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Research Paper

Investigation on HCl Leaching of Ti Mixture Obtained by Deoxidation of Off-grade Ti Sponge Using Mg Metal

Mg을 이용한 Off-grade 타이타늄 스폰지 탈산 산물의 산 침출에 관한 연구

Hyunjin Na1†
,
Sung-Hun Park23†
,
Tae-Hyuk Lee4
,
Jungshin Kang25*
나 현진1†
,
박 성훈23†
,
이 태혁4
,
강 정신25*
1Western Australian School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Bentley, WA 6102, Australia
2Research Institute of Energy and Resources, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
3By-Product Resource Research Group, Research Institute of Industrial Science & Technology, 67, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
4Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro Yuseong-gu, Daejeon 34132, Republic of Korea
5Department of Energy Resources Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
1Curtin University, Western Australian School of Mines: Minerals, Energy and Chemical Engineering
2서울대학교 에너지자원신기술연구소
3포항산업과학연구원 부산물자원화연구그룹
4한국지질자원연구원 자원활용연구본부
5서울대학교 에너지자원공학과
*Corresponding Author
†These authors contributed equally to this work as first author.
28 February 2026. pp. 29-42
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Abstract

To recycle off-grade Ti sponges, deoxidation using Mg in H2 gas has been recently developed. After deoxidation, acid leaching plays an important role in producing high-purity Ti without contamination by O. In this study, conditions for the HCl leaching of Ti mixtures obtained by deoxidation of an off-grade Ti sponge were optimized. The influences of leaching time, temperature, molarity of HCl solution, and bubbling gas on the O concentration in Ti were investigated, in addition to the dissolution behaviors of Mg, Ti, and Fe. When HCl leaching was conducted at 313 K under argon gas bubbling, the O concentration in Ti was 0.168 mass%, and the fractions of dissolved Ti and Fe were 1.01 % and 43.84 %, respectively. These results demonstrate the feasibility of mitigating O contamination in Ti with minimal Ti loss during the HCl leaching of a Ti mixture obtained after deoxidizing an off-grade Ti sponge.

Keywords
titanium
recycling
deoxidation
HCl leaching
oxygen concentration

최근, off-grade 타이타늄 (Ti) 스폰지의 재활용을 위해 수소 가스 (H2) 분위기에서 마그네슘 (Mg) 금속을 이용한 탈산 공정이 개발되고 있다. 탈산 후 고순도의 Ti을 얻기 위해서는, 산 침출의 제어를 통한 산소 (O) 오염의 최소화가 중요하다. 본 연구에서는 off-grade Ti 스폰지를 수소 혼합 가스 분위기 중 Mg 금속으로 탈산하여 얻은 Ti 혼합물의 염산 (HCl)을 이용한 최적 침출 조건을 조사하였다. 특히, 침출 시간, 온도, HCl 용액의 몰농도 및 공급 가스의 종류가 Ti 내 O 농도와 Mg, Ti 및 철 (Fe)의 침출 거동에 미치는 영향을 조사하였다. 아르곤 (Ar) 가스를 버블링하며 313 K에서 HCl 침출을 수행한 결과, Ti 내 O 농도는 0.168 mass%였으며, Ti과 Fe의 침출률은 각각 1.01 %와 43.84 %를 나타냈다. 결과적으로, off-grade Ti 스폰지의 탈산 후 Ti 혼합물의 HCl 침출 최적화를 통해 Ti 손실 및 O에 의한 오염을 최소화하였고, 저산소 Ti의 회수가 가능함을 입증하였다.

키워드
타이타늄
재활용
탈산
염산 침출
산소 농도
References
1

Kroll, W., 1940. US. 2,205,854.

10.1136/bmj.2.4171.854
2

Kroll, W., 1940 : The production of ductile titanium. Trans. Electrochem. Soc. 78(1), pp.35-47.

10.1149/1.3071290
3

Earlam, M. R., 2020 : Ch. 6 The Kroll process and production of titanium sponge, pp.97-112, Extractive metallurgy of titanium - Conventional and recent advances in extraction and production of titanium metal, Ed. by Fang, Z. Z., Froes, F. H. and Zhang, Y., Elsevier Inc., Amsterdam, Netherlands.

