Relationship between the Assimilation Properties of Fine Ores and the Strength of Sinter

Abstract

Ore properties influence the strength of sinter. It should be evaluated separately for coarse particles and for fine particles because of the different behavior during sintering; that is, the former remains as unmelted parts in sinter and the latter melts to be bonding phase. This report focused on the assimilation behavior of fine particles and showed a relationship between the behavior and the strength of sinter.
Press-formed tablets consisting of fine ores (-0.5 mm) and limestone (-0.5 mm) (fine ore/limestone=10/1) were heated at 1300°C in an electric furnace with air flow. The heated specimens were observed with microscope and the pore structures were analyzed with image processing.
The crushing strength of tablets after the assimilation test decreased with an increase in porosity. The porosity was influenced by the number of pores more than the diameter of those. The number increased with an increase in Al₂O₃ content of the ore. Sinters after heating quasiparticles with varying adhering fines showed similar behavior concerning the pore formation and its influence on strength. In conclusion, Al₂O₃ content of adhering fine was favorable to be less than 1.5 mass% and nuclei are was desirable to contain less combined water.