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ArticleName Calcium thermic production of rare metal and intermetallic powders
DOI 10.17580/tsm.2021.01.05
ArticleAuthor Kasimtsev A. V., Levinskiy Yu. V., Yudin S. N.

Metsintez LLC, Tula, Russia:

A. V. Kasimtsev, Director, Doctor of Technical Sciences, e-mail:
S. N. Yudin, Head of the Production Control Office, Candidate of Technical Sciences, e-mail:

Merzhanov Institute of Structural Macrokinetics and Materials Science of the Russian Academy of Sciences, Chernogolovka, Russia:

Yu. V. Levinskiy, Lead Researcher, Laboratory of Physical Stimulation of Physico-Chemical Processes, Doctor of Technical Sciences, Professor, email:


This paper analyzes the thermodynamic and kinetic environment for calcium thermic production of rare metal and intermetallic powders and the status of this method among other thermal reduction methods. The discussion of thermodynamic processes focuses on gas phase equilibrium. A close consideration is given not only to binary metal-calcium systems but also to three- and multi-component systems. The role of such auxiliary substances as calcium hydride and calcium chloride is discussed. It is shown that, when the final product includes intermetallides of rare metals, calcium can even be used for the reduction of oxides of metals that are more sensitive to oxygen than calcium. There are cases when the presence of calcium chloride during reduction leads to a lower equilibrium content of oxygen in the reduced rare metal than during calcium reduction. The paper describes thermal reduction flow charts and the process equipment. This review is meant for Russian researchers and experts engaged in research and development of the calcium thermic techniques for powder metal and alloy production.

keywords Calcium thermic reduction, calcium hydride reduction, powder metallurgy, intermetallic compounds, metal powders, synthesis

1. Kroll W. J. Method for Manufacturing Titanium and Alloys Thereof. US Patent. 2205854. Published 25.06.1940.
2. Kroll W. J. The production of ductile titanium. Transactions of The Electrochemical Society. Vol. 78, Iss. 1. pp. 35–47. DOI: 10.1149/1.3071290.
3. Kasimtsev A. V., Levinsky Yu. V., Yudin S. N. Calciothermic powders of rare metals and intermetallic compounds. Non-ferrous Metals. 2020. No. 2. pp. 31–50. DOI: 10.17580/nfm.2020.02.05.
4. Jacob K. T., Gupta S. Calciothermic reduction of TiO2: A diagrammatic assessment of the thermodynamic limit of deoxidation. JOM. 2009. Vol. 61, Iss. 5. pp. 56–59. DOI: 10.1007/s11837-009-0072-0.
5. Kasimtsev A. V., Levinsky Yu. V. Calcium-Hydride Powders of Metals, Intermetallic Compounds, refractory compounds and composite materials. Moscow : MITKhT, 2012. 247 p.
6. Meerson G. A., Katz G. A., Khokhlova A. V. Reduction of refractory metals oxides with calcium hydride. Zhurnal Neorganicheskoy i Prikladnoy Khimii. 1940. Vol. 13, No. 12. pp. 1770–1776.
