Experimental Investigations of the Effect of Chemical Additives on the Rheological Properties of Highly Concentrated Iron Ore Slurries

Abstract

Chemical additives are widely used in iron ore industry in various processing steps such as classification, crushing, grinding, and pelletization. These additives are also used in transportation of iron ore through highly concentrated slurry pipelines which are currently operating and coming up in large number across the world. These additives are usually categorized by their functions rather than chemical composition. In this study, the effect of quick lime (QL), hydrated lime (HL), Sodium hexametaphosphate (SHMP) and Acti-Gel on the rheological behaviors of iron ore slurries at volumetric concentrations (Cv) of 18.8 %, 22.1 % and 25.8 % and dosages of additives ranging from 0.05–2 % were investigated. The rheological parameters were measured using computerized rotational rheometer. All the sample data were best represented by Herschel-Bulkley model. Minimum shear stress and viscosity were obtained at 2 % dosage of QL for 18.8 % and minimum flow behaviour index was obtained at 25.8 % with 2 % additive dosage. The addition of HL markedly increases all the rheological parameters. When SHMP is used, minimum shear stress and viscosity were obtained at dosage of 1.5 %, 2 % and 2 % for Cv of 18.8 %, 22.1 % and 25.8 % respectively. Acti-Gel resulted higher values of yield stress and flow behaviour indices at all solid concentrations.

Keywords

• iron ore slurry
• highly concentrated slurry
• chemical additive
• rheological property
• herschel-bulkley fluid