10.1016/B978-0-12-817200-1.00006-5
4

Takeda, O., Ouchi, T. and Okabe, T. H., 2020 : Recent progress in titanium extraction and recycling, Metall. Mater. Trans. B, 51, pp.1315-1328.

10.1007/s11663-020-01898-6
5

Okabe, T. H. and Takeda, O., 2020 : Ch. 5 Fundamentals of thermochemical reduction of TiCl4, pp.65-95, Extractive metallurgy of titanium - Conventional and recent advances in extraction and production of titanium metal, Ed. by Fang, Z. Z., Froes, F. H. and Zhang, Y., Elsevier Inc., Amsterdam, Netherlands.

10.1016/B978-0-12-817200-1.00005-3
6

Xia, Y., Lefler, H. D., Fang, Z. Z., et al., 2020 : Ch. 17 Energy consumption of the Kroll and HAMR processes for titanium production, pp.389-410, Extractive metallurgy of titanium–Conventional and recent advances in extraction and production of titanium metal, Ed. by Fang, Z. Z., Froes, F. H. and Zhang, Y., Elsevier Inc., Amsterdam, Netherlands.

10.1016/B978-0-12-817200-1.00017-X
7

Marui, Y., Kinoshita, T. and Takahashi, K., 2002 : Development of a titanium material by utilizing off-grade titanium sponge, Honda R&D Tech. Rev., 14(1), pp.149-156.

10.4271/2002-32-1816
8

Sohn, H., 2021 : Current status of titanium recycling technology, Resour. Recycl., 30(1), pp.26-34. (in Korean)

10.7844/kirr.2021.30.1.26
9

ASTM International, 2020 : Standard specification for titanium and titanium alloy strip, sheet, and plate, ASTM B265-20, ASTM International, West Conshohocken, PA, United States.

10

Li, C. L., Narayana, P. L., Reddy, N. S., et al., 2019 : Modeling hot deformation behavior of low-cost Ti-2Al-9.2Mo-2Fe beta titanium alloy using a deep neural network, J. Mater. Sci. Technol., 35(5), pp.907-916.

10.1016/j.jmst.2018.11.018
11

Lütjering, G. and Williams, J. C., 2007 : Titanium – Engineering materials and processes, pp.23-28, 2nd Edition. Springer Berlin, Heidelberg.

12

Fisher, R. L., 1990. US. 4,923,531.

10.1103/PhysRevLett.65.923
13

Okabe, T. H., Suzuki, R. O., Oishi, T., et al., 1991 : Thermodynamic properties of dilute titanium-oxygen solid solution in beta phase, Mater. Trans. JIM, 32(5), pp.485-488.

10.2320/matertrans1989.32.485
14

Cho, G. H., Kim, T., Chae, J., et al., 2020 : Preparing low-oxygen titanium powder by calcium reductant from titanium hydride, Adv. Powder. Technol., 31, pp.3774-3780.

10.1016/j.apt.2020.07.020
15

Oh, J. M., Roh, K. M., Lee, B. K., et al., 2014 : Preparation of low oxygen content alloy powder from Ti binary alloy scrap by hydrogenation-dehydrogenation and deoxidation process, J. Alloys Compd., 593, pp.61-66.

10.1016/j.jallcom.2014.01.033
16

Roh, K. M., Suh, C. Y., Oh, J. M., et al., 2014 : Comparison of deoxidation capability for preparation of low oxygen content powder from TiNi alloy scraps, Powder Technol., 253, pp.266-269.

10.1016/j.powtec.2013.10.028
17

Okabe, T. H., Oishi, T. and Ono, K., 1992 : Preparation and characterization of extra-low-oxygen titanium, J. Alloys Compd., 184, pp.43-56.

10.1016/0925-8388(92)90454-H
18

Xia, Y., Fang, Z. Z., Sun, P., et al., 2017 : The effect of molten salt on oxygen removal from titanium and its alloys using calcium, J. Mater. Sci., 52, pp.4120-4128.

