The performance level of blast furnace has enhanced remarkably during the last 2 decades leading to higher cost efficiency. Productivity has increased and fuel rate has reduced substantially. Concurrently, metal quality and campaign life have improved considerably.
The prerequisites for high productivity, low fuel rate and stable operation are good gas-materials contact to secure optimum level of indirect reduction of iron oxides; lower heat loss; optimum heat flow ratio; enhanced melting rate; proper condition in the cohesive zone, dripping zone, deadman and hearth zones; reduced slag volume; easy slag drainage from cohesive zone to bottom of the hearth and trouble free evacuation from the hearth. To fulfil these requirements burden materials should have low level of impurities, optimum size, narrow size range, adequate strength, low reduction degradation, high reducibility and higher fusion temperature. Coke should have large size, low ash content, sufficient strength at low and high temperature and reducing condition to ensure adequate permeability of code grid in the wet zone of blast furnace. Consistency in characteristics of the raw materials is important. Proper distribution of raw materials in the blast furnace is a critical requirement for efficient operation.
This paper discusses raw material characteristics for improved blast furnace performance in conjunction with raw materials scenario in India and measures to optimize blast furnace performance.