Effective Deoxidation Process of Titanium Scrap Using MgCl2 Molten Salt Electrolytic

To overcome the scarcity and resource limitations of Ti metal, deoxidation of Ti scrap was conducted through electrolytic refining and chemical reaction with MgCl2 molten salt electrolysis. The oxygen concentration in Ti scraps was decreased by the electrochemical and chemical reactions generated by the applied voltages. The optimized conditions for the process were derived by controlling the conditions and parameters by decreasing the thermodynamic activity of the reactants. The correlation between the deoxidation efficiency and the behavior of the voltage and current was confirmed by setting the conditions of the electrolysis process in various voltage ranges. In addition, the correlation between the presence of impurities and the measured oxygen concentration was evaluated. The surface element analysis result indicated that the salt that was not removed contained a certain amount of oxygen. Thus, the removal efficiencies of impurities and particles by deriving various post-treatment process conditions were analyzed. The results confirmed that the most stable and efficient current was formed at a specific higher voltage. Moreover, the best deoxidation result was 2425 ppm, which was 50% lower than that of the initial Ti scrap.

[1]  S. Schafföner,et al.  A review on alpha case formation and modeling of mass transfer during investment casting of titanium alloys , 2021 .

[2]  H. Nersisyan,et al.  Hf metal powder synthesis via a chemically activated combustion-reduction process , 2021 .

[3]  Liao Kaihua,et al.  Inflow process of Fe, Ni, and Cr impurities in Ti sponge during kroll process , 2020, Metallurgical Research & Technology.

[4]  H. Sohn.  Production Technology of Titanium by Kroll Process , 2020, Journal of the Korean Institute of Resources Recycling.

[5]  T. Okabe,et al.  Electrochemical Deoxidation of Titanium Scrap in MgCl2-HoCl3 System , 2019, Journal of The Electrochemical Society.

[6]  M. Kaur,et al.  Review on titanium and titanium based alloys as biomaterials for orthopaedic applications. , 2019, Materials science & engineering. C, Materials for biological applications.

[7]  Jae-Hong Lim,et al.  Removal of Mg and MgO By-Products Through Magnesiothermic Reduction of Ti Powder in Self-Propagating High-Temperature Synthesis , 2019, Metals.

[8]  T. Okabe,et al.  Deoxidation of Titanium Using Mg as Deoxidant in MgCl2-YCl3 Flux , 2019, Metallurgical and Materials Transactions B.

[9]  S. Alpay,et al.  Insight into point defects and impurities in titanium from first principles , 2018, npj Computational Materials.

[10]  G. Chen,et al.  Development of the Fray-Farthing-Chen Cambridge Process: Towards the Sustainable Production of Titanium and Its Alloys , 2017, JOM.

[11]  S. Madhukar,et al.  A Review on Machinability Aspects of Titanium Grade-2 , 2017 .

[12]  A. Javey,et al.  Conductive and Stable Magnesium Oxide Electron‐Selective Contacts for Efficient Silicon Solar Cells , 2017 .

[13]  Jae-Young Jung,et al.  Current Status of Titanium Smelting Technology , 2016 .

[14]  T. Okabe,et al.  Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride , 2016, Metallurgical and Materials Transactions B.

[15]  Wenjie Zhang,et al.  Surface thermal oxidation on titanium implants to enhance osteogenic activity and in vivo osseointegration , 2016, Scientific Reports.

[16]  K. Roh,et al.  Preparation of low oxygen content alloy powder from Ti binary alloy scrap by hydrogenation–dehydrogenation and deoxidation process , 2014 .

[17]  R. Mohadi,et al.  PREPARATION OF CALCIUM OXIDE FROM Achatina fulica AS CATALYST FOR PRODUCTION OF BIODIESEL FROM WASTE COOKING OIL , 2013 .

[18]  Nan Zhang,et al.  Defective TiO2 with oxygen vacancies: synthesis, properties and photocatalytic applications. , 2013, Nanoscale.

[19]  Yan-qing Su,et al.  Deoxidation of Titanium alloy using hydrogen , 2009 .

[20]  A. Fedoročková,et al.  Effects of pH and acid anions on the dissolution kinetics of MgO , 2008 .

[21]  Xuan Liu,et al.  CaO solubility and activity coefficient in molten salts CaCl2–x (x = 0, NaCl, KCl, SrCl2, BaCl2 and LiCl) , 2008 .

[22]  R. Suzuki.  Direct reduction processes for titanium oxide in molten salt , 2007 .

[23]  L. Jaffe.  CALCIUM EXPLOSIONS AS TRIGGERS OF DEVELOPMENT , 1980, Annals of the New York Academy of Sciences.

[24]  J. Nettle,et al.  Some Observations on the Kroll Process for Titanium , 1954 .

[25]  M. Z. Mubarok,et al.  Synthesis of Magnesium Oxide from Ferronickel Smelting Slag Through Hydrochloric Acid Leaching-Precipitation and Calcination , 2017 .

[26]  S. Gerdemann.  Titanium process technologies , 2001 .

[27]  M. Abbate,et al.  Probing depth of soft x‐ray absorption spectroscopy measured in total‐electron‐yield mode , 1992 .