WHAT IS A "SLURRY"?
A slurry is any mixture of fluid and fine solid particles. Such as starch, cement, manure, or coal suspended in water. Slurries are used as a convenient way to handle solids in mining, foundries, steel processing, and power generation.
Slurries normally behave the same way as thick, viscous fluids, flowing under gravity, but also pumped as needed. Slurries are divided into two general categories: settling and non-settling.
Settling slurries are formed by coarse particles that tend to form an unstable mixture. Particular attention should be given to flow and power calculations when selecting a pump. The majority of slurry applications are made up of coarse particles and because of this, have higher wear properties.
Non-settling slurries consist of very fine particles, which give the illusion of increased apparent viscosity. These slurries usually have low-wearing properties but do require very careful consideration when selecting the correct pump because they do not behave in the same manner as a normal liquid does.
These are common characteristics of slurries:
• Abrasive
• Thick consistency
• Can contain a high amount of solids
• Usually settle fast
• Require more power to work than a water pump
SLURRY PUMP SELECTION
A slurry is one of the most challenging fluids to move. It is thick, abrasive, sometimes corrosive, and contains a high concentration of solids. Therefore, slurries are tough on pumps. But choosing the proper pump for these abrasive applications can make all the difference in long-term performance.
Many types of pumps are used for pumping slurries, but the most common slurry pump is the centrifugal pump. The centrifugal slurry pump uses the centrifugal force generated by a rotating impeller to impact kinetic energy into the slurry, similar to how a water-like liquid would move through a standard centrifugal pump.
Slurry applications reduce the expected wear life of pumping components. Pumps made for these heavy-duty applications must be selected from the beginning. Consider the following when making selections:
BASIC PUMP COMPONENTS
To ensure the pump will hold up against wearing, the impeller size, material, and discharge configurations must be properly selected.
Open impellers are the most common on slurry pumps because they are the least likely to jam. Closed impellers on the other hand are the most likely to jam and hard to clean if they jam.
Slurry impellers are large and thick. This helps them operate longer in harsh slurry mixtures.
