Effect of Oxygen Enrichment on Melting Behavior in Sintering Process

In the sintering process, productivity and strength are essential indicators, and it is known that they are closely related to the sintering time and temperature. Since the sintering time and high temperature holding time vary greatly depending on the combustion behavior of coke breeze, various studies have been conducted on the influence of oxygen which is critical element in the sintering phenomena. However, the influence of oxygen enrichment on sinter strength and yield has not yet been unified. In this study, the sintering productivity, strength, and yield were investigated when the oxygen concentration of the inlet gas was increased to 40 vol%. In addition, the heat profile on pot tests and the effect of oxygen partial pressure on the melting property were analyzed from the viewpoint of thermodynamics. As a result, it was found that the yield showed the maximum value at 30 vol% oxygen concentration, and the strength increased with oxygen enrichment. As for the yield, it was found that the effect of the heat profile was significant, and the deviation between the heat transfer speed and the combustion speed started when the oxygen concentration exceeded 30 vol%. On the other hand, it was suggested that the strength improvement was caused by the increase in the amount of melt produced by oxygen enrichment in addition to the effect of high temperature holding time.