SEM, and EDX, and electrochemical measurements were carried out using a three-electrode cell. The working electrode was the titanium disk covered with MBRO or BRO, which was mounted in a rotating-disk electrode equipment, and the electrolyte was 0.1 mol/L KOH solutions. Linear sweep voltammetry was performed for anodic and cathodic polarization, and oxygen reduction current was obtained with the difference in current measured in the solutions under N2 or O2 bubbling. The specific activity was evaluated with the normalized current by the catalyst’s weight, i w, or by the double layer charge, i c, and Tafel plots of polarization curves gave Tafel slope and exchange current density, i 0, for MBRO and BRO.The XRD patterns of MBRO were close to that of BRO except that some peaks of MBRO in the high 2θ region showed the peak sift to a higher angle with increasing manganese. EDX measurements of MBRO indicated that the metal ratio of the obtained oxide was almost the same as that of the precursor solution. SEM observation also revealed that the particle size of MBRO ranged from 20 nm to 60 nm with no clear dependence with the metal ratio. The polarization of MBRO for oxygen reduction was smaller than that of BRO and was more reduced with increasing manganese up to 30 at%, while a little difference in polarization for oxygen evolution was seen between MBRO and BRO. The analysis of Tafel slope and exchange current density from LSV data gave some interesting relationship between these parameters and the polarization for ORR and OER that the exchange current density of MBRO was 6 to 8 times larger than that of BRO at high manganese ratios, which is the main reason why MBRO showed a reduction in ORR polarization, while Tafel slope of MBRO for ORR was almost the same as or slightly higher than that of BRO, and Tafel slope for OER was hardly changed between MBRO and BRO. From the results, we found that the B-site modification of BRO with manganese can enhance the kinetics of electron transfer for the oxygen reactions.

Preparation of hierarchical LiNixCoyMnzO2 from solvothermal [NixCoyMnz](OH)2 via regulating the ratio of Ni, Co, and Mn and its excellent properties for lithium‐ion battery cathode

AbstractThe ternary‐layered oxide (LiNixCoyMnzO2) has become the most promising cathode material for lithium‐ion batteries due to the advantages of higher discharge platform, better conductivity, and higher theoretical capacity. The [NixCoyMnz](OH)2 with different ratios of nickel, cobalt, and manganese (NCM) was prepared by solvothermal method, and then ternary cathode material LiNixCoyMnzO2 was obtained by mixing lithium and calcining. In this paper, ternary cathode materials with different ratios of NCM were prepared by the solvothermal method. The structure and morphology of the materials were analyzed by X‐ray diffraction, scanning electron microscopy, and energy‐dispersive spectroscopy. The effects of the ratio on the electrochemical properties of the materials were investigated by constant current charge and discharge test and electrochemical impedance spectroscopy test. The synthesized lithium‐nickel‐cobalt‐manganese oxide belongs to the hexagonal system and has an α‐NaFeO2 layered structure, which is an R‐3m space group. The NCM ternary cathode materials with different morphologies were obtained by changing the ratio of NCM. The sample with NCM ratio of 5:3:2 has a unique sheet‐like spherical shape and has the best rate performance.

The Research on Characteristics of Li-NiMnCo Lithium-Ion Batteries in Electric Vehicles

The energy density of canode materials for lithium-ion batteries has a major impact on the driving range of electric vehicles. In order to study the charge-discharge characteristics and application feasibility of Li-NiMnCo lithium-ion batteries for vehicles, a series of charge and discharge experiments were carried out with different rates of Li-NiMnCo lithium-ion batteries (the ratio of nickel, cobalt, and manganese was 5 : 2 : 3) in constant-current-constant-voltage mode. Firstly, a set of charge-discharge experiments were performed on different types of single-cell lithium-ion batteries. The results show that, under temperature conditions, the charge and discharge voltage-capacity curves of the four different types of Li-NiMnCo lithium batteries mentioned in the paper are not much different, and the charge-discharge characteristic curves are similar, indicating that different types of batteries with the same material composition have similar charge and discharge characteristics. Subsequently, a series of charge and discharge tests with different rates were conducted on such ternary lithium batteries. The characteristic curves with different charge-discharge rates indicate that this new type of ternary lithium battery has high current charge and discharge capability and is suitable for use in new energy electric vehicles. In addition, by analyzing the voltage-SOC curve under different magnification conditions, it is known that there is an approximate linear relationship between the battery voltage value and the SOC within a certain SOC range. The SOC value can be evaluated by the battery voltage, which should be controlled within a reasonable range to avoid overcharge or overdischarge of battery, thereby, causing permanent damage to the battery.

