Zinc Powder Research Articles

Bifunctionality of Zn dust in Ullmann C–C cross-coupling by Ni/Pd dual catalysis: theoretical insight

Zinc powder presents bifunctionality for heterogeneous single-electron reduction and homogeneous transmelation in Ullmann C–C bond cross-coupling by Ni/Pd dual catalysis.

Polyethylene glycol coating on zinc powder surface: Applications in dendrite-free zinc anodes with enhanced utilization rate

Zinc powder (Zn-P) anode is a more practical choice in industrial production compared with zinc foil, benefiting from its high exposed surface area and potential utilization rate for achieving high energy density. However, Zn-P-based anode still suffers from huge side-reaction (e.g., hydrogen evolution) and uncontrolled dendrite growth, which limit its further application. Herein, a polyethylene glycol (PEG) coating was introduced onto the surface of zinc powder to achieve corrosion-resistant, dendrite-free and high utilized zinc anodes. The PEG coating not only effectively suppressed the hydrogen evolution reaction, but also induced the ordered plating/stripping of Zn2+ via the oriented and preferred Zn (002) planes. Thus, the assembled Zn-P/PEG anode symmetric battery achieved a long cycle life of 1000 h at current densities of 5 mA cm−2. Furthermore, the energy density of Zn-P/PEG based full cell is nearly 1.7 times of that assembled by Zn foil anode. This work is the first to achieve the inhibition of hydrogen evolution on the surface of zinc powder while inducing the ordered deposition of zinc ions, achieving the effect of killing two birds with one stone. The proposed strategy of coating zinc powder with polymer provides new prospects for the modification of zinc powder anodes.

Applying an external reduction potential to reduce the consumption of zinc powder during gold cementation

One of the factors limiting the practical application of gold thiosulfate leaching is the inefficient recovery of Au(S2O3)23−, which can be recovered by cementation using active metals. In gold cementation, the application of electrochemical reduction on the solution can simultaneously reduce metal consumption, and meet the recycling requirements. By introducing an applied potential of 0.14 V to an 80 mL solution of 5 mM CuSO4, 0.5 M NH3, 0.1 M Na2S2O3, and 10 mg/L gold ion, the concentration of Cu(NH3)42+ in the solution and the corresponding redox potential can be reduced from 5 mM to 0.261 mM, and 0.26 V to 0.06 V, respectively. Under these conditions, gold cementation was carried out, and the consumption of zinc powder was found to be reduced by 70%. By stirring for 12 h after the cementation, the concentration of Cu(NH3)42+ in the solution can be recovered to 80% of the initial concentration resulting in redox potential of 0.23 V. Using this solution to leach gold ore, the gold leaching rate can reach 80% within 6 h, which meets the needs of requirements for dissolving gold in the leaching stage.

Removal of toxic cadmium (II) from zinc sulfate solution with zinc powder enhanced by ultrasound: Kinetics and mechanism

Currently, removing cadmium (II) from zinc sulfate electrolytes using zinc powder presents several problems, such as the agglomeration and encapsulation of the zinc powder, which leads to increased consumption of the zinc powder and poor removal performance. To overcome this limitation, ultrasound is used to assist the replacement of the zinc powder to remove cadmium (II) from zinc sulfate electrolytes. Compared with conventional replacements, the ultrasonic-assisted replacements reduce the reaction time from 120 to 40 min, the reaction temperature from 60 to 55 ℃, and the required amount of zinc powder from 5 to 3 g/L. Under the same process conditions, the replacement rate of cadmium (II) is increased from 68.9 to 98.7 %. According to kinetic studies, ultrasound reduces the required activation energy for replacement from 34.77 to 16.83 kJ/mol, which significantly reduces the energy barrier of the cadmium precipitation. In addition, ultrasound can remove the reaction layer between the zinc powder and cadmium (II), thus accelerating the chemical reaction rate. The kinetic behavior changes when the initial cadmium (II) concentration is in the range of 800–1200 mg/L in conventional experiments, and 1600–2000 mg/L in ultrasound experiments. The characterization of the purification slags confirms that ultrasound can refine particles, improve the replacement rate of cadmium (II), and significantly reduce the consumption of the zinc powder. The ultrasound-enhanced purifying technology of zinc sulfate electrolytes with zinc powder is of great significance for zinc electrowinning and comprehensive recovery of cadmium.

