A. A. Baikov Institute of Metallurgy and Materials Science, Moscow, Russia:

K. V. Goncharov, Researcher, e-mail: goncharov-imet@mail.ru
K. G. Anisonyan, Researcher
D. Yu. Kop'jov, Researcher
G. B. Sadykhov, Head of Laboratory

All investigations were carried out on vanadate solutions with 20–35 g/l of V₂O₅ and pH = 2.5, produced during the leaching of annealed vanadium slag with limestone addition. There is shown the principal possibility of obtaining of pure vanadium pentaoxide from sulfuric acid vanadate solutions due to their preliminary deep purification from manganese and other impurities by processing with ammonium carbonate. Addition of ammonium carbonate makes possible not only the vanadium binding in ammonium vanadate, but also the manganese and calcium isolation in sediment in carbonate form. There was investigated the influence of concentration of vanadate solution and process temperature on the grade of solution purification from impurities. There was described the chemism of the process of ammonium carbonate solution interaction with calcium and manganese vanadates in sulfuric acid medium. On the first stage, the solution is neutralized, which leads to the sharp growth of pH to 7 and to intensive sedimentation of manganese and calcium carbonates. On the third stage, during the increasing of ammonium carbonate consumption, the impurities' sedimentation is almost completely finished, and solution pH increases up to 8 and higher (because of ammonia excess). At the same time, vanadium is in solution in the form of ammonium vanadates. Increasing of V₂O₅ concentration in solution from 20 to 35 g/l leads to some worsening of the results of solution purification, because the manganese sedimentation grade is decreased up to 94.2%, and vanadium losses are increased to 2.2%. The temperature, suitable for the solution purification is in the range of 25–35 ^oC. Temperature increasing to 40–50 oC leads to complete sedimentation of manganese (99.3–99.99%), but, at the same time, vanadium losses are significantly increased (up to 7.5–13.4%), which, probably, is connected with the process of secondary formation of less-soluble manganesium methavanadate. The set optimal conditions allow the almost complete (>97.7%) purification of the solution from manganese. At the same time, vanadium losses with sediment are ~1.6%.
This scientific work was carried out with the support of the Russian Foundation for Basic Research No.26 16-3301124\16.

1. Kagawa A. Absorption of hydrogen by vanadium-titanium alloys. Reports of the Faculty of Engineering. Nagasaki University. 1995. Vol. 25, No. 45. pp. 233–239.
2. Yamamoto Y., Miyachi M., Yamanoi Y., Minoda A. et al. Synthesis of vanadium-doped palladium nanoparticles for hydrogen storage materials. Journal of Nanoparticle Research. 2011. Vol. 13, No. 12. pp. 6333–6338.
3. Zhevago N. K., Glebov V. I., Denisov E. I. et al. Micro-capillary reservoirs for hydrogen storage. Alternativnaya energetika i ekologiya. 2012. No. 9 (113). pp. 106–115.
4. Kear G., Shah A. A., Walsh F. C. Development of the all-vanadium redox flow battery for energy storage: a review of technological, financial and policy aspects. International Journal of Energy Research. 2012. Vol. 36, No. 11. pp. 1105–1120.
5. Jacques С. Lower-cost Flow Batteries to create $190 Million Energy Storage Market in 2020. Lux Research. Available at: http://www.luxresearchinc.com/news-and-events/press-releases/read/lower-cost-flow-batteries-create-190-million-energy-storage
6. Vanadium. U. S. Geological Survey, Mineral Commodity Summaries. Available at : http://minerals.usgs.gov/minerals/pubs/commodity/vanadium/mcs-2015-vanad.pdf
7. Deryabin Yu. A., Smirnov L. A., Deryabin A. A. Prospects of processing of Chineiskiy massif titanium magnetites. Ekaterinburg : Sredne-Uralskoe knizhnoe izdatelstvovo, 1999. 368 p.

8. Chumarova V. I. Production of vanadium alloys abroad. General information. Chermetinformatsiya. Seriya: Ferrosplavnoe proizvodstvo. 1986. No. 2. 22 p.
9. Rohrmann B. Vanadium in South Africa. Journal of the South African Institute of Mining and Metallurgy. 1985. Vol. 85, No. 5. pp. 141–150.
10. Hall J. The Extraction of Iron and Vanadium from Titanoferous Magnetite Ore with Particucar Reference to the Contribution by the Republic of South Africa. Proceedings of International Symposium on Exploitation and Utilization of Vanadium-Bearing Titanomagnetite. Panzhihua, China, Beijing : The Metallurgical Industry Press, 1989. pp. 38–48.
11. Mizin V. G., Rabinovich E. M. Complex processing of vanadium raw materials: chemistry and technology. Ekaterinburg : UrO RAN, 2005. 416 p.
12. Technological instruction TI 127-F-01–2002. Production of technical vanadium pentoxide. Tula, 2002. 85 p.
13. Basis of metallurgy. Vol. 4. Rare metals. Moscow : Metallurgiya, 1967. pp. 128–167.
14. Strepetov S. V., Dobosh V. G., Surat L. L. Phase equillibriums in the systems: Fe₂O₃ – CaO – V₂O₅ – MnO(Mn₂O₃), CaO – V₂O₅ – SiO₂ – MnO(Mn₂O₃) and TiO₂ – V₂O₅ – MnO(Mn₂O₃). Thesis of reports of the V All-Union meeting on chemistry, technology and usage of vanadium compounds. Chusovoy, 9–11 June 1987. Part II. Sverdlovsk, 1987. p. 48.
15. Krasheninin A. G., Khalezov B. D., Vatolin N. A., Bornovolokov A. S. Technology of complex processing of vanadium-containing converter slags with extraction of vanadium pentoxide of increased purity and manganese oxides. Tsvetnye Metally. 2013. No. 12. pp. 70–74.
16. Sadykhov G. B., Lyakishev N. P., Reznichenko V. A., Goncharenko T. V., Petrova V. A., Dyudina S. Yu. Obtaining of pure V₂O₅ during the processing of vanadium slags according to lime sulfuric acid technology. Thesis of reports of the XVII Mendeleev meeting of general and applied chemistry. Volume 3. Materials and nanotechnologies. Kazan, 21–26 September 2003. Kazan, 2003. p. 372.
17. Sadykhov G. B., Ivanova S. Yu., Reznichenko V. A., Goncharenko T. V., Petrova V. A. Obtaining of pure V₂O₅ on different stages of processing of vanadium slags by lime sulfuric acid technology. Thesis of reports of the IX All-Russian conference “Chemistry, technology and usage of vanadium”. Tula : Tulachermet, 2004. pp. 87, 88.
18. Vatolin N. A., Moleva N. G., Volkova P. I. et al. Oxidation of vanadium slags. Moscow : Nauka, 1978. 150 p.