Coupled Catalytic Oxidation–Reduction and Hydrolysis with Ce1Mn2 Catalysts for HCN and NO Removal

Metal oxide catalysts with different cerium and manganese ratios were synthesized by a co-precipitation method to remove HCN and NO from exhaust gas. Ce1Mn2 exhibited the highest HCN conversion and...

Preparation and Characterization of Rare Earth-Doped Ti/SnO2-Sb-Mn Electrodes for the Electrocatalytic Performance

The modified Ti/SnO2-Sb-Mn/Re electrodes were prepared using rare earth (Re) Gd, Eu, Ce, and Er and various molar ratios of tin and manganese by thermal decomposition. To investigate the electrocatalytic performance of electrodes, phenol was applied as a model pollutant. Phenol removal pursued pseudofirst-order kinetics in the experimental range. The experimental outcomes show that the phenol degradation at ~95% and ~97% was found in Mn (1 mol%)/Re and Mn (2 mol%)/Re electrodes after treatment for 140 min. Accelerated lifetime testing showed that the best-accelerated service life could be measured only in Mn (3 mol%)/Re and Mn (4 mol%)/Re compared with other prepared Mn (0%,1%, and 2%)/Re electrodes under the condition of 500 mAcm-2 current density in this study. The modified electrodes were then characterized, including oxygen evolution potential (OEP), crystal structure, and surface composition of the electrode coatings.

High performance 0.9LiMnPO4-0.1LiFePO4/C composite

The rate performance of lithium manganese phosphate is seriously tarnished by its sluggish surface kinetics, which could be addressed by LiFePO4-surface coating. For a higher energy output, here we explore thinner coating layers with 10% and 5% LiFePO4 via the lab-developed DMSO assisted method. The core-shell structured 0.9LiMnPO4-0.1LiFePO4/C maintains a high specific capacity, 153, 148 and 140 mA h g−1 under 0.1, 1 and 5 C respectively, which are the best results for this composition till date. As for 0.95LiMnPO4-0.05LiFePO4/C, the discharge capacity is lower than 110 mA h g−1 even in 0.1 C, which cannot meet the requirements of practical application. Our approaches push the manganese ratio of LiMnPO4-based composite to 90% from 80%, further improving the energy-density of the olivine phosphates.

Glucose enhanced the oxidation performance of iron-manganese binary oxides: Structure and mechanism of removing tetracycline

In this work, iron-manganese binary oxides (FMO) modified with different proportions of glucose addition (FMOCx) by co-precipitation method showed good activity in activating hydrogen peroxide (H2O2) for tetracycline degradation. The structure and surface characterizations of the FMO and FMOCx were measured by XRD, FTIR, TEM, BET and XPS. With increased glucose addition, FMOCx has more surface functional groups such as –OH and –COOH, particle size decreases, surface area gradually increases, and the ratio of high valence iron and manganese also increases. In addition, the glucose might be oxidized by KMnO4 to form amorphous carbon on the catalyst surface. Glucose modified iron-manganese binary oxides FMOC3 (with 0.003 mol glucose added) showed the highest efficiency removal capability for tetracycline up to 85%, which attribute to it has a larger surface area, more surface functional groups and higher surface active Mn(IV) site content. The results also demonstrated that FMOC3 could efficiently activate hydrogen peroxide. This study proves that glucose modified iron-manganese binary oxides (FMOCx) can offered a possibility of degradation of refractory organic pollutants as an environmentally friendly catalyst in the absence of H2O2 or not.

