... are used as functional fillers or extender in the manufacture of plastics, paints,resins, thermal coatings, epoxies, mastics; ... and functionality. Cenospheres are environmentally: 100% recycledMade up of silica, iron and alumina, cenospheres have a size range ... many benefits over mined materials,primarily cost and weight reduction. Of their many uses, microspheresare used as light weight aggregate ...