Effect of Ultrafine Iron Ore Addition on Green Bed Properties and Sinter Productivity

In iron ore sintering, the green bed properties and sinter productivity are influenced by the ore blend mixture including the proportions of ultrafine iron ores in the blend. In this work, iron ore granules, green bed properties and sinter productivity were investigated for blends containing ultrafine iron ores. The granulation and sintering experiments were conducted in a granulation drum with an internal diameter of 500 mm and a length of 310 mm, and a steel pot with an internal diameter of 108 mm and a height of 500 mm, respectively. The results of this study show that the reference blend was representative of a commercial sinter plant mixture in terms of comparable granule size and green bed properties at a similar moisture content of approximately 7%. An increase in the proportion of ultrafine iron ores in the blend resulted in a deterioration of green bed properties. A simple correlation was derived to link green bed voidage (ε) to α, the ratio of granule SMD and dry sinter feed SMD, as . This equation provides a simple yet effective expression that relates green bed voidage to both sinter feed size and granule size, enabling the prediction of bed voidage with a level of accuracy that is comparable to Hinkley’s equation. It was concluded that an increase in the proportion of ultrafine iron ores has a negative impact on green bed properties and causes a decrease in the gas flow rate during sintering. Consequently, the productivity of the sinter pot decreased.