Siberian Federal University (Krasnoyarsk, Russia):

Gilmanshina T. R., Associate Professor, Candidate of Engineering Sciences, gtr1977@mail.ru
Koroleva G. A., Associate Professor, Candidate of Сhemical Sciences, gakorol47@mail.ru
Baranov V. N., Director of the Institute of Non-Ferrous Metals and Materials Science, Candidate of Engineering Sciences, Associate Professor, vnbar79@mail.ru
Kovaleva A. A., Associate Professor, Candidate of Engineering Sciences, angeli-kovaleva@yandex.ru

At present, cryptocrystalline graphite is supplied for the industry from the Kureyskoye deposit. However, the quality of casting grade graphite, produced by Krasnoyarskgrafit (Krasnoyarsk) factory, does not to the full extent comply with the up-to-date requirements. The paper introduces a mechano-thermochemical modification technology of cryptocrystalline graphite from the deposits in the Krasnoyarsk Territory, which includes the following stages: mechanoactivation of graphite and alkali metal salts, sintering of the activated mix, water leaching of graphite followed by washing, chemical modification of graphite with a mixture of acids with subsequent washing, graphite drying. The conditions of high-rate material deformation under high loads and when exposed to increasing high spot temperatures in mechanoactivation process have allowed to suppose that watersoluble salts are formed from ash components — SiO₂, Fe₂O₃, Al₂O₃. Mechanoactivation as a material treatment method cannot completely supersede sintering operation, but it permits to lower graphite and alkali metal salt mix sintering temperature to 700–750 °С and alkali metal salt consumption by 40–45 % per ton of graphite (if compared with crystalline graphite benefication technology). Application of this benefication method provides for the Kureyskoye deposit graphite ash content decrease from 15–20 to 2–4 %.

1. Tomilin V. N. Graphites and coals of Turukhansk region. Gornyi Zhurnal. 1992. No. 6–9. pp. 274–294.
2. Smirnov O. M., Krushenko G. G., Shchipko M. L., Smirnov O. O., Makhrova J. V. Beneficiation of the graphite ore from the Kureyka deposit. Obogashchenie Rud. 1999. No. 1–2. pp. 19–22.
3. Gurin I. V., Gurin V. A., Gribanov Yu. A., Kravtsov Ya. V., Bukolov A. N., Gujda V. V., Kolosenko V. V. Highpurity carbon composite materials. Problems of Atomic Science and Technology (PASТ). 2014. No. 1 (89). pp. 16–20.
4. Vasumathi N., Vijaya Kumar T. V., Ratchambhigai S., Subba Rao S., Prabhakar S., Bhaskar Raju G., Shivakumar S., Raman U. Single reagent for graphite flotation. Proceedings of the ХIII International Seminar on Mineral Processing Technology (MPT—2013). December 10–12, 2013. Bhubaneswar (India). pp. 145–153.
5. Wei Gao, Mainak Majumder, Lawrence B. Alemany, Tharangattu N. Narayanan, Miguel A. Ibarra, Bhabendra K. Pradhan, Pulickel M. Ajayan. Engineered graphite oxide materials for application in water purification. ACS Applied Materials & Interfaces. 2011. Vol. 3, Iss. 6. pp. 1821–1826.
6. Li H., Ou L., Feng Q., Chang Z. Recovery mechanisms of sericite in microcrystalline graphite flotation. Physicochemical Problems of Mineral Processing. 2015. Vol. 51, Iss. 2. pp. 387–400.
7. Lavigne M., de l’Étoile R., Pierre R. Technical Report on the Lac Knife Project, Northern Quebec, Canada. NI 43-101 Report. Project #1868. Focus Graphite Inc. October 30, 2012. URL: http://www.infomine.com/index/pr/pb268588.pdf (accessed: 17.07.2017).
8. Gilmanshina T. R., Lytkina S. I., Zhereb V. P., Koroleva G. A. Cryptocrystalline graphite chemical-mechanical preparation for subsequent processing stages. Obogashchenie Rud. 2016. No. 2 (362). pp. 14–19.
9. Gilmanshina T. R., Lytkina S. I., Khudonogov S. A., Kritskiy D. Yu. Cryptocrystalline graphite properties study following treatment by different methods. Obogashchenie Rud. 2017. No. 1 (367). pp. 15–18.
10. Shokhin V. N., Esepkin V. A., Chizhevskiy V. B., Glazkov V. A. Low-ash graphite production technology. Graphites and their use in industry: collection of research papers. Moscow, 1974. pp. 68–71.
11. Pat. 2357803 Russian Federation.
12. Pat. 2368450 Russian Federation.