Refractory Technology
Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except

Thermal conductivity
Cost
Electrical conductivity
Fusion point

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Refractory Technology
Addition of grog in fireclay brick during its manufacture is advantageous, because it results in

Less shrinkage in heating, decreased apparent porosity & increased specific gravity
Less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production
High strength & thermal spalling resistance
All of these

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