MODERN TECHNICAL SOLUTIONS FOR NEW AND RECONSTRUCTED SINTER PLANTSReport 2MIXING AND PELLETIZING OF AGGLOMERATION BATCH

Abstract

The concept according to which the sinter mix should be mixed in a waterfall mode has been confirmed in industrial conditions. It has been established that with increased moisture of the mix, not only mixing but also granulation of the mix can be carried out in the granulating drum. The homogeneity of the mix by granulometric composition should be limited by the conditions of segregation of the mix by size and, accordingly, the fuel content by the height of the bed on the sinter machine. Drum devices fully comply with this requirement, the degree of homogeneity of the mix after which is at the level of 90%. The use of intensive mixers that exceed the specified limits of homogeneity when using concentrate-based mix, complex design, a large number of drives, conditions of their maintenance, as well as due to high specific energy consumption, is not fit at Russian sinter plants. At sinter plants sintering concentrate-based mixes, granulating drums should be installed in the mix sintering building and not at zero level. They should have design capabilities for regulating both the rotation speed and the angle of inclination. With the existing design of the granulating drum, the mix load and the rational rotation speed, the optimal degree of its filling (11–13%) should be set by regulating the angle of inclination of the apparatus. When designing and upgrading both apparatuses, a wide range of ratios between water consumption in them (from 20/80 to 80/20) should be provided for in order to select a rational value during setup. Moistening of the mix should be limited to ~60% of the of granulating drum length and performed in a drip mode to enable granulation of the mix “on a drop water” as nucleating centers. It is efficient to equip the pelletizing drum with a system for heating the batch with steam up to 60 °C to minimize the condensation of water vapor in the mix bed and increase the speed of its sintering. It is recommended to equip the granulating drum with removable conical inserts to optimize the distribution of the mix bed along the length of the apparatus in combination with a rational angle of inclination. The mixing drum and granulating drum of Russian manufacturers meet the modern requirements imposed on them in the entire range of productivity for iron ore raw materials and mix.