TECHNOLOGY AND EQUIPMENT FOR PROCESSING OF LARGE-SIZED VERMICULITE MICAS OF THE KOVDOR DEPOSIT

The development of technology and equipment for the processing of large-sized vermiculite mica obtained from mining waste from the Kovdorsky deposit allows the large-scale vermiculite to be returned to processing industry. This article reviews the aspects of the technology for processing of large-sized mica with dimensions of 20 mm or more. The aim of the research is to study the grinding technology of large-sized vermiculite raw materials by the chopping overall particles, to develop the technological equipment and to study of its operating processes. The object of the research is the operating process of the chopping unit for grinding the large-sized vermiculite raw materials and its design. The methods are based on study of simulated movement of chopped large-sized particles and the determination of the main characteristics of the chipping unit operating process. It was found that the firing of large particles without grinding in chopping units requires a significant increase in firing time, which reduces the productivity of electric furnaces. The time of dropping particles out in the slot of the receiving drums of the chopping unit is determined, based on which the rotation speed of the receiving drums and its operational efficiency are calculated.

Evolution of mineral composition of fluxed sinter from iron ore concentrate of the Kovdor deposit

Metallurgical conversion methods are still missing iron ore with heterogeneous structure magnetite of the Kovdor deposit. Sintering mechanism of Kovdor concentrate was investigated in the wide CaO/SiO2 basicity range of 1.2 – 3.0 for sintering process conditions. Main influence of magnetite crystal structure on the way of charge phase changing in sintering process is shown for the first time. As a result of sintering with the low basicity of 1.2 – 2.0 two phases sinter system was formed, containing magnetite and silicate bond of melilitic composition. The analysis has shown that melilitic bond is the straight analog of the basic and acid blast furnace slag. The difficult mineral composition, containing four phases, is formed with the high basicity of 2.0 – 3.0. Magnetite and bond of crystals of calciumalumosilicoferrite are the main minerals, which occupy almost the whole volume of the sinter. By composition and number of phases, magnetite-ferritic composition is two-phase sinter system. Development of appropriate sintering process regimes is required for each of the determined sinter systems.

Removal of metals from technogenic waters from abandoned coal mines using geochemical barriers

A study was made of the possibility of using natural materials (vermiculites, zeolite) and wastes (ash from the Partizansk Coal-Burning Power Plant) as sorbents in geochemical barriers to manage discharges (technogenic waters) from abandoned coal mines and reduce metal concentrations to established, acceptable standards. Vermiculite from the Kovdor deposit was shown to reduce the concentrations of Fe, Co, Ni, Cu, and Zn cations, in both direct and inverse soil column models, by between two and five times.