Electrolytic magnesium production using coaxial electrodes

Demirci, Gökhan
Main reason for the current losses in electrolytic magnesium production is the reaction between electrode products. Present study was devoted to effective separation of chlorine gas from the electrolysis environment by a new cell design and thus reducing the extent of back reaction between magnesium and chlorine to decrease energy consumption values. The new cell design was tested by changing temperature, cathode surface, current density, anode cathode distance and electrolyte composition. Both the voltages and the current efficiencies were considered to be influenced by the amount and hydrodynamics of chlorine bubbles in inter-electrode region. Cell voltages were also found to be affected from the nucleation of magnesium droplets and changes in electrolyte composition that took place during the electrolysis. A hydrodynamic model was used to calculate net cell voltage by including the resistance of chlorine bubbles on anode surface to theoretical decomposition voltage during electrolysis. Good correlations were obtained between experimental and calculated voltages. The same model was used to calculate current efficiencies by considering chlorine diffusion from bubble surfaces. A general agreement was obtained between calculated and experimental current efficiencies. Desired magnesium deposition morphology and detachment characteristics from cathode were obtained when MgCl2-NaCl-KCl-CaCl2 electrolytes were employed. Current efficiencies higher than 90% could be achieved using the above electrolyte. The cell consumes around 8 kWhkg-1 Mg at 0.43 Acm-2 as a result of high chlorine removal efficiency and capability of working at low inter-electrode distances. Furthermore, the cell was capable of producing magnesium with less than the lowest energy consumption industrially obtained, at about double the commonly practiced industrial current density levels.


Demirci, Gokhan; Karakaya, İshak (2012-03-15)
An experimental electrolytic magnesium production cell was designed to remove chlorine gas from the electrolyte rapidly and demonstrate the beneficial effects of reduced chlorine dissolution into the molten salt electrolyte. The back reaction that is the main cause of current losses in electrolytic magnesium production was reduced as a result of effective separation of electrode products and decreased contact time of chlorine gas with the electrolyte. Moreover, smaller inter electrode distances employed and...
Multiscale & in-situ forming analysis of AZ31 magnesium alloy under different strain paths
Alkan, Kıvanç; Efe, Mert; Department of Metallurgical and Materials Engineering (2018)
Formability of AZ31 Magnesium alloy is limited and strain path dependent below 180 ᵒC. In this thesis, formability behavior and fracture mechanisms of AZ31 Magnesium alloy are investigated by in-plane biaxial testing. In-situ and multiscale strain analysis reveal the microstructural features and deformation mechanisms responsible form the unusual forming behavior of the AZ31 alloy and offer possible solutions to control the forming defects and instabilities. The strain measurements show that the equivalent ...
Production of fly ash-magnesium phosphate cements
Bilginer, Baki Aykut; Erdoğan, Sinan Turhan (null; 2019-05-02)
Magnezyum fosfat çimentolu (özellikle magnezyum potasyum fosfat çimentolu [MKPC]) bağlayıcılar Portland çimentosuna kısmi alternatif olabilecek sistemlerdir. MKPC yaygın olarak kalsine MgO tozu ve potasyum dihidrojen fosfat tuzu kullanılarak hazırlanır. Sulu karışımda meydana gelen asit-baz tepkimesi çok hızlı gerçekleştiğinden, bir geciktirici (boraks) de eklenir. MKPC’nin çabuk priz alma, çok hızlı dayanım kazanma ve yüksek nihai dayanım gibi geleneksel çimentolu sistemlere üstün yan...
Ionic conductivity of microporous titanosilicate ETS-10 and ion-exchanged Mn+-ETS-10 (where, Mn+ = Li+, Na+, Mg2+, Zn2+, Ca2+) thin films prepared by secondary growth method
Galioglu, Sezin; Çam, İbrahim; Akata Kurç, Burcu (2017-09-15)
Impedance spectroscopy was used to investigate the long-range ionic conductivity of the microporous, titanosilicate (Na,K)-ETS-10 and ion-exchanged Mn+-ETS-10 (where, Mn+ = Li+, Na+, Mg2+, Zn2+, Ca2+) thin films prepared by secondary growth method. To figure out the effect of grain boundary on ionic conduction, as-synthesized (Na,K)-ETS-10 films possessing different thicknesses of columnar grain structure (i.e., films prepared via 4h-, 6h-, 8h-, and 10h-growth) were tested. The conductivities of the films w...
Electrolytic magnesium production and its hydrodynamics by using an Mg-Pb alloy cathode
Demirci, Goekhan; Karakaya, İshak (Elsevier BV, 2008-10-06)
Physical interaction of magnesium and chlorine was minimized by collecting magnesium in a molten Ph cathode at the bottom of the electrolyte and placing anode at the top where the chlorine gas was evolved. Thus the magnesium losses associated with the formation of suspending droplets and fine magnesium particles were eliminated and current losses were mainly due to the recombination reaction of dissolved magnesium and chlorine. Current yield changed by changing the tip angle of the conical anode. It was due...
Citation Formats
G. Demirci, “Electrolytic magnesium production using coaxial electrodes,” Ph.D. - Doctoral Program, Middle East Technical University, 2006.