Current efficiency of recycling aluminum from aluminum scraps by electrolysis

Extracting aluminum from aluminum alloys in AlCl3-NaCl molten salts was investigated. Al coating was deposited on the copper cathode by the method of direct current deposition using aluminum alloys as anode. The purity of the deposited aluminum is about 99.7% with the energy consumption of 3-9 kW＆#183;h per kg Al, and the current efficiency is 44%-64% when the deposition process is carried out under 100 mA/cm2 for 4 h at 170 ＆#176;C. The effects of experimental parameters, such as molar ratio of AlCl3 to NaCl, cathodic current density and electrolysis time, on the current efficiency were studied. The molar ratio of AlCl3 to NaCl has little effect on the current efficiency, and the increase of deposition temperature is beneficial to the increase of current efficiency. However, the increase of current density or electrolysis time results in the decrease of current efficiency. The decrease of current efficiency is mainly related to the formation of dendritic or powder deposit of aluminum which is easy to fall into the electrolyte.

Preparation of electrolytic copper powders with high current efficiency enhanced by super gravity field and its mechanism

Super gravity field was employed to enhance electrolytic reaction for the preparation of copper powders.The morphology, microstructure and size of copper powders were characterized by scanning electron microscopy,X-ray diffractometry and laser particle analysis.The results indicated that current efficiencies of electrolytic copper powders under super gravity field increased by more than 20% compared with that under normal gravity condition.Cell voltage under super gravity field was also much lower.The size of copper powders decreased with the increase of gravity coefficient(G).The increase of current efficiency can be contributed to the disturbance of electrode/electrolyte interface and enhanced mass transfer of Cu2+ in super gravity field.Meanwhile,the huge gravity acceleration would promote the detachment of copper powders from electrode surface during electrolytic process,which can prevent the growth of copper powders.

Current Efficiency, Corrosion and Structural Changes in SnO2-Sb2O3-CuO Inert Anodes for Aluminium Electrolysis

A systematic study was conducted on current efficiency （CE）, corrosion and structural changes in SnO2-based inert anodes （made of 96wt%SnO2＋2wt%Sb2O3＋2wt%CuO） on a laboratory Hall-Heroult aluminium cell. The influence of operating parameters and electrolyte composition on the CE and corrosion process were evaluated. The CE was found to be more than 90% and catastrophic corrosion took place at low percent of Al2O3, high percent of LiF, low cryolite ratio and high current densities. From all the structural changes that took place in the SnO2-based inert anodes, we assumed that the most important contribution was due to the migration of CuO towards the outer limits of the constituent grains of SnO2 based ceramic. The complex process occurred during the formation of various phases and their sintering ability both directly depended on Cu/Sb molar ratio.

Current efficiency in electro-winning of lanthanum and cerium metals from molten chloride electrolytes

The objective of this study is to prepare lan- thanum and cerium metals by fused salt electrolysis of their anhydrous chloride in molten media such as LiCl-KCl, NaCl-KCl, KCl, NaCl, and LiCl and to characterize the metal deposit by X-ray diffraction, energy dispersive X-ray fluorescence, and inductive coupled plasma-atomic emis- sion spectroscopy. Deposit metal of purity more than 99 % was obtained in each of the experiments. The entire process starting from preparation of anhydrous lanthanum/cerium chloride to electrolysis yielding of metal deposits has been described. The effect of process parameters such as tem- perature, electrolyte composition, and current density on the current efficiency was studied. All these parameters were varied to get the highest current efficiency and metal yield. The major non-rare earth impurities with the deposit are found to be Fe, Cr, and Ni along with - 1× 10^-3 of total gaseous impurities.

Current efficiency improvement of Zn-Fe alloy electrodeposition by hydrogen inhibitor

In order to inhibit hydrogen evolution and enhance current efficiency of Zn-Fe alloy electrodeposition from alkaline zincate solution, hydrogen inhibitors composed of the sulfur group elements were optimized on the basis of atom structures analysis. The effects of hydrogen inhibitor on the current efficiency of Zn-Fe alloy electroplating and their electrochemical behaviors were studied. The results indicate that hydrogen inhibitor can increase the current efficiency of Zn-Fe alloy electroplating evidently, from 63.28% without hydrogen inhibitor up to 83.54% with a hydrogen inhibitor at a volume fraction of 2.0%, while it has a minor influence on that of pure Zn plating, which maintains at 80%. The optimum volume fraction of hydrogen inhibitor is 2.0%.

