Optimizing the Charge Pelletizing Parameters for Silicon Smelting Based on Technogenic Materials

Abstract

The pelletizing parameters for fine technogenic raw materials generated in the production of metallurgical silicon (Si_met) are optimized. The technogenic waste of Si_met production in ore-smelting furnaces (OSF) is barely used in other industries. Silica-containing waste (gas-treatment dust and sludge) containing 86.3 to 95.8% SiO₂ is proposed to use as a charge component. The other charge components (fine waste) are petcoke screenings, charcoal fines, and silicon screenings (Si_scr). Liquid glass laced with dust from aluminum-production precipitators is used as a binder. To be transported and loaded in an OSF, the pelletized charge must have sufficient mechanical strength. This is why the drop resistance coefficient (R_dr) is used as an optimization parameter in mathematical processing of experimental data on charge pelletizing. A model equation that describes the effects of the following three factors is derived: pelletizing duration, binder content of the charge, and Si_scr particle size. For the optimal pelletizing parameters, R_dr is equal to 82.5%. Based on the study results, a process flow diagram for the production of Si_met using an additional facility for pelletizing technogenic materials is proposed.