Investigation of the Role of Manganese Transport Repressor DR2539 in Mn/Fe Homeostasis

Mn and Fe ions are necessary for fundamental cellular processes, where they serve as enzyme cofactors or impart structural stability to proteins. However, Mn and Fe are toxic in excess. For example, dysregulation of Mn/Fe homeostasis results in manganism, a neurological disorder with symptoms similar to Parkinson’s disease. Therefore, tight regulation of intracellular Mn/Fe ratios is critical. Understanding the mechanisms used to regulate Mn/Fe homeostasis has both medical and bioremediation implications. D. radiodurans is particularly successful at establishing maintaining a high Mn/Fe ratio, making it an ideal model to investigate. DR2539, a metal ion dependent transcription factor of the DtxR family, plays a major role in maintaining the intracellular ratio of manganese to iron within D. radiodurans. DR2539 has been shown to bind to the promoter of the Mn importer protein, MntH and repress it in a Mn‐ and Fe‐ dependent manner. 64 other genes are either up‐ or downregulated in the absence of functional DR2539. To further elucidate the role of DR2539 in Mn homeostasis, we recombinantly expressed DR2539 from E. coli and purified it to homogeneity. Preliminary differential light scattering (DLS) and differential scanning fluorimetry (DSF) results suggest DR2539 can bind to Mn, and Mn binding induced oligomerization of the protein. Comparative modeling suggest the Mn‐induced oligomer is either a homodimer or a homotetramer with a similar structure to other members of the DtxR family. Preliminary crystallization screening experiments have identified potential conditions which may lead to samples suitable for high‐resolution structural studies. In total these experiments represent a first step toward elucidating the molecular basis of DR2539 function.Support or Funding InformationNSF HRD 1547757 Grant

Observational constraints on the origin of the elements

The abundance ratios of manganese to iron in late-type stars across a wide metallicity range place tight constraints on the astrophysical production sites of Fe-group elements. In this work, we investigate the chemical evolution of Mn in the Milky Way galaxy using high-resolution spectroscopic observations of stars in the Galactic disc and halo stars, as well as a sample of globular clusters. Our analysis shows that local thermodynamic equilibrium (LTE) leads to a strong imbalance in the ionisation equilibrium of Mn I and Mn II lines. Mn I produces systematically (up to 0.6 dex) lower abundances compared to the Mn II lines. Non-LTE (NLTE) radiative transfer satisfies the ionisation equilibrium across the entire metallicity range, of −3 ≲ [Fe/H] ≲ −1, leading to consistent abundances from both ionisation stages of the element. We compare the NLTE abundances with Galactic Chemical Evolution models computed using different sources of type Ia and type II supernova (SN Ia and SN II) yields. We find that a good fit to our observations can be obtained by assuming that a significant (∼75%) fraction of SNe Ia stem from a sub-Chandrasekhar (sub-Mch) channel. While this fraction is larger than that found in earlier studies (∼50%), we note that we still require ∼25% near-Mch SNe Ia to obtain solar [Mn/Fe] at [Fe/H] = 0. Our new data also suggest higher SN II Mn yields at low metallicity than typically assumed in the literature.

