Final answer:
Heating mantles are often used with refractories, such as magnesia, to retain their essential properties at high temperatures.
Step-by-step explanation:
Heating mantles are often used in conjunction with refractories. Refractories are substances that retain their essential properties at high temperatures. They are used for high-temperature applications such as furnace tubes, lighting tubes, and melting crucibles. One example of a refractory is magnesia, which is used to insulate electric heating elements and line high-temperature furnaces.