Fluidization and Flow Regimes of Titaniferous Solids

Abstract

Physical properties of ilmenite and titania slag particlesproperties such as particle density, bulk density, packed-bed voidage and sphericityhave been determined for narrow size fractions ranging from 50 to 850 μm of each material. Particle sphericities measured by image analysis decrease with particle size. A comparison with other techniques shows that image analysis predicts lower values of sphericity. For both materials, the minimum fluidizing velocity, Umf, and transport velocity, Utr, were determined in air at room temperature and atmospheric pressure. The measured minimum fluidizing velocities are higher for ilmenite particles than for slag particles because the density and sphericity of the ilmenite are higher. Separate correlations for Umf, based on a simplified version of the Ergun equation, were fitted for ilmenite and slag particles. Both of these correlations tend to underestimate the minimum fluidizing velocity for small (<50-μm) particles. The experimental values of the transport velocity were fitted to a single equation, which predicts Utr for both materials with a maximum deviation not exceeding 8%. Flow-regime maps for the upward transport of Cl2−ilmenite and Cl2−slag systems at 1000 °C and 0.1 MPa were constructed.