scholarly journals A Novel Electrochemical Process for Desulfurization in the CaO-SiO2-Al2O3 System

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2478
Author(s):  
Sang Hoon Lee ◽  
Dong Joon Min
Keyword(s):  
Thermodynamic Stability ◽  
Electric Potential ◽  
Electrochemical Reaction ◽  
Sulfide Capacity ◽  
Partition Ratio ◽  
Electrochemical Process ◽  
Cathodic Potential ◽  
Potential Region ◽  
Anodic Potential ◽  
Co Gas

The effect of electric potential on the sulfide capacity of the CaO-SiO2-Al2O3 system was evaluated by applying voltages in the range of −1.5 to 1.5 V at 1823 K in a C/CO gas equilibrium. When the cathodic potential (−1.5 to 0 V) was applied, it was confirmed that the sulfur partition ratio increased based on the electrochemical reaction of sulfur (S + 2e− = S2−). However, the reversibility of the electrochemical resulfurization reaction (S2− = S + 2e−) in slag was not established in the reverse (anodic) potential region (0–1.5 V), yet the sulfur partition ratio increased. In particular, sulfur evaporation was observed in the anodic potential region. Therefore, in the present study, potential anodic electro-desulfurization mechanisms based on sulfur evaporation are proposed. To verify these mechanisms, sulfur evaporation is discussed in detail as a function of the thermodynamic stability of sulfur in the slag.

Calcium Phosphate Coating on Titanium Plates by Electrodeposition

2001 ◽  
Vol 711 ◽  
Author(s):  
Masahiko Ishikawa ◽  
Kouji Nishikawa ◽  
Kensuke Kuroda ◽  
Ichino Ryoichi ◽  
Masazumi Okido ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Electrochemical Process ◽  
Calcium Phosphate Coating ◽  
X Ray Diffraction ◽  
Cathodic Current ◽  
Solution Ph ◽  
Cathodic Potential ◽  
Peeling Test ◽  
Film Adhesion ◽  
Phosphate Film

ABSTRACTCalcium phosphate films were deposited on titanium electrodes cathodically from CaCl2·2H2O and Ca(H2PO4)2 · H2O aqueous solutions. In this study, H2O2 addition into electrolytes was applied to enhance the electrochemical process at the solution/electrode at a smaller cathodic potential than no H2O2 addition. Deposited films were analyzed by scanning electron microscopy (SEM) observation and X-ray diffraction (XRD). Cathodic current of the Ti electrode decreased once and increased in the solution with H2O2. It shows a cathodic current peak at c.a. 25 min in the case of potentiostatic condition at - 0.756 V (vs. Ag - AgCl, sat. KCl). The calcium phosphate film grows mainly with the decrease in current after the cathodic peak. The characteristics for the electrodeposited film such as crystal morphology depends on cathodic potential, solution pH, deposition temperature and amount of H2O2 addition. Dense calcium phosphate film composed of relatively good crystalline was obtained at pH 5.5 and – 0.756 V. Film adhesion on Ti appeared to be strong by peeling test. At larger cathodic potential of – 1.156 V, the film coverage on titanium plates was smaller and film adhesion worsened. Larger cathodic polarization of more than – 1.556 V was necessary to reduce water in case without H2O2 addition.

Research on the Antifouling Mechanisms of Copper and its Alloys

2009 ◽  
Vol 79-82 ◽  
pp. 2179-2182 ◽  
Author(s):  
Shi De Ma ◽  
Xia Zhao ◽  
Hong Ren Wang ◽  
Ji Zhou Duan
Keyword(s):  
Electrochemical Reaction ◽  
Copper Alloys ◽  
Electrochemical Process ◽  
Toxic Substances ◽  
Biological Factors ◽  
Corrosion Properties ◽  
Biology Process ◽  
Antifouling Ability ◽  
In Situ Exposure

In this paper, the in-situ exposure tests of 15 kinds of copper and its alloys were carried out in seawater at Zhanjiang Harbor for 12 months in order to study their anti-fouling abilities and anti-corrosion properties. In the same way, the in-situ anti-fouling tests of copper and bronze were performed in Qingdao for 8 years. Successively, the anti-fouling properties were analyzed combining with the electrochemical process of copper alloy corrosion and biology process of the adhesion. The chemical, physical and biological factors influencing the fouling properties of copper alloys were also investigated. The results showed that the coppers can equip themselves with antifouling performance by producing some toxic substances during the processes of chemical and electrochemical reaction. In addition, the antifouling ability was proved to relate to the exfoliation effect, which was the result of interaction between stain layer adhesion and spalling force of the attachments.

