Manganese Dioxide Powder Research Articles

Lucky strike: testing the utility of manganese dioxide powder in Neandertal percussive fire making

Late Middle Palaeolithic Neandertals in France are known to have engaged in the collection and grinding of black minerals rich in manganese dioxide (MnO2), generally presumed for symbolic use as powdered pigments. However, lab-based experiments conducted by Heyes and colleagues (Sci Rep 6: 22159, 2016) have shown that the addition of powdered MnO2 to wood turnings both reduces the temperature required for combustion by ca. 80–180 °C and significantly increases the rate of combustion. This special pyrotechnic property of powdered MnO2 may have been observed and leveraged by Neandertals to aid in fire making—a technology known to Neandertals in this region by at least 50,000 years ago. To test this idea, a series of actualistic fire-making experiments were performed to determine the practical applicability of MnO2 as a tinder-enhancing additive. The flint-and-pyrite percussive fire-making method was employed to produce sparks that were directed onto eight different types of tinder common to temperate Northwest Europe to determine if and to what degree the addition of MnO2 powder improved their ability to capture sparks that then propagate into glowing embers. The results show that MnO2 does indeed considerably improve the ignition efficiency of tinder material over untreated tinder, both in terms of the point of first ignition and the total number of ignitions achieved. It was observed, however, that the incidental addition of pyrite dust onto a tinder over the course of an experiment also appeared to improve its ability to capture sparks. Supplemental experiments using tinder pre-mixed with powdered pyrite confirmed this hypothesis, suggesting pyrite powder similarly expedites fire production. While this finding may raise questions regarding the need for collecting MnO2 for this purpose, its potential utility may lie in (1) its relative softness compared to pyrite, making it much easier to grind or scrape into powder, and (2) the greater potential for MnO2-bearing deposits to yield larger quantities of usable raw material compared to pyrite-bearing outcrops, making it relatively more abundant in some areas. Thus, when available, it is clear that adding MnO2 to tinder would have noticeably reduced the time and energy required to produce fire, making it a potentially novel Neandertal innovation complementary to the fire-making process.

Process Development for the Recovery of Manganese Dioxide, Cobalt(II) Sulfate, and Nickel(II) Sulfate Powders from the Reduction Smelted Alloys of Spent Lithium-Ion Batteries

ABSTRACT The smelting reduction of spent lithium-ion batteries at high temperature results in metallic alloys containing cobalt, copper, nickel, and manganese, in addition to aluminum and lithium oxides. A process has been proposed to selectively recover high-purity powders of manganese dioxide, cobalt(II) sulfate, and nickel(II) sulfate from these metallic alloys. Initially, the metallic alloys were completely dissolved using a mixture of 2.0 M sulfuric acid and 15% (v/v) hydrogen peroxide with a pulp density of 25 g/L over a duration of 120 minutes. Subsequently, copper(II) ions were removed through cementation with manganese powder, and aluminum hydroxide was precipitated by adjusting the solution pH to 4.5 at room temperature. Pure manganese dioxide was then obtained from the resulting filtrate through oxidative precipitation, utilizing sodium hypochlorite as an oxidizing agent. The separation of cobalt(II) and nickel(II) was achieved via a two-stage counter-current extraction using a 20% saponified 0.5 M Cyanex 272 solution. The loaded cobalt(II) was stripped using a 0.3 M sulfuric acid solution, leading to the crystallization of cobalt(II) sulfate powders. The pH of the raffinate was adjusted to 9.0, resulting in the precipitation of nickel(II) hydroxide, which was subsequently dissolved to recover nickel(II) sulfate powders from the solution. Most of the experiments were conducted at ambient temperature, except for the evaporation stage of crystallization. Continuous experiments verified that the purity of the recovered cobalt, manganese, and nickel powders was 99.9%.

Intensifying low-pressure membrane performance based on bio-cake layers coupled with pre-loading layers

Low-pressure ultrafiltration membranes (LPM) are a promising technology for the decentralized water supply. However, currently available ultrafiltration membranes cannot easily achieve the simultaneous removal of ferrous iron (Fe2+), manganese (Mn2+), and ammonia (NH4+). In this study, LPM coupled with three pre-loading layers consisting of manganese dioxide (MnO2) powder, powdered activated carbon (PAC), and zeolite powder, labeled M-LPM, C-LPM, and Z-LPM, respectively, in order to improve the effluent quality and shorten the ripening time without reducing the stable flux. The results show that the stable flux of M-LPM and C-LPM increased, while decreased for Z-LPM due to the viscosity of the pre-loading layer material. The ripening time of the three LPM systems was shortened, with M-LPM showing excellent Mn2+ removal throughout filtration, while Z-LPM exhibited notable adsorption of Mn2+ and NH4+. CLSM analysis revealed that the biological reactions occurred intensely in the upper area of the bio-cake layer. Based on the analysis of key enzyme genes, the microbial pollutant removal pathways were constructed. In addition, the optimal loading curve of the M-LPM pre-loading layer was established. Overall, the enhanced performance highlights the feasibility and potential of applying the LPM strategy in decentralized water supplies.

