Refractory should possess the ability to be perfectly

A refractory should have the ability to perfectly: *Possess high refractoriness by featuring high mechanical strength in the operating temperature range *Maintain optimum porosity or optimum ratio of pore volume to bulk volume *Overcome thermal spalling that causes pealing, cracking or breaking off refractory materials under high temperatures *Indicate dimensional stability and not undergo volume changes when subject to high temperatures for a prolonged period