LAUSR

Abstract The contributions of three operating parameters (moisture content, hydrated lime addition, magnetite concentrate substitution) to the crushing strength and Young’s modulus of granules in each stage of iron ore sintering were studied by applying the Taguchi method. The results indicated that the strength properties of the iron ore granules were greatly affected by its structure, which is composed of inner nuclei and an outer adhering layer. The granules with a thick adhering layer showed a clear changing trend in strength with increasing temperature, whereas those with a thin adhering layer showed additional fluctuations as their force–displacement responses were greatly determined by the nuclei. The granules with a thick adhering layer were generally more deformable and easier to break than that those with the thin adhering layer in most states. The signal-to-noise ratio and variance analysis indicated that moisture was the dominant parameter affecting the strength properties of the iron ore granules, as this factor controls the primary granule structure and material distribution. With the progress of sintering, the contribution of moisture to the quality characteristics gradually decreased (from ∼80% to 50%), whereas the contributions of hydrated lime and magnetite concentrate increased correspondingly (from ∼5% to 20%).