Requirements on Carbon-Based Reducing Agents for Electrothermal Processes

Solid carbon-based reducing agents used in the electrothermal production of industrial-grade silicon are compared. The properties and structure of traditional and nontraditional reducing agents are considered. Nontraditional reducing agents are produced by rapid oxidative pyrolysis of nonclinkering long-flame coal from fields in Central Kazakhstan (the Shubarkol and Kuu-Chek fields). The microstructure (pore size, thickness of pore walls) of the reducing agents is determined. With increase in heating rate, the pore size decreases. A developed pore structure appears in the special coke, and its reactivity increases. The reactivity is the most important parameter in the electrothermal production of silicon.