scholarly journals Kinetics and Energy Consumption for a Three-Stage Electrocoagulation Process for the Recovery of Au and Ag from Cyanide Leachates

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 758 ◽  
Author(s):  
Cristina García-Carrillo ◽  
José Parga-Torres ◽  
Héctor Moreno-Casillas ◽  
Francisco S. Sellschopp-Sanchez
Keyword(s):  
Energy Consumption ◽  
Electrochemical Process ◽  
Constant Current ◽  
Constant Voltage ◽  
Oxidation Reduction ◽  
Electrocoagulation Process ◽  
Cyanide Solutions ◽  
Exchange Resins ◽  
Kinetics Of

The most common processes used for the recovery of gold and silver from cyanide leachates are Merril-Crowe, activated carbon in pulp, and ion exchange resins; the process of electrocoagulation (EC) also is a promising new technique. EC is an electrochemical process whose mechanisms include oxidation, reduction, decomposition, deposition, coagulation, absorption, flotation, and precipitation. It has been used for the treatment of water and wastewater with different degrees of success. This study aimed to determine the kinetics of the reaction and the energy consumption at constant voltage, and at constant current using aluminum electrodes with two different distances between electrodes. EC was run in three stages for the removal of gold and silver from aqueous cyanide solutions from samples supplied by a Mexican mining company. Characterization of the sample showed initial concentrations of 49.48 and 383 mg/L of gold and silver, respectively. Results showed the effectiveness of the process by achieving removals up to 98.59% of gold and 99.43% of silver. Additionally, it was determined that the kinetics of the reaction is of zero order and that the lowest energy consumption can be achieved when working at constant voltage and with a separation of 0.8 cm between electrodes.

scholarly journals Energy consumption analysis of constant voltage and constant current operations in capacitive deionization

Desalination ◽  
2016 ◽  
Vol 400 ◽  
pp. 18-24 ◽  
Author(s):  
Yatian Qu ◽  
Patrick G. Campbell ◽  
Lei Gu ◽  
Jennifer M. Knipe ◽  
Ella Dzenitis ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Constant Current ◽  
Capacitive Deionization ◽  
Constant Voltage ◽  
Energy Consumption Analysis

Anodizing of Pure Magnesium in Sodium Hydroxide Electrolyte Solution

2020 ◽  
Vol 405 ◽  
pp. 440-444
Author(s):  
Michal Páleníček ◽  
Martin Papula ◽  
Michaela Remešová ◽  
David Jech ◽  
Ivana Ročňáková ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Image Analysis ◽  
Electrochemical Process ◽  
Pure Magnesium ◽  
Constant Current ◽  
Constant Voltage ◽  
Corrosion Resistant ◽  
Anodic Layer ◽  
Scanning Electron

Anodizing is an electrochemical process to produced anodic coatings for improving magnesium (Mg) properties such as corrosion-resistant. In this study, anodizing of pure magnesium in 1 M NaOH electrolyte for 1800 s and at 21 °C and different constant current or voltage was investigated. The effect of voltage and current on morphology and thickness of the resulting anodic layers was evaluated by scanning electron microscopy (SEM) equipped with EDX analyser. The thickness of the produced layers was determined to utilize digital image analysis. The results showed that using lower current of 0.08 A non-compact anodic layer was produced. When a higher current of 0.2 and 0.5 A was used compact and thicker anodic layers were produced compare to lower current of 0.08 A. The anodic layer produced at a constant voltage of 20 V was rougher, thicker and contained microcracks compare to anodic layers formed at constant voltage of 12 V and at constant current (0.2 and 0.5 A).

scholarly journals Energy consumption in capacitive deionization – Constant current versus constant voltage operation

2018 ◽  
Vol 143 ◽  
pp. 367-375 ◽  
Author(s):  
J.E. Dykstra ◽  
S. Porada ◽  
A. van der Wal ◽  
P.M. Biesheuvel
Keyword(s):  
Energy Consumption ◽  
Constant Current ◽  
Capacitive Deionization ◽  
Constant Voltage