A Novel Procedure for Comprehensive Recovery of Zinc Fluoride, Manganese Fluorides, Manganese Dioxide, and Carbon Powder from the Electrode Powder of Spent Alkaline Batteries

A Novel Procedure for Comprehensive Recovery of Zinc Fluoride, Manganese Fluorides, Manganese Dioxide, and Carbon Powder from the Electrode Powder of Spent Alkaline Batteries

Synthesis of flower-like MnO2 nanostructure with freshly prepared Cu particles and electrochemical performance in supercapacitors

Four types of flowerlike manganese dioxide in nano scale was synthesized via a liquid phase method in KMnO4-H2SO4 solution and Cu particles, wherein the effect of Cu particles was investigated in detail. The obtained manganese dioxide powder was characterized by XRD, SEM and TEM, and the supercapacity properties of MnO2 electrode materials were measured. The results showed that doping carbon black can benefit to better dispersion of copper particles, resulting in generated smaller size of Cu particles, and the morphology of MnO2 nanoparticles was dominated by that of Cu particles. The study of MnO2 synthesis by different sources of Cu particles showed that the size of MnO2 particles decreased significantly with freshly prepared fine copper powder compared with using commercial Cu powder, and the size of MnO2 particles can be further reduced to 120 nm by prepared Cu particles with smaller size. Therefore, it was suggested that the copper particles served as not only the reductant and but also the nuclei centre for the growth of MnO2 particles in synthesis process MnO2, and that is the reason how copper particles worked on the growth of flower-like MnO2 and electrochemical property. In the part of investigation for electrochemical property, the calculated results of b values indicated that the electrode materials have pseudo capacitance property, and the highest specific capacitance of 197.2 F g-1 at 2 mV s-1 and 148 F/g at 1 A/g were obtained for MCE electrode materials (MnO2 was synthesized with freshly prepared copper particles, where carbon black was used and dispersed in ethanol before preparation of Cu particles). The values of charge transfer resistance in all types of MnO2 materials electrodes were smaller than 0.08 Ω. The cycling retention of MCE material electrode is still kept as 93.8% after 1000 cycles.

Enhanced heating-healing performance of asphalt concrete modified with heterogenous microwave sensitive admixtures

Microwave heating technology has promising application potential in self-healing promotion of asphalt concretes. Addition of microwave absorbers or microwave reflecting admixtures to asphalt concretes improves the heating-healing efficiency under microwave radiation. Radiated by microwave, the asphalt concrete with heterogenous admixtures, namely both microwave absorbers and reflecting admixtures, is supposed to have higher healing ratio than the concrete with monotypic admixtures, due to the synergy interaction between the two heterogenous admixtures. In this research, an asphalt concrete incorporating manganese dioxide powder as microwave absorber and steel fiber as microwave reflecting admixture was developed through an orthogonal design. Then the heating-healing capacity and road performances of the developed concrete were compared versus other concretes with same content of monotypic microwave sensitive admixtures. It is found that the healing ratio of the developed concrete exceeds other research subjects after 210 s of microwave heating. The content interaction of manganese dioxide powder and steel fiber has a statistically significant influence on the healing capacity. Besides, the monotypic addition of manganese dioxide powder also generates noteworthy enhancement in microwave heating-healing capacity and other road performances of the asphalt concrete. The results provide references to further increase the heating-healing capacity within limited admixture content.

Studies on Energy Cells Based on Si-, Si-Ge- and Ge-Air Systems

Silicon metal may be used as a fuel in Si-Air fuel cells. The most important characteristics of theseenergy cells is its thermodynamic reversibility. The Silicon-air energy cell is highly promising for electric vehicles due to its high theoretical energy density (8470 Wh kg-1) and its discharge products are non-toxic. For the first time, pure silicon and germanium powders are used as anode material. Nickel wire mesh embedded with charcoal and manganese dioxide powder as cathode and concentrated potassium hydroxide is used as electrolyte. Voltage-time curves have been presented in this study for pure silicon and germanium powder, and 5% and 10% germanium with silicon powder.