7. Chen G. Z., Fray D. J., Farthing T. W. Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride. Nature. 2000. Vol. 407, Iss. 6802. pp. 361–364. DOI: 10.1038/35030069.
8. Jiang K., Hu X., Ma M. et al. “Perovskitization”-assisted electrochemical reduction of solid TiO2 in molten CaCl2. Angewandte Chemie. 2006. Vol. 118, Iss. 3. pp. 442–446. DOI: 10.1002/anie.200502318.
9. Schwandt C., Doughty G. R., Fray D. J. The FFC-Cambridge process for titanium metal winning. Key Engineering Materials. 2010. Vol. 436. pp. 13–25. DOI: 10.4028/
10. Katsutoshi Ono, Ryosuke O. Suzuki. A new concept for producing Ti sponge: Calciothermic reduction. JOM. 2002. Vol. 54, Iss. 2. pp. 59–61. DOI: 10.1007/BF02701078.
11. Katsutoshi Ono. Fundamental aspects of calciothermic process to produce titanium. Materials Transactions. 2004. Vol. 45, Iss. 5, pp. 1660–1664. DOI: 10.2320/matertrans.45.1660.
12. Moxson V. S., Senkov O. N., Froes F. H. Innovations in titanium powder processing. JOM. 2000. Vol. 52, Iss. 5. pp. 24–26. DOI: 10.1007/s11837-000-0027-y.
13. He-Li Wan, Bao-Qiang Xu, Yong-Nian Dai et al. Preparation of titanium powders by calciothermic reduction of titanium dioxide. Journal of Central South University. 2012 Vol. 19, Iss. 9. pp. 2434–2439. DOI: 10.1007/s11771-012-1293-x.
14. Okabe T. H., Sadoway D. R. Metallothermic reduction as an electronically mediated reaction. Journal of Materials Research. 1998. Vol. 13, Iss. 12. pp. 3372–3377. DOI: 10.1557/jmr.1998.0459.
15. Okabe T. H., Uda T. Reduction process of titanium oxide using molten salt. Titanium Japan. 2002. Vol. 50. No 4. pp. 325–330.
16. Bayat O., Khavandi A. R., Ghasemzadeh R. Effect of blend granulometry on calciothermic reduction of TiO2. International Journal of Self-Propagating High-Temperature Synthesis. 2012. Vol. 21, Iss. 3. pp. 151–155. DOI: 10.3103/s1061386212030028.
17. Okabe T. H., Oda T., Mitsuda Y. Titanium powder production by preform reduction process (PRP). Journal of Alloys and Compounds. 2004. Vol. 364, Iss. 1-2. pp. 156–163. DOI: 10.1016/s0925-8388(03)00610-8.
18. Suzuki R. O., Ikezawa M., Okabe T. H., Oishi T., Ono K. Preparation of TiAl and Ti3Al powders by calciothermic reduction of oxides. Materials Transactions, JIM. 1990. Vol. 31, Iss. 1. pp. 61–68. DOI: 10.2320/matertrans1989.31.61.
19. Yamaguchi K., Kim D.-Y., Ohtsuka M., Itagaki K. Heat content and heat of formation measurements of RNi5 ± x alloys (R  La, Ce, Pr or Nd) and heat balance in a reduction-diffusion process. Journal of Alloys and Compounds. 1995. Vol. 221, Iss. 1-2. pp. 161–168. DOI: 10.1016/0925-8388(94)01422-1.
20. Tanabe T., Takahashi K., Yoshida H., Asaki Z. Formation of LaNi5 by Reduction-Diffusion Process with CaH2. Materials Transactions, JIM. 1994. Vol. 35, Iss. 8. pp. 516–521. DOI: 10.2320/matertrans1989.35.516.

