Reduction processing of technogenic microsilica with the use of a brown coal semi-coke

Thermodynamics is investigated and optimal temperature-time regimes of carbidization of briquetted charge "microsilica – brown coal semi-coke" are determined. In Si-O-C and Si-O-C-H systems the carbide formation process is dominant: with the stoichiometric composition of the charge, the maximum content of silicon carbide reduction products is achieved at 1700 K. The complete carbidization of the charge in the conditions of heat treatment is achieved at a temperature of 1923 - 1973 K with a duration of 20 - 15 minutes. The technological expediency, conditions and chemical enrichment indices of carbidization products are established. The phase, chemical, granulometric compositions and morphology of silicon carbide particles are studied. It was found that carbidization forms a carbide of the cubic structure (β-SiC). The content of carbide after enrichment is more than 90%. Silicon carbide is obtained in the form of a micropowder with a specific surface area of 8000 - 9000 m²/kg from irregularly shaped particles with a size range of 0.2-1.0 μm. (paper)