10.1007/s10853-016-0674-1
19

Suzuki, R. O. and Inoue, S., 2003 : Calciothermic reduction of titanium oxide in molten CaCl2, Metall. Mater. Trans. B, 34, pp.277-285.

10.1007/s11663-003-0073-2
20

Xia, Y., Fang, Z. Z., Fan, D., et al., 2018 : Hydrogen enhanced thermodynamic properties and kinetics of calciothermic deoxygenation of titanium-oxygen solid solutions, Int. J. Hydr. Energy., 43(27), pp.11939-11951.

10.1016/j.ijhydene.2018.03.170
21

Li, B., Hou, G., Jin, H., et al., 2021 : The deep deoxygenation behavior of fine hydrogenated Ti alloy powders, JOM, 73(4), pp.1188-1195.

10.1007/s11837-021-04571-8
22

Park, S., Kang, J. and Sohn, H., 2024 : Investigation of calciothermic reduction of TiO2 for the green production of Ti and TiH2 powders, Korean J. Met. Mater., 62(3), pp.190-203. (in Korean)

10.3365/KJMM.2024.62.3.190
23

Yoon, M. W. and Sohn H., 2013 : Deoxidation of titanium scrap by calciothermic reduction, J. of Korean Inst. of Resources Recycling, 22(6), pp.41-47. (in Korean)

10.7844/kirr.2013.22.6.41
24

Hong, C. I. and Lim, J. W., 2018 : Efficacy of acid cleaning on the deoxidation of titanium powder using calcium, Korean J. Met. Mater., 56(3), pp.205-209.

10.3365/KJMM.2018.56.3.205
25

Zhang, Y., Fang, Z. Z., Sun, P., et al., 2016 : Thermodynamic destabilization of Ti - O solid solution by H2 and deoxygenation of Ti using Mg. J. Am. Chem. Soc., 138, pp.6916-6919.

10.1021/jacs.6b00845
26

Xia, Y., Fang, Z. Z., Zhang, Y., et al., 2017 : Hydrogen assisted magnesiothermic reduction (HAMR) of commercial TiO2 to produce titanium powder with controlled morphology and particle size, Mater. Trans., 58(3), pp.355-360.

10.2320/matertrans.MK201628
27

Dong, Z., Xia, Y., Guo, X., et al., 2020 : Direct reduction of upgraded titania slag by magnesium for making low-oxygen containing titanium alloy hydride powder, Powder Technol., 368, pp.160-169.

10.1016/j.powtec.2020.04.050
28

Zheng, C., Ouchi, T., Iizuka, A., et al., 2019 : Deoxidation of titanium using Mg as deoxidant in MgCl2 - YCl3 flux, Metall. Mater. Trans. B, 50, pp.622-631.

10.1007/s11663-018-1494-2
29

Jung, J. H., Lee, S. Y., Park, S. H., et al., 2021 : Deoxidation of off-grade Ti scrap by molten Mg in YCl3 - MgCl2 molten malt, Resour. Recycl., 30(2), pp.46-52. (in Korean)

10.7844/kirr.2021.30.2.46
30

Kong, L., Ouchi, T. and Okabe, T. H., 2019 : Direct deoxidation of Ti by Mg in MgCl2 − HoCl3 flux, Mater. Trans., 60(9), pp.2059-2068.

10.2320/matertrans.MT-M2019135
31

Tanaka, T., Ouchi, T. and Okabe, T. H., 2020 : Magnesiothermic reduction of TiO2 assisted by LaCl3, J. Sustain. Metall., 6, pp.667-679.

10.1007/s40831-020-00296-1
32

Lim, K. H., Jeoung, H. J., Lee, T. H., et al., 2022 : Deoxidation of off-grade titanium sponge using magnesium metal in argon and hydrogen mixed gas atmosphere, Metall. Mater. Trans. B, 53, pp.220-231.