21. Tanabe T., Nagai Y., Kubota T., Asaki Z. Formation of Sm–Fe intermetallic compounds by the reduction-diffusion process with CaH2. Materials Transactions, JIM. 1992. Vol. 33, Iss. 12. pp. 1163–1170. DOI: 10.2320/matertrans1989.33.1163.
22. Suzuki R.O., Inoue S. Calciothermic reduction of titanium oxide in molten CaCl2. Metallurgical and Materials Transactions: B. 2003. Vol. 34, Iss. 3. pp. 277–285. DOI: 10.1007/s11663-003-0073-2.
23. Liu S. F., Lin J. H., Qian X. L., Bayi J. M., Su M. Z. Synthesis of NdFe10Mo2 by a reduction-diffusion process. Chemistry of Materials. 1996. Vol. 8, Iss. 11. pp. 2545–2547. DOI: 10.1021/cm950513i.
24. Mukherjee T. K., Kamat G. R., Gupta C. K. Preparation of columbium metal by calcium hydride reduction of columbium pentoxide. JOM. 1970. Vol. 22, Iss. 2. pp. 50–53. DOI: 10.1007/bf03355939.
25. Li Z., Yasuda K., Itagaki K. Calciothermic reduction of mischmetal oxide and formation of RmNi5. Journal of Alloys and Compounds. 1993. Vol. 193, Iss. 1-2. pp. 26–28. DOI: 10.1016/0925-8388(93)90299-3.
26. Ilayaraja M., Berchmans L. J., Sankaranarayanan S. R. Preparation of rare earth – transition metal (RE: Y, Tm: Co) intermetallic compounds by calciothermic reduction diffusion process. Metallurgical and Materials Engineering. 2014. Vol. 20, Iss. 1. pp. 35–40. DOI: 10.5937/metmateng1401035i.
27. Guilherme E. da G., Hechenberg H. R., Pascoal J. O. A. Reduction-diffusion preparation of Nd15Fe77B8, NdFe11Ti, NdFe10.5Mo1.5 and NdFe10.75Mo1.25 alloys for magnets. Materials Science Forum. 2006. Vol. 530–531. pp. 181–186. DOI: 10.4028/
28. Chen C.-Q., Kim D., Choi C. Influence of Ca amount on the synthesis of Nd2Fe14B particles in reduction-diffusion process. Journal of Magnetism and Magnetic Materials. 2014. Vol. 355. pp. 180–183. DOI: 10.1016/j.jmmm.2013.12.023.
29. Ilayaraja M., Berchmans L. J., Sankaranarayanan S. R. Synthesis of Y – Ni alloy by calciothermic reduction diffusion process. Metallurgical and Materials Engineering. 2015. Vol. 21, Iss. 2 pp. 65–72. DOI: 10.30544/96.
30. Chen H.-B., Zheng J.-W., Qiao L. et al. Preparation of Sm2Fe17 alloy by reduction-diffusion process. Rare Metals. 2015. Vol. 37, Iss. 11. pp. 989–994. DOI: 10.1007/s12598-015-0584-4.
31. Travessini D., Favero T. A. C., Teixeira C. S., Wendhausen P. A. P. The Effect of Si on the Formation of the La(Fe, Si)13 Phase Synthesized by the Reduction-Diffusion (R/D) Process. IEEE Transactions on Magnetics. 2013. Vol. 49, Iss. 8. pp. 4634–4637. DOI: 10.1109/tmag.2013.2258141.
32. Deng G., Jing Q., Wang X., He G., Ye X. Synthesis mechanism of Sm2Fe17 alloy produced in reduction-diffusion process. Journal of Rare Earths. 2010. Vol. 28. pp. 420–424. DOI: 10.1016/s1002-0721(10)60357-2.
33. Dzneladze Zh. I., Shchegoleva R. P., Golubeva L. S. et al. Powder Metallurgy of Steels and Alloys. Moscow : Metallurgiya, 1978. 264 p.
34. Meerson G. A., Kolchin O. P. Calcium hydride reduction of chemically stable oxides: The physico-chemical basis. Сollected Scientific Papers of the Moscow Institute of Nonferrous Metals and Gold named after M. I. Kalinin. Moscow : Metallurgizdat, 1955. No. 25. pp. 195–208.
35. Levinsky Yu. V. Phase diagrams of metals with gases. Moscow : Metallurgiya, 1975. 296 p.
36. Levinsky Yu. V. Pressure dependent phase diagrams of binary alloys. Vol. 1. ASM. Materials Park, OH 44073. 1997. 920 p.
37. Levinsky Yu. V. P-T-x phase diagrams of binary systems. Moscow : Metallurgiya, 1982. 111 p.
38. Kasimtsev A. V., Zhigunov V. V. Phase and structural transformations during the production of intermetallic powders. Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsionalnye Pokrytiya. 2009. No. 3. pp. 5–12.
39. Doronin N. A. Calcium. Мoscow : Gosatomizdat, 1962. 192 p.
40. Bayat O., Khavandi A. R., Ghasemzadeh R. Calciothermic co-reduction of TiO2–Cr2O3 oxides in molten CaCl2: Effect of particle size of starting materials. Russian Journal of Non-Ferrous Metals. 2012. Vol. 53, Iss. 6. pp. 476–482. DOI: 10.3103/s1067821212060028.