A Turn-On–Type Fluorescence Resonance Energy Transfer Eco-friendly Method for Nitazoxanide Quantification in Pharmaceutical Dosage Form and Spiked Plasma: Evaluation of Greenness Profile Using Different Assessment Tools

A brand-new class of anti-infective drugs that work against bacteria, viruses, and protozoan parasites is nitazoxanide and related thiazolides. Thiazolides have also been shown to cause cell cycle arrest and apoptotic cell death in cancer cells in recent years. In this study, an eco-friendly, spectrofluorimetric technique that is verified, easy, and sensitive has been proposed for quantifying nitazoxanide (NTZ), a broad-spectrum antiparasitic drug. When NTZ is reduced with zinc (Zn) powder in an acidic media, a highly fluorescent product is produced. To get the highest sensitivity, different experimental conditions impacting the response were examined and optimized. Following excitation at 299 nm, scanning of the fluorescent product was done at 440 nm. The intensity of the fluorescence was proportional to the drug concentration in the range of 0.1–0.6 μg/mL. The approach was validated according to International Conference on Harmonization (ICH) guidelines, and the outcome was satisfactory. The detection and quantitation limits were calculated to be 0.013 and 0.038 μg/mL, respectively. The suggested technique was successful in analyzing commercially available NTZ dosage forms. Furthermore, the proposed technique was used to assess NTZ levels in human plasma and it was bio-analytically validated according to European Medicines Agency (EMA) guidelines. The suggested method can be used in quality control laboratories as well as in pharmacokinetic studies. In order to picture the green profile of the developed method, four greenness assessment tools have been applied. National Environmental Methods Index (NEMI), analytical Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical Greenness metric (AGREE) are the relatively most widely used metrics. So, they were utilized to perform a detailed greenness comparison between the proposed method and some of the reported methods for the determination of NTZ. The developed method was found to be an excellent green method with the highest AGREE score.

Controlled growth of Ag-ZnO thin films by thermal evaporation technique for optimized thermoelectric power generation

This manuscript is described the facile and cost-effective growth of silver Zinc Oxide (Ag-ZnO) thin films by simple thermal evaporation method for thermoelectric power generation applications. Growth of samples is started by making pellets of pure silver (Ag) and zinc (Zn) powders which are composed of 1:1 ration and evaporated in vacuum tube furnace. The other growth parameters are fixed as; evaporation time (45 min), evaporation temperature (1010 0C) and oxygen flow rate (60 sccm). Five samples are prepared at different source to substrate distances (6.5–8.5 in.) and post deposition annealing of all samples is carried out at 800 °C using semi-programable muffle furnace. Prepared thin films are analyzed using X-Ray Diffraction (XRD), Raman spectroscopy, Scanning Electron Microscope (SEM) and Seebeck measurements to study the impact of various source to substrate distances on the structural morphological and thermoelectric behavior of Ag-ZnO nanocomposite thin films. The obtained results are revealed that different source to substrate distances strongly influence the structural, morphological, and thermoelectric behavior of prepared thin films. Optimal values for electrical conductivity, Seebeck coefficient and powerful factor of synthesized thin films are calculated as 3.05 × 103 S/m, 645 µV/°C and 1.27 × 10−3 Wm−1 oC−2 respectively at source to substrate distance of 7.0 in.

