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Slurry pumps have some features that make them different than chemical pumps.

• The pumps are more massive
• They have looser tolerances.
• The clearances are more open.
• The parts have blunt rather than tapered edges.
• The metal parts are harder.
• They utilize “through bolt construction” because it is difficult to drill and tap the harder metal.
• Some designs are rubber lined to absorb the impact of abrasive fluids.
• They are less efficient than chemical pumps.
• Many slurries are dilatants. Their viscosity increases with agitation. You may have to convert to a positive displacement design if you have this problem. Kaoline or china clay is a good example of a dilatant. Some sugar syrups fall into this category also.
• Almost every centrifugal solids handling pump has an upper limit of solids content of 4 to 6 percent. True slurry pumps can handle solids content of upwards of 70 percent.
• Some large slurry handling pumps run at just a few hundred RPM but compensate with a large impeller; it is not uncommon to find impellers in the 7- to 8-ft range in pumps specifically designed for slurry applications

The speed of slurry pumps is important because of the wear rate of the pump volute, impeller and wear rings.

• The wear is generally proportional to relative velocity between the slurry and the pump elements to the power of two or three. In other words if you went from 1750 (1450) rpm to 3500 (2900) rpm. You would get four to eight times the wear.

Impeller tip speed is often used as the guide in selecting slurry pumps:

• For dirty water type applications limit the tip speed to 130 feet/sec (40 m/sec)
• For medium slurries up to 25% solids concentration by weight and solids size of 200 microns, limit the tip speed to 115 feet/sec (35 m/s)
• For slurries with higher concentration and larger solids, limit tip speed to 100 feet/sec (30 m/s)
• Pumps fitted with elastomeric impellers (rubber like) are commonly limited to 85 feet/sec (26 m/s) tip speed.