A Pulse Voltage Application in Electrochemical Reduction of Solid CaWO4 Powder

Date

2016-09-01

Author

Goksu, Orhan Gokce
ERDOĞAN, METEHAN
Karakaya, İshak

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

200
views

0
downloads

Scheelite is the most abundant mineral of tungsten, but wolframite is used more than scheelite due to easier dissolution in alkaline solutions used in present processing methods. An alternative method based on electrochemical reduction of CaWO4 by direct current applications in molten salt solutions was recently reported. Pulse voltage and constant voltage reduction mechanisms were compared and an optimization of reduction kinetics was achieved in this study. The results have shown that faster reduction rates could be achieved during pulse voltage applications compared to constant voltage applications, when average value of pulse voltage application was the same as its constant counterpart. Furthermore, analysis of charge, energy and theoretical reduction graphs showed that reduction of calcium tungstate occurs at higher potential differences than 2.2 V, between calcium tungstate and graphite.

Subject Keywords

General Engineering

URI

https://hdl.handle.net/11511/39143

Journal

ECS Transactions

DOI

https://doi.org/10.1149/07233.0031ecst

Collections

Department of Metallurgical and Materials Engineering, Article

Suggestions

OpenMETU
Core

An Electrochemical Procedure to Form Metal Powders from Recycled Hard Particle Embedded Composite Cutting Tools Altunbasak, Tansu; KUL, MEHMET; Karakaya, İshak (2017-06-01) Used valuable particle embedded composite cutting tools, obtained by powder metallurgy techniques by mixing metallic powders with hard, abrasive particles were electrolyzed for reclamation of metallic powders and valuable particles. The effects of copper ion and sulfuric acid concentrations and pH of the electrolyte, current density and temperature on microstructure of produced copper powders were investigated in detail. Copper powders were characterized by X-Ray diffraction (XRD) and scanning electron micr...
AN EXPERIMENTAL INVESTIGATION OF POLYVINYL-CHLORIDE) EMULSION POLYMERIZATION - EFFECT OF INITIATOR AND EMULSIFIER CONCENTRATIONS ON POLYMERIZATION KINETICS AND PRODUCT PARTICLE-SIZE Karakaş, Gürkan (Wiley, 1989-01-01) Effects of concentration changes in initiator species Na2SO3, (NH4)2S2O8 and CuSO4, and emulsifier, ammonium stearate, on poly(vinyl chloride) (PVC) emulsion polymerization kinetics and on product particle size were experimentally investigated. It was observed that to obtain industrially significant rates and overall conversions, not only an optimum concentration ratio of Na2SO3/(NH4)2S2O8/CuSO 4 must be used, but also the concentrations of these species must be above certain limits. Increasing the concentr...
A Modeling Study on the Layout Impact of with-in-die Thickness Range for STI CMP Kıncal, Serkan; BAŞIM DOĞAN, GÜL BAHAR (2012-10-01) Chemical Mechanical Planarization process has a proven track record as an effective method for planarizing the wafer surface at multiple points of the semiconductor manufacturing flow. One of the most challenging aspects of the CMP process, particularly in applications like Shallow Trench Isolation (STI), is the difference in relative removal rates of the different materials that are being polished. A certain amount of over-polish is required to clear oxide on top of the nitride, however, this over-polish m...
The use of Silicon Wafer Barriers in the Electrochemical Reduction of Solid Silica to Form Silicon in Molten Salts Akpınar, Burcu; ERDOĞAN, MUSTAFA; Akduman, B.; Karakaya, İshak (2017-06-01) Nowadays, silicon is the most critical element in solar cells and/or solar chips. Silicon having 98 to 99% Si as being metallurgical grade, requires further refinement/purification processes such as zone refining [1,2] and/or Siemens process [3] to upgrade it for solar applications. A promising method, based on straightforward electrochemical reduction of oxides by FFC Cambridge Process [4], was adopted to form silicon from porous SiO2 pellets in molten CaCl2 and CaCl2-NaCl salt mixture [5]. It was reported...
A new method for processing of monazite and examination of the products by X-ray analysis Kizilyalli, Meral; Welch, Alastair J. (Elsevier BV, 1987-1) Sintering reactions of lanthanide orthophosphates with Na2CO3 gave the expected products (Na3PO4 and Ln2O3) with stoichiometric amounts of Na2CO3. When less than the theoretical amounts of Na2CO3 were used, two intermediate products eventually characterized by X-ray diffraction as Na3Ln(PO4)2 and Ln3PO7 were detected. Application of the sintering method to naturally occurring phosphates, particularly the mineral monazite, proved to be very successful. By using the optimum amount of Na2CO3 to form Na3Ln(PO4)...

Citation Formats

O. G. Goksu, M. ERDOĞAN, and İ. Karakaya, “A Pulse Voltage Application in Electrochemical Reduction of Solid CaWO4 Powder,” ECS Transactions, pp. 31–39, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39143.