Development of Asbestos-free Disc Brake Pad Using Periwinkle Shell Powder and Coconut Shell Ash as Base Materials

Brake pads are integral part of an automobile braking system that contribute to the full control of the vehicle. The composite materials for their production must therefore possess adequate chemical, mechanical, physical, and thermal properties. The development of asbestos-free disc brake pad using Periwinkle Shell (PS) powder and Coconut Shell Ash (CSA) as reinforcement and frictional filler material respectively is presented. This was done with a view of establishing suitability of PS powder and CSA as replacements for asbestos which has been found to be carcinogenic and capable of causing Asbestosis and Mesothelioma [1]. Other ingredients used are graphite as lubricant, epoxy resin as binder, copper, zinc, and aluminum powders as abrasives and also to impact mechanical strength. The optimum percentage formulation of these materials for the pad was arrived at by using the ANOVA tool of the Box-Behnken technique of Design Expert Software, DX-13. The CSA and PS powders were sieved into grades of 106 µm, 150 µm, 212 µm and 300 µm and then combined with other constituents to produce the brake pad. The pads were characterized in terms of their physical, mechanical and tribological properties. It was observed that increase in particle size distributions leads to decrease in densification and carbon crosslinking of the produced composite brake pads. Therefore, the 106 µm particle size sample has better properties than others. Comparison analysis shows that the performance parameters of the 106 μm size brake pad compares well, and in some cases better, with typical after-market replacement pads, an asbestos-based brake pad and brake pads developed from past research works.

A Semi-solid Zinc Powder-based Slurry Anode for Advanced Aqueous Zinc-ion Batteries.

The booming of aqueous zinc-ion batteries (AZIBs) draws the researchers' attention to issues of zinc metal anodes, such as uncontrollable dendrite growth, corrosion, and volume effects. Zinc powder anode is more suitable for the industrial application of AZIBs than the widely used zinc foil anode due to its low cost, tunability and processability. However, the related solutions are rarely studied because the above issues of zinc metal anode are more serious in zinc powder anode. Herein, for the first time, we design a semi-solid zinc slurry anode consisting of zinc powder and zincophilic tin additive dispersed in a conductive elastic rheological network. Zinc can be deposited homogeneously on the dispersed tin particles, which avoids agglomerative zinc deposition and alleviates volume change during repeated zinc stripping/plating. Moreover, the practical application of the full cell with slurry is very promising since its operating life can be easily extended by facile slurry renewal.

A Semi‐solid Zinc Powder‐based Slurry Anode for Advanced Aqueous Zinc‐ion Batteries

AbstractThe booming of aqueous zinc‐ion batteries (AZIBs) draws the researchers’ attention to issues of zinc metal anodes, such as uncontrollable dendrite growth, corrosion, and volume effects. Zinc powder anode is more suitable for the industrial application of AZIBs than the widely used zinc foil anode due to its low cost, tunability and processability. However, the related solutions are rarely studied because the above issues of zinc metal anode are more serious in zinc powder anode. Herein, for the first time, we design a semi‐solid zinc slurry anode consisting of zinc powder and zincophilic tin additive dispersed in a conductive elastic rheological network. Zinc can be deposited homogeneously on the dispersed tin particles, which avoids agglomerative zinc deposition and alleviates volume change during repeated zinc stripping/plating. Moreover, the practical application of the full cell with slurry is very promising since its operating life can be easily extended by facile slurry renewal.

