St. Petersburg State Technological Institute (Technical University) (Russia):

Syroyezhko A. M., Doctor of Chemistry, Professor, syroejko@rambler.ru

REC «Mekhanobr-Tekhnika» (Russia):

Gerasimov A. M., Ph. D. in Engineering Sciences, Researcher, gerasimov_am@npk-mt.spb.ru

Gubkin Russian State Oil and Gas University (Russia):

Abrosimov A. A., Postgraduate, andreich.gis@gmail.com

In high-ash coal beneficiation, mainly «wet» processes are applied, demanding up to 5–10 m³ of water consumption per 1 ton of beneficiated coal. The considerable water consumption creates a number of serious economic and ecological problems, related to partial discharge of water into surface water bodies, as well as to necessary pumping, storage, transport of large volumes of watered or moist products, and also to high energy inputs for drying of marketable coal. A promising trend in improvement of primary beneficiation of coal is application of dry processing technologies, that would eliminate a considerable part of the above problems related to «wet» processes. A rational approach to design of dry coal beneficiation flow sheets is inversion of sequence of main processing operations — at the head of process, except for dry disintegration of coal, its thermochemical modification is performed, transforming its clay constituent into condition, suitable for magnetic and electrostatic separation. Thermal treatment of coals was performed in accordance with coal devolatilization regime — by heating coal in special air-tight furnaces to the temperature of up to 500–550 °С. It is shown that thermal treatment provides for physical and chemical transformations of coal mass, producing significant effect upon possibilities of its further processing and conversion, more specifically: liberation of non-combustible mineral fraction particles along carbon part interface owing to differences in physical and chemical properties, as well as increasing caloric content of remaining carbon mass through removal of moisture and volatiles. Accomplishment of the above chemical transformations opens up fresh opportunities for further conversion of thermally treated coal mass without water consumption.

The study were performed with the aid of the Russian Science Foundation Grant (Project No. 15-17-30015).

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