10.1007/s11663-021-02358-5
33

Park, S. H., Lim, K. H., Na, H., et al., 2023 : Scale-up study of deoxidation of off-grade titanium sponge using magnesium metal under argon and hydrogen mixed gas atmosphere, J. Sustain. Metall., 9, pp.497-510.

10.1007/s40831-023-00662-9
34

Park, S. H., Jeoung, H. J., Lee, T. H., et al., 2024 : Development of deoxidation process for off-grade titanium sponge using magnesium metal with wire mesh strainer type of crucible, Sci. Rep., 14, 542.

10.1038/s41598-023-50765-238177401PMC10766949
35

Park, S. -H., Oh, J., Song, Y., et al., 2025 : Direct TiH2 powder production by the reduction of TiO2 using Mg in Ar and H2 mixed gas atmosphere, Sci. Rep., 15, 1818.

10.1038/s41598-024-84433-w39805950PMC11729853
36

Song, Y., Park, S. -H. and Kang, J. 2025 : Direct production of TiH2 powder with 0.21 mass%O from TiO2 using magnesiothermic reduction in high hydrogen chemical potential, Sustain. Mater. Technol., 45, e01540.

10.1016/j.susmat.2025.e01540
37

Kong, L., Ouchi, T. and Okabe, T. H., 2021 : Deoxidation of Ti using Ho in HoCl3 flux and determination of thermodynamic data of HoOCl, J. Alloys Compd., 863, 156047.

10.1016/j.jallcom.2020.156047
38

Tanaka, T., Ouchi, T. and Okabe, T. H., 2020 : Lanthanothermic reduction of TiO2, Metall. Mater. Trans. B, 51, pp.1485-1494.

10.1007/s11663-020-01860-6
39

Tanaka, T., Ouchi, T. and Okabe, T. H., 2020 : Yttriothermic reduction of TiO2 in molten salts, Mater. Trans., 61(10), pp.1967-1973.

10.2320/matertrans.MT-M2020123
40

Iizuka, A., Ouchi, T. and Okabe, T. H., 2020 : Development of a new titanium powder sintering process with deoxidation reaction using yttrium metal, Mater. Trans. 61(4), pp.758-765.

10.2320/matertrans.MT-M2019340
41

Ouchi, T., Akaishi, K., Kamimura, G., et al., 2023 : Direct oxygen removal from titanium by utilizing vapor of rare earth metals, Mater. Trans., 64(1), pp.61-70.

10.2320/matertrans.MT-MLA2022022
42

Kamimura, G., Ouchi, T. and Okabe, T. H., 2022 : Deoxidation of titanium using cerium-chloride flux for upgrade recycling of titanium scraps, Mater. Trans., 63(6), pp.893-902.

10.2320/matertrans.M-M2022805
43

Iizuka, A., Ouchi, T. and Okabe, T. H., 2022 : New deoxidation method of titanium using metal filter in molten salt, Metall. Mater. Trans. B, 53, pp.1371-1382.

10.1007/s11663-021-02400-6
44

Kamimura, G., Akaishi, K., Ouchi, T., et al., 2024 : Deoxidation of titanium utilizing thulium and halide flux, J. Sustain. Metall., 10, pp.2588-2600.

10.1007/s40831-024-00893-4
45

Ouchi, T., Akaishi, K., Kamimura, G., et al., 2024 : Deoxidation of titanium using ytterbium-halide-flux method, J. MMIJ, 140(11), pp.157-169.

10.2473/journalofmmij.MMIJ-2024-007
46

Okabe, T. H., Kamimura, G. and Ouchi, T., 2024 : Thermodynamic consideration of the direct removal of oxygen from titanium by utilizing metallothermic reduction of rare earth metal halides, Metall. Mater. Trans. B, 55, pp.4015-4026.

10.1007/s11663-024-03118-x
47

Kamimura, G., Ouchi, T. and Okabe, T. H., 2025 : Thermodynamic consideration on the deoxidation of liquid titanium using a rare-earth element and fluoride flux, JOM.

10.1007/s11837-024-07022-2
48

Okabe, T. H., Kamimura, G., Ikeda, T., et al., 2024 : Direct production of low-oxygen-concentration titanium from molten titanium, Nat. Commun., 15, 5015.