Comparative Analysis of the particle size on the porosity and the tensile properties of aluminium based metal matrix nano-composites

Milling a mixture of aluminium and manganese dioxide (MnO2) powders mixed in ratio of 1:7 by weight and the particle size has been varied by milling in a vibratory disc mill for 450, 600 and 750 min at 700 rpm to obtain Nano-sized alumina particles. Melting commercially pure aluminium followed by addition of different duration of milled powder mix while stirring the melt to synthesis nano-composites. The remaining aluminium powder will melt when the powder mixture will be added to molten Al-Mg alloy during composite processing. The remaining manganese oxide will also react with molten Al-Mg alloy during solidification processing of composite and generate alumina particles (in-situ). The reaction between manganese dioxide and molten alloy releases manganese for alloying with the molten Al-Mg alloy. To enhance wetting of resulting alumina particles by the melt, magnesium is added. It is observed that the porosity in the cast composite increases with increasing addition of particles milled for a given time and it is interesting to observe that for the same amount of addition, powders milled for higher milling time cause higher porosity. There is increasing strength and ductility compared with base alloy and composite prepared with 2wt% addition of different duration milled powder. The tensile properties for AM alloy shows yield strength of 75.9 MPa, tensile strength of 169.8 MPa and elongation of 11.12%. Tensile properties of different composites for addition of 2 wt% powder mix milled for 450, 600 and 750 min shows that 113.3 MPa, 91.8 MPa and 77.3 MPa of yield strength respectively, 250 MPa, 225.2 MPa and 216.8 MPa of tensile strength respectively and 25.65%, 25.68% and 23.91% of elongation respectively. For addition of 2 wt% powder mix milled for 450 min, there is improvement in yield strength by about 25%, tensile strength by about 35% and ductility by more than 120% in the nano-composite over those observed in the base alloy.

Novel conical section design for ultra-fine particles classification by a hydrocyclone

To overcome the limitation of the conventional hydrocyclone for the ultra-fine particles classification, the novel conical section design of the hydrocyclone is computationally investigated in this work. The electrolytic manganese dioxide (EMD, MnO2) powder, whose size is in the range from 0.2 μm to 70 μm, is took as a study case, and the feed solid concentration (SC) is up to 20%wt. The conical section with the modified cone design is proposed to enhance the performance of hydrocyclones. In addition, all the hydrocyclones are equipped with an arc inlet to obtain the pre-classification effect. The micron particles classification with the demarcation at 5 μm is accomplished in the novel hydrocyclone as the classification sharpness (Ss) is improved from 0.833 to 0.938 at the feed solid concentration of 5% wt. The combination of moderate conical length and modified cone with wide radial space near spigot is the outline of the high classification sharpness hydrocyclone. The dynamics analysis illustrates that the classification performance is attributed to the comprehensive effects of force, residence time, and separation space.

Tritium separation from parts-per-trillion-level water by a membrane with protonated manganese dioxide

This study shows a membrane containing a protonated manganese dioxide powder that is able to continually extract tritium from light water at room temperature. The method of using membrane-supplied protons through a proton conductive polymer film from acidic aqueous solution was remarkably effective at maintaining a continual extraction of tritium from light water, compared to the use of the protonated manganese dioxide powder alone. The extraction mechanism of tritium might be based on the prior oxidation of OT− at the interface of protonated manganese dioxide and water via neutralization between H+/T+ and OH−/OT−.

Preparation of polypyrrole nanocomposites for supercapacitor using spent battery powder as raw materials

A strategy has been developed to prepare conductive polymer-based nanocomposites as the electrode materials for supercapacitor with spent battery powder (SBP) as raw materials. Thus the waste resources from power could be sustainably recycled for new energy storage devices. The SBP containing manganese dioxide (MnO2) and graphite powder was obtained from the spent zinc-carbon battery, in which MnO2 was utilized for the oxidative polymerization of pyrrole. The binary graphite/polypyrrole (G/PPy) and ternary MnO2/graphite/polypyrrole (MnO2/G/PPy) nanocomposites were obtained under different reaction conditions, such as hydrochloric acid concentration, MnO2/pyrrole molar ratio, sodium p-toluene sulfonate (p-TSNa)/pyrrole molar ratio, and acid solution volume. The results showed that the electrochemical properties of the G/PPy nanocomposites were better than those of the MnO2/G/PPy. Under the optimized preparation condition (100mL of 1.5mol/L HCl with 0.03mol/L pyrrole, and MnO2/pyrrole/p-TSNa molar ratio of 1:1:1), the G/PPy nanocomposite possessed a relatively high Coulombic efficiency, a high electrical conductivity of 20.0S/cm, and the highest specific capacitance of 212.4F/g at 1mV/s scan rate tested by CV, as well as a retention of 89.5% of its original capacitance after 1000 cycles.