A New Approach for the Diffusion Coefficient Evaluation of Sulfur in CaO-SiO2-Al2O3 Slag

2011 ◽  
Vol 312-315 ◽  
pp. 626-634
Author(s):  
Luckman Muhmood ◽  
Nurini N. Viswanathan ◽  
Seshadri Seetharaman
Keyword(s):  
Diffusion Coefficient ◽  
Sulfide Capacity ◽  
Chemical Diffusion ◽  
Partition Ratio ◽  
Critical Parameters ◽  
New Approach ◽  
Matlab Program ◽  
Order Of Magnitude ◽  
Concentration Changes ◽  
Silver Metal

The Diffusion coefficient of sulfur in a ternary slag with composition of 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 was measured at 1723 K by chemical diffusion from the variation of concentration of sulfur in silver metal. A MATLAB program was developed to find the concentration variation of sulfur in silver metal using various critical parameters like the diffusion coefficient of sulfur in slag available in literature, sulfur partition ratio, sulfide capacity of the slag and the its density. The PS2 and PO2 pressures were calculated from the Gibbs energy of the equilibrium reaction between CaO in the slag and solid CaS and confirming the same by using ThermoCalc. The density of the slag at 1723 K was obtained from earlier experiments. Initially the order of magnitude for the diffusion coefficient was taken from the works of Saito and Kawai but later was modified so that the concentration changes of Sulfur obtained from the program agreed with the experimental results. The diffusion coefficient of sulfur in 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 slag at 1723 K was estimated as 4.14x10-6 cm2/sec.

scholarly journals Formation of Gd-Al Alloy Films by a Molten Salt Electrochemical Process

2008 ◽  
Vol 63 (1-2) ◽  
pp. 98-106
Author(s):  
Concha Caravaca ◽  
Guadalupe De Córdoba
Keyword(s):  
Cyclic Voltammetry ◽  
Intermetallic Compounds ◽  
Surface Characterization ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Electrochemical Process ◽  
Single Step ◽  
Al Alloy ◽  
Cathodic Potential

The electrochemistry of molten LiCl-KCl-GdCl3 at a reactive Al electrode has been studied at 723 to 823 K. Electrochemical techniques such as cyclic voltammetry and chronopotentiometry have been used in order to identify the intermetallic compounds formed. Cyclic voltammetry showed that, while at an inert W electrode GdCl3 is reduced to Gd metal in a single step at a potential close to the reduction of the solvent, at an Al electrode a shift towards more positive values occurs. This shift of the cathodic potential indicated a reduction of the activity of Gd in Al with respect to that ofW, due to the formation of alloys. The surface characterization of samples formed by both galvanostatic and potentiostatic electrolysis has shown the presence of two intermetallic compounds: GdAl3 and GdAl2. Using open-circuit chronopotentiometry it has been possible to measure the potentials at which these compounds are transformed into each other. The values of these potential plateaus, once transformed into e. f. m. values, allowed to determine the thermodynamic properties of the GdAl3 intermetallic compound.

Electrode processes at mercury in the far cathodic potential region

1972 ◽  
Vol 34 (1) ◽  
pp. 55-68 ◽  
Author(s):  
R.M. Reeves ◽  
M. Sluyters-Rehbach ◽  
J.H. Sluyters
Keyword(s):  
Cathodic Potential ◽  
Potential Region ◽  
Electrode Processes

Electrode processes at mercury in the far cathodic potential region

1973 ◽  
Vol 48 (3) ◽  
pp. 411-418 ◽  
Author(s):  
M. Sluyters-Rehbach ◽  
J.S.M.C. Breukel ◽  
J.H. Sluyters
Keyword(s):  
Cathodic Potential ◽  
Potential Region ◽  
Electrode Processes

Analysis of Electric Field of Pulse Electrochemical Finishing of Shaped Cathode on Gears

2013 ◽  
Vol 677 ◽  
pp. 207-210 ◽  
Author(s):  
Xiao Bing Zhai
Keyword(s):  
Numerical Simulation ◽  
Electric Potential ◽  
Potential Distribution ◽  
Electrochemical Reaction ◽  
Gear Tooth ◽  
Negative Electrode ◽  
Control Technology ◽  
Gear Teeth ◽  
Reaction Region ◽  
Electrochemical Finishing

Gear’s pulse electrochemical finishing (PECF) technology by shaped electrodes based on the numeral control technology, which controls gear dividing device and feed movement, is put forwards. Based on numerical simulation, electrochemical reaction region is dispersed. According to gear tooth profile and negative electrode surface equations, boundary conditions are inferred. The numerical simulation of the electric potential distribution in the calculation region has been shown. Under the optimized parameters, a mirror-like surface of gear teeth could be gained by PECF. The results show PECF can fulfill the advantages in the finishing some special gears with hard teeth.

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