Rheological properties of magnetite suspensions

摘要

Rheological properties of aqueous suspensions ofmagnetite, varying in particle size distribution and solids contenthave been studied.Three models, the Bingham, the Herschel - Bulkley, and theCasson were found to describe the experimental flow curves quitewell. The Casson model turned out to be very effective indescribing the flow curves in a broad range of magnetite particlesizes (from d_(63.2) = 30 #mu#m resembling commercialmagnetite down to a micronized magnetite with d_(63.2) = 2.7##mum), and over the solid content range from 5 percent to 25percent by volume.The two rheological parameters obtained from the experimentaldata using the Casson model, the Casson yield stress and theCasson viscosity were evaluated, and it was concluded that whilethe Casson viscosity was nearly constant over the magnetitemedium density range of 1.3 to 1.7 (5 percent to 20 percent byvolume), the Casson yield stress varied in a predictable way withmagnetite particle size and solids content.