Effects of rheological properties on reactivity of energetic thin films

Magnesium (Mg) and manganese dioxide (MnO2) powders were mixed with polyvinylidene fluoride (PVDF) binder and n-methyl pyrrolidone (NMP) solvent and blade cast onto stainless steel foil. The rheological properties of these mixtures were investigated to quantify the mixing condition. Parameters including wet film thickness, equivalence ratio and solids loading were varied. Flame speed and calorific output were investigated for each of these parameters. Results show energy propagation rates increased as a function of dry film thickness, although calorific output remained relatively constant. Stoichiometrically fuel rich compositions were self-quenching, demonstrating the necessity of available oxygen for reaction propagation. A 0.45 solids–liquid mixing ratio resulted in up to an order of magnitude higher energy propagation rate for both open and confined configurations. Rheometry measurements and physical characterizations of the films reveal that the solids loadings resulting in the most stable suspensions also produced the highest energy propagation. Changing solids loading affects the density of the film, which in turn affects energy propagation. Capillary drying forces at high liquid loadings result in higher porosity leading to reduced deposition density and thickness. Very high solids loading results in films with dilatant properties and poor mixing. These results show solids loading affects mixing and energy propagation and could impact slurry cast energetic materials as in additive manufacturing processes.

Investigation of the toxicity of common oxidants used in advanced oxidation processes and their quenching agents

The inhibitory effect of commonly known oxidants and their quenching agents was investigated by employing a battery of toxicity tests. Hydrogen peroxide toxicity could be effectively eliminated by the enzyme catalase, whereas sodium thiosulfate and ascorbic acid were recommended as suitable quenching agents for the removal of the oxidants persulfate and peroxymonosulfate in the Vibrio fischeri bioassays. None of the studied quenching agents was found to be suitable for persulfate and peroxymonosulfate in the Daphnia magna bioassays since high inhibitory effects were obtained for both oxidants. In the case of Pseudokirchneriella subcapitata, manganese dioxide powder should be used as an alternative quenching agent to catalase, since this enzyme exhibited a highly toxic effect towards these microalgae. Sodium sulfite, which is extensively used as a quenching agent, was not appropriate for quenching peroxymonosulfate in all studied bioassays.

Synthesis and Characterization of γ-Al2O3 Nano Powder by Disc Milling of Al and MnO2 Powder

Nano-sized alumina particles have been generated by milling mixture of aluminium and manganese dioxide powders mixed in ratio of 1:7 by weight in a vibratory disc mill for different milling time of 450, 600 and 750min. The mill was operated at 700rpm. High energy milling of manganese dioxide particles with excess of aluminium powder ensures that nanoparticles generated, either of MnO2 or alumina, are mostly separate and surrounded by aluminium particles. The structural changes of powder particles during mechanical alloying were studied by X-ray diffraction, scanning electron microscopy and TEM. In the mixture of milled powders with particle size in the range 10 to 200nm. The addition of toluene was used as the process control agent to avoid severe agglomeration appears to be efficient to enhance the milling effect.

Analysis of a Gas Supply Unit Based on Hydrogen Peroxide Decomposition for Wearable Robotic Applications

With the aim of developing new solutions for powering pneumatic actuators in the field of wearable robotics, a principle scheme of a pressurized gas supply unit (GSU) based on hydrogen peroxide decomposition is proposed and a dynamic mathematical model is developed to simulate its operation. In the application scenario considered for the simulations, the GSU feeds a pneumatic ankle prosthesis during a standard daily living at-home activity. Furthermore, experiments of hydrogen peroxide decomposition on manganese dioxide powder have been carried out in an apparatus that partially mimics the behavior of the GSU. The results show that the GSU proposed is suitable for the implementation in a mobile robotic system, and, more in general, the use of the hydrogen peroxide decomposition process as a gas source for pneumatic actuators can be a viable approach to solve the principal issues related to powering wearable robotic devices.

