A pipeline is installed to transport a red mud slurry from an open tank in an alumina plant to a disposal pond. The line is 5 in. sch 80 commercial steel, 12,000 ft long, and is designed to transport the slurry at a rate of $300 \mathrm{gpm}$. The slurry properties can be described by the Bingham plastic model, with a yield stress of $15 \mathrm{dyn} / \mathrm{cm}^{2}$, a limiting viscosity of $20 \mathrm{cP}$, and an SG of 1.3. You may neglect any fittings in this pipeline.

(a) What delivered pump head and hydraulic horsepower would be required to pump this slurry?

(b) What would be the required pump head and horsepower to pump water at the same rate through the same pipeline?

(c) If $100 \mathrm{ppm}$ of fresh Separan AP-30 polyacrylamide polymer were added to the water in case (b) above, what would be the required pump head and horsepower?

(d) If a pump with the same characteristics as those illustrated in Figure 8.2 could be used to pump these fluids, what would be the proper impeller size and motor horsepower to use for each of cases (a), (b), and (c) above? Explain your choices.

Figure 8.2

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Size 2 3 R & C 1% in. Pedestal 3500 rpm 4' minimum NPSH 400 Impeller dia. 300 200 8% in 8% in 7% in 7% in 6% in. 6% in. I Total head feet 100 50 MISSION VALVE AND PUMP COM Semi-open impeller Dia. 6%-8% in. Eye area 9.8 in. Curve 8 S1 20 ft Max. sphere 1% in. Maximum normal capacity for slurries and abrasive fluids 7ft 30% 10ft. 140% 15 ft 145% 50% 50 50 40HP 15 HP 20 HP 30 HP1 25 HP 25ft, 50% 45% 60 HP 50 HP 400 40% 500 600 700 Capacity-U.S. gallons per minute 100 200 300