Preparation of hollow glass microspheres by flame synthesis from waste glasses

<p>Hollow glass microspheres (HGMs) are a low cost but high performance material with a number of various<br> applications. HGMs are desirable in many industries for use as fillers for various organic and inorganic matrices, or<br> can find applications in the medical field, for fabrication of lightweight composite materials, buoyancy materials,<br> thermal insulation materials and for gas storage. The use of HGMs has expanded in last years for their excellent<br> properties. The combination of heat resistance, lightweight and favorable mechanical properties offered by these new<br> materials opens up application in aviation transport and the automotive industry. This paper illustrates the possibility<br> of using recycled glass to obtain hollow glass microspheres with Na2SO4 blowing agent. HGMs were prepared from<br> soda lime glasses (automotive glasses) by flame spheroidization process in oxygen-methane (O2/CH4) flame. We<br> investigated the influence of glass precursors (glass powders with blowing agent) preparation, Na2SO4 concentration,<br> melting temperature, holding time, diffusing or dissolving SO3 element into the glass of the glass powders, particle<br> size distribution of glass precursors, feed rate of precursors into the flame, on formation of hollow glass microspheres.<br> The amorphous nature of HGMs was confirmed by X-ray diffraction (XRD). The morphology of the hollow glass<br> microspheres was examined by scanning electron microscopy (SEM) and the composition of the waste glass powders<br> and produced HGMs were determined using SEM-EDS.