Electrochemical Deoxidation of Titanium in Molten MgCl2–YCl3

Zheng, Chenyi; Ouchi, Takanari; Kong, Lingxin; Taninouchi, Yu Ki; Okabe, Toru H.

doi:10.1007/s11663-019-01602-3

Cited by 32 publications

(17 citation statements)

References 35 publications

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“…The detailed calculation method is available in literatures. 44,61) The vertical axis in the diagram represents the oxidation reduction potential, E (V). The reference potential is defined by the Cl 2 (g)/Cl ¹ (p Cl 2 ¼ 1) equilibrium, i.e., the standard Gibbs energy of formation of the chloride ion (ÁG f,Cl À ) is 0, which is expressed as follows, 180706-1.…”

Section: Feasibility Of Deoxidation By Using An Electrochemical Methodsmentioning

confidence: 99%

“…When electrolysis is conducted in the YCl 3 MgCl 2 system, O 2¹ can also be expelled from the system, so the Ti is deoxidized to 100 mass ppm O. 44) In addition, even if oxide ions are introduced into the system (such as adding MgO), the deoxidation limit is still very low (360 mass ppm O at 1200 K), indicating that a large volume of Ti scrap can be deoxidized in the system.…”

Section: Introductionmentioning

confidence: 99%

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Direct Deoxidation of Ti by Mg in MgCl2–HoCl3 Flux

2019

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A new method for removing the dissolved oxygen (O) in titanium (Ti) is developed, wherein magnesium chlorideholmium chloride (MgCl 2 HoCl 3) and Mg are used as a flux and a reducing agent, respectively. Through the thermodynamic assessment using a p O2 p Cl2 diagram as well as the experimental results, the deoxidation of Ti to a level below 1000 mass ppm O (and even 500 mass ppm O) via the formation reaction of holmium oxychloride (HoOCl), O (in Ti) + Mg + HoCl 3 ¼ HoOCl + MgCl 2 , was confirmed. The deoxidation limit decreases with the increase of the activity of HoCl 3 in the MgCl 2 HoCl 3 flux. One advantage of this method is that the activity of the deoxidized product, a MgO , in the system can be effectively maintained at a low level by the formation of HoOCl. The EpO 2¹ diagram of the MOCl system (M = Ho, Mg) constructed in this study indicates that the electrochemical deoxidation of Ti scraps in MgCl 2 HoCl 3 system will be more effective because the a MgO can be further decreased via the formation of HoOCl, and/or the electrochemical oxidation of oxide ions on the carbon anode. This new deoxidation technique using rare-earth-containing MgCl 2 flux can be applied to the recycling of Ti scraps in the future.

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Section: Feasibility Of Deoxidation By Using An Electrochemical Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct Deoxidation of Ti by Mg in MgCl2–HoCl3 Flux

2019

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“…Currently, 12 t of Ti products are manufactured from 100 t of Ti ingots, while a large amount of Ti scrap is produced in the process (scrap, turning, etc.) [2] .…”

Section: Introductionmentioning

confidence: 99%

“…Hence, the removal of the attached salts using evaporation is necessary. Figure 2 shows the vapor pressures of some chlorides and Mg as a function of temperature [2,4] . MgCl2 and Mg can be easily removed from metallic Ti by vacuum distillation because of their high vapor pressure.…”

Section: Introductionmentioning

confidence: 99%

“…MgCl2 and Mg can be easily removed from metallic Ti by vacuum distillation because of their high vapor pressure. In effect, in the Kroll process, the most commonly used Ti smelting process, MgCl2 generated as a byproduct of the Ti-reduction step can be removed directly from the Ti sponge by evaporation [2] . To obtain Ti with a low oxygen concentration using metallic Mg as a deoxidant in molten MgCl2, the activity of MgO (s), aMgO(s), in the system must be reduced to a low level.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Deoxidation of Titanium in Molten MgCl₂-HoCl₃

2020

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A new electrochemical deoxidation method is proposed for Ti, wherein a mixture of magnesium chloride and holmium chloride (MgCl2-HoCl3) is used as a flux. In the new process, Ti and C are used as the cathode and anode, respectively. Mg is deposited on the Ti cathode, which reduces the O in Ti to oxide ions (O2). The activity of the generated O2- (aO2-) in the system was effectively maintained at a low level by the formation of holmium oxychloride (HoOCl) and further decreased by the electrochemical oxidation reaction on the anode. By applying a voltage of 3.0 V between the cathode and anode at 1173 K, Ti was effectively deoxidized to approximately 1000 mass ppm O. Based on the results, in this study, an electrochemical cell, that simultaneously deoxidize Ti scrap or powders and recover HoOCl, is designed.

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