Effect of Manganese Addition on 94NBT-6BT Lead Free Multilayer Ceramics

In this study, lead-free 94Bi0,5Na0,5TiO3-6BaTiO3 (94NBT-6BT) ceramics were fabricated by solid-state synthesis method at ambient atmosphere. Glassy phase and rounded particles in 94NBT-6BT was observed with increasing Mn content. The effects of doping manganese on the ferroelectric properties of 94NBT-6BT bulk ceramics were evaluated. From the XRD results of the calcined powders, peaks were slightly changed to higher 2 theta value while increasing manganese ratio. Multivalence additive Mn ions act as acceptor dopant in 94NBT-6BT structure at ambient atmosphere. Samples were sintered from 1075 ℃ to 1175 ℃ for 2 hours to obtain highest piezoelectric values. SEM results show that glassy phase and rounded particles in 94NBT-6BT was observed with increasing Mn content so, bulk density was enhanced up to 1125C. From the results, 0.3 wt% manganese doped 94NBT-6BT samples have highest electromechanical coupling factor about 0.23, mechanical coupling factor (Qm) 150 and d33 110 pC/N respectively. Further work, 94NBT-6BT and Mn-doped 94NBT-6BT multilayer actuators were manufactured by water-based tape casting technique. The active area was 49 mm2 MLA and was fabricated by using Ag-Pd internal electrode without Pd-Bi reaction at the electrode-ceramic interface. Hysterisis loop measurements of manufactured lead free actuators were done by using Aixacct CMA module. Remnant polarization values of Mn-doped 94NBT-6BT MLA for a layer were higher than 6 µC/cm2.

Remaining-useful-life prediction via multiple linear regression and recurrent neural network reflecting degradation information of 20Ah LiNixMnyCo1−x−yO2 pouch cell

This paper presents the results of various experiments and analyses pertaining to lithium‑nickel‑cobalt‑manganese oxide (NCM) batteries having a nominal capacity of 20 Ah. This pouch type battery is characterized by high power rating and high energy density. The batteries used in the experiments were manufactured by varying the design ratios of nickel, cobalt, and manganese (5:2:3 and 6:2:2) in the NCM cathode materials. An accelerated deterioration test was carried out by applying a current of 80 A at 4C-rate (C-rate is the charge-discharge rate of a battery relative to its nominal capacity). The characteristics of the differential capacity were analyzed under varying deterioration conditions. The impedance characteristics for a given state of charge (SOC) and deterioration level were analyzed through electrochemical impedance spectroscopy (EIS) tests. In addition, the battery-equivalent circuit model was designed to estimate the model parameters of the alternating current (AC) impedance. The model parameters of the direct current (DC) impedance were estimated and compared through the direct current internal resistance (DCIR) test. Machine learning was performed by using the data extracted from the accelerated deterioration test as learning data, and by applying it to the multiple linear regression and the recurrent neural network methods. Finally, a study was carried out to estimate and analyze the remaining useful life (RUL) of the NCM lithium-ion batteries with machine learning.

Effect of Slime and Impurity Removal as a Pre-Treatment Stage Using a Low-Grade Zinc-Oxide Sample

A low-grade zinc-oxide sample (6–8% Zn) from Mehdiabad mine in Iran, with a high amount of slime and iron (17–19% Fe) and manganese (5–7% Mn) impurities was studied. Pre-treatment processes, such as desliming and wet high-intensity magnetic separation were applied for impurity removal. Petrographic studies showed that the zinc minerals were hemimorphite, hetaerolite, smithsonite, sphalerite and a low amount of zincite; lead was present in galena and manganese was in hetaerolite and pyrolusite. The gangue minerals were dolomite, calcite, hematite, goethite, pyrite and quartz. From a processing perspective, the sample can be characterized as a low-grade zinc-oxide sample. Experimental data and scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis showed that desliming prior to magnetic separation is required, and the optimum concentration ratio and recovery in the absorbed part can be determined by applying one stage of wet high-intensity magnetic separation with grinding and a magnetic field intensity for 16 min and 14 000 G. By considering the abovementioned conditions, the concentration ratio and recovery of iron and manganese in the absorbed part have been obtained as 1.42 and 1.54 and 73.28% and 79.79%, respectively, and the non-absorbed part of the pre-treatment stage with 10.56% Fe, 3.29% Mn and 6.83% Zn can be considered as flotation feed.