Current Efficiency of Low Temperature Aluminum Electrolysis Studied by Neural Network

A prediction model for Current Efficiency (CE) of low temperature aluminum electrolysis (LTAE) with the low molar ratioelectfolyte of Na3AIF6-AIF3 - CaF2-MgF2-LiF -Al2O3 system was investigated based on artificial neural network principles. The nonlinearmapping between CE of LATE and various electrolytic conditions was obtained from a number of experimental data and used to predictCE of LATE. The trsined neural networks possessed high precision and resulted in a good predicting effect. As a result, attificial neuralnetworks as a new cooperating and predicting technology provide a new approach to the further studies on low temperature aluminumelectrolysis.

Mechanism of current efficiency improvement of Zn-Fe alloy electroplating by hydrogen inhibitor

The effect of hydrogen inhibitor on partial current densities ofZn, Fe and differential capacitance of electrode/electrolyte interface, and adsorbing type of hydrogen inhibitor were studied by the methods of electrochemistry. The mechanism of current efficiency improvement were explained from the point of valence electron theory. The results indicate that the partial current density of Fe increases in addition of hydrogen inhibitor, which reaches the maximum of 0.14 A/dm^2 when current density is 0.2 A/din〈 Differential capacitance of electrode/electrolyte interface decreases obviously from 20.3μF/cm^2 to 7 μF/cm^2 rapidly with the concentration varying from 0 to 20 mL/L, because hydrogen inhibitor chemically adsorbs on active points of Fe electrode surface selectively. Element S in hydrogen inhibitor with negative electricity and strong capacity of offering electron shares isolated electrons with Fe. The adsorption of H atom is inhibited when adsorbing on active points of Fe electrode surface firstly, and then current efficiency of Zn-Fe alloy electroplating is improved accordingly.

Fine-tuning N-doped species of C catalysts for 98%current efficiency of electrocatalytic decarboxylation into hindered ether

Regulating the interaction between the substrate and electrode is crucial for maximizing catalytic performance.In this study,we developed a method for controlling the sintering temperature and introducing H2O2 post-treatment to modulate the N-doping of c catalysts,enhancing the interaction between the substrate and elec-trode to cause a radical reaction,thereby promoting electrocatalytic decarboxylation.When 10g of feedstock was used,the electrocatalytic system exhibited 9.4-and 4.2-fold increases in productivity and current efficiency,respectively,compared with the conventional method.A systematic investigation combining experiments and theoretical calculations revealed that pyridine N-oxide units not only promote bridging adsorption of the sub-strate and the formation of a substrate-enriched electric layer but also the transfer of mass and electrons,gen-erating more reactive carboxyl radicals.The electrocatalytic system delivers a current efficiency of 98%,which is exceptional compared to previously reported electrocatalysts.The system is in line with the development trend of the green chemical industry,combining flow reactors and photovoltaic technology.This study offers valuable insights and guidance for advancing electrocatalytic organic synthesis for future industrial applications.

Investigation of electron cyclotron current drive efficiency on the J-TEXT tokamak

Electron cyclotron current drive(ECCD) efficiency research is of great importance for the neoclassical tearing mode(NTM) stabilization.Improving ECCD efficiency is beneficial for the NTM stabilization and the ECCD power threshold reduction.ECCD efficiency has been investigated on the J-TEXT tokamak.The electron cyclotron wave(ECW) power scan was performed to obtain the current drive efficiency.The current drive efficiency is derived to be approximately η_(0)=(0.06-0.16)×10^(19)A m^(-2)W^(-1)on the J-TEXT tokamak.The effect of the residual toroidal electric field has been included in the determination of the current drive efficiency,which will enhance the ECCD efficiency.At the plasma current of I_(p)=100 kA and electron density of n_(e)=1.5×10^(19)m^(-3),the ratio of Spitzer conductivity between omhic(OH)and ECCD phases is considered and the experimental data have been corrected.The correction results show that the current drive efficiency η_(1)caused by the fast electron hot conductivity decreases by approximately 79%.It can be estimated that the driven current is approximately 24 kA at 300 kW ECW power.

