Which non-metallic material is used as furnace lining for high melting temperatures?

Refractories are specialized non-metallic materials designed to withstand high temperatures and are commonly used for furnace linings. The key characteristic of refractories is their ability to retain strength and stability at elevated temperatures, which is crucial in high-temperature environments like furnaces where materials are subjected to extreme heat.

Refractories are made from various compounds, typically including alumina, silica, and magnesia, and they are engineered to provide thermal insulation and resistance to thermal shock, chemical corrosion, and wear. This makes them suitable for applications where they come into direct contact with molten materials or where they are exposed to intense heat.

Other materials may serve specific roles in high-temperature applications, but they often do not possess the comprehensive combination of thermal resistance and structural integrity required for effective furnace lining. Quartz bricks and dolomite clay bricks, while useful in certain circumstances, do not match the overall performance characteristics of refractories. Silica sand can withstand high temperatures but lacks the structural capabilities needed for long-term use as a lining material in high-stress environments. Therefore, refractories are the preferred choice for high-temperature furnace linings.