Study on Microstructure and Properties of Mechanically Deposited Zn-Sn Coating

A Zn-Sn coating of ~30 µm thickness was prepared on an iron substrate by mechanical deposition using zinc and tin powders as raw materials. The Zn-Sn coating consists of zinc powder particles physically stacked with tin powder particles and filled with reduced tin, and the tin content in the coating is 20%–30%. The resulting Zn-Sn coating was characterized and analyzed with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), polarization curves (Tafel), electrochemical impedance (EIS), and energy dispersive X-ray spectrometry (EDS). The results showed that the Zn powder was co-deposited with the Sn powder in a portable manner and the Sn powder was deflected and deformed to a great extent. The spot-flocculated reduced Sn also covered the surface of the Zn powder to fill the interstices of the coating to make the coating more compact. Compared with the pure Zn coating, the Zn-Sn coating has a positive shift of 68 mV in the self-corrosion potential in the polarization test, and the corrosion current was only 20% of that of the pure Zn coating. The reduced Sn had a shielding effect on the Zn powder and at the same time, in combination with inert tin powder, the polarization resistance of the plated layer increased to 1118 Ω/cm2. Furthermore, compared to the pure zinc layer, the time of white rust and red rust increased by 24 and 240 h, respectively. In addition, the XPS results showed that the Zn-Sn plating layer was clearly passivated, which was mainly due to the formation of Zn(OH)2 and Sn(OH)2. The results also emphasized that the tin element in the Zn-Sn plated layer can maintain the morphology of zinc powder, compact the plating layer, and prevent the release of corrosion products, thus improving the corrosion resistance of the Zn-Sn coating.

Binder-Free Freestanding 3D Zn-Graphene Anode Induced from Commercial Zinc Powders and Graphene Oxide for Zinc Ion Battery with High Utilization Rate

Aqueous zinc-ion batteries (AZIBs) have received widespread attention owing to the increasing demand for safety and inexpensive batteries. However, a zinc metal anode suffers from dendrite growth during continuous cycling, and side reactions occurred on anode surface such as hydrogen evolution reaction (HER) and passivation. Moreover, the low utilization of Zn metal is also a neglected issue leading to a low energy density at the cell-level. Herein, a nondendrite Zn anode with high utilization was designed by spontaneous reaction of commercial Zn powders and graphene oxide (GO). The formed binder-free three-dimensional (3D) anode Zn_G achieves a cycling time over 550 h and extremely low voltage hysteresis of ∼20 mV with 7.4% DOD (130 h for Zn foil with 1.3% DOD and 80 h for Zn powders with 7.4% DOD) at a current density of 1 mA cm–2 in a symmetric cell. In Zn||MnO2 full batteries, Zn_G greatly enhances the gravimetric energy density on the cell level and achieved more than 1600 cycles much higher than Zn foil (Zn_F) with 700 cycles and Zn powders (Zn_P) with 500 cycles. The low N/P ratio of 3 also achieved high stability with 126 mAh g–1 and 74.5% retention after 1000 cycles.

Enhancement of Mechanical Properties and Bonding Properties of Flake-Zinc-Powder-Modified Epoxy Resin Composites.

As a typical brittle material, epoxy resin cannot meet its application requirements in specific fields by only considering a single toughening method. In this paper, the effects of carboxyl-terminated polybutylene adipate (CTPBA) and zinc powder on the mechanical properties, adhesion properties, thermodynamic properties and medium resistance of epoxy resin were studied. A silane coupling agent (KH-550) was used to modify zinc powder. It was found that KH-550 could significantly improve the mechanical properties and bonding properties of epoxy resin, and the modification effect of flake zinc powder (f-Zn) was significantly better than that of spherical zinc powder (s-Zn). When the addition amount of f-Zn was 5 phr, the tensile shear strength and peel strength of the composites reached a maximum value of 13.16 MPa and 0.124 kN/m, respectively, which were 15.95% and 55% higher than those without filler. The tensile strength and impact strength reached a maximum value of 43.09 MPa and 7.09 kJ/m2, respectively, which were 40.54% and 91.11% higher than those without filler. This study provides scientific support for the preparation of f-Zn-modified epoxy resin.

Modification of graphene and its effect on anticorrosive properties of coatings

In this paper, zinc particles were grafted on the surface of graphene by KH550. It was proved that zinc powder was successfully connected to the surface of graphene by KH550 through IR, SEM, energy spectrum and thermogravimetric analysis. The modified graphene is added to the anti-corrosion coating, which effectively improves the anti-corrosion performance of the coating.

