The Effect of Microspheres on the Properties of Thermal Insulating Refractory Materials
Microspheres are currently a very important raw material mixture component for production of high-quality thermal insulating refractory materials with low bulk density. At present there are several sources of microspheres on the market. Although the price range of offered microspheres is not wide, their quality varies greatly. It is therefore necessary to examine the influence of various brands of microsphere on the thermal insulation properties of refractory materials. The aim of this paper is to describe the basic properties of available microspheres (grain size di7stribution, powder density, loss on ignition, chemical analysis) and determine their impact on the properties of dry-pressed bodies (bulk density, coefficient of thermal conductivity, firing shrinkage, Pyrometric Cone Equivalent (PCE) and microstructure). The results show significant differences in the ability of individual test microspheres to produce a body with low thermal conductivity and high refractoriness according to PCE testing.
Keywordsmicrosphere refractory materials porosity thermal conductivity
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