Abstract
This article contains the research results of the thermodynamic modeling of interaction of iron phosphides Fe2P and FeP with FeSi2, obtained by a method of the total thermodynamic analysis on the basis of the program HSC-5.1 of the Finnish metallurgical company Outokumpu, developed on both a principle of the Gibbs energy minimization, and also kinetics of the phosphorus release by ferrosilicon from the electrothermal ferrophosphorus – a by-product of the yellow phosphorus production. It was found, that temperature of the beginning of the phosphorus formation in systems iron phosphides – FeSi2 depends on a mole ratio of phosphorus in the phosphides. At the increasing this ratio from 33.3 to 50%, the temperature of the beginning of the phosphorus formation decreases from 1362 K to 1290 K. At lower temperature (773 K) there is the formation of intermediate FeP2 and FeP in a system Fe2P-FeSi2 and intermediate FeP2 in a system FeP-FeSi2, which react with FeSi2 with temperature increasing and form a gaseous phosphorus. The process proceeds in kinetic mode and is characterized by apparent activation energy of 281-389 kJ/mol.