10.1038/s41467-024-49085-438866754PMC11169373
49

Chen, G. Z., Fray, D. J. and Farthing, T. W., 2000 : Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride, Nature, 407, pp.361-364.

10.1038/35030069
50

Chen, G. Z., Fray, D. J. and Farthing, T. W., 2001 : Cathodic deoxygenation of the alpha case on titanium and alloys in molten calcium chloride, Metall. Mater. Trans. B, 32, pp.1041-1052.

10.1007/s11663-001-0093-8
51

Tripathy, P. K., Gauthier, M. and Fray, D. J., 2007 : Electrochemical deoxidation of titanium foam in molten calcium chloride, Metall. Mater. Trans. B, 32, pp.893-900.

10.1007/s11663-007-9094-6
52

Sarkar, S., Free, M. L., Benedict, J., et al., 2020 : Factors affecting the leaching mechanism of Mg bearing oxide impurities in hydrogen assisted magnesiothermic reduction (HAMR) of TiO2, Mater. Today Chem., 16, 100259.

10.1016/j.mtchem.2020.100259
53

Choi, S. H., Sim, J. J., Lim, J. H., et al., 2019 : Removal of Mg and MgO by-products through magnesiothermic reduction of Ti powder in self-propagating high-temperature synthesis, Metals, 9(2), 169.

10.3390/met9020169
54

Suzuki, R. O., Ikezawa, M., Okabe, T. H., et al., 1990 : Preparation of TiAl and Ti3Al powders by calciothermic reduction of oxides, Mater. Trans. JIM, 31(1), pp.61-68.

10.2320/matertrans1989.31.61
55

Na, H., Yoo, K., Jeon, H. S., et al., 2022 : Leaching of copper from cementation precipitate in sulfuric acid solution with cupric ion and oxygen, Mater. Trans., 63(4), pp.607-611.

10.2320/matertrans.M-M2021855
56

ASTM International, 2018 : Standard specification for titanium sponge, ASTM B299M-18, ASTM International, West Conshohocken, PA, United States.

57

Cho, J., Roy, S., Sathyapalan, A., et al., 2016 : Purification of reduced upgraded titania slag by iron removal using mild acids, Hydrometallurgy, 161, pp.7-13.

10.1016/j.hydromet.2016.01.014
58

Zhang, Y., Fang, Z. Z., Xu, L., et al., 2018 : Mitigation of the surface oxidation of titanium by hydrogen, J. Phys. Chem. C, 122(36), pp.20691-20700.

10.1021/acs.jpcc.8b04684
59

HSC Chemistry Software ver. 7.11, 2011 : Reaction Equations Module, Outokumpu Research Oy, Pori, Finland.

60

Taxiarchou, M., Panias, D., Douni, I., et al., 1997 : Removal of iron from silica sand by leaching with oxalic acid, Hydrometallurgy, 46(1-2), pp.215-227.

10.1016/S0304-386X(97)00015-7
61

Panias, D., Taxiarchou, M., Paspaliaris, I., et al., 1996 : Mechanisms of dissolution of iron oxides in aqueous oxalic acid solutions, Hydrometallurgy, 42(2), pp.257-265.

10.1016/0304-386X(95)00104-O
62

Zhong, X., Yu, S., Hu, J., et al., 2017 : Corrosion electrochemical behaviors of titanium in HCl-acidizing fluid used in natural gas exploitation, Int. J. Electrochem. Sci., 12(4), pp.2875-2892.

10.20964/2017.04.26
Information
  • Publisher :The Korean Institute of Resources Recycling
  • Publisher(Ko) :한국자원리싸이클링학회
  • Journal Title :Resources Recycling
  • Journal Title(Ko) :자원리싸이클링
  • Volume : 35
  • No :1
  • Pages :29-42
  • Received Date : 2025-08-20
  • Revised Date : 2025-12-20
  • Accepted Date : 2025-12-22
  • DOI :https://doi.org/10.7844/kirr.2026.35.1.29
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