ASSESSMENT OF MECHANICAL DAMAGES IN THE PRIMARY Zn-MnO2 BATTERIES BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

By current study determined dependence between changing of the average capacitance of the destroyed electrodes of chemical current sources, surface geometry and chemical composition of electrodes surface. In case of the minimum destruction of the surface of the electrode, the maximum value of the average capacity is achieved with the ratio Zn: Mn = 2: 1. The minimum capacity was been at a maximum concentration of manganese on the surface (Zn: Mn = 1: 3) and the maximum degree of destruction. That is, the destruction of the surface of the electrodes leads to a change in the ratio of Zinc and Manganese and with strong surface destruction, the number of Manganese increases significantly. The using of the second frequency-dependent parameter (capacitance dispersion) as a lumped parameter was allowed the application of the principles of electric current commutation for register the layered change in the electric characteristics of the destroyed electrodes. Due to that mathematical technique was obtained a visual picture of the quantitative and qualitative changes on the destroyed surfaces. The general view of the received diagrams repeated the contours of the SEM microphoto images of the same surfaces. There is a presence of sites with the local concentrated deviations from the total distribution of the capacitance in the specific frequency range in case of deep damage in the diagrams. Thus, these diagrams (EIS images) give a clear picture of the electrodes surface of and can be used to evaluate the type of surface damage and the degree of destruction of the electrodes of chemical current sources.

Preparation and electrochemical properties of nickel–manganese composite sulfide

Nickel–manganese sulfide microspheres were prepared with the electrodepositon method, and the supercapacitive properties of this substance as composite electrode materials were explored. Pretreated nickel foam and thiourea were used as the substrate and sulfur source, respectively. Deposition duration was the main factor affecting the morphology of the material, and the degree of morphological dispersion affected the electrochemical properties. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques were used to investigate the electrochemical properties of the material. The highest specific capacitance was determined to be 2076 F g−1 at 1 A g−1 when the deposition time was 5 min, the thiourea concentration was 0.2 M, the nickel to manganese ratio was 1:3, and the deposition potential was − 1.1 V. The specific capacitance retention of the material was 48.5% after 1000 cycles at a scan rate of 10 mV s−1.

Studies on preparation and properties of low temperature phase of MnBi prepared by electrodeposition

MnBi alloy with low-temperature phase (LTP) is a promising candidate as rare-earth-free permanent magnet for its high intrinsic coercivity and the unique positive temperature coefficient. Many works have investigated on the preparation of the LTP-MnBi using physical methods, while there are few reports about the successful fabrication using electrodeposition method although this low cost process has been used for many material preparations so far. The main difficulty is the large negative reduction potential of manganese ions and on the basis the big difference between the reduction potentials of manganese ions and bismuth ions. In this paper, we reduced the reduction potentials of manganese ions and bismuth ions firstly and on this basis, the MnBi films with different ratios of manganese and bismuth were prepared using different deposited potentials. After annealed treatment of 380 °C, there appears the low temperature phase in XRD pattern for the sample in which the ratio of manganese and bismuth is 54:46. This is the first report in electrodeposited method so far and the corresponding coercivity reaches 1450 Oe measured by the physical property measurement system (PPMS).

Electrochemical Behavior of Manganese Oxide Ores Using Coke Wastewater in Sulfuric Acid Solution

The coke wastewater reductive leaching of pyrolusite ore in sulfuric acid solution was studied. This study was performed in two stages. First, the influence of tractable and refractory pollutants of coke wastewater on manganese leaching was determined. It was shown that the leaching efficiency of manganese is very sensitive to the decomposition of intractable pollutants. With the decrease of 1.85 g/L CODcr value of those contaminants, the extraction ratio of manganese increased more than 16% and exceeded 97.3%. Second, the corrosion behavior of pyrolusite ore in simulative wastewater solution was investigated using cyclic voltammograms, polarization curves, and Mott–Schottky curves. The reduction of manganese oxide ore by recalcitrant organic compounds involves two courses—the inducing conversion of manganese oxide to MnO·OH intermediate with hydrogen and free electron, which is from the oxidation of easily oxidized substances and the oxidation of persistent organic matter by this derivative. As a consequence, the latter process leads to the increment in manganese extraction efficiency. Coke wastewater is a promising reducing agent for MnO2. Likewise, it could be clarified and recycling. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13039, 2019