... are used as functional fillers or extender in the manufacture of plastics, paints,resins, thermal coatings, epoxies, mastics; light weight ... range from 1 to 500 microns with an average compressive strength of 3000+psi. Colors range from white to dark gray. ... , improved flow, excellent thermal insulation, light weight, and high strength. Environmentally friendly and 100% they aid not only the coal ...