All valid points above of course.
For pumps handling abrasive slurries, the properties of the solids within the carrier fluid also have to be taken into account. The minimum requirement that is needed for correct pump selection and derating is:-
Solids specific gravity
% solids by volume or weight
d50 or d85 particle size (50% pass or 85% pass)
If the carrier liquid is anything other than water, then fluid properties are also needed, including