Highly concentrated iron ore slurry flow through pipeline with and without chemical additive; part I: Experimental investigations and proposed model for the prediction of pressure drop

The present study comprises experimental and numerical analysis for flow of iron ore slurry (having particles with mean diameter, geometric standard deviation, and maximum static settled concentration of 55 µm, 2, and 75.2 w/w, respectively) flow through a 2-inch diameter pipeline in the flow velocity range of 1 to 3.5 m/s at high concentrations ranging from 60 to 72 % w/w without, and with chemical additive (Sodium-hexametaphosphate) at different dosages from 0.1 to 1.5% w/w of solids. The optimal dosage of chemical additive for maximum reduction in the rheological properties (absolute viscosity and yield stress) and pressure drop varies with solids concentration and increases from 0.8 to 1.2 % w/w of solids with an increase in solids concentration from 60 to 72% w/w. The critical deposition velocity also increases with an increase in solids concentration and additive dosages used in the present study in the range of 1 to 1.95 m/s. Modified Slatter’s method is proposed by replacing d₈₅ with a more accurate optimum particle diameter using the rheological and pilot plant pipe loop testing data collected in the present study. Based on comparison with experimental data, it is observed that the proposed modified Slatter’s method can predict the pressure drop with an error of ±15%.