Bondar N. Obtaining of materials by annealing in reducing environments for the рroduction of precision alloys ТM-RЕM

The dissertation is devoted to obtaining structural materials through the processing of iron ore raw materials, both natural and man-made. In dissertation work the analysis of the features of obtaining of high-energy magnetic materials based of TM-REM was carried out. The tendencies of development of high-energy magnetic materials and the use of rare-earth magnets are considered. The types of phase equilibria of the Fe-Nd-(B, C) system and the physical and chemical properties of iron oxides are analyzed. The analysis of existing methods of obtaining TM and REM. The probability of chemical reactions of Fe2O3 → Fe3O4 → Fe reduction in various media (C, H2) was theoretically investigated by analyzing the changes in the free energy of Gibbs ΔG for the corresponding chemical reactions. The paper studies the in fluence of mechanoactivation and annealing in different environments on hematite reduction processes. It was established that grinding of iron-containing material in the liquid nitrogen leads to purification from components Р2О5 and СаО, and crushing in a vibratory mill – to graphitization of the material. Due to the thermal effect (annealing in a vacuum at a temperature t = 600 ºС) on the dispersed hematite-containing material, a phase transition from Fe2O3 to Fe3O4, where the reducing agent is carbon. In the medium of molecular hydrogen (р = 0,6 МPа) the transformation processes of Fe2O3 → Fe3O4 → Fe occur at t > 400 °С. A method for extracting valuable components from iron ore and metallurgical wastes due to annealing in reducing environments is proposed. Show, that the transfer of hematite to the magnetic state allows the effective removal of the iron-containing component, which is necessary for the processing of red mud and the production of a REM (R). In work the high energy magnet system R-Fe-B-С-Сu was made on the basis of the extracted mixture of REM. Key words: hematite material, mechanoactivation, annealing, recovery, phase transition, high-power magnet, magnetic properties.