Cenospheres are hollow silicate micro-spheres extracted from the fly ash generated in coal-fired power plants. It is in white or light gray color and has a particle size ranged from 20 to 500 microns. It has excellent fluidity as well as sound, electric and heat insulation. cenospheres are a filler used to replace minerals and resins where the benefits may be as diverse as weight reduction, improved thermal insulation, reduced shrinkage, improved fire resistance or simply easier application