There is one factor that is responsible for much of the failure of refractories in furnaces and other metallurgical processes and boilers, namely spalling. Many times this action has been the cause of roofs to cave in, side walls to slump, and bungs to fail. Consequently it is a factor that is of utmost importance. The erosion and slag effects are also of greatest importance to refractory stability. Spalling, as referred to refractories, is defined as the breaking or crushing of the unit due to thermal, mechanical, or structural stresses, presenting newly exposed surfaces of the residual mass. Taking the above definition for what it is worth and studying the various parts of it in detail, some light may be thrown on the subject of spalling, its cause and cure --Introduction, page 1-2
