Foaming Mechanism Characterization in Cathode Ray Tube Glass Foams
Date
2016-05-08
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Abstract
Waste cathode ray tube (CRT) glass contains hazardous heavy metals, and is often disposed of at landfill sites. This disposal method of waste CRT glass possesses potential impact on the environment of landfill sites given its poor retention of heavy metals. This study uses waste CRT glass in producing fast sintered (~ 600 seconds) and highly porous (from ~ 30% to 90% porosity) glass foams. Redox and thermal decomposition foaming agents were used to prepare glass foams in an attempt to understand the relationship between amounts of released gas and porous structure. Two different types of CRT glass, panel glass and funnel glass, were compared to study the effect of glass composition on porous structure. The waste CRT glass was pulverized, mixed with silicon carbide or calcium carbonate (at a given volume of released gas), pressurized into pellet shape using uniaxial press, and then sintered at 900oC. The as-prepared foam glasses were characterized using Archimedes method, pycnometer, X-ray diffraction (XRD) and scanning electron microscopy (ESEM) to investigate the structural, processing, and composition relationship. Samples foamed using redox foaming method maintained a closed pore structure, and the bulk density decreased with increasing addition of foaming agent; samples foamed by thermal decomposition method displayed open pore structures, and the bulk density increased with increasing addition of foaming agent. All foams made with funnel CRT glass have a lower bulk density comparing to their panel glass counterparts. The porous structure was found to be governed by the gas release rate. The glass foams from redox foaming method showed potential to be used in applications such as shock-wave absorption, sound absorption, and heat retardation.
Description
Thesis completed in partial fulfillment of the requirements for the Alfred University Honors Program.
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Thesis
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Keywords
Honors thesis, Glass engineering, Glass foam, Characterizing foams