A novel CO2 foaming agent for the preparation of foamed sulfoaluminate cement material: Application to coal mine filling

High-risk areas in coal mines have become an increasingly serious issue in recent years. However, the chemical foaming agents used in coal mine filling management are mostly hydrogen peroxide which produces combustible O2 and aluminum or zinc powder which is explosive H2. All of the above chemical foaming agents do not have safe filling conditions. In this paper, we propose a new inorganic foaming material that generates inert gas CO2. Foamed sulfoaluminate cement-based grouting material (FSCGM) was prepared by chemical foaming. The expansion capacity of CO2 foaming agent was studied. The effects of W/C, foaming agent admixture, and Lime/Anhydrite (L/A) on expansion times, foaming time and setting time were studied and the optimum proportion of FSCGM was determined. The mechanical properties, durability, and fire prevention performance of the FSCGM with the optimal proportion were studied and simulated filling tests were conducted. The results showed that the CO2 foaming agent with 30% dosing expands 8.8 times after 10 min of foaming. The best proportion of W/C was 2.2, CO2 foaming dosing was 25%, L/A was 3:5, 6 h compressive strength was 0.52 MPa, 7 d water absorption rate was 46.2%, softening coefficient was 0.75. With the increase of foam admixture and W/C, the CO2 concentration gradually increased, and the fire prevention effect became more apparent. After simulated filling, the slurry did not collapse the mold, the expansion times was 1.74 times, and the dry density of the sampled specimens was about 0.3 g/cm3. It is observed that the bubbles were evenly distributed, and the hole structure was small and dense. Therefore, we prepared FSCGM with ultra-low density, high early compressive strength, and good fire prevention performance by using novel CO2 foaming agent. In addition, the feasibility results indicate that the FSCGM has great potential for engineering applications.

Analysis of coiling stable roll of hot-dip galvanized strip

The coiling stable roll of hot-dip galvanized is a defect formed in the galvanizing process. The zinc slags and floating foreign matters in the zinc pot will directly or indirectly adhere to the roll surface of the stabilizer roll with the flow of zinc liquid. When the strip steel contacts the stabilizer roll, the zinc slag will extrude and deform the iron base plate and form pits. In this paper. The causes of the defects were analyzed. There were two methods to eliminate the coiling stable roll, that is, to reduce the generation and accumulation of zinc slags in the zinc pot. The main measures are first to control the temperature of the strip entering the zinc can plate and the temperature of the molten zinc, and then control the amount of residual bottom residue before the zinc pot goes online. Another is to ensure the cleanliness of the steel strip before it enters the molten zinc. Based on this, the main measures implemented are: improving the cleaning ability of the cleaning section and improving the reducing ability during annealing to inhibit the formation and accumulation of zinc powder in the furnace head area.

Effect of regularly arranged reduced graphene oxide on the anti-corrosion performance of waterborne silicate zinc-rich coatings

ABSTRACT The effect of a barrier layer composed of reduced graphene oxide (rGO) with edge adsorption of K+ (rGOK+) on anticorrosive performance was investigated. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), DC polarisation technique and electrochemical impedance spectroscopy (EIS) were used to investigate the morphology, corrosion product, corrosion mechanism and process. XPS results show that the corrosion products are ZnCl2, Zn(OH)2, ZnCO3 and Zn5(OH)8Cl2. SEM, energy-dispersive spectrometer (EDS), polarisation curve and EIS show that the coating with the most rGOK+ not only builds a barrier layer but also improves the utilisation of zinc powder, thereby providing better corrosion protection for the substrate despite the 30% reduction in zinc powder usage.

Zinc Promoted Simple Synthesis of Z-Arnino Acids Under Neutral Conditions

Abstract: The introduction of benzyloxylcarbonyl (Z) group into amino acids is described at neutral pH using benzyloxylcarbonyl chloride and activated zinc powder. The reaction is simple, fast and clean. Thus the Z-amino acids are prepared in good yield and purity

Portable Colorimetric Hydrogel Test Kits and On-Mobile Digital Image Colorimetry for On-Site Determination of Nutrients in Water.

