🔍 Key Concepts

• Heat transfer in boilers – how slag buildup affects heat flow to the furnace floor and brickwork • Thermal expansion and insulation – what happens to refractory brick when exposed to higher or uneven temperatures • Purpose of slag removal – why operators are concerned about slag on furnace surfaces

💭 Think About

• Think about whether a thick layer of slag acts more like an insulator or like a conductor for the furnace floor and brickwork underneath. • Ask yourself: if the furnace floor is being insulated by slag, which part is more likely to overheat – the metal/brick underneath or the slag surface exposed to flame? • Consider whether uneven heating and cooling of brickwork can lead to mechanical stress that might cause peeling or spalling.

✅ Before You Answer

• Verify whether insulation from slag would increase or decrease the temperature at the surface of the furnace floor metal/refractory below it. • Check how refractory brickwork typically fails: does high localized temperature and thermal cycling promote peeling/spalling? • Confirm whether operators practice regular slag removal specifically to prevent either overheating, damage to brickwork, or both.