41. Byun J.-Y., Kim Y.-S., Shim J.-D. Effects of Ca and CaCl2 amounts in preparation of Nd – Fe alloys using NdF3 – Ca – CaCl2 – Fe reaction system. Shigen-to-Sozai. 1994. Vol. 110, Iss. 15. pp. 1203–1208. DOI: 10.2473/shigentosozai.110.1203.
42. Suzuki R. O., Aizawa M., Ono K. Calcium-deoxidation of niobium and titanium in Ca-saturated CaCl2 molten salt. Journal of Alloys and Compounds. 1999. Vol. 288, Iss. 1-2. pp. 173–182. DOI: 10.1016/s0925-8388(99)00116-4.
43. Xu B., Yang B., Jia J. et al. Behavior of calcium chloride in reduction process of titanium dioxide by calcium vapor. Journal of Alloys and Compounds. 2013. Vol. 576. pp. 208–214. DOI: 10.1016/j.jallcom.2013.04.107.
44. Suzuki R. O., Ueki T., Ikezawa M. et al. A fundamental study on preparation of Al3Ti powders by calciothermic reduction of oxides. Materials Transactions, JIM. 1991. Vol. 32, Iss. 3. pp. 272–277. DOI: 10.2320/matertrans1989.32.272.
45. Ono K., Okabe T. H., Ogawa M., Suzuki R. O. Production of titanium powders by the calciothermic reduction of TiO2. Tetsu-to-Hagane. 1990. Vol. 76, Iss. 4. pp. 568–575. DOI: 10.2355/tetsutohagane1955.76.4_568.
46. Levinsky Yu. V., Lebedev M. P. Theoretical bases of metal powder sintering processes. Moscow : Nauchnyi Mir, 2014. 372 p.
47. Geguzin Ya. E. Physics of Sintering. 2nd ed. Moscow : Nauka, 1984. 311 p.
48. Lindemann I., Herrich M., Gebel B. et al. Synthesis of spherical nanocrystalline titanium hydride powder via calciothermic low temperature reduction. Scripta Materialia. 2017. Vol. 130. pp. 256–259. DOI: 10.1016/j.scriptamat.2016.11.018.
49. Frau D. J. Emerging molten salt technologies for metals production. JOM. 2001. Vol. 53. pp. 27–31.
50. Kamali A. R., Aboutalebi M. R., Farhang M. R. A low-temperature combustion synthesis process for production of Ti from TiO2. International Journal of Self-Propagating High-Temperature Synthesis. 2008. Vol. 17, Iss. 4. pp. 233–236. DOI: 10.3103/S1061386208040055.
51. Oh J.-M., Lee B.-K., Suh C.-Y. et al. Preparation method of Ti powder with oxygen concentration of <1000 ppm using Ca. Powder Metallurgy. 2012. Vol. 55, Iss. 5. pp. 402–404. DOI: 10.1179/1743290112y.0000000013.
52. Oh J.-M., Kwon H., Ki W., Lim J.-W. Oxygen behavior during non-contact deoxidation of titanium powder using calcium vapor. Thin Solid Films. 2014. Vol. 551. pp. 98–101. DOI: 10.1016/j.tsf.2013.11.076.
53. Mukherjee A., Awasthi A., Krishnamurthy N. Studies on calcium reduction of yttrium fluoride. Mineral Processing and Extractive Metallurgy. 2016. Vol. 125, Iss. 1. pp. 26–31. DOI: 10.1179/1743285515y.0000000017.
54. Niiyama H., Tajima Y., Tsukihashi F., Sano N. Deoxidation equilibrium of solid titanium, zirconium and niobium with calcium. Journal of the Less Common Metals. 1991. Vol. 169, Iss. 2. pp. 209–216. DOI: 10.1016/0022-5088(91)90069-g.
55. Bertheville B., Bidaux J.-E. Enhanced powder sintering of near-equiatomic NiTi shape-memory alloys using Ca reductant vapor. Journal of Alloys and Compounds. 2005. Vol. 387, Iss. 1-2. p. 211–216. DOI: 10.1016/j.jallcom.2004.06.079.
56. Kasimtsev A. V., Shuitsev A. V., Yudin S. N., Levinskiy Yu. V., Sviridova T. A., Alpatov A. V., Novosvetlova E. E. Calcium hydride synthesis of powder alloys on the basis of Ti – Nb. Metally. 2017. No. 5. pp. 52–63.
57. Kasimtsev A. V., Yudin S. N., Logacheva A. I., Sviridova T. A. Properties of Nb3Al produced by calcium hydride method. Neorganicheskiye Materialy. 2015. Vol. 51, No. 1. pp. 49–56.
58. Kim C. W., Kim Y. H., Cha H. G., Kang Y. S. Study on synthesis and magnetic properties of Nd – Fe – B alloy via reduction-diffusion process. Physica Scripta. 2007. Vol. 129. pp. 321–325. DOI: 10.1088/0031-8949/2007/t129/071.
59. Baba M., Ono Y., Suzuki R. O. Tantalum and niobium powder preparation from their oxides by calciothermic reduction in the molten CaCl2. Journal of Physics and Chemistry of Solids. 2005. Vol. 66, Iss. 2-4. pp. 466–470. DOI: 10.1016/j.jpcs.2004.06.042.
60. Cupta C. K., Krishramurthy N. Oxide reduction processes in the preparation of rare-earth metals. Minerals and Metallurgical Processing. 2013. Vol. 30, No. 1. pp. 38–44.

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