Portable colorimetric hydrogel test kits are newly developed for the on-site detection of nitrite, nitrate, and phosphate in water. Griess-doped hydrogel was prepared at the bottom of a 1.5 mL plastic tube for nitrite detection, a nitrate reduction film based on zinc powder was placed on the inner lid of a second 1.5 mL plastic tube for use in conjunction with the Griess-doped hydrogel for nitrate detection, and a molybdenum blue-based reagent was entrapped within a poly(vinyl alcohol) hydrogel matrix placed at the bottom of a third 1.5 mL plastic tube to detect phosphate. These test kits are usable with on-mobile digital image colorimetry (DIC) for the on-site determination of nutrients with good analytical performance. The detection limits were 0.02, 0.04, and 0.14 mg L−1 for nitrite, nitrate, and phosphate, respectively, with good accuracy (<4.8% relative error) and precision (<1.85% relative standard deviation). These test kits and on-mobile DIC were used for the on-site determination of nutrients in the Pak Bang and Bang Yai canals, the main canals in Phuket, Thailand. The concentrations of nitrite, nitrate, and phosphate were undetectable to 0.60 mg L−1, undetectable to 2.98 mg L−1, and undetectable to 0.52 mg L−1, respectively.

Selective and Reversible 1,3-Dipolar Cycloaddition of 2-(2-Oxoindoline-3-ylidene)acetates with Nitrones in the Synthesis of Functionalized Spiroisoxazolidines.

The 1,3-dipolar cycloaddition of 2-(2-oxoindoline-3-ylidene)acetates with functionalized aldo- and ketonitrones proceeds with good selectivity to provide new highly functionalized 5-spiroisoxazolidines. A characteristic feature of these reactions is reversibility that allows for the control of the diastereoselectivity of cycloaddition. The reduction of obtained adducts using zinc powder in acetic acid leads to 1,3-aminoalcohols or spirolactones. For a number of the spiro compounds obtained, anticancer activity was found.

Statistical Approach to Design Zn Particle Size, Shape, and Crystallinity for Alkaline Batteries

The modern alkaline primary battery is composed of a highly alkaline, gelled electrolyte-zinc powder anode dispersion (slurry), a cellulose-based separator, and an electrolytic manganese dioxide (EMD) cathode pellet – typically arranged in a cylindrical cell geometry. This battery system has its origins in the 1950s and thus has had decades to be researched and matured and it is known that the limiting performance of this battery system is concentrated at the slurried zinc anode. This had led many researchers to focus on the anode for improvement with most previous engineering efforts targeting enhanced performance, capacity, and stability of this material. Due to the various material fabrication processes involved with manufacturing industrial zinc powder, there exists an array of unique zinc particle size, shape, and crystallinity combinations that distinguish industrial zinc powders from one another. These industrial zinc powders are typically produced through trial-and-error processes using existing “rules of thumb”. Consequentially, it is possible that something has been missed and a data-driven approach could elucidate the optimum combination of zinc particle properties.In this study, we investigate the effect of Zn particle size, shape, and degree of crystallinity on the achievable capacity and corrosion current. Various types of zinc powders were sieved into size fraction ranges and chemically and thermo-chemically treated to control their crystallinity. The procedure for producing zinc powders of various sizes, shapes, and crystallinities led to a 64-powder Zn matrix that was then electrochemically analyzed by linear sweep voltammetry to determine the corrosion current and galvanostatically discharged to determine the achievable capacity. These experiments were done in a newly-designed, custom-built electroanalytical cell that will be described in the talk. Following the data collection, a 4k factorial statistical analysis was performed. This analysis identified which of the controlling variables have a statistically significant influence on the achievable capacity and corrosion. The statistical model was also able to provide guidance regarding the preferred particle shape. This information can be used to develop actionable procedures for battery manufacturers to create cells that are more stable, longer lasting, and have higher energy densities.