Refractory Technology
What is Thoria?

Thoria Has high fusion temperature (> 3000°C) but poor resistance to thermal shock
Thoria Has high resistance to basic slags
Which is expensive & radioactive, is used in crucibles for melting high purity metals
All of these

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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
All of these
High strength & thermal spalling resistance

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