Magnesia thermal insulation

Furnaces. Electric furnaces are used for higher temperatures. These are obtainable commercially, but satisfactory ones can be made in the laboratory (see Fig. 24-1). A pregrooved Alundum core is wound with suitable heating wire (nichrome, Chromel A, Kanthal) of 12 to 20 gauge, and covered with a thick coating of Alundum cement. This is surrounded by several inches of powdered magnesia, for thermal insulation, in a large... 

Thermal insulators comprise an equally broad range of materials. Such inorganics as mineral fibers, magnesia, aluminum silicate, cellulose, and glass fibers are widely used for steam and hot-water pipes, furnaces, and blown-in home insulation. Organic products that are effective include plastic foams (polyurethane, polyvinyl chloride, polystyrene) and cellular rubber. There are a number of materials that may be called double insulators, since they have both electrical and thermal insulating properties,... 

Both the lime-alumina-borosilicate t3 pe E glass and the silica-alumina-magnesia type S glass are used for reinforcement. The less expensive E glass is preferred where electrical or thermal insulation properties take precedence over strength, whereas the more expensive S glass reinforcement is preferred where strength and modulus requirements dominate. 

High-temperature The predominant industrial application of magnesium compounds is in the use of thermal insulation magnesite and dolomite in refractory bricks. Bricks of high-purity magnesia are (2%) exceptionally wear and temperature resistant, with high heat capacity and... 

Would it be feasible to use a magnesia insulation which will not stand temperatures above 615 K and has a thermal conductivity 0.09 W/m K for an additional layer thick enough to reduce the outer surface temperature to 370 K in surroundings at 280 K Take the surface coefficient of heat transfer by radiation and convection as 10 W/m- IC... 

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