Effect of flame-front speed on the pisolite-ore sintering process

Flame-front speed has a large influence on sinter quality and production. To study the influence of flame-front speed on pisolite-ore sintering, five tests were conducted in a laboratory sinter pot. Through varying mix moisture, flame-front speeds ranging from 23.9 to 27.8 mm/min were obtained. The results revealed that when the flame-front speed increased from 23.9 to 27.7 mm/min, sinter productivity increased from 34.1 to 38.6 t/m2 d at relatively unchanged sinter strength. At higher moisture and flame front speeds, while productivity and TI both deteriorated, suggesting the optimum moisture and flame-front speed for the blend has been past. Similarly, with increasing flame-front speed sinter size distribution, as indicated by the Sauter mean size, initially improved but deteriorated as flame-front speed increased further to 27.8 mm/min. Mineralogy studies carried out on the sinters showed that faster flame-front speeds favored the formation of acicular SFCA (silico-ferrite of calcium and aluminum), while columnar SFCA was more abundant at slower flame-front speeds. With decreasing flame-front speed, sinter pore area results indicated that bubble coalescence and escape from the melt increased. But when flame-front speed reached 25.1 mm/min, changes in pore area were not as large.