Slurry Pumping Aids such as dispersant viscosity modifiers or rheology modifiers work to reduce the rheological properties of the slurry, while allowing for increased slurry solids to be transferred over greater distances.

A good example of this can be found in the transfer of phosphate concentrate to the phosphoric acid chemical plant which can be hundreds of miles away. 

Slurry Pumping Aids also assist in preventing or reducing the cementation process which can occur in the slurry pipeline due to downtime in the transportation process.

A rheology modifier will allow for the slurry to redisperse upon restarting the plant, instead of cementing or compacting at the bottom of the pipeline. Some minerals require a stable dispersion for transportation in drums as they are shipped across the world.

If shipped in the absence of Slurry Pumping Aids, the drums will also develop some level of cementation.