Study of iron content in iron ore concentrate increasing effect on sintering process indices and on metallurgical properties of sinter

Abstract

Effectiveness of blast furnaces operation in many respects depends on metallurgical properties of agglomerate, in particular, iron content in the sinter and its basicity. At the same time, it is accepted that usage of iron ore concentrates with iron content more than 66–67% for sinter production results in decreasing of its strength. As a result of the planned modernization of the technological sections of the concentration plant JSC “Stoilensky GOK”, iron content in the concentrate will be increased to 68–70%. It makes it actual to accomplish comprehensive studies of metallurgical properties of the sinter while increasing iron content in the raw material. Results of the study of sinter properties presented, the sinter being obtained with utilization of iron concentrate with iron content 66.6 % (base), 68.0 and 69.2 % (exp. 1 and exp. 2 correspondently). The iron ore mixture for all the stages was the same and consisted of iron ore concentrate – 78.3%, sintering ore – 8.0%, lime – 5.5% and sintering additives (sludge, dust, scale) – 8.2%. The sintering mixtures composition for all the study stages differed only by fluxes and iron ore mixture consumption. 18 test sintering operations at three values of basicity 1.6, 1.8 and 2.0 units were accomplished. It was established that increase of iron content in the concentrate and basicity of the sinter results in improving of the sintering process indices, increase of the vertical sintering rate, sintering machines productivity, recovery and the sinter cold strength. Increase of the sinter basicity and its production with increased content of iron results in improving RDI indices at low temperature reducing. Results of the study of porosity indices and metallurgical properties of the sinter presented, in particular the collapsibility during reducing and temperature interval softening-melting presented. The advisability of concentrate with increased iron content utilization in the iron ore mixture shown.