The refractory lining of the bottom in a basic electric arc furnace is made of

ANS:C - magnesia

Magnesia refers to materials primarily composed of magnesium oxide (MgO). It is a refractory material known for its high melting point, excellent thermal shock resistance, and resistance to basic environments. Magnesia-based refractories are widely used in various high-temperature industrial applications, particularly where basic conditions prevail, such as in steelmaking processes like basic oxygen furnaces (BOFs) and electric arc furnaces (EAFs). The properties of magnesia that make it suitable for these applications include:

1. High Melting Point: Magnesia has a high melting point, making it capable of withstanding extremely high temperatures encountered in industrial processes.
2. Thermal Shock Resistance: Magnesia exhibits good thermal shock resistance, which allows it to withstand rapid changes in temperature without fracturing or spalling.
3. Resistance to Basic Environments: Magnesia is highly resistant to basic slag and alkaline environments, making it ideal for applications where exposure to basic compounds is common.
4. Chemical Stability: It shows stability in various chemical environments, particularly under high-temperature conditions.
5. Refractory Applications: Magnesia is commonly used as a refractory material in the construction of linings for furnaces, kilns, and other high-temperature equipment where resistance to heat and chemical attack is essential.