Investigation of cavity microelectrode technique for electrochemical study with manganese dioxides

Crystallized manganese dioxide powders (cryptomelane type α-MnO2 and birnessite type δ-MnO2) were electrochemically investigated in mild aqueous electrolytes with the cavity microelectrode (CME) technique. Cyclic voltammetry was performed with isolated MnO2 powder and mixed acetylene black/MnO2 powder. High electrochemical performance is achieved showing the pseudocapacitive behavior of cryptomelane and the birnessite signature, which is exhibited by large, intense and more defined peaks, than for a composite electrode. The microcavity electrode (about 10−3mm3) allows studies with only a few micrograms of MnO2 powder in order to display its intrinsic electrochemical behavior and to improve the understanding of the role of the different components in the composite electrode performance.

Targetry and nuclear data for the cyclotron production of 55Fe via various reactions

The radionuclide iron-55 (T1/2 = 2.73 a) decays by electron capture and consists of small percentage of weak gamma rays. 55Fe can be employed for industrial, medical and agriculture applications. First, calculation of the excitation functions of iron-55 via the 55Mn(p,n)55Fe, 55Mn(d,2n)55Fe and 54Fe(α,n2p)55Fe reactions were performed and investigated by ALICE/ASH (hybrid model) and EMPIRE (3.1 Rivoli) codes. Then the required thickness of the target was calculated by the SRIM code; moreover, the theoretical physical yields of 55Fe production reactions were obtained. Consequently, the best reaction, 55Mn(p,n)55Fe, was suggested to take full benefit of the excitation function and to avoid formation of radioactive and non-radioactive impurities as far as possible. Furthermore, the optimum energy range were predicted to be 2–18 MeV and the theoretical physical yield were obtained to be 0.35 MBq/μA h. Lastly, manganese dioxide (MnO2) powder was used to prepare the thick layer; it was deposited on an elliptical copper substrate by means of sedimentation method. Target was irradiated at 20 μA current and 18 MeV proton beam. The radioactivity of 55Fe was determined via X-ray detector.

Cavity microelectrode for studying manganese dioxide powder as pH sensor

The potential–pH response of an electrolytic manganese dioxide is investigated by means of a cavity microelectrode (CME). The potential–pH curves show a complex evolution that could be explained by the disporportionation of MnOOH species, leading to the formation of Mn 2+ ions on the MnO 2 surface. Such a behaviour is not suited for pH sensor application. However when the tip of the electrode is coated by a Nafion membrane, the potential–pH evolution shows a unique slope close to −60 mV pH −1. In addition, the sensor exhibits short time responses to pH variations, a good selectivity, and it can be easily renewed compared to classical sensors.

Electrophoretically deposited manganese oxide coatings for supercapacitor application

In the present study, manganese oxide electrodes with promising pseudo-capacitive properties were prepared by electrophoretic deposition (EPD) using needle-like manganese dioxide powders. As-deposited coating exhibited a porous microstructure where the size and shape of the starting powders can be observed. The electrochemical performance of the as-deposited coating was then evaluated by cyclic voltammetry (CV) up to 300 times. The initial specific capacitance was 236 F/g which dropped to 200 F/g after 25 CV tests, and decreased gradually to 190 F/g thereafter. The electrochemical behaviors during EPD and CV were examined by synchrotron X-ray absorption spectroscopy techniques from which it was deciphered that a reduction reaction from Mn 4+ to Mn 3+ occurred during EPD concomitant with re-oxidization during repetitive CV cycles.

Composite electrodes for electrochemical supercapacitors

Manganese dioxide and Ag-doped manganese dioxide powders were prepared by a chemical precipitation method using KBH4 as a reducing agent. The powders were studied by X-ray analysis, thermogravimetry, and electron microscopy. Composite electrodes for electrochemical supercapacitors (ES) were fabricated by impregnation of slurries of the precipitated powders and carbon black into porous nickel foam current collectors. In the composite electrodes, carbon black nanoparticles formed a secondary conductivity network within the nickel foam cells. Obtained composite electrodes, containing manganese dioxide and 20 wt% carbon black with total mass loading of 50 mg cm−2, showed a capacitive behavior in the 0.5 M Na2SO4 solutions. The capacitive behavior of the composite electrodes can be improved by mixing of manganese dioxide and carbon black in solutions or using Ag-doped manganese dioxide powders. The highest specific capacitance (SC) of 150 F g−1 was obtained at a scan rate of 2 mV s−1. The electrodes showed good cycling behavior with no loss in SC during 1,000 cycles.