🔍 Key Concepts

• Effects of salt contaminants in fuel on high-temperature furnace materials • How thermal expansion differences between materials can cause cracking or damage • Whether slag deposits generally protect or harm refractory surfaces over time

💭 Think About

• Think about what happens when two materials attached to each other heat up and cool down at different rates. How would that affect the refractory bricks or lining? • Ask yourself: does a hard, glassy coating usually move and flex with the refractory, or is it more likely to be brittle and rigid? • Consider your experience (or theory) from boilers and furnaces: do slag deposits usually improve efficiency and equipment life, or are they considered a maintenance problem?

✅ Before You Answer

• Verify whether glassy slag is typically considered beneficial or detrimental to refractory and boiler surfaces in marine engineering references • Check how differential expansion between slag and refractory could affect joints, surfaces, or brickwork during heating and cooling cycles • Confirm whether improved furnace efficiency is commonly associated with clean surfaces or with coated/slagged surfaces