National Polytechnic University of Armenia (Erevan, Armenia):

V. A. Martirosyan, Dr. Eng., Prof., Department of General Chemistry and Chemical Processes, e-mail: v.a.martirosyan@mail.ru
E. G. Zakaryan, Applicant of the Department of Materials Science and Metallurgy, e-mail: edgarzakaryan@yandex.ru
M. E. Sasuntsyan, Cand. Eng., Associate Prof., Department of General Chemistry and Chemical Processes, e-mail: msasuntsyan@mail.ru

Behavior of MoS₂ that is part of the molybdenite concentrate is discussed during mechanical activation, and its thermal properties in an activated state are investigated. It is revealed that the regularities of molybdenite oxidation by thermal and mechanochemical activation are characterized by the same nature. Thus, when heated and ground, the crystal structure of molybdenite is decomposed up to formation of molybdenum oxide, i.e. oxidation of bivalent molybdenum (MoS₂) takes place to produce hexavalent molybdenum (MoO₃). Therefore, mechanochemistry replaces the fi ring process. This means that the chemical processes taking place during fi ring at high temperatures are similar to the processes occurring during mechanochemical grinding. But hightemperature firing is accompanied by formation of undesirable SO₂. As a result of experiments, pure, amorphous MoO₃ with a homogeneous structure is obtained. The results of the study are confi rmed by X-ray diffraction and thermogravimetrical analyses.

The study has been carried out with the financial support of the State Committee on Science and Education of the Ministry of Education and Science of the Republic of Armenia within the framework of the Armenian-Belarussian joint scientific project No. AB16-48.
The authors are grateful to colleagues from Belarus for their assistance in performing X-ray phase and derivatographic analyzes.

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