Saint-Petersburg Mining University, Saint Petersburg, Russia:

M. Yu. Nazarenko, Post-Graduate Student, e-mail: max.nazarenko@mail.ru
N. K. Kondrasheva, Head of a Chair
S. N. Saltykova, Assistant Professor

According to the experts, the oil shale industry is the world’s largest industry when it comes to processing of low-grade mineral raw materials, their production and their transfer on a large scale. The mineral part of oil shale and shale ash is actually an interesting multi-purpose raw object. Its complex use (including not only its organic, but also inorganic part) will improve the efficiency of oil shale in various fields of industry. Departing from mineral and chemical composition of the inorganic portion of oil shale, conclusions were made about their possible use as a carbonaceous reducing material (the organic carbon component will act as a reducing agent, and the mineral component as a fluxing agent). Oil shale ash can be used as a fluxing agent. It is a waste, produced during the processing of oil shale, so no additional costs are required for its manufacture. The aim of this work was to determine the effect of temperature on the properties of oil shale. It was established that, regardless of the atmosphere heat treatment (air or nitrogen), the porosity of oil shale is changed in 4 steps: I — 25–200 °С; II — 200–400 °С; III — 400–600 °С; IV — 600–900 °С. The resistivity of various fractions of oil shale does not vary much, whilst it decreases when the temperature is increased, from 37.93·10⁶ to 0.17·10⁶ Ohm·cm. The results of simultaneous thermal analysis led to the conclusion that the change of oil shale mass occurs in five stages, resulting in 43.5% loss of mass in total.

1. Rudin M. G., Serebryannikov N. D. Shale processor reference book. Leningrad : Khimiya, 1988. 256 p.
2. Yudovich Ya. E. Kerosene shales of the Komi Republic. Problems of mastering. Syktyvkar : Geoprint, 2013. 90 p.
3. Smirnova T. S., Vakhidova L. M., Mirabidinov Sh. N. U., Molotov S. A. Mineral resources of Russia and nature management international experience. Vestnik Permskogo natsionalnogo issledovatelskogo politekhnicheskogo universiteta. Geologiya. Neftegazovoe i gornoe delo. 2013. No. 7. pp. 7–17.
4. Strizhakova Yu. A., Usova T. V., Tretyakov V. F. Kerosene shales — the potential raw material source for fuel-energetic and chemical industry. Vestnik MITKhT. 2006. No. 4. pp. 76–85.
5. Xia Y., Xue H., Wang H., Li Z., Fang C. Kinetics of isothermal and nonisothermal pyrolysis of oil shale. Oil shale. 2011. Vol. 28, No. 3. pp. 415–424.
6. Raado L.-M., Kuusik R., Hain T., Uibu M., Somelar P. Oil shale ash based stone formation — hydration, hardening dynamics and phase transformations. Oil shale. 2014. Vol. 31, No. 1. pp. 91–101.
7. Xie F. F., Wang Z., Lin W. G., Song W. L. Study on thermal conversion of Huadian oil shale under N₂ and CO₂ atmospheres. Oil shale. 2010. Vol. 27, No. 4. pp. 309–320.
8. Raado L.-M., Hain T., Liisma E., Kuusik R. Composition and properties of oil shale ash concrete. Oil shale. 2014. Vol. 31, No. 2. pp. 147–160.
9. Bityukova L., Motlep R., Kirismae K. Composition of oil shale ashes from pulverized firing and circulating fluidized-bed boiler in Narva thermal power plants, Estonia. Oil shale. 2010. Vol. 27, No. 4. pp. 339–353.
10. Nazarenko M. Yu., Bazhin V. Yu., Saltykova S. N., Sharikov F. Yu. Change of chemical composition and properties of kerosene shales during thermal treatment. Koks i khimiya. 2014. No. 10. pp. 46–49.
11. Nazarenko M. Yu., Kondrasheva N. K., Saltykova S. N. Investigations of products of kerosene shale pyrolysis. Koks i khimiya. 2015. No. 4. pp. 38–42.
12. Vanyukov A. V., Zaytsev V. Ya. Slags and mattes of non-ferrous metallurgy. Moscow : Metallurgiya, 1969. 408 p.
13. Bobkova N. M. Physical chemistry of refractory non-metallic and silicate materials. Minsk : Vysheyshaya shkola, 2007. 303 p.
14. Nazarenko M. Yu., Kondrasheva N. K., Saltykova S. N. Reaction ability of the surface of burning shales of Baltic basin. Koks i khimiya. 2016. No. 5. pp. 33–37.
15. State Standard GOST 4668–75. Carbonaceous materials. Method of electrical resistance definition of powder. Introduced: 1977–01–01.