INFLUENCE OF MAXIMUM TEMPERATURE, HOLDING TIME AND COOLING RATE ON THE STRENGTH OF SINTER ANALOGUES

摘要

Typically a large proportion of the ferrous burden charged to the ironmaking blast furnace is iron ore sinter. The quality of iron ore sinter has a strong influence on the productivity and fuel efficiency of the furnace. Therefore high quality sinter is desirable. Individual pieces of sinter product from industrial sinter strands and sinter pot tests are variable in composition and structure. This is caused by the heterogeneous distribution of raw materials and spatial differences in sintering conditions (temperature profile and pO2), and complicates the analysis of sintering mechanisms. To reduce the variability in sinter samples an infra-red rapid heating furnace was used to produce laboratory-scale analogue sinter tablets under tightly controlled temperature and gas conditions. The tablets were made from -1.0 mm natural ore fluxed with laboratory-grade chemical powders to basicity 2.0. Maximum temperature was found to be a more important factor than integrated time at temperature above 1100 oC (EA, enclosed area) in determining the strength of these analogue sinter tablets. At the lowest firing temperature of 1250 °C, increasing EA did not increase strength. Surprisingly, at the highest firing temperature of 1320 °C, increased EA values led to weaker tablets. These had more magnetite formation which is discussed in the paper.