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

HOMOGENITAS PRODUKSI BATERAI ION LITIUM BERDASARKAN VARIANS KAPASITAS PENGISIAN, KAPASITAS PELEPASAN DAN EFISIENSI PENGISIAN-PELEPASAN

2016 ◽  
Vol 6 (1) ◽  
pp. 35
Author(s):  
Daniel Fajar Puspita ◽  
Susanto Sigit Rahardi
Keyword(s):  
Constant Current ◽  
Constant Voltage ◽  
Constant Current Charging

Penelitian  mengenai  stabilisasi  produksi  baterai  ion  litium  berdasarkan  parameter  kapasitas  pengisian, kapasitas pelepasan  dan  efisiensi  pengisian-pelepasan  telah  dilakukan. Tujuan  dari penelitian  ini adalah  untuk mengetahui apakah prosedur pembuatan baterai ion litium ini dapat menghasilkan produk yang homogen. Pada penelitian material selanjutnya hal ini berguna untuk meyakinkan bahwa perubahan kualitas   dari produk baterai yang dihasilkan merupakan pengaruh dari material, bukan karena variabel proses perakitan. Pada penelitian ini dipakai lembaran elektroda siap pakai untuk meniadakan pengaruh variasi bahan baku terhadap kualitas sel baterai yang dihasilkan. Sel baterai dibuat di laboratorium riset baterai B4T. Baterai dibuat sebanyak 3 batch dengan jumlah baterai 8 buah setiap batch. Baterai yang dihasilkan diuji dengan alat battery analyzer merek Berkeley buatan USA dengan arus 0,5 C pada saat constant-current charging dan voltase 4,2 V sewaktu constant-voltage charging selama 10 siklus pada saat uji kinerja  dan arus 0,1 C pada saat pengisian  awal.  Hasil yang didapat adalah  batch C menghasilkan sel-sel baterai yang lebih homogen yang ditandai dengan nilai varians dan simpangan baku yang paling kecil dibandingkan batch lainnya.  Selain itu pada saat uji pengisian-pelepasan  10 siklus, batch C juga memperlihatkan kinerja yang lebih tinggi. Hal ini menunjukkan bahwa proses yang dipakai pada batch C dapat menghasilkan sel baterai ion litium berkinerja baik dan homogen.Kata kunci: stabilisasi produksi, ion litium, kapasitas, efisiensi

Removal of Hydrophobic and Hydrophilic Constituents by Anion Exchange Resin

1999 ◽  
Vol 40 (9) ◽  
pp. 207-214 ◽  
Author(s):  
J.-P. Croué ◽  
D. Violleau ◽  
C. Bodaire ◽  
B. Legube
Keyword(s):  
Molecular Weight ◽  
Anion Exchange ◽  
Water Source ◽  
Atomic Ratio ◽  
Size Exclusion ◽  
Salting Out ◽  
Anion Exchange Resins ◽  
Hydrophilic Character ◽  
Exchange Resins

The objective of this work was to compare the affinity of well characterized NOM fractions isolated from two surface waters with strong (gel matrix and macroporous matrix) and weak anion exchange resins (AER) using batch experiment conditions. The structural characterization of the fraction of NOM has shown that the higher the hydrophilic character, the lower the C/O atomic ratio, the lower the SUVA, the lower the aromatic carbon content and the lower the molecular weight. In general (not always), strong AER was more efficient to remove DOC than weak AER. For the same water source (Suwannee River), the higher the molecular weight of the NOM fraction, the lower the affinity with AER. Increasing the ionic strength favored the removal of the hydrophobic NOM fraction (“salting out” effect) while increasing the pH apparently reduced the removal of the hydrophilic NOM fraction. Results were discussed in terms of size exclusion, adsorption, anion exchange and also hydrophobic/hydrophilic repulsion.

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