Rheology of Non-Newtonian slurries and its effects on pipeline transportation for economical handling of bulk iron ore

Abstract

This study examines the rheological properties, flow characteristics, and wear behaviour while transporting iron ore slurries through the pipeline. The slurries containing 60-75 wt% iron ore exhibit yield-shear thinning flow behaviour when sheared in the shear rate range of 15-350 s-1, free from slip and Taylor vortices artefacts. The viscosity model indicates that the packing and distribution of iron ore particles in carrier water impacts the slurry viscosity. The head loss and energy consumption increase with increasing 60-75 wt% iron ore concentrations and slurry velocities from 2 to 5m/s. Conversely, these entities reduce with increasing pipe diameter from 0.15 to 0.25 m. Results reveal that the increased rate of continuous impingement of iron ore particles at higher velocity causes erosion wear. Besides, the increasing contact time from 4 to 7 hours and impact angle from 45 to 90 degrees also contribute to the erosion rate. These interpretations are supported by microscopy data, where pitting and micro-cracks are witnessed on mild steel specimens. Moreover, the slurry becomes more abrasive at 75 wt% iron ore loading. The outcomes propose that transporting 70 wt% iron ore slurry via a pipe of diameter 0.25 m in a velocity range of 2-2.5 m/s lowers the transportation cost and enhances the pipeline's service life.