Physicochemical regularities of complex reduction of iron chromite

Abstract

Physicochemical patterns of complex reduction of multicomponent charge have been studied in the absence of liquid phases in order to obtain spongy ligatures. The charge contained both simple oxides and complex oxide compounds. The reduction was conducted being realized at the expense of carbon and gases (CO and H2) as well as with the participation of the carbide phase, which was formed during the reduction process. The dependence of the phase composition of the reduction products on the initial ratios O/(C+H) and C/H was determined. The possibility of the presence of Femet in the products was shown at increasing the C/H ratio and the formation of complex carbide based on (1/60 Fe3C+1/3 Cr3C2). The temperature limits of the appearance of metallic and carbide phases have been theoretically determined based on both thermodynamic modeling of the system Cr–Fe–C–O–H using the software HSC Chemistry 5.1 and the results of X-ray phase analysis of the reduction products. The equilibrium composition of the gas phase for the complex reduction of iron chromite under different conditions was calculated. To evaluate the kinetic features of the reduction of iron chromite, the rate of the complex reduction of Fe(CrO2)2 was determined under conditions of chemical-catalytic action. Salts of alkali metals (potassium and sodium) were used as catalytic additives. The influence of temperature, reducing agent composition and the nature and amount of catalytic additive on the process rate was investigated. Conclusions on the type and optimal proportion of additives have been made. The mechanism of influence of catalytic additives on the kinetic characteristics of the complex reduction of iron chromite was analyzed.