A Study of Energy Conversion Efficiency Versus Plasma Density by Lower Hybrid Current Drive in HT-7 Tokamak

Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 1.0% has been achieved during the ramp-up phase. The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversion efficiency.

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.

Electrochemical Degradation of Indigocarmine Dye at Ni/Graphite Modified Electrode in Aqueous Solution

Nickel Graphite modified electrode (Ni/GME) was prepared by electrochemical method and degradation of Indigocarmine (IC) dye was carried out. An investigation between the efficiency of degradation by graphite electrode and the Ni/graphite modified electrode has been carried out. The different effects of concentration, current density and temperature on the rate of degradation were studied. This study shows that the rate of the degradation is more for Ni doped modified graphite electrode. UV-Visible spectra before and after degradation of the dye solution were observed. The thin film formation of Ni or encapsulated in graphite rod is observed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM & EDAX). The instantaneous current effectiveness values of different experimental conditions are evaluated. The anodic oxidation by Ni/ graphite modified electrode showed the complete degradation of aqueous solution indigocarmine, which is confirmed by UV-Visible and chemical oxygen demand (COD) measurements. The dye is converted into CO2, H2O and simpler inorganic salts. The results observed for reuse of modified electrodes indicate that the Ni/graphite modified electrode would be a promising anode for electrochemical degradation of indigocarmine. This method can be applied for the remediation of waste water containing organics, cost-effective and simple.

Efficiency of a blue organic light-emitting diode enhanced by inserting charge control layers into the emission region

We demonstrate high current efficiency of a blue fluorescent organic light-emitting diode （OLED） by using the charge control layers （CCLs） based on Alq3 . The CCLs that are inserted into the emitting layers （EMLs） could impede the hole injection and facilitate the electron transport, which can improve the carrier balance and further expand the exciton generation region. The maximal current efficiency of the optimal device is 5.89 cd/A at 1.81 mA/cm2 , which is about 2.19 times higher than that of the control device （CD） without the CCL, and the maximal luminance is 19.660 cd/m2 at 12V. The device shows a good color stability though the green light emitting material Alq3 is introduced as the CCL in the EML, but it has a poor lifetime due to the formation of cationic Alq3 species.

Influence of anode current density on carbon parasitic reactions during electrolysis

In the electro-deoxidation process,carbon parasitic reaction(CO_(3)^(2-)+4e–=C+3O^(2-))usually occurs when using carbon materials as the anode,which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process.The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density.The results indicate that lower graphite anode area can achieve higher current density,which is helpful to increase the nucleation site of CO_(2) bubbles.Most of CO_(2) would be released from the anode instead of dissolution in the molten CaCl_(2) and reacting with O^(2-)to form CO_(3)^(2-),thus decreasing the carbon parasitic reaction of the process.Furthermore,the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm^(2),CO_(2) concentration in the released gases increases significantly,the carbon mass content in the final metal product decreased from 1.09%to 0.13%,and the current efficiency increased from 6.65%to 36.50%.This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.

Numerical simulation of electron cyclotron current drive characteristics on EAST

Electron cyclotron current drive （ECCD） will be applied in the EAST tokamak during its the new campaign. In order to provide theoretical predictions for relevant physical experiments, some numerical simulations of ECCD with the parameters of EAST have been can＇ied out by using TORAY-GA code based on the understanding of ECCD mechanisms. ECCD efficiencies achieved in different plasma and electron cyclotron （EC） wave parameters are given. The dependences of ECCD characteristics on EC wave injection angle, toroidal magnetic field, plasma density, and temperature are presented and discussed.

Transport enhancement and efficiency optimization in two heat reservoir ratchets

We study a Brownian motor moving in a sawtooth potential in the presence of an external driving force and two heat reservoirs.Based on the corresponding Fokker-Planck equation,the analytical expressions of the current and efficiency in the quasi-steady-state limit are obtained.The effects of temperature difference and the amplitude of the external driving force on the current and efficiency are discussed,respectively.The following is our findings.（i） The current increases with both δ and A.In other words,δ and A enhance the transport of the Brownian motor.（ii） The competition between the temperature difference and the amplitude of the external driving force can lead to efficiency optimization.The efficiency is a peaked function of temperature,i.e.,δ 0 and a lower amplitude value of the external driving force is necessary for efficiency optimization.（iii） The efficiency increases with δ,and decreases with A.δ and A play opposite roles with respect to the efficiency,which indicates that δ enhances the efficiency of energy transformation while A weakens it.

Effect of oxide and fluoride addition on electrolytic preparation of Mg-La alloy in chloride molten salt

Mg-La alloys were prepared by constant voltage electrolysis in the molten salt system of MgC12-LaC13-KC1 at 750℃, with a graphite crucible as the anode and a tungsten rod as the cathode. The effect of oxide and fluoride addition on the electrolysis was investigated comprehensively. X-ray diffraction （XRD） was used to characterize some of the Mg-La alloy products and the sludges. As the content of MgO or La203 in the electrolyte increased, both the current efficiency and the mass of alloy product decreased, indicating that both MgO and La203 may take part in the reactions in the electrolyte. When the same mass of the oxide was added, compared with La203, MgO had a more pronounced effect on both the current efficiency and the mass of alloy product. XRD studies confirmed the formation of LaOC1 when MgO or LazO3 was added into the electrolyte. The formation of LaOCl sludge would be the main reason for the negative effect of the oxide addition on both the current efficiency and the mass of alloy. In the electrolytic system, the addition of CaF2 was not helpful to suppress the negative effect of MgO on the electrolysis, probably due to the complex reactions of the La compounds in the electrolyte.

Organic Light-Emitting Diodes by Doping Liq into an Electron Transport Layer

Organic light emitting diodes （OLEDs） incorporating an n-doping transport layer comprised of 8-hydroxy-quin- olinato lithium （Liq） doped into 4＇ 7- diphyenyl-1,10-phenanthroline （BPhen） as ETL and a p-doping transport layer that includes tetrafluro-tetracyano-quinodimethane （F4- TCNQ） doped into 4,4′, 4″-tris （3-methylphenylphenylamono） triphe- nylamine （m-MTDATA） are demonstrated. In order to examine the improvement in the conductivity of transport layers, hole-only and electron-only devices are fabricated. The current and power efficiency Of organic light-emitting diodes are improved significantly after introducing an n-doping （BPhen：33wt% Liq） layer as an electron transport layer （ETL） and a p-doping layer composed of m-MTDATA and F4- TCNQ as a hole transport layer （HTL）. Compared with the control device （without doping） , the current efficiency and power efficiency of the most efficient device （device C） are enhanced by approximately 51% and 89% ,respectively, while driving voltage is reduced by 29%. This improvement is attributed to the improved conductivity of the transport layers that leads to efficient charge balance in the emission zone.

Study on Methanol Oxidation at Pt and PtRu Electrodes by Combining in situ Infrared Spectroscopy and Differential Electrochemical Mass Spectrometry

Methanol oxidation reaction （MOR） at Pt and Pt electrode surface deposited with various amounts of Ru （denoted as PtxRuy, nominal coverage y is 0.17, 0.27, and 0.44 ML） in 0.1 mol/L HClO4＋0.5 mol/L MeOH has been studied under potentiostatic conditions by in situ FTIR spectroscopy in attenuated-total-reflection con guration and di erential electro-chemical mass spectrometry under controlled flow conditions. Results reveal that （i） CO is the only methanol-related adsorbate observed by IR spectroscopy at all the Pt and PtRu electrodes examined at potentials from 0.3 V to 0.6 V （vs. RHE）; （ii） at Pt0.56Ru0.44, two IR bands, one from CO adsorbed at Ru islands and the other from COL at Pt substrate are detected, while at other electrodes, only a single band for COL adsorbed at Pt is observed; （iii） MOR activity decreases in the order of Pt0.73Ru0.27〉Pt0.56Ru0.44〉Pt0.83Ru0.17〉Pt; （iv） at 0.5 V, MOR at Pt0.73Ru0.27 reaches a current e ciency of 50% for CO2 production, the turn-over frequency from CH3OH to CO2 is ca. 0.1 molecule/（site sec）. Suggestions for further improving